dyno
 

Last weekend I had a chance to put the 49 on a dyno. The engine is a260 cu 4 inch. by 30 thou. isky. cam 77-b stock heads cut 60 stock intake with one ford 94 carb fenton headers with 2 smittes ss chev. valves and bubbas dissey. at 3,820 rpm max power 82.39. at 2,590 rpm max torque 157.22. Just a little bit of nothing news. jack

Re: dyno
 

Engine dyno or chassis dyno?

Re: dyno
 

chassis dyno. It was a hoot to do, a first for me. Jack.

Re: dyno
 

So what do they project as the drivetrain loss?

Re: dyno
 

The operator told me that the average loss is 15%, I don't know the horse power of the 49 engine but I would guess it would have 120 hp?. Jack.

Re: dyno
 

What was the rear wheel horsepower ?


Sal

Re: dyno
 

That sounds really close to me. I also think 15% drive train loss at such low speeds is over stating the issue. Most people do not realize the work necessary to make an honest 130 HP with our Flatheads.

If you want bigger numbers you can go to New Mexico.

Re: dyno
 

Hi Sal, The HP. at rear wheels is 82HP.

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Thank you shoe box Jack.


Sal

Re: dyno
 

If the rear wheel HP numbers are correct you have about 100 HP at the flywheel!

We have a couple very experienced chassis dyno operators in our area and just about all feel comfortable with a 16% to 18% power loss through the drivetrain!

Thanks, Gary in N.Y.

P.S. For the parts you mention in your build above this 100 HP number is really not all that bad, it should still be fun ride!

Re: dyno
 

For those of you who might be interested enough to learn about drivetrain power loss I suggest you read the SAE (Society of Automotive Engineers) papers on this subject. As you might guess they have conducted testing and written extensively about the subject. You will soon see the 15, 16, 18 percent BS is just that. As a matter of fact all cars are different and using a standard number is pathetically uninformed.

Re: dyno
 

When I recently put my 32 Cabriolet on a chassis dyno at Ida Automotive (before TROG), it made just under 150 HP at the rear wheels. It is a heavily modified 284 cubic inch engine, big ports, huge roller cam, etc.. It only has two Stromberg 48's on it - so it is most likely a bit under-carbed. It easily revved to 5500 in all three gears. It is not easy to get to even these HP numbers on a street engine (without a blower) - this engine probably makes about 170 - 175 HP at the flywheel. It is running an Eddie Meyer hi-rise two-pot manifold (not the best for the engine size - but it sure looks good). I'm going to port the top manifold piece and try a set of Holley 2110 carbs - just for shits and giggles (and go back to the same dyno). Of course I need to replace the rear end first . . . the early 32 rear did NOT like that dyno run! LOL