planning an engine test cell/dyno

[acannell]

I think having the 2.5 4cyl in a little brick building attached to a zillion sensors with easy component swapping and adjustments might be a more fun hobby than the car itself.

The two main roadblocks I see are:

1) dealing with exhaust noise in a residential area

2) the $1k to $2k for the water-brake style load (http://www.land-and-sea.com/absorber/dynamometer_water-brake_absorber.htm)

So to deal with number 1, some ideas:

-build some kind of crazy thing to absorb the exhaust noise without causing restriction..doesnt have to fit on a car and can involve lots of big space or holes in the ground or water or who knows what

-put the engine cell on a trailer and tow it out to a big empty place where nobody cares if you make noise

-rent a small industrial space with no sound restrictions and put the dyno in there

-maybe if you only do a few runs a day a couple times a week nobody will even notice..not much different than your average shade tree mechanic racing an engine during troubleshooting

-maybe its not that loud with the turbo?


And to deal with #2:

-The water brake is an old device so there might be a patent somewhere I can use to machine my own.
-Look on the used market for some kind of load..to make it worthwhile would have to be $500 or less
-Eat the $$$ and write it off as a business expense for all the insane new products I could develop from having an engine test cell.

Anyone have any experience with this stuff? Seems like a lot of fun! Imagine being able to sit in your comfy chair and fully test out the engine, modifying it and tweaking things without having to do it on the road or at a racetrack. So much more convenient and fast. Then when its outputting 200hp/liter you can plop it into the car lol

http://www.land-and-sea.com/images/dyno/auto/engine/Plumbing_with_Cooling_Tower_1000.jpg

[acannell]

fascinating thread on exhaust soundproofing ideas for suburban/residential dynos

http://www.eng-tips.com/viewthread.cfm?qid=164042

[zin]

Lots of possibilities, but most would be most effectively implemented in an industrial situation. I've had a friend who is a glass-blower have his kilns "evicted" because his neighbors didn't like the idea of them being so close to their houses.

So, if you do this "at home", you'd need to make it super quite and/or run it at a time that would draw the least attention from those around you.

Personally, I think it would be a neat challenge to make the test cell "sound proof". One of the biggest would be silencing the exhaust while not materially affecting back-pressure.

Many years ago Jim McFarlan built a very advanced dyno facility in Ontario Ca, one if the neat sound isolating features he incorporated into it was to have the test cell's "slab" isolated from the rest of the floor. The sound couldn't be transmitted directly to any of the surrounding structures and radiate from them, all sound had to either go through the ground (which muffles things quite well), or the air, and those sound waves can be dealt with fairly straightforwardly.

Any way you slice it, at the least it will be a fun "engineering experiment".

Mike

[zin]

Oh, as for mufflers, we used a pair locomotive mufflers mounted on the roof, though that was more of a space thing than an engineering thing...

Mike

[acannell]

okay some more things to ponder:

-My backyard has a pool so that can act as both the source and the return for the water supply for the water brake dyno. That eliminates quite a bit of cost as far as a huge tank to store water and some way to cool it off, or just letting it run off and the wasted $$$ and also the spectacle of all that water being drained.

-Land and sea says 1gpm @ 30psi for every 20hp of dyno. So for 700hp thats about 35gpm. Looks like most pool pumps can keep up with that, at the required head of about 69 feet. I have an old pool pump that would fit the bill perfectly.

-I would imagine this "building" would be a very short, very thick walled structure, that I would wheel the engine into and would not actually be able to go into myself. That saves on cost and size issues of constructing it. Perhaps concrete blocks, maybe some other free material I can get off craigslist and turn into a short shack.

-A reasonable muffling solution described in that thread is a large brick lined cavity, buried, and filled with gravel or old tires, with a very large diameter pipe in it with holes, which goes up to the exhaust. I have a perfect little dirt area to do that.

-Muffling the intake could be tricky since I have to build the shack so small. But perhaps something similar could be done. Or maybe its not that loud since its got the turbo?

-To put things in perspective, its not completely out of the question to do a few dyno runs totally unmuffled out in the open. People work on their cars on my street all the time and are revving the engines up for hours trying to fix things. I wouldnt be doing this "for hire" so it wouldnt be very often. I bet a lawnmower would be just as loud, and maybe I can mask the sound with a lawnmower lol! How long does a dyno run take? 30 seconds? Big deal! Start the mower up and let it run and see if they can hear the engine over the mower hah!

