My latest Dyno readings

Very interesting. I had mine hub dyno'd at competizione. See here:

http://www.ferrarichat.com/forum/showthread.php?t=173001

My best run at the hub was 264hp with tubi and hyperflows, but I subsequently found out it was tuned to run very lean. That has since been adjusted but I have not had a new dyno run.

 

btw, the guys here felt the transaxle layout was pretty inefficient and that 20% was a better correction factor than 15%. In my run we applied 15% and that came to engine HP of 303 which is basically stock. I think the running too lean probably is worth another 10hp or so but who knows.

 

If we take the 20% correction factor, his car is putting out 352HP! Seems high with only the exhuast mods.

 

the other interesting thing is that on my run they programed the dyno to stop the revs at 7300. Stock specs are max hp at 7200rpm right. You went all the way 8170. and got that little bump in the end. at 7500 you are at 270 hub HP which is much closer to my reading at 7300.

Do you have a chip that allows you to over rev? I thought redline was before 8000rpm with the standard motronic. Does anyone know for sure?

 

To make it short, there is no xy % powerloss such calculations are like looking into a crystal ball. You postet a TAT dynorun the TAT software messures drivetrain loss. Sadly it is not on the paper. But i draw the line roughly to the dynosheet. Sadly there are already temp and pressure corrections on the crank hp curve so the drivetrainloss curve is not that precise but it is already muuuccchhh better then to say 15% , 20% , 23,423423%. So you can use this line add it to your messured wheel hp and you got ~ crank horsepower. ofcorse that is also nothing precise because the drivetrainloss depents on the wear of the gearbox, on the tires, on the dyno itself .... so better only use dynos wich messure drivetrainloss after the wheel hp messurement.

http://img151.imageshack.us/img151/6518/rollingroadgv0.jpg

 

I am also curious as to how you got 8000 out of the motor. Is your rev limiter removed?

 

The rev's are not always accurate on the rolling dynos it depends on the rpm pickup. How did they picked up the rpm? Inductive, Piezzo or simple mph -> rpm factor calculation? The last one is the inaccuratest. Also the dynos have heavy filters to get a flat curve this also valsifies the resultat of it.

 

My dyno used induction rev measurement off a spark plug wire. My SS redlines at 7500 and shuts off at 7750 or so (hard to get the exact number). There is a test we have been comtemplating to measure the parasitic drag of the drive line and accessories and I might do it for grins. So far as we could correlate between goth's car and mine, it works out to over 20% on our cars, or about 70 Hp. This is really surprising for a mid-engined rear-transaxeled car. This is about what we'd lose in our 350 cu in Vettes when I used to do this. The parasitic is not going to be a percentage; it really is a measurable specific value that can be affected by anything that causes drag on the power train, including whether or not your A/C is hooked up and/or running.

Lastly, we should all remember that the measurements are not absolute and the estimates of gross Hp are really just that - estimates. Rather than be concerned with the absolute values, we should be looking at the relative difference of stock and modded configurations. My car read 246 net stock and is now 257 modded. I'm happy with that gain. Add 70 and you get 327 gross, plus 30 lbs less weight.

Lastly we just are not going to get 355 smog legal power out of a 348 engine, although we'd like to think it's there for the taking. The engine differences are just too great - higher compression, better intake and fuel management, 5 valves and much higher rev range where the engine is really making its extra power. What we are going to get is a better performing engine, however, across its available power range.

 

It's my understanding that the late 348's increased power was due to a better exhaust system. Is this correct? And if so, you both have aftermarket exhaust systems so shouldn't you both have the same baseline power?

 

These 70hp are gear and rpm dependend. So if you messure the drivetrainloss and have 70hp loss on f.e. 7500rpm you only can add these 70hp to the wheel hp on 7500rpm not on 5000rpm. And you can't say it is 20% because if you tune your engine to double of the hp befor the loss is not 20% its then 10% because 70hp keeps the same. Also you will have less loss on 5000rpm because its exponential so the % loss is not steady on the rpm band. F.e. two calculations one wrong and one right

Wrong calculation :

You messure the drivetrainloss and get 80hp on 8000rpm. and a 230hp @ 7500rpm wheel hp max. Now you calculate 26% drivetrainloss wich
would be failure one because the max hp is on 7500rpm and there is only 70hp drivetrainlos ok now we took this for the calculation and get 23% drivetrainloss. Now we turbocharge the engine to 460hp @ 6000rpm wheel hp max. Calculate it with 23% would be 566hp.

Right calculation :

Messure 230hp @ 7500rpm and the drivetrainloss diagramm. Messure again 460hp and look on the drivetrainloss diagram in the exact same rpm then the 460hp see its only 40hp because the rpm is lower then befor add these 40hp to it. 500hp on the crank would be the right figure. So 66hp failure.



And to Angelis if you like to know your real crank hp you need to know the drivetrainlos on 8170rpm if it is the same like on the TAT Dyno you should have ~360hp at the crank. But every dyno is different in the drivetrainloss f.e. twin roll dynos get much more drivetrainloss then single roll dynos.But everything we do here is just guessing so i would recomman to move the car to a good dyno and messure the crank hp there. These TAT Dynos are great or in england you should also find MAHA dynos wich would work too. Or a Bosch FLA206 would do it also.

 

You forgot about the racing stripes those ad at least 15hp...

 

Red, white and green.....

 

Sy, you car is gorgeous. I am so depressed since mine is STILL in the shop.

 

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