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...e_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

[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=item20f41 0ef96&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..