A new Dynomax muffler-best of both worlds and NO drone!

[turbovanman²]

Check this out, a built in muffler check valve, going to get one and try it. I think it has a 90 day money back guarantee-

Its the first muffler, VT.

http://www.dynomax.com/mufflers.php

http://www.dynomax.com/mufflers.php?muffler=vt

[raccoon]

at what point would a check valve stop air going the other way? help me out here.

[turbovanman²]

at what point would a check valve stop air going the other way? Help me out here.

huh????

[shackwrrr]

not really a check valve but a spring loaded flapper valve so at low flow air has to go through a different route with more sounds deadening

[raccoon]

ah i see,

[turbovanman²]

not really a check valve but a spring loaded flapper valve so at low flow air has to go through a different route with more sounds deadening

Ding ding ding, :thumb:

With a money bad guarantee, you really can't lose.

[raccoon]

so wtf, are you getting a free one or something, you sure seem to like it. :)

[tsiconquest88]

wtf lol, an open exhaust just wasnt good enough hahahaha

[turbovanman²]

so wtf, are you getting a free one or something, you sure seem to like it. :)

I have mega drone issues, this should solve it so yes, I am really excited. :thumb:

[GLHNSLHT2]

so you need to have a bunch of pressure to push the flapper open? Why don't you just put a cork with a little hole in in in the end of your tail pipe? :)

[Force Fed Mopar]

so you need to have a bunch of pressure to push the flapper open? Why don't you just put a cork with a little hole in in in the end of your tail pipe? :)

:lol::thumb:

[turbovanman²]

so you need to have a bunch of pressure to push the flapper open? Why don't you just put a cork with a little hole in in in the end of your tail pipe? :)

Yeah, like that will work, :confused:

Are you not understanding the principle or do you need it spelled out with pictures? ;)

[GLHNSLHT2]

I understand the principle just fine. They put a stop in the exhaust, the back pressure pushes it open when under WOT. Like I said, a cork with a hole. gonna make the GT35R more laggy huh?

[johnl]

Look at the picture; the pivot for the flapper plate is off center and the pivot shaft, outside the exhaust flow is a bell crank with its lever attached to a spring. Presumably the spring pressure holds the flapper plate in somewhat closed position during part throttle - droning down the highway - mode. When you open the throttle, the volume and speed of the exhaust gasses overcomes the spring/bell crank and the flapper is then fully open.

I'm with Simon; this is a great innovation. I had to extend the outlet of the 3" system on the GLHT; I also had to play with the angle of the turn down - all to minimize drone. The exhaust pulses reflect off the pavement and hit the undersides of these cars like Gene Krupa hitting a bass drum.

[turbovanman²]

I understand the principle just fine. They put a stop in the exhaust, the back pressure pushes it open when under WOT. Like I said, a cork with a hole. gonna make the GT35R more laggy huh?

Its not a cork with a hole, you really need to look out of the box, beats the muffler you posted up awhile ago, :p


Look at the picture; the pivot for the flapper plate is off center and the pivot shaft, outside the exhaust flow is a bell crank with its lever attached to a spring. Presumably the spring pressure holds the flapper plate in somewhat closed position during part throttle - droning down the highway - mode. When you open the throttle, the volume and speed of the exhaust gasses overcomes the spring/bell crank and the flapper is then fully open.

I'm with Simon; this is a great innovation. I had to extend the outlet of the 3" system on the GLHT; I also had to play with the angle of the turn down - all to minimize drone. The exhaust pulses reflect off the pavement and hit the undersides of these cars like Gene Krupa hitting a bass drum.

Exactly, if it doesn't work then it doesn't but in theory, it should work perfectly fine.

[johnl]

I understand the principle just fine. They put a stop in the exhaust, the back pressure pushes it open when under WOT. Like I said, a cork with a hole. gonna make the GT35R more laggy huh?

Didn't mean it that way; just tryin to make clear exactly how it works. Yeah, no one would use in a full race app but like Simon, I'm drivin a street car

[GLHNSLHT2]

John you gotta let me bust simon's balls a bit more :)

[Spraynlog]

That does look interesting, I'm sure my neighbors would like it better.:D The way it is now, I can't even hear a 12 gauge pump being racked....:p

[GLHNSLHT2]

what do you have for an exhaust now sprayn?

[Spraynlog]

what do you have for an exhaust now sprayn?I have a side exit 2 1/2" with an Edelbrock SDT chambered muffler.(careful how you arrange the letters....) It's like a Flowmaster, but smaller in size.

I get up early for work, I'd like something quieter.

[GLHNSLHT2]

hmm, sounds like my 3" rear exit with the magnaflow round might be quieter than that. I leave for work at 630am and drive within 3 ft of the neighbors house :)

[johnl]

John you gotta let me bust simon's balls a bit more :)

OK, OK, BTW, I drive a road race motorcycle faster than Simon.:D:wow1::fencing:


I'm gonna buy one of these Drone-Frees right away. Will report back. Gotta install the exhaust system on the R/T 1st though . . . .

[mopar-tech]

Check out this thread- They do have different units with stronger/weaker springs.

http://board.moparts.org/ubbthreads/showflat.php?Cat=0&Board=QuestionAnswer&Number=6055780&PHPSESSID=&fpart=1#Post6055780

Download the PDF from Summit to get a handle on the different part numbers and applications.

Gary D.

[turbovanman²]

Thanks for the thread, can't wait to see how they work out.

As for corroding etc, it looks like where the spring is its sealed from exhaust gas's, so that should help extend life.

[turbovanman²]

Just talked to the Dynomax tech, they have a lighter spring, they say this is for 4.0L and under, 3", #17156, and a heavier spring for over 4.0L, 3", 17957, he said to add 50% for turbo's so a 2.5 is right at the border of each muffler. He said try the lighter spring, if you don't like it, they will trade it for the heavier spring, :amen:

The lighter spring won't affect lag but he said the heavier spring could.

[johnl]

Simon - I'm confused. When you say - "Just talked to the Dynomax tech, they have a lighter spring, they say this is for 4.0L and under, 3", #17156"

I'm looking at Dynomax' chart and I see under the column "up to 4.0 liter,"

part # 17156 for 2.5" (not 3")
and
part # 17157 for 3"

So, how do I get (do I want?) a light spring in a 3" . . . . . . ?

[turbovanman²]

Simon - I'm confused. When you say - "Just talked to the Dynomax tech, they have a lighter spring, they say this is for 4.0L and under, 3", #17156"

I'm looking at Dynomax' chart and I see under the column "up to 4.0 liter,"

part # 17156 for 2.5" (not 3")
and
part # 17157 for 3"

So, how do I get (do I want?) a light spring in a 3" . . . . . . ?

Yeah, he must have given me the wrong number, so its lighter spring 3" is 17157, heavier spring, #17957 and they have no plans of a center in, center out, :(

The spring controls the flapper door so lighter spring means it will open up easier so on a higher flowing application, it could open during cruise defeating the purpose of the muffler. I described my setup and he said I was on the border for either spring, so try the lighter one, if it doesn't work, return it and get the heavier one, :D

[OmniLuvr]

i think the z06 and the turbo porshce's have tuned mufflers like this, but they have an actuator like a wastegate that opens the blade, but this actuator is vacuum operated. once it loses vacuum (ie WOT) the actuator opens allowing a more free flowing exhaust...