-So I would just try to make it quiet to be nice. Plus I want an enclosed fireproof space to do it in for safety if it catches fire or who knows what.

[acannell]

welp I was way off on the cost..an 800hp water absorber and torque arm are $5550 from land and sea, and they dont lease to personal users

so it looks like Id have to machine my own to do any of this..or find a way to make/acquire some other kind of absorber

[Rrider]

Trailer is the way to go.

[wallace]

home made dyno info on the retarder fluid flyweel: http://youtu.be/D11fwgU1Pvg

[acannell]

home made dyno info on the retarder fluid flyweel: http://youtu.be/D11fwgU1Pvg

verrrryyy interesting thank you! I wonder how much torque that could handle. I wish there was more info on how the retarder works. I suppose thats a fluid retarder as opposed to an electric one, ill have to do some learning. It sounded like he was running the engine at a fairly low rpm but Im not sure. Definitely a possible solution for this.

[wallace]

verrrryyy interesting thank you! I wonder how much torque that could handle. I wish there was more info on how the retarder works. I suppose thats a fluid retarder as opposed to an electric one, ill have to do some learning. It sounded like he was running the engine at a fairly low rpm but Im not sure. Definitely a possible solution for this.

I THINK he's using a torque converter for the fluid retarder. He said its out of a diesel truck.
he cranks the rpm up and then he increases the fluid load and drags it down.

[shackwrrr]

http://www.ebay.com/itm/Telma-Brake-Retarder-/141533704086?pt=Other_Vehicle_Parts&hash=item20f410ef96&vxp=mtr

Eddy current retarder, would make a nice dyno


What about a cheap high power 3 phase electric motor with a load bank? Im sure you would need an equal hp motor to what you wanted to put into it though so that's probably out of the question.



edit: Kept getting that 403 forbidden, found that if you make a plain text post with no links or pictures it will go through, once the post is made then you can edit the links back in.

[acannell]

I THINK he's using a torque converter for the fluid retarder. He said its out of a diesel truck.
he cranks the rpm up and then he increases the fluid load and drags it down.

from what I gather retarder = a sort of brake for trucks. Ive heard of "eddy current" ones that electrically create a load but I have not heard of water ones. He says that the brake has been removed in the video. Im sort of confused exactly what hes using. I dont know if a torque converter would do the job, it seems like it would but I dont seem to see people mentioning using them

[Reaper1]

I am pretty darn sure he's using a torque converter. If it's not a converter, but a true "retarder" that goes behind the transmission it might have had a brake on it. I've seen on some large industrial type vehicles there be a brake on the actual prop shaft (monster trucks have been doing it this way for decades).

As for what a "retarder" is...it seems like it's nothing more than a manually controlled torque converter that uses the fluid coupling action as an energy dissipation. From reading about some made by a German company it seems that they can also mount the stator on a helical gear and use it as an internal brake like a lock-up clutch to make it even more effective. That action is similar to how a Torsen differential works.

[acannell]

I am pretty darn sure he's using a torque converter. If it's not a converter, but a true "retarder" that goes behind the transmission it might have had a brake on it. I've seen on some large industrial type vehicles there be a brake on the actual prop shaft (monster trucks have been doing it this way for decades).

As for what a "retarder" is...it seems like it's nothing more than a manually controlled torque converter that uses the fluid coupling action as an energy dissipation. From reading about some made by a German company it seems that they can also mount the stator on a helical gear and use it as an internal brake like a lock-up clutch to make it even more effective. That action is similar to how a Torsen differential works.

I shall have to look into it and find something affordable.

I think having the engine on a cart would make a huge change in how quickly development can occur. No more smogging hassle or waiting for race tracks to test out ideas, and of course saving the huge amount of when it comes to working on the engine in-car. Plus the difficulty in observing certain things in-car like valvetrain anomalies at high rpm. Heck I could literally put dial indicators on the thing while its running lol

That said if I make it trailerable, where do I get a water supply? Thats a problem. Hmmmm

[zin]

Go bandit style and use a fire hydrant😈

Mike

[turismolover22]

I would suggest water to muffle engine noise. You already have a large supply of it. Have you heard a boat outside of water, conpared to inside? Water muffling is the way to go, me thinks. And I dont think it would add a terrible amount of backpressure either. Its not like you wouldnt have gauges to monitor pressure ratios anyway.

