log header Qs

[ottawa rogue]

i read the manifold flow test thread last night, and noticed that some people said that the manifolds didn't flow well because of the "t"s that were used.
why is this?
is it because the gasses are able to flow either way when they hit the t part of the manifold?
if that were the case i could see where a log made of 90' bends would be better
any opinions?

[BadAssPerformance]

If cylinder #2 is "T"ed into the log there is nothing to direct the exhaust pulse towards the manifold outlet and into the turbo. With no director the pulse just takes th epath of least resistance which is possibly upstream towards cylinder #1 which fires right after #2 and would also suffer from the backwash of the #2 pulse.

So instead of a "T", #2 (and all runners) should be slanted towards the turbo inlet.

[Dave]

Bang on, JT. Every substance, atleast all that I can think of right now, will always take the easiest path or area with less matter. Think of how you can drink water from a straw. You're drawing the air out from the straw and the water rushes to fill it, even though it's working against gravity.

Same principle to our crappy manifold. Also to note that with so much backpressure and terrible flow, there is a bit of reversion. A properly built exhaust manifold will be orchestrated, if you will. I say that because in this manifold it will do what it's supposed to do and not flow in the wrong direction or stack up before the collector or cause any reversion.

Basically with the "T's" the exhaust gas doesn't know where to go and it goes to the easiest path. At the collector there is more gas, the cylinder next to it might be empty and the gas will take this path then be forced back to the collector.

[ottawa rogue]

that makes sense, but even in a tube style header with the end of the tubes facing the inlet of the turbine, wouldn't you still get some reversion in whatever pipe didn't have exhaust blowing out of it?

what size ells are used? about the only thing i can find is 2" sch40.

[Dave]

that makes sense, but even in a tube style header with the end of the tubes facing the inlet of the turbine, wouldn't you still get some reversion in whatever pipe didn't have exhaust blowing out of it?

what size ells are used? about the only thing i can find is 2" sch40.

You'll always get some reversion, but considerably less in a well designed, directed, symetrical header. I would use 1 7/8" or 1 3/4" to promote high speed gas velocity.

[ottawa rogue]

how do you determine the angle which the turbo flange is welded at?
i don't have a manifold to compare it to or a head to mock up with yet.
I just won an auction on fleabay for some weld ells, ended up with 3 90s, 4 tees, and 4 45deg elbows.
looks like i need to order some flanges now. where's the best place to get them?

[tryingbe]

If you have the space....

http://www.thelostartof.net/tryingbe/dodge/tbiheader0.jpg
http://www.thelostartof.net/tryingbe/dodge/tbiheader1.jpg
http://www.thelostartof.net/tryingbe/dodge/tbiheader6.jpg

[ottawa rogue]

I've thought about that too, i've got a TBI manifold in the garage.
i should have enough space for one of those, i've got a lebaron.
i'm gonna try the welded ell route first since i've got them coming though

[WVRampage]

Why does the TU header use tees,or is it just with tees the manufacturing cost is less and faster.Im geting ready to build a header like that for my experiment and am looking for all the info I can.And with the angle of the flange for the turbo you want the flange of the drain level right.

[Aries_Turbo]

I would use 1 7/8" or 1 3/4" to promote high speed gas velocity.

wrong.... those are large and will decrease the velocity and kill the low end torque. the header pipe size should be around the same size as the area of the exhaust port cross section when it exits the head.

Brian

[8valves]

Since we're being techincal, that would all depend on pipe/tube construction material for size consideration.

My 1.900" OD piping is 1.682" ID... that's standard schedule 10 cast stainless pipe. Schedule 40 OD is 1.900" and ID is 1.610".

[ottawa rogue]

I'm not exactly sure wha the id is of these fittings, once i get them i'll mike 'em.
here's a link to the auction so you can see what i got
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=120161668250&ssPageName=STRK:MEWN:IT&ih=002

[tryingbe]

Personally, I rather have something like this.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=300151722665&ssPageName=STRK:MEDW:IT&ih=020

[8valves]

WTF... that is very strange. T3 flanged, wierd merge/fabbed section off of 3 and 4... funky.

That auction you won looks as though it's schedule 40.

[Directconnection]

i read the manifold flow test thread last night, and noticed that some people said that the manifolds didn't flow well because of the "t"s that were used.
why is this?
is it because the gasses are able to flow either way when they hit the t part of the manifold?
if that were the case i could see where a log made of 90' bends would be better
any opinions?


Its not due to theories posted in this thread, but a real simple thing. The T's are just that. The air exiting the flange from the head goes straight out and hits the log portion (a wall) and then has to make an abrupt 90 degree turn. Fortunately, those welded els have alot of weld inside (actually, outside) giving a radius on the exterior. So... I ported a radius as big as i could on the inside turn leading to the turbo flange, and left the other side of the T untouched.

[ottawa rogue]

is it possibly Mexican? or something that someone cobbled together?
doesn't look like any T1 manifold that i've seen
a shot of the head end would be nice

[ottawa rogue]

So... I ported a radius as big as i could on the inside turn leading to the turbo flange, and left the other side of the T untouched.

I could see that. how thick of a wall did you end up with after you ported your tees?
i was thinking of running a thick bead on the "off side" wall of the tee and blending it in to make kind of a very short "flow director", but i like the sound of your idea better.

[Directconnection]

Not sure how thick exactly... kinda went by feel. I guess about .060 to .080 or so.

[ottawa rogue]

And with the angle of the flange for the turbo you want the flange of the drain level right.

but can't you clock the center section to get your drain fairly level?

[Directconnection]

i was thinking of running a thick bead on the "off side" wall of the tee and blending it in to make kind of a very short "flow director", but i like the sound of your idea better.

I should have mentioned I thought about that same idea... just making sure it didn't protrude into the log area as it would restrict flow of the adjacent ports goign throught hat area. I decided it would be a PITA and with my luck and lack of welding knowledge when it comes to cast headers, i didn't want to take a chance of it cracking later on. I will say, the results I got were better than I was expecting.

[ottawa rogue]

got my ells this morning, sounds like it was a good day to be home with a sick kid.;)
the tees have a really nice radius-it looks like a velocity stack.
i may try to run a couple of beads in there and smooth it out to give some direction to the flow

[WVRampage]

The turbo I have can only be turned so far as it is a VNT and then the actuator for the vanes will not work properly.Keep the pics coming so I can see what I should do with mine.Also are there any places that do coatings cheap after the header is welded up.

[Aries_Turbo]

i wonder if there is a place that could take a piece of mild steel or stainless the same thickness as the wall of the piping and bend it into a very slight, long cone with the small end of the cone having the same inner diameter as a 90 deg weld el (ie cyl # 1) and the other end having the same area as a piece of pipe that has roughly the same area as the inlet of the turbine housing.

then for each cyl you use a 90 deg large radius elbow and you cut an oval in the cone and trim the bend to sit flush with the cone and weld it up. you have the elbow exit so that it already is directing the flow the correct way with the other cylinder exhaust streams. that would be ideal and basically a similar design as the TU cast manifold but more of a home brew design. :)

Brian

[ottawa rogue]

that's a good idea, i might play around with that some. plus it would give me something to use all those 45deg elbows for. i could probably section a couple of them to get what i need.
Thanks!