[cobra2411]

Has anyone tried these yet? I'm doing a 2.4 swap and have heard that with the wrong mufflers they sound like rice...

My current thought is cat - resonator (3" bullet?) - turbo muffler. I may put a VT at the end if they seem to work.

[turbovanman²]

Has anyone tried these yet? I'm doing a 2.4 swap and have heard that with the wrong mufflers they sound like rice...

My current thought is cat - resonator (3" bullet?) - turbo muffler. I may put a VT at the end if they seem to work.

2.4's sound great with Ultraflo's or Magnaflows.

Haven't tried it yet, need to see if my current setup will still drone first.

[audiomaninc]

So which one do I get???

[dds78910]

Here is a video of the muffler in action.

http://www.off-roadweb.com/videos/index.html

[bakes]

Here is a video of the muffler in action.

http://www.off-roadweb.com/videos/index.html

I think you just made Simon happy:p

[Force Fed Mopar]

Not a very good video :(

[The Pope]

what a great idea for no turbo people with NA engines. You go out and buy a muffler and system that is too big for your engine. Then you add a valve in there that maintains back pressure so that the engine doesn't cavitate and lose power. Then at high RPM the valve opens when the NA engine catches its breath and really starts moving air.

So what is the turbo goal here? To have a restrictive exhaust before boost to cause slower spool up untill the turbo gets spooled and forces the valve open? Is this a joke thread, your all kidding? This muffler is made for foolish small block owners that put dual 3" exhaust on there cars and killed low end power. There made to create back pressure at low volumes when a turbo is trying to move enough air to spool. Then there is no SS packing around the perforated tube to remove sound so there still loud.

These will be sweet on my motor home. But on my turbo cars? Kidding? I suppose it will be exciting. You G valve the car and it will be plugged till the poor turbo gets up to about 5 PSI. Then BAAAAAMMM the valve opens violently and you hit full boost like a sledge hammer blowing the tires loose. It'll be like driving a TBI with a 200 HP nitrous shot on a 6 second throttle based delay.

[Vigo]

lol, well that was a dramatic post..

I agree its a bad idea for a turbo car. IMO you'd be better off with a quiet full exhaust with an electric (or otherwise automatic) cutout coming off the big downpipe and run off your tps signal. But that is more expensive and complicated.

Try the muffler and let us know how it works.

[turbovanman²]

So which one do I get???

The lighter spring unit unless your making big power.


I think you just made Simon happy:p

Yep.


Not a very good video :(

Agreed it could be better but its quiet until he tromps it, :D


what a great idea for no turbo people with NA engines. You go out and buy a muffler and system that is too big for your engine. Then you add a valve in there that maintains back pressure so that the engine doesn't cavitate and lose power. Then at high RPM the valve opens when the NA engine catches its breath and really starts moving air.

So what is the turbo goal here? To have a restrictive exhaust before boost to cause slower spool up untill the turbo gets spooled and forces the valve open? Is this a joke thread, your all kidding? This muffler is made for foolish small block owners that put dual 3" exhaust on there cars and killed low end power. There made to create back pressure at low volumes when a turbo is trying to move enough air to spool. Then there is no SS packing around the perforated tube to remove sound so there still loud.

These will be sweet on my motor home. But on my turbo cars? Kidding? I suppose it will be exciting. You G valve the car and it will be plugged till the poor turbo gets up to about 5 PSI. Then BAAAAAMMM the valve opens violently and you hit full boost like a sledge hammer blowing the tires loose. It'll be like driving a TBI with a 200 HP nitrous shot on a 6 second throttle based delay.


Wow, did you actually read the reason for using it?


lol, well that was a dramatic post..

I agree its a bad idea for a turbo car. IMO you'd be better off with a quiet full exhaust with an electric (or otherwise automatic) cutout coming off the big downpipe and run off your tps signal. But that is more expensive and complicated.

Try the muffler and let us know how it works.

No doubt, but only trying one will show how good/bad it is. Like I said, if my new setup drones, I will be trying one and I'll report back. I am sure though someone will try one first.

[mopar-tech]

Like I said, if my new setup drones, I will be trying one and I'll report back. I am sure though someone will try one first.

God forbid that someone actually tries a new product before condeming it out of hand.

It might actually work!

[cobra2411]

Ok, have to chime in here...


This muffler is made for foolish small block owners that put dual 3" exhaust on there cars and killed low end power.

I've personally seen a back to back dyno of a stock 92 Mustang GT going from 2-1/4" to a 3" off road H pipe and 3" exhaust and it lost a max of 3 ft-lb of torque down low yet picked up 17hp up top. I was a little surprised. The guy was getting a supercharger and wanted to upgrade the exhaust so it wasn't a restriction. Everybody was curious so that's why they dyno'd the car before and after.

Exhaust systems are just that - A System. So many people think you need "back pressure" to make good TQ & HP. What you really need is the negative pressure waves that form at the end* of the exhaust system. The end of the exhaust isn't always the end of the pipe in the rear, it's any large change in volume. That creates a negative pressure wave that goes back to the engine and helps pull the next pulse. The exhaust system must be tuned to the engine. That's where the fallacy of "back pressure" comes from. People change the exhaust to lower back pressure and end up screwing up the tune and they believe it's because they don't have enough back pressure.

The reason for the flap is to control drone. With my 93 Cobra I used to drive by ear; I knew by sound and by what gear I was in how fast I was going. From the factory many dual exhaust cars have left and right mufflers that are tuned slightly different so they can eliminate the drone.

I don't suspect that the flap in the muffler would be any significant form of restriction in the exhaust to effect the engine N/A or Turbo.

I'm interested because I want my car to be silent. At least until I hammer on it. :)

[prepared]

Exhaust systems are just that - A System. So many people think you need "back pressure" to make good TQ & HP. What you really need is the negative pressure waves that form at the end* of the exhaust system. The end of the exhaust isn't always the end of the pipe in the rear, it's any large change in volume. That creates a negative pressure wave that goes back to the engine and helps pull the next pulse. The exhaust system must be tuned to the engine. That's where the fallacy of "back pressure" comes from. People change the exhaust to lower back pressure and end up screwing up the tune and they believe it's because they don't have enough back pressure.


OMG!! Somebody GETS IT!!! *gasp*

I've actually seen n/a systems that leave the headers, enter into large, open chambers where the pressure drops (fluid dynamics). The pressure drop essentially fools the motor into thinking thats the end of the exhaust. Then from those chambers back through tailpipes and decently quiet mufflers.

Now, all the theory and math behind this system was sound, but I never was given back-to-back proof that it worked.



But, definitely, without the turbo as a wall, the movement of the exhaust gasses through a tuned exhaust from one cylinder will PULL the exhaust out of another cylinder thus increasing volumetric efficiency above 100%

[Vigo]

Exhaust systems are just that - A System. So many people think you need "back pressure" to make good TQ & HP. What you really need is the negative pressure waves that form at the end* of the exhaust system. The end of the exhaust isn't always the end of the pipe in the rear, it's any large change in volume. That creates a negative pressure wave that goes back to the engine and helps pull the next pulse. The exhaust system must be tuned to the engine. That's where the fallacy of "back pressure" comes from. People change the exhaust to lower back pressure and end up screwing up the tune and they believe it's because they don't have enough back pressure.