[acannell]

I would suggest water to muffle engine noise. You already have a large supply of it. Have you heard a boat outside of water, conpared to inside? Water muffling is the way to go, me thinks. And I dont think it would add a terrible amount of backpressure either. Its not like you wouldnt have gauges to monitor pressure ratios anyway.

this would be interesting...but I think if I use the pool it would make the pool dirty. Plus it does take power to pump exhaust through water, unless I do it really shallow.

I suppose I could go out on the driveway and connect the daytona exhaust to a bucket of water and see what happens lol

[Reaper1]

If you run the exhaust through a water curtain (think waterfall), that will help dampen noise and offer very low restriction (if any as long as the exhaust chamber is large enough). Also think about harmonics tuning. Use different offshoots from the main chamber to help create destructive interference for the sound waves. This shouldn't mess with the performance of the engine because it should be well away from it. Might even look into active noise cancellation like noise cancelling headphones.

[bakes]

Have you looked into a used engine dyno's for sale? there is some e bay

[acannell]

Have you looked into a used engine dyno's for sale? there is some e bay

i didnt see any when you posted..maybe I searched wrong?

Heres another idea...an inertial load like a dynojet. Gear the engine down with a stock tranny and connect the output of the tranny to a huge roller of some kind.

Im a little concerned ive never heard of this though..maybe theres a reason.

How to make a huge roller...hmm I wonder what size they use on a dynojet?

Fun opportunity for some flywheel energy storage calcs!

EDIT: im not sure dynojets are inertial or partially inertial or what..

[zin]

How to make a huge roller...hmm I wonder what size they use on a dynojet?

Fun opportunity for some flywheel energy storage calcs!

EDIT: im not sure dynojets are inertial or partially inertial or what..

IIRC, Dynojet, initially anyways used rail car axles and added the drive drums to the wheels... I do believe they are inertial, though I'm sure you could add an eddy current brake to them to add some load... Last I heard, Roush was using eddy current dynos for their endurance testing and engine development, selling the generated power back to the utility!

Mike

[turismolover22]

Why not a balanced roller off the end of the engine, that rolls on another roller. Then usea large electric motor to create an "electric brake" or gear that down with viscous couplers.

[acannell]

Why not a balanced roller off the end of the engine, that rolls on another roller. Then usea large electric motor to create an "electric brake" or gear that down with viscous couplers.

The thing is you cant avoid having to dissipate 100% of engine power somehow even if its geared down. Even if I gear it down 100:1 and at 6000rpm the dyno load is only turning at 60rpm, the brake would still have to deal with whatever 300hp or 500hp the engine is putting out, the torque will just be that high.

But for a short dyno pull maybe it could work out. Maybe putting a bunch of disc brakes in series and engaging them simultaneously, theyd be able to dissipate all that energy for 10 seconds or so, especially if they are immersed in a liquid bath of some kind? I could get used disc brakes from the junkyard I would imagine? The amount of energy in a car going 80mph gets dissipated by just 4 brakes, mostly just 2, right? So what if I had 10 in series, all with liquid cooling? How bad can things get in 10 seconds at 500hp?

A 3500lb car at 80mph has about 1 million joules of energy.

Lets say that in an EMERGENCY stop, just 2 disc brakes can handle that without exploding or melting, with air cooling. Im not sure how long that stop would take, but probably alot less than 10 seconds. But lets say 10 seconds. So the brakes can handle 500,000J being dumped into each brake if done over 10 seconds.

So if we have a 500hp engine, and we assume it outputs 500hp continuously for 10 seconds (which it will not, but lets do worst case).

Thats about 400,000J per second. In ten seconds, 4 million J total, or 2million per brake. So 4 times the energy. So if we quadruple the number of brakes involved and involve a very good cooling system (liquid or air or whatever), and then take into consideration that the engine does not output 500hp continuously, I think we are in the ballpark.

[bakes]

google redneck dyno and have a laugh but it works

[turismolover22]

I was going to suggest having a turbine type viscous coupler, like a torque convertor. Then making multiple ones, and chambering them seperately, but in parallel. Then filling it with a thick fluid, like motor oil. Have their vanes designed to fan out when a higher engine load is required, I.E. like a windmill variating vanes dependent on windspeed. You could have this attached by some sort of clutch system, so the engine does not have to overcome the load immediately. Just random ideas.BTW me thinks you will have to figure out a highly inventive way to keep those brake discs cool. Dunking them in any fluid while operational is asking for poor performance, and dunking in cool liquid immediately after hard breaking is asking for embrittlement and a time bomb.

