Poor man's Engine Dyno wanted - any help?

johnowhite

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Using and engine stand, I put gas, dry sump, battery, set it up for fuel injection or carb so that I could start and run the engines I build or use before putting them in the car.

That is almost done...a little more than a weekend deal do to chasing parts, changing design, etc.

The next level, is to put some resistance on the engine, so I can tune the carberator (in this case) to have a 12.5 to 1 air fuel mixture.

I have a Lamda setup, with a sensor that give me the air/fuel. There is room to run a outpu shaft through the test stand and hook it up to a load.

Any ideas on how to put a load on an output shaft?

This is for a Type 1 VW and i have clutch plates for VW or Chevy output shafts.

Someone said a disk brake would work, he also said I could use a torque converter, but a water brake is $3500.

Any ides? Pictures? Engine dynos for sale cheap?

Thanks

John
 

FABRICATOR

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The cheapest, and pretty darn accurate, is to bolt it into a car. A disk brake would be an extremely reliable source for mixed results. A large torque converter like a turbo 350-400 is getting a little better, but you will need something like metered fluid volume or a secondary dynamic load. Someone around that neighborhood ought to have a farm size water pump laying around getting rusty. It would take some water and some industrial sized plumbing, but would probably end up being the most predictable. :)
 

johnowhite

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I wanted something small and simple just to put a load on the engine for air fuel. The horsepower is what it is and tuning finer on the chassis Dyno at Bottle Blown Racing is where I'd go for that. For the engine build, that 12.3-12.7/1 air/fuel should get it really close, if not right on.....That's what the last 5 cars seemed to do best at.


Thanks....I was leaning towards the disc brake idea myself, given to me by a guy who built a similar stand......He said it only works about 5-10 minutes, but that would be enough to get a load on the engine and see where the air/fuel mixture is, make an adjustment and try again.
 

zukIzzy

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I wanted something small and simple just to put a load on the engine for air fuel. The horsepower is what it is and tuning finer on the chassis Dyno at Bottle Blown Racing is where I'd go for that. For the engine build, that 12.3-12.7/1 air/fuel should get it really close, if not right on.....That's what the last 5 cars seemed to do best at.


Thanks....I was leaning towards the disc brake idea myself, given to me by a guy who built a similar stand......He said it only works about 5-10 minutes, but that would be enough to get a load on the engine and see where the air/fuel mixture is, make an adjustment and try again.

I don't know what engine you are working on but I would use and auto trans with a high stall converter and a trans brake for a quick one off gotta have it by friday deal.

If this is something that you are going to use often use a LARGE water pump plumb it in a loop and install a gate valve to get variable resistance to the flow fill it with 50/50 antifreeze and water so you dont have to empty it every time.

You could mount the left side of the engine on a swivel (Heavy duty one) and put a Hydraulic cylinder filled with oil and a preasure guage on the port on the right side and with a little math you could get a rough torque/hp figure out of it.

We did this with an airplane engine once to do the same thing you are doing but used a huge propeller for the resistance and lifted the free side with a torque wrench then a bit of math and we had torque, we knew the rpm and from there hp is easy. It was dangerous having the big meat chopper spinning 3 feet from you though.

Your tunning will be limited unless you can have variable resistance to fully explpore the range bu you shoudl get cloes with just the transbrake and auto trans.

Cover that thing with a scatter sheild they go BOOOOOOOM!!!! when they let go.


wayne
 

John F2000

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Re: Poor man's (redneck) Engine Dyno wanted - any help?

The cheapest way is to locate 2 heavy duty cables and multiple garage door springs. Attach the cable to the springs. Might require multiple springs tied together in parallel. Then attach, the other end of the cable to the rear bumper of your car. And attach the other end of the springs to the other cable. Then attach that cable to a nearby tree. Put the car in gear and step on the gas. Have a brainless friend stand by the springs and measure the amount of stretch incurred at the springs. Try to keep tire smoking down to a minimum it will make your readings inaccurate. :)
 
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