Good stuff.

I still think the flap in the muffler will be bad for turbo spool (by what degree, i dont know) because essentially it is affecting noise by limiting the size of the aperture through which the exhaust exits.. any time you have to move a given volume of something of through a given hole in a certain amount of time and you make the hole smaller, the pressure is going to go up. Since the turbo spools because of the pressure differential across it, increasing the pressure on the exhaust side is going to slow spool, and there's been plenty of people (like Shadow) running around saying or implying that TINY difference in psi on the backside of the turbo have disproportionately large effects on how the turbo works.

Again, i dont know how BAD it will be in any real terms, but it seems like the best case scenario is that it will be so little worse that you wont notice it in normal driving. It is definitely going to have SOME negative effect, however minor.

[turbovanman²]

God forbid that someone actually tries a new product before condeming it out of hand.

It might actually work!

We can't possibly try new products, nothing works unless its from the 1900's, :o


Ok, have to chime in here...



I've personally seen a back to back dyno of a stock 92 Mustang GT going from 2-1/4" to a 3" off road H pipe and 3" exhaust and it lost a max of 3 ft-lb of torque down low yet picked up 17hp up top. I was a little surprised. The guy was getting a supercharger and wanted to upgrade the exhaust so it wasn't a restriction. Everybody was curious so that's why they dyno'd the car before and after.

Exhaust systems are just that - A System. So many people think you need "back pressure" to make good TQ & HP. What you really need is the negative pressure waves that form at the end* of the exhaust system. The end of the exhaust isn't always the end of the pipe in the rear, it's any large change in volume. That creates a negative pressure wave that goes back to the engine and helps pull the next pulse. The exhaust system must be tuned to the engine. That's where the fallacy of "back pressure" comes from. People change the exhaust to lower back pressure and end up screwing up the tune and they believe it's because they don't have enough back pressure.

The reason for the flap is to control drone. With my 93 Cobra I used to drive by ear; I knew by sound and by what gear I was in how fast I was going. From the factory many dual exhaust cars have left and right mufflers that are tuned slightly different so they can eliminate the drone.

I don't suspect that the flap in the muffler would be any significant form of restriction in the exhaust to effect the engine N/A or Turbo.

I'm interested because I want my car to be silent. At least until I hammer on it. :)

Thank you, :thumb:

[Spraynlog]

We can't possibly try new products, nothing works unless its from the 1900's, :o



Thank you, :thumb:I've kinda felt like this running E85, but it works good.

[cobra2411]

We can't possibly try new products, nothing works unless its from the 1900's, :o


1972... That's when technology peaked and everything went down hill. ;) or that's what the muscle car guys will have you believe.

[turbovanman²]

1972... That's when technology peaked and everything went down hill. ;) or that's what the muscle car guys will have you believe.

LMAO, how true. Like old Muscle cars were the fastest things and still are since sliced bread when most couldn't run faster than 13's or 14's, :wow1: :D

[GLHNSLHT2]

God forbid that someone actually tries a new product before condeming it out of hand.

It might actually work!

LOL! Look at Gary (the pot) calling the kettle black!

[johnl]

Here in CA, we have to run CATs, so that likely affects spooling as much or more so, especially since the CAT has to go right after the downpipe.

I'm going to try one on the Spirit R/T, all 3" with cat and the Dynomax at the rear bumper and hoping that whatever affect it may have on initial spooling is attenuated by system volume/length.

The Spirit is a comfy TM commuter and I really don't want drone. Some compromises are unavoidable.

And another thing, 2.5" is probably better than 3" for most TM street cars (especially after the CAT) but with the restriction of the Dynomax . . .? . . .

[supercrackerbox]

Simon, do keep us posted on this. I'm strongly considering a pair of them for my Buick. Helps that I work for Tenneco, so I get a 50% reimbursement for them. ;)

[turbovanman²]

Simon, do keep us posted on this. I'm strongly considering a pair of them for my Buick. Helps that I work for Tenneco, so I get a 50% reimbursement for them. ;)

Looks like "johnl" will beat me to it.

[4 l-bodies]

I'm with Simon; this is a great innovation. I had to extend the outlet of the 3" system on the GLHT; I also had to play with the angle of the turn down - all to minimize drone. The exhaust pulses reflect off the pavement and hit the undersides of these cars like Gene Krupa hitting a bass drum.

Sounds like an interesting muffler. I'll bet it's been tried before though.
John,
Your maybe old enough to remember Pontiac way back in the early 60's had optional pneumatic controlled mufflers. For real! They were introduced and failed so miserably that they became NS1 months after their introduction. About the same time frame as the ill fated aluminum headers Pontiac also came out with on their 421 SD cars. Who would have thunk:p:o
Todd

[Vigo]

Yes, all the hottest cars have had mufflers with internal valves! like the 2000 3.0L Nissan Maxima! :p

[supercrackerbox]

The Humbler . . .


Sounds like an interesting muffler. I'll bet it's been tried before though.
John,
Your maybe old enough to remember Pontiac way back in the early 60's had optional pneumatic controlled mufflers. For real! They were introduced and failed so miserably that they became NS1 months after their introduction.

And yet came back a generation later in the form of the previously mentioned Corvette muffler (which my company also makes ;) ).

[Vigo]

Speaking of putting moving parts where they probably shouldnt go..

If they ever master that variable angle stator in torque converters (i.e. vnt, cool eh?) that they tried in the 60s, ill be damn tickled. Variable stall converter, come to papa.

[4 l-bodies]

Speaking of putting moving parts where they probably shouldnt go..

If they ever master that variable angle stator in torque converters (i.e. vnt, cool eh?) that they tried in the 60s, ill be damn tickled. Variable stall converter, come to papa.
Ah yes the old switch pitch Buick converters. My next door neighbor has one in his 34 cabriolet Ford street rod. Doesn't work to good with a big camshaft.
Todd

[Vigo]

I was thinking itd be cool to isolate the torque converter fluid from the trans fluid and use some magnetorheological fluid in it.. who needs a cvt when your converter stall can move from 5000 rpm to 800 rpm by running current through it?

[turbovanman²]

I was thinking itd be cool to isolate the torque converter fluid from the trans fluid and use some magnetorheological fluid in it.. who needs a cvt when your converter stall can move from 5000 rpm to 800 rpm by running current through it?

I thought they had something like this in the works or tested at some point?

[contraption22]

And another thing, 2.5" is probably better than 3" for most TM street cars (especially after the CAT) but with the restriction of the Dynomax . . .? . . .

Performance wise, it's always better to have a largest, shortest, straightest exhaust on a turbo car.

[johnl]

Performance wise, it's always better to have a largest, shortest, straightest exhaust on a turbo car.

Well, yes of course, you ARE correct. I could have been more precise, as for balancing street performance and street driveability, IMO (seat of the pants of course) a 2.5" exhaust works better than 3"

I once met an engineer who makes his living telling big companies and governments with industrial plants that they should convert all of their long twisty small diameter pipes into short fat straight ones. Seriously, that's what he does. The engineers who preceded him, who designed those inefficient plants, were more concerned about costs of construction and ease of routing, and ease of assembly, and a compact footprint, than they were about saving pumping costs/energy. He lowers the pressure and uses slow high volume pumps and claims to pay for the rework with energy savings.