[Reaper1]

Water spray cooling for brakes isn't anything new...even for disc brakes. The PPG LeBaron pace cars had water spray cooling for the brakes. Also, look at the European semi-truck racing. They use water spray cooling for their brakes.

The thing is I don't think you can spray it directly on the friction surface. I think it has to be sprayed into the cooling vanes (I could be wrong here, so research is needed).

Seeing as there have been many cars that have been tuned on the street using the brake drag method, I don't see why this wouldn't work. You would just have to figure out how to measure the energy. Maybe mount the brake calipers on a pivoting fixture that when the brakes are applied it presses against a load cell and torque is calculated that way. As long as you can stall the acceleration of the engine, then you should be able to get a semi-accurate reading.

[bakes]

All logging trucks use water cooling for brakes here in Canada

[acannell]

Water spray cooling for brakes isn't anything new...even for disc brakes. The PPG LeBaron pace cars had water spray cooling for the brakes. Also, look at the European semi-truck racing. They use water spray cooling for their brakes.

The thing is I don't think you can spray it directly on the friction surface. I think it has to be sprayed into the cooling vanes (I could be wrong here, so research is needed).

If we spread the energy out over alot more disc brakes..like 10 brakes or something, maybe nothing beyond the normal brake venting would be needed. Or we could add forced mist jets right into the intake of each vented disc.


Seeing as there have been many cars that have been tuned on the street using the brake drag method,

wwwwwaaaaaaahhh??? more info plez!



I don't see why this wouldn't work. You would just have to figure out how to measure the energy. Maybe mount the brake calipers on a pivoting fixture that when the brakes are applied it presses against a load cell and torque is calculated that way. As long as you can stall the acceleration of the engine, then you should be able to get a semi-accurate reading.

I would think the same way as any other dyno load..whether it be water, eddy, intertia...you put a load cell on whatever is preventing the rotation, in this case, the caliper that pinches the disc brake, and that gives you torque. Then with rpm you have power. Very accurate and just like the "real" dynos.

Problem is 6000 rpm is like 400 mph on 205 50 R 15s..so most disc brakes are probably not designed for that speed, so some kind of gearing would be needed. I suppose you could just use a stock tranny or make some bad --- reduction gear. All it needs to do is survive and reduce like 5:1. Doesnt need to be small, light, or sound nice.


I think maybe one of the problems would be a non-linear load from brake fade or whatever other kind of behavior happens. So you would probably need enough disc brakes or a way of doing it so that the brake acts very linear or things are going to go wonky. Eddy current dynos are braking the disc with a magnetic field so theres no weird gas formation or getting hot and changing coefficients of friction..

This seems so weird that its hard to do on the cheap/simple. Theres got to be a way to pump energy into something for 10 seconds that keeps the load steady and controllable.

I guess you could put a huge roller under ground mounted wheel hubs and fill it with concrete, but not sure where the relationship between it exploding at high rpm and you being able to gear it down but still store enough energy in it at lower speed mates up. Im guessing its not in our favor.

[Rrider]

Pull the gen head out of a big old diesel power backup system with a blown engine. Use that as your load. When the power blacks out power your neighborhood with your 8valve.

The water load idea sounds simple, or maybe you could even push air like the fan exercise bikes do. Would need something huge to drive air. Industrial compressor? The brakes sound like a bunch of trouble. I have an eddy current absorber if you want to check it out to see how its built. I think its pretty simple.

[Reaper1]

Ken (5digits) has described a few times how he has done a few tunes on the highway using the brakes to put load on the engine and gears to get the rpm desired. Think brake boosting. Same idea. Of course you WILL wear out the brakes doing it this way, so use less expensive parts until you get the tune nailed down. The clutch will also have to be up to the task (or converter if you are using an auto).

If you are holding an engine at a constant rpm at a given throttle position, then the load is steady, so even if the brakes get hot and it takes more master cylinder pressure to hold the rpm steady things are golden. The power is being turned into heat and there isn't enough power to overcome the load.

Eddy current load generators can also have a change in load applied over a period of time due to the electrics heating up, which increases resistance and requires more power.