Ozzmosis67

I am looking to find out what kind of power loss is experienced through the drive train of a stock FD with a 5-speed. Has anyone dyno'd a low milage, completely stock FD? I know most cars have an approximate 20% loss from the flywheel to the wheel. Can anyone help me with this? I would appreciate anyone's insight.

Andy

Bill B

iTrader: (1)

I seems that an FD has a average DT loss of 15-17%. Nothing scientific I've dynoed on both engine and chassis dynos and did one back in 94 that showed a loss of 16%.

rynberg

On a stock car, you can estimate the driveline loss at 15%. In reality, I don't think you can apply that 15% loss when you are modded as I don't think that the losses will linearly increase with horsepower output.

If you dyno 215-220 rwhp with a stock FD, it's healthy.

I hit 240 rwhp with a downpipe and cat-back, although my boost was only 7 psi above 6k. (If you want to see the plots, do a search for "dyno results" under my username.) Installing a Profec B Thanksgiving weekend so I hope to be getting a solid 10 psi till redline (unless my cat is clogged...), so I should dyno higher.

azndisgrace

your boost is supposed to drop as you near redline

RX7SpiritR

iTrader: (1)

I wanna dyno mine once I get the turbos fixed. Plus I will have a DP on it after the turbos are fixed and then I will work on mostly reliability mods (no performance until after the relaibility mods are done). Yet some of those reliability mods are also performance mods and will help me run cooler and better.

rynberg

Yes, it's true that on a STOCK car, your boost should decline to 7-8 psi at redline. However, my boost goes from 10 to 7 instantly at 6k rpm. I've heard of other people with the same problem. Once you open your exhaust and intake, you should be able to hold 10 psi longer.

jimlab

The generally accepted percentages are 15% for a manual transmission car and 20% for an automatic. Drivetrain losses do increase as power increases, but the percentage takes that into account. It's all an approximation anyway, since you will never really know what your engine is putting out unless you put it on an engine dyno.

A "healthy" 3rd gen. will put down about 215-220 RWHP, as stated above, but I've seen as much as 227. That doesn't mean that drivetrain losses were less in that car, that means that production variances resulted in an engine that made more power than others. My Z06 dyno'd 355.4 RWHP bone stock. With 15% losses that's 419 flywheel horsepower for an engine rated at 405. In this case, it might be a result of GM underrating the Z06 a little, but two other '02 Z06s that dyno'd on the same day produced horsepower in the high 340s, so production variances could also account for my numbers.