[johnl]

Sounds like an interesting muffler. I'll bet it's been tried before though.
John,
Your maybe old enough to remember Pontiac way back in the early 60's had optional pneumatic controlled mufflers. For real! They were introduced and failed so miserably that they became NS1 months after their introduction. About the same time frame as the ill fated aluminum headers Pontiac also came out with on their 421 SD cars. Who would have thunk:p:o
Todd

Well, I'm old but I don't remember that one. Pontiac did a lot of edgy things. Was there a vacuum hose going all the way to the muffler?:lol:

Aluminum . . . . Pontiac . . . . my grandfather won a '67 Pontiac Tempest in a boxtop contest. He sold it to my dad - who could have added a few bucks and got a GTO . . . . Anyway, that Tempest had the OHC straight six and after two warped heads/gaskets, he sold it.

And that makes me think of those aluminum nail head Buicks and Cutlasses . . . except for the valves, I always liked those engines - even the Land Rover version, LOL.

[turbovanman²]

Well, yes of course, you ARE correct. I could have been more precise, as for balancing street performance and street driveability, IMO (seat of the pants of course) a 2.5" exhaust works better than 3"


With a turbo motor, bigger is better and going larger won't affect driveability unless you figure more boost and power is bad, :nod:

[GLHNSLHT2]

not sure how 3" pipe affects driveability on a street car.......???????? other than makes it better?

[contraption22]

Well, yes of course, you ARE correct. I could have been more precise, as for balancing street performance and street driveability, IMO (seat of the pants of course) a 2.5" exhaust works better than 3"


Nope. The larger exhaust will always be better for performance and driveability on a turbocharged engine, whether you are on the track, street, land, sea or air. The only reason not to have the largest possible exhaust on a turbo engine is cost, emissions, noise control or packaging.

The only POSSIBLE exception is if the the turbo system is engineered with a restrictive exhaust in mind and boost control becomes an issue with a larger exhaust. An example of this would be the 2.2 VNT cars. But generally this is a sign of certain compromises made by the manufacturer to satisfy noise, space and emissions restrictions.

[johnl]

Nope. The larger exhaust will always be better for performance and driveability on a turbocharged engine, whether you are on the track, street, land, sea or air. The only reason not to have the largest possible exhaust on a turbo engine is cost, emissions, noise control or packaging.

The only POSSIBLE exception is if the the turbo system is engineered with a restrictive exhaust in mind and boost control becomes an issue with a larger exhaust. An example of this would be the 2.2 VNT cars. But generally this is a sign of certain compromises made by the manufacturer to satisfy noise, space and emissions restrictions.

So . . . . why not bigger still?

There's room for 4", even 5", in lots of street cars, especially with side dumps, yet . . . .

[turbovanman²]

So . . . . why not bigger still?

There's room for 4", even 5", in lots of street cars, especially with side dumps, yet . . . .


There is a point where bigger stops beggetting gains, so no point going larger. Fitting 4+" exhaust is a chore except in a van, ;) and the noise will be hard to control.

[contraption22]

So . . . . why not bigger still?

There's room for 4", even 5", in lots of street cars, especially with side dumps, yet . . . .

There is a point of diminshing returns (0 backpressure), and of course practicality is an issue. However, some people on this forum are moving to 4" exhausts, and 4" and 5" exhausts are quite common in the diesel truck aftermarket. Of course NEGATIVE backpressure (vaccuum) after the turbine would be ideal, but I don't know how that can be achieved.

Think of the turbocharger as an engine in and of itself. It converts exhaust energy to motion on the exhaust side, then converts that motion back into air flow.

The turbine works on a pressure differential. The less pressure on the exhaust side, the less pressure is needed on the turbine inlet side to do the same work. Less backpressure at the turbine means more eninge power.

On the same token, at the compressor side of the turbo, the less restiction there is on the inlet of the compressor, the less work the turbo has to do to move the same amount of air.

[mopar-tech]

There is a point of diminshing returns

The bottleneck or weakpoint in the system moves somewhere else.

I had a 4" short system on the Reliant at one point, with the turbo that was on the car at the time there was no difference in power output.

[johnl]

There is a point of diminshing returns (0 backpressure), and of course practicality is an issue. However, some people on this forum are moving to 4" exhausts, and 4" and 5" exhausts are quite common in the diesel truck aftermarket. Of course NEGATIVE backpressure (vaccuum) after the turbine would be ideal, but I don't know how that can be achieved.

Think of the turbocharger as an engine in and of itself. It converts exhaust energy to motion on the exhaust side, then converts that motion back into air flow.

The turbine works on a pressure differential. The less pressure on the exhaust side, the less pressure is needed on the turbine inlet side to do the same work. Less backpressure at the turbine means more eninge power.

On the same token, at the compressor side of the turbo, the less restiction there is on the inlet of the compressor, the less work the turbo has to do to move the same amount of air.

Well stated. :hail:

[trannybuster]

Im running 3.0 in GLHS with all the way no cat with just a borla at the end, it doesnt really drone at all. I tried straight pipe, that sucked, so I got the borla which I didnt think would help much cause you can see right through it, but it did. NOW if I could finding something to cut the drone on my Apex, that would nice, there isnt anything that drones like that thing.

[bakes]

Im running 3.0 in GLHS with all the way no cat with just a borla at the end, it doesnt really drone at all. I tried straight pipe, that sucked, so I got the borla which I didnt think would help much cause you can see right through it, but it did. NOW if I could finding something to cut the drone on my Apex, that would nice, there isnt anything that drones like that thing.

Not to side track got any pics of the 3.0l Glhs?

[trannybuster]

^ LOL sry 3.0 exhaust...

[Vigo]

What's an Apex again?

[trannybuster]

Its Yamaha's 4stroke snowmobile, 150hp. That thing is the king of drone, but itll leave a grin on your face eberytime you ride it. Thinkin about turbo charging it, 235hp....do a you tube search for 'turbo apex mountain climb' you wont believe what these things do.
ANyhow Im sure the vans are bad for dorne, my brothers extendedcab cummins does and its something he didnt notice until he rode in my reg cab, its that certain length and bends I guess.

[Will Martin]

I went ahead and bit the bullet on one. I don't care about max flow or whatever, my car is a DD and I wanted something a bit better than stock that's quiet and without drone. And something that wouldn't take away the sleeper effect of the Spirit. If it does the job I'm happy, if not, then it'll be in the for sale section soon! lol :) BTW, ignore the Holset.....

http://i6.photobucket.com/albums/y238/mgouki/DSC00017.jpg

http://i6.photobucket.com/albums/y238/mgouki/DSC00019.jpg

http://i6.photobucket.com/albums/y238/mgouki/DSC00018.jpg

[turbovanman²]

Which one did you get and when are you putting it on?

Sent my stuff yet? :lol:

[Will Martin]

I got the 2.5", 16"L one. Part # 17159

It's still buried in my second garage. :(

[turbovanman²]

I got the 2.5", 16"L one. Part # 17159

It's still buried in my second garage. :(

Glad to see your back, :amen:

No problemo, ;)

When are you putting it on?

[Will Martin]

As soon as I get my 2.5" cat back from FWDP, which should be at the end of the week (hopefully). I'll take a video of it.

[turbovanman²]

As soon as I get my 2.5" cat back from FWDP, which should be at the end of the week (hopefully). I'll take a video of it.

