strange dyno chart...help
#17
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From: Denver
Ah yes, I forgot about the Nm-Tq conversion.
From factory the car is rated at the flywheel. Drivetrain loss is expected, so the rear-wheel-hp will be less.
And if you are on stock turbo - then I think you have a pre-turbo exhaust leak causing the slow-spool up.
-Rogue
From factory the car is rated at the flywheel. Drivetrain loss is expected, so the rear-wheel-hp will be less.
And if you are on stock turbo - then I think you have a pre-turbo exhaust leak causing the slow-spool up.
-Rogue
#18
243tq at the wheels minus 15% drivetrain loss = 206tq
From factory the car is rated at the flywheel. Drivetrain loss is expected, so the rear-wheel-hp will be less.
And if you are on stock turbo - then I think you have a pre-turbo exhaust leak causing the slow-spool up.
And if you are on stock turbo - then I think you have a pre-turbo exhaust leak causing the slow-spool up.
Yeah,the turbo is stock as well as everything else but wouldn't an exhaust leak be easily noticeable?
#19
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From: Denver
The dyno is converted for FWHP?
An exhaust leak you should be able to hear, might not be able to see easy though if it is under the shields.
A couple of other options is that the crossover pipe has collapsed; the downpipe has collapsed, or the factory wastegate isn't sealing properly. All these will cause slow-spool and loss of power.
-Rogue
An exhaust leak you should be able to hear, might not be able to see easy though if it is under the shields.
A couple of other options is that the crossover pipe has collapsed; the downpipe has collapsed, or the factory wastegate isn't sealing properly. All these will cause slow-spool and loss of power.
-Rogue
#20
I dont know if the dyno is converted for FWHP or if the data was converted after.Just look at the dyno sheet ,potenza motore=engine power , copia max=max torque and potenza ruote max=max wheel hp .
Ok everything will be checked and i'll let you know how it turns out.
ps:the guy at the dyno said that the piston rings might be kaput and the engine is losing compression but i think that is very unlikely.
What do you think?
Ok everything will be checked and i'll let you know how it turns out.
ps:the guy at the dyno said that the piston rings might be kaput and the engine is losing compression but i think that is very unlikely.
What do you think?
#21
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From: Denver
If the rings are that bad, then it would be burning quite a bit of oil. I doubt the rings are the problem. I think it is one of the things I mentioned earlier.
-Rogue
-Rogue
#22
+1 on WG
on another note i heard something sad the other day, a corvette ZR1 dynoed at like 505WHP versus 640 at the crank, thats about 50 off of what I would expect, unless the 640HP number is not accounting for supercharger drive loss.
on another note i heard something sad the other day, a corvette ZR1 dynoed at like 505WHP versus 640 at the crank, thats about 50 off of what I would expect, unless the 640HP number is not accounting for supercharger drive loss.
#23
Another thing to consider regarding the ZR1 dyno number you heard is that there's no mention of the brand of chassis dyno being used. IIRC, the Dyno Dynamics chassis dyno reads much lower than a Dynojet.
#25
On a Superflow Dyno alone you have four different correction factors that can easily swing 50+hp between the two extreme numbers.
Also, dyno's like Mustang and Superflow have operator adjustable parameters that can produce some very wild numbers if setup incorrectly (or "tweeked" to produce better numbers).
Reason why (for the most part) dyno's should be used to compare changes before / after. Not to compare absolute numbers from different cars at different dyno's.
#27
Two separate 'Vettes were tested, and the average output was about 535 horsepower at the rear wheels. After factoring in the normal 15-percent drivetrain losses for a rear-wheel drive car, that's pretty darn close to the claimed 638. After a bit of tinkering the team got that number up near 570, saying it's running a bit rich from the factory.
#29
#30
Our local Porsche club uses a ratio of 1.32 when calculating drivetrain loss, not 15%. I thought that was excessive but they maintain that it's in line with the Factory?