Awesome, :hail:

[vanquisheder]

As soon as I get my 2.5" cat back from FWDP, which should be at the end of the dynomax exhaust systems (http://www.allexhaust.com) week (hopefully). I'll take a video of it.

Please post the video.

[prepared]

As soon as I get my 2.5" cat back from FWDP, which should be at the end of the week (hopefully). I'll take a video of it.

Which week?


Please post the video.

Yes, please!

[Will Martin]

I acutally have everything on and buttoned up. Just have to put in the recharged battery and start her up.

Unfortunately, because of my job, I will be temporarily away from home for quite a while, so things are pretty crazy now. But this shouldn't stop me from doing a little video which I can try to take care of tonight.

[prepared]

I acutally have everything on and buttoned up. Just have to put in the recharged battery and start her up.

Unfortunately, because of my job, I will be temporarily away from home for quite a while, so things are pretty crazy now. But this shouldn't stop me from doing a little video which I can try to take care of tonight.

Awesome! :thumb:

[turbovanman²]

I acutally have everything on and buttoned up. Just have to put in the recharged battery and start her up.

Unfortunately, because of my job, I will be temporarily away from home for quite a while, so things are pretty crazy now. But this shouldn't stop me from doing a little video which I can try to take care of tonight.

Damn dude, thought things were finally calm, :o

[pauly_no_van]

[Insert anit-climax remark here]

[Will Martin]

Damn dude, thought things were finally calm, :o


Never! Remember I work for the U.S. government, and at any time things can go from good to bad! After 22 years, you'd think I would've learned my lesson....

Before I deployed to Desert Shield, I had a 2 hour notification!

Before I deployed in support of 9/11, I had a 4 day notification!

This time around, I have a 5 day notice. :clap:

Don't worry guys, I'll get it to you today-promise. Yesterday when I got home things were really crazy but I'm good for today.

[prepared]

is it installed? If so, how about an opinion in lieu of a video?

[turbovanman²]

Tick tock, hehehe, :p

[Will Martin]

Sorry for the late response. Had to use an old camera, could find my video cam! :(

Got the battery in, but couldn't read the adj. fpr gauge, as it's not moving. Even when I adjust the screw (with vac line removed), it doesn't move. So either it's the gauge or adj. fpr. Even my wide band didn't change at idle, and remained at about 14.3 at idle. This is with an old TIII ND Performance 2 bar cal. So since I was running out of time, I could only take a video of it at idle.

Note; my IROC RT with a 3" exhaust and Borla muffler is not only loud, but pops a lot and has the drone of a 747. This wasn't that bad, but remember it's not under load. I noticed that it's fairly "quiet" inside but the true test will come when it's driven on the street.

Mods: full 2.5" exhaust, stock turbo, cold air intake, couple other goodies.

At idle:

http://s6.photobucket.com/albums/y238/mgouki/?action=view&current=MOV00042.mp4

http://s6.photobucket.com/albums/y238/mgouki/?action=view&current=MOV00044.mp4

http://s6.photobucket.com/albums/y238/mgouki/?action=view&current=MOV00041.mp4

[turbovanman²]

Love the sound of the last clip, :thumb:

[GLHNSLHT2]

I'm sorry but that sounds like A$$. Like an exhaust leak. Thanks for the clip though. I like the view of the valve. Would be nice to see if it moves.

[zin]

Your maybe old enough to remember Pontiac way back in the early 60's had optional pneumatic controlled mufflers. For real! They were introduced and failed so miserably that they became NS1 months after their introduction. About the same time frame as the ill fated aluminum headers Pontiac also came out with on their 421 SD cars. Who would have thunk:p:o
Todd

Actually they "failed" due to complaints about the noise (not from the owners BTW), they were basically cut-outs! The AL headers were for drag racing only, so for 10-20sec, they'd be fine... run them much longer and... drip, drip, drip.

Mike

[Will Martin]

I'm sorry but that sounds like A$$. Like an exhaust leak. Thanks for the clip though. I like the view of the valve. Would be nice to see if it moves.

Nothing to be sorry about. :confused: If you look at one of the videos closely, you'll see the valve move.

Like I said, the true test comes from inside the car when it's moving. The issue is drone, the way it sounds while idling....to each his own.

[Ondonti]

The bottleneck or weakpoint in the system moves somewhere else.

I had a 4" short system on the Reliant at one point, with the turbo that was on the car at the time there was no difference in power output.

Most people going to the larger sizes (who are doing it for a legit reason) are using setups that have limited powerbands or running Ethanol.

I've heard of a supra making 928whp on a 3"
At that level is does hurt power by a good 50-60hp.
Now the turbo required to make 928whp on a 3.0L engine is going to hate the 3" exhaust when it comes to building boost.

If 3" hurts spool on a 464whp car (928/2=464), imagine how much it hurts a 928whp car.

My best times/dyno were all with full 3" exhaust/dynomax muffler but I could tell a huge difference in turbo response whenever I have been open downpipe. Feels like a different car.

Auto trans 57-trim with a stage III .63 (or whatever) 8 valve probably would be much harder to notice any spool difference. If you ran a 5 speed when you had your car at full 400+hp tilt, I bet you would have noticed it more if you tried lugging gears out of the powerband.

Anyone who claims there is a big HP gain is just wrong. I've heard from supra land 600hp is the point to upgrade from 3", but there is 3.5" people can jump to. Divorced wastegates also allow more power on the same size exhaust and obviously the Supra was externally dumping.
Extra fuel volume of Ethanol does require a larger exhaust.

Another reason people go to 4" is so they can get the performance of a 3" open downpipe with the sound deadening of a full exhaust. Full 4" exhaust is very heavy :yuck: I know some baller guy who went 5" on his 1340whp 3000gt and then removed it because he had spent tens of thousands on custom subframes, carbon fiber panels and doors, tube frame replacement of the OEM chassis into stock steel body and then put on a 150+ pound exhaust. :drum: He had this silly obsession with pretending his car was a "street car" to the point of having rear leather seats that you couldn't sit in because of the 7 second cage. A lot of the people making the 600-1000hp supras want to pretend their car is a street car and 4" and 5" exhaust fills the bill.

Ah, plan on going 3.5 or 4" when I change manifolds but I myself am having a hard time choosing 3.5" (matches vband on my t4 .96 housing that I will swap to) when the Basmati in my head wants 4".
Guy I know kept facebooking about his 3.5" bumper dump exhaust 67mm DSM and I just always thought "shoulda' gone 4" :eyebrows:" even though a bumper dump exhaust has absolutely zero backpressure no matter how hard he cranks that turbo.

[Ondonti]

And regarding moving the bottleneck, I think any 10 second cars here running a t3 turbine housing should change to a small t4 housing and P or the smaller O trim wheel.

The HP gains from going to the t4 housing will be MUCH higher then trying 4" exhaust. This has been shown over and over in the import world, with no spool loss.

[mopar-tech]

The AL headers were for drag racing only, so for 10-20sec, they'd be fine... run them much longer and... drip, drip, drip.


Actually they were noted for leaving drops of aluminum flying out the exhaust while cranking down the track! The early 60's Pontiac race program was pretty wild.

Ever seen a Lemans with a trans in the back? Pontiac did it in 62 or 63.

[puppet]

Ya, the "rope" drive. Delorian had lots of good ideas. Porsche used this scheme on the 924/944. Makes for a nice balanced car weight wise.

[Force Fed Mopar]

Porsche used this scheme on the 924/944. Makes for a nice balanced car weight wise.

So does the Corvette.

[zin]

Ever seen a Lemans with a trans in the back? Pontiac did it in 62 or 63.

Seen? My Brother owns one! Of course it didn't stay that way for long...

Mike

[pauly_no_van]

meh. Its a neat Idea, but for 100 bux I'd rather buy a VGT Holset or airbags for back of van....

[Vigo]

After watching that valve move in the video, i have to wonder what it will be doing at cruise. If its opening that much just from free-revving, i wonder if it wont just be basically wide open during low-throttle cruise as well.

However,seeing how easily it opened up also makes me think it wont do ALL that much to slow turbo spool.

[zin]

Anyone run one of these yet? I'm curious how effective they are....

Mike

[turbovanman²]

After watching that valve move in the video, i have to wonder what it will be doing at cruise. If its opening that much just from free-revving, i wonder if it wont just be basically wide open during low-throttle cruise as well.

However,seeing how easily it opened up also makes me think it wont do ALL that much to slow turbo spool.

There are 2 options, a light spring and stronger one.

Wish Will would hurry up and post his findings.

[Will Martin]

There are 2 options, a light spring and stronger one.

Wish Will would hurry up and post his findings.

I can't post anything as I'm away from home, I'm deployed right now. That was the whole point of me mentioning it in a earlier post. Right as I was getting it on and about to tune the car I got notification to leave. I'm far away from home and won't be back for a while. :(

Tell you what, I'll buy you one and you can try it out for free! :lol:

[johnl]

I put full length 3" system with the Dynomax on the Spirit R/T last weekend. Getting clearance between the swing axle pivot the gas tank and on and over the axle was a PIA. Got it done and no knocking anywhere. I got the kit second hand; the over the axle bend was a joke. As for the fit of the Dynomax - just fits the spot - the rectangular shape, offset inlet/outlet, and its length complicated the fitting.

It does not drone on the road and at idle it sounds near stock.

She is definately perkier but since the cal and everything but the exhaust is stock, I've kept my foot out of it. So . . . . until I get a cal and something to show fuel/air ratio wired up, we'll have to wait . . . .

[johnl]

After driving it some more, it does seem to stall the spool up; I'm missing the turbo wooosh; it's more a four cylinder feel to the sound, if that makes any sense. That said, it's far better than what was on there.

Might have to take the turn down off so I can lock the flapper in the open position to get a better idea of the difference.

[johnl]

Here's some pics.

Maybe this weekend I'll remove the turn down and see if I can wedge the flapper into the open position for a test.

[turbovanman²]

Thanks John, :nod:




Tell you what, I'll buy you one and you can try it out for free! :lol:

Deal, :partywoot::peace:

[contraption22]

After driving it some more, it does seem to stall the spool up; I'm missing the turbo wooosh; it's more a four cylinder feel to the sound, if that makes any sense. That said, it's far better than what was on there.

Might have to take the turn down off so I can lock the flapper in the open position to get a better idea of the difference.

What do you mean by stalling the spoolup? You mean it's has a bit more turbo lag?

[johnl]

Yes. It's lag but overall the system is more powerful across the band than the stock system that was on there before.

It's a weird effect, maybe the flapper is bouncing open and closed, up and down? or just fluttering? Maybe a resonance in the pipe? Maybe the resonance gets out of sync with the pulses coming down the pipe? It's a weird sound/feeling; it's similar to an ignition miss.

I just suspect that if I lock the flapper open it will improve the spool up but be about the same power at full boost, and, obviously, locked open it will sound like a 3" at idle and while driving by a LEO and it will drone on the highway . . . .

FYI, there's a 3" cat too.

[Vigo]

I have a full 3" system on my dynasty and it doesnt noticeably drone at all..

When i was still trying to get my hangers just right i hung the turndown on the muffler with another exhaust band clamp. You could do that while trying your experiment of blocking open the valve. Beats grinding a tack weld off every time.

[turbovanman²]

Yes. It's lag but overall the system is more powerful across the band than the stock system that was on there before.

It's a weird effect, maybe the flapper is bouncing open and closed, up and down? or just fluttering? Maybe a resonance in the pipe? Maybe the resonance gets out of sync with the pulses coming down the pipe? It's a weird sound/feeling; it's similar to an ignition miss.

I just suspect that if I lock the flapper open it will improve the spool up but be about the same power at full boost, and, obviously, locked open it will sound like a 3" at idle and while driving by a LEO and it will drone on the highway . . . .

FYI, there's a 3" cat too.


Maybe we need the heavier spring?

[johnl]

I have a full 3" system on my dynasty and it doesnt noticeably drone at all..

When i was still trying to get my hangers just right i hung the turndown on the muffler with another exhaust band clamp. You could do that while trying your experiment of blocking open the valve. Beats grinding a tack weld off every time.

Yeah I could, if I had anothe band clamp! Cut off wheels are cheap, so are tacks. Of course dragging the stuff out is a PIA. And yeah, I don't know if I'll have drone . . . .

Simon - spring, I went with the lighter spring, thinking it would inhibit spool up less . . . . .

[turbovanman²]

Simon - spring, I went with the lighter spring, thinking it would inhibit spool up less . . . . .

That's what I'll try first, then if that doesn't work, go to the heavier one.

[contraption22]

This one time... at band clamp...

[turbovanman²]

This one time... at band clamp...

Ack. :faint::drum:

[Mr overkill]

sooooo

[johnl]

Aaaaah, haven't got to it. Doin work and bike stuff.

Messin with the Norton for a BSA Owners Club ride comin up in the lower Sequoia Natl Forest, Lake Isabella area. We'll be doing some dirt biking while we're there too and some trout fishin too. The Ramerati will haul the Norton and the dirt bike. Love that trucklet. FWD works good on those mountain dirt roads.

[turbovanman²]

Well, I've tried 3 mufflers in a week and I can't take it anymore, I phoned my local parts store, they stock them, its going on tonight. I ordered the 17157.

[turbovanman²]

Damn Walker, they didn't make holes a full 3 inch's coming out of the case so even though the muffler is identical in length to the Ultraflo, the pipe won't go all the way in hence it won't fit without cutting some pipe, plus, WTF is up with the slotted pipe, going to make sealing it with band clamps a pain, :(

[bakes]

They want to sell you muffler cement:eyebrows:

[Vigo]

If im picturing it right having the slotted pipes would make it WAAAAY easier to separate for all the cheapos and shops in the world that use regular exhaust clamps. If you think about it band clamps are a luxury for the small minority that are enthusiasts (us) so they're gonna design the parts for their bread and butter market.

[supercrackerbox]

If im picturing it right having the slotted pipes would make it WAAAAY easier to separate for all the cheapos and shops in the world that use regular exhaust clamps. If you think about it band clamps are a luxury for the small minority that are enthusiasts (us) so they're gonna design the parts for their bread and butter market.

That's pretty much exactly right. We notch one end or the other of pretty much every slip fit exhaust component we manufacture. However, at least for our OEM applications, the notched end has a Torca clamp spot welded to it (for quick and easy assembly on the assembly line) which is more like a band clamp, but much thicker steel and only one bolt.

http://www.classicchambered.com/pic/clamp3.gif

[turbovanman²]

If im picturing it right having the slotted pipes would make it WAAAAY easier to separate for all the cheapos and shops in the world that use regular exhaust clamps. If you think about it band clamps are a luxury for the small minority that are enthusiasts (us) so they're gonna design the parts for their bread and butter market.

So why only this muffler and not the rest of their line? :confused: Also, the metal sleeve is thinner metal than their Ultraflo's, :(

Anyhow, thank god I have a hydraulic pipe expander, :D

So, the results so far, I am in heaven. Idle and around town, you can't even hear the exhaust anymore, get on the gas, it barks like an Ultraflo. The turbo seems to spool the same and its just as peppy around town.

On the highway, its quiet until around 3000 rpm-100 km/h, the drone zone, sigh. It took some pedal playing to keep it quiet, its alot better than anything I've tried but some is still there. On stretch's of road I could almost get rid of it and it wasn't bad at 120 km/h. WOT testing, the boost read a bit higher but it barked and seemed to pull just like the Ultraflo, maybe a bit less but I feel pretty close. As for the hearing the valve flapping, I can't hear anything.

I have 90 days to mess around, so if the drone gets worse, I might try the heavier spring unit.

[Ondonti]

Simon, one of the band clamps I bought came with some sort of urethane on it. So when I had to clamp up a pipe that was malformed from a previous band clamp that I ditched, I took some windshield urethane and packed it into the gap before I clamped it down.
This is not the wet stuff, but the stuff that comes in a roll and never dries. It never blew out, and I actually had another band clamp blow off during a backfire (spark blowout at big boost) and that one stayed intact and didn't leak. That crap would not burn off.

[1BADVAN]

Simon, one of the band clamps I bought came with some sort of urethane on it. So when I had to clamp up a pipe that was malformed from a previous band clamp that I ditched, I took some windshield urethane and packed it into the gap before I clamped it down.
This is not the wet stuff, but the stuff that comes in a roll and never dries. It never blew out, and I actually had another band clamp blow off during a backfire (spark blowout at big boost) and that one stayed intact and didn't leak. That crap would not burn off.

i noticed that too where did you pick the "dry urethane" up? or does it have an official name? i have a leaking clamp i would like to fix soon

[johnl]

Red RTV? Works for me. Not much is needed, just near the joint.

BTW, I'm with Simon, the muffler muffles nicely yet delivers full power when you want it. A worthy compromise.

[turbovanman²]

Simon, one of the band clamps I bought came with some sort of urethane on it. So when I had to clamp up a pipe that was malformed from a previous band clamp that I ditched, I took some windshield urethane and packed it into the gap before I clamped it down.
This is not the wet stuff, but the stuff that comes in a roll and never dries. It never blew out, and I actually had another band clamp blow off during a backfire (spark blowout at big boost) and that one stayed intact and didn't leak. That crap would not burn off.

Thanks, I'll keep that in mind if they leak. With me making the hole larger, I can get more of the clamp on and passed the slots.


Red RTV? Works for me. Not much is needed, just near the joint.

BTW, I'm with Simon, the muffler muffles nicely yet delivers full power when you want it. A worthy compromise.

Hi-temp copper RTV would work too.

More driving, almost no drone on the highway today, 120 km/h is quiet. Took off from a stoplight and the tires let go in 2nd so its flowing. Very, very impressed. :nod:

[1BADVAN]

Red RTV? Works for me. Not much is needed, just near the joint.




Hi-temp copper RTV would work too.


thanks that's a great idea if someone has tried it I will too i have a tube of copper silicone in my toolbox so i will give it a whirl

[Mr overkill]

thanks simon for being the guy that tries it. so the light spring is ok huh not to "light" im actually in the middle of a tu order for a 3" from the sw so i can finally finish the order with the muffler

[turbovanman²]

thanks simon for being the guy that tries it. so the light spring is ok huh not to "light" im actually in the middle of a tu order for a 3" from the sw so i can finally finish the order with the muffler

Yeah, its just right, even with my free flowing turbo/exhaust setup. If we/I went with the heavy spring, I think it would really hurt the spool.

John posted up earlier with his results, ;)

[Ondonti]

I use copper rtv on my turbo etc but I think the urethane is better for larger gaps, and I have found a lot of uses for it. I stuffed it into my coil wire because it had been shorting and damaging the boot. Fill holes. etc.

Autozone just sells a flat box and its a roll of urethane "sausage" if you will.
It is NOT good for windows, I don't care what they say :P The fact that it doesnt dry is a bad thing for windows.
My dusters rear window blew out on my drive to Seattle. Towing it on a dolly 80+mph, extra air catching under. The window actually started to blow out on a lil 140mph blast against my nissan friend but I didn't notice anything except the car seeming a LOT louder on the freeway. You could see how the urethane was just stretching out as the window started to pull away. Now I don't have to fix my foggy lexan :P

[johnl]

Simon has a better perspective than I do as he can compare his prior a 3" setup with a 3" free flowing muffler that droned against the same system with the new flapper valved 3" free flowing Dynomax.

I, by comparison, went from the stock 2.5/2.25/2.0 inch system that was stock on the Spirit R/T straight to a full over the axle 3" system with the 3" flapperized (LOL - just made that up, hee hee) Dynomax.

Simon's got the back to back comparo. So, I know nuthin & Simon's the xprt.

[83rampage]

Sorry for being kind of off topic, but are you guys confusing urethane and butyl tape.

Butyl tape was used for windshields until the early 80s, when urethane took over. Butyl tape comes on a roll separated by waxy paper, and stuck like snot to anything it touches, but always stays soft.

It can't be used for modern windshields because it doesn't have the strength to make the windshield a structural component of the car.

[Vigo]

is that the same nasty goopy ---- that holds the plastic liners to inner doors?

I used some stuff that came in a roll.. bought it from pep boys and used it to replace the back window in my Avenger back in the day. It never flew out but i dont recall whether i ever took it up to 120 or anything after putting that window in... too long ago.

[83rampage]

Yes same stuff. You can get it in different thickness. The windshield stuff is usually at least 5/16 or 3/8" square bead.

It is still the method of choice for older vehicles, so "back in the day" you probably used the right stuff. If the surfaces are prepped properly, it should not allow the glass to come off.

Urethane is NOT recommended for older windows that were butyl taped in. Urethane does not like UV from the sun. That is why all windshields on newer vehicles have that black border around the edge of the glass. If you urethane an old windshield that has no black border, the glass ends up separating clean from the urethane.

Now back on topic.....:bolt:

[turbovanman²]

Urethane is NOT recommended for older windows that were butyl taped in. Urethane does not like UV from the sun. That is why all windshields on newer vehicles have that black border around the edge of the glass. If you urethane an old windshield that has no black border, the glass ends up separating clean from the urethane.



Very interesting, I did not know that, :clap:

[turbovanman²]

Well, after I guess a few weeks of testing, I took it off. Around town and up to 100 km/h, it was quiet, but then getting on the freeway, the dreaded drone came back, I could find sweet spots but its hard and actually turning off the LU helped, :(

So I said f*ck it, put my cat on, then the Ultra-flo and its surprisingly quiet, so quiet its going to stay until race season, I can hear my radio no problem without cranking the volume. I'll have an electric cut-out installed and I'll change my goal of running full exhaust when racing for next season.

I hope this helps guys, too bad it didn't work out, for the 5 speed guys, this would be the ticket.

[GLHNSLHT2]

so why weren't you happy with it?

[Vigo]

sounds like a drone in the 100-120 kph region at the rpm he was running.

[zin]

Well, after I guess a few weeks of testing, I took it off. Around town and up to 100 km/h, it was quiet, but then getting on the freeway, the dreaded drone came back, I could find sweet spots but its hard and actually turning off the LU helped, :(

Did you have the light or heavy spring version? I ask because I'm wondering if you have the light spring, it may be opening up at a certain RPM/exhaust volume, and the heavier spring should shift that to a higher point, but still allow full open at WOT... I guess I just really want these things to work!

Mike

PS As I haven't had one in my hands I can't say, but do you think they could be adapted to use a vacuum motor or solenoid to actuate the flapper? If so, a vacuum/pressure switch could control it...

[johnl]

It could be modified but not that easy. There is no external access to the pivot/axle that the flapper rotates on. So, yeah, the side of the muffler could be cut open . . . . .

I haven't noticed any drone at any engine speed . . . . but then my freeway commute when I take the R/T is only about 3 miles and I wonder if Simon's system is shorter and if his van has more "droney" flat floor panel area.

[Vigo]

Vans have a LOT of flat-ish, largely unsupported panels in them. I think the roof and the left side/quarter panel are probably the worst in that sense.

[turbovanman²]

so why weren't you happy with it?

Its awesome to 100 km/h, then I have the drone zone to 120, which depending on traffic, hills etc, I can sometimes get the drone gone, but its really too much of a game, plus with the LU on, its actually worse until 120.


Did you have the light or heavy spring version? I ask because I'm wondering if you have the light spring, it may be opening up at a certain RPM/exhaust volume, and the heavier spring should shift that to a higher point, but still allow full open at WOT... I guess I just really want these things to work!

Mike

PS As I haven't had one in my hands I can't say, but do you think they could be adapted to use a vacuum motor or solenoid to actuate the flapper? If so, a vacuum/pressure switch could control it...

Light spring, I don't think the heavier spring will make a difference, I think for vans, they need a larger muffler so they can add more volume and silencing material.

You could use the motor but you'd have to cut it apart, not worth it.


It could be modified but not that easy. There is no external access to the pivot/axle that the flapper rotates on. So, yeah, the side of the muffler could be cut open . . . . .

I haven't noticed any drone at any engine speed . . . . but then my freeway commute when I take the R/T is only about 3 miles and I wonder if Simon's system is shorter and if his van has more "droney" flat floor panel area.

The lack of insulation is definately a factor. I will simply return it for now, then after I get it back from the body shop, I am going to "dynamat" the floor, doors, hatch and sides. Then if they still have the guarantee, I'll try it again.

[DaytonaTurboZ]

I love my Dynomax RM!

[turbovanman²]

I love my Dynomax RM!

What's that?

[karlak]

Any updates on this?

[johnl]

I'm running the 3" version on the Spirit R/T. No drone on the highway and I can hear it and feel it when the flapper opens up. Car is stock except for 3" exhaust. I speculate that it slows spooling as compared to the same muffler without the flapper but I'll trade that for civility at idle and while cruising. It is my "go to the office" car after all.

[turbovanman²]

Glad you had good luck, I returned it, :(

[karlak]

Glad you had good luck, I returned it, :(

This is not what I wanted to hear.

---------- Post added at 07:21 AM ---------- Previous post was at 07:20 AM ----------


I'm running the 3" version on the Spirit R/T. No drone on the highway and I can hear it and feel it when the flapper opens up. Car is stock except for 3" exhaust. I speculate that it slows spooling as compared to the same muffler without the flapper but I'll trade that for civility at idle and while cruising. It is my "go to the office" car after all.

This is what I wanted to hear.

---------- Post added at 07:23 AM ---------- Previous post was at 07:21 AM ----------


This is not what I wanted to hear.

---------- Post added at 07:21 AM ---------- Previous post was at 07:20 AM ----------



This is what I wanted to hear.

Leaves me still looking for something that wont wake the neighbors.

[turbovanman²]

This is not what I wanted to hear.

I think as John found out, its fine for a car as you don't have the whole rear section, like a van, acting as an amplifier, its brutally hard to shut this thing up at highway speeds. If i had a 4th gear or a 5 speed, I woudn't be having these type of issues as the LU really helped, so that proves I need lower highway rpm to be quiet.

I will be adding sound deadening to the van this year, I hope, so that should finish off any remaining issues.

[johnl]

It doesn't wake the neighbors, not at all. It's stock quiet.

[karlak]

Wonder how having this flap suddenly open would effect tuning.

[turbovanman²]

It doesn't wake the neighbors, not at all. It's stock quiet.

Yeah, it was eerily quiet at idle and low speed cruise.


Wonder how having this flap suddenly open would effect tuning.

I noticed nothing on my AF gauge and never really noticed the flap opening, but maybe that's because my setup is high flowing, it was more of a gradual thing.

[Force Fed Mopar]

Here's another one you might try:


http://www.youtube.com/watch?v=pqbS6Md5Y5o


http://www.youtube.com/watch?v=K7jGYnhbQQU

[Ondonti]

I was excited until I saw 500 dollars...

Right now I am thinking about putting a cutout on my daily near the rear axle and then have a little offshoot exhaust to a moped muffler. That would still end up costing
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=260769702560&viewitem=

So 55 bucks for moped muffler, then 130 for
http://www.summitracing.com/parts/SUM-670150-1
Buy some small pipe to run to the moped and some 3" 3 bolt flanges.
Then I get to hear the Ultraflow or straight pipe, instead of that thing. To be honest that subbie sounded terrible, and they are normally easy to sound good.

I would love to jump on that muffler in question but 14 db difference does not seem like a lot since the car didnt seem that loud when open. What would it do for a much louder car...just 14db?

[johnl]

I honestly think that the Dynomax is a great product; the only problem I have with it is that it doesn't fit my GLHS. The muffler (model 17959 - 2.5") is rectangular and it has an inlet offset from the outlet such that it really will not line up under an Omni; the rear facia cut out for the exhaust just won't line up with that I/O offset considering the spot where the exhaust pipe comes out between the frame and the gas tank as it comes over the axle and where it's gotta go to get to that notch in the facia. If only Dynomax made this flapper muffler in a round version, or even one with no offset, or at least with a center outlet . . . .

I was able to fit the 3" version under the Spirit just fine.

[turbovanman²]

My issue wasn't loudness, it was drone.

Its almost gone but at a cost of flow, :(

One large body GM cat, one large oval Magnaflow and one medium round Magnaflow in the back.


Just watched the vids, pretty cool product but hard to fit and justify that muffler on the van, :p

Price, not really that bad considering what your getting.

[Vader85]

Yeah, it was eerily quiet at idle and low speed cruise.



I noticed nothing on my AF gauge and never really noticed the flap opening, but maybe that's because my setup is high flowing, it was more of a gradual thing.
why not a 3" inlet Magnaflow glasspack (18129) and a huge 5" x 11'' x 22" muffler (12579)......that should help or run a 6" round before the muffler perhaps a 6" x 30" (12641).....you can find these cheaper on Amazon.com..:nod: