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Took my car down to Speed Productions in Jackson Mississippi to get a dyno run on it, I had been wanting to do this for awhile and when the chance came for 3 dyno runs for $50 I couldn't pass it up, so I brought my car down and had them run it.
My car is an A4 with 2.73's, mods are SLP LM1 cat-back, SLP lid, and Ported & Polished throttle body, nothing else.
The car put up some surprising numbers:
325.55 RWHP
347.43 RWTQ
Temperature in the garage was 99 degrees, humidity was 31%.
With an 18% drive train loss, which I think is standard for the 4 speed automatics, the car should be making 384.19 horsepower to the crank. Did a cat-back, lid, and TB really help to add 34HP to the car? Or was it a little bit higher than 350 to begin with do you think? People were impressed and thought it had to have heads or headers to be making those numbers.
Also, I apologize, but since I uploaded the video to YouTube it seems to be very quiet, you will probably have to turn up your volume to be able to hear it. Let me know what you guys think.
your car is not a freak of any type. The LS1 was producing about 290-300 HP on the dyno's stock back in 98-02. You're right where I'd expect...I wouldn't really use the 18% loss value, the more modern 4L60E's weren't terrible pigs on the dyno. And the engines were underrated from the factory anyway, making similar power to their identical corvette powerplants.
your car is not a freak of any type. The LS1 was producing about 290-300 HP on the dyno's stock back in 98-02. You're right where I'd expect...I wouldn't really use the 18% loss value, the more modern 4L60E's weren't terrible pigs on the dyno. And the engines were underrated from the factory anyway, making similar power to their identical corvette powerplants.
Most people say it's an 18% loss on the autos, what value would you use?
I know the car actually produced 350HP to the crank in stock form, but 325WHP is still way over 350 crank HP. When they dyno'd the '98 models stock they only made about 290WHP, I have a few really basic bolt on's. Some guys with headers and tune are making the same as what I'm making.
your car is not a freak of any type. The LS1 was producing about 290-300 HP on the dyno's stock back in 98-02. You're right where I'd expect...I wouldn't really use the 18% loss value, the more modern 4L60E's weren't terrible pigs on the dyno. And the engines were underrated from the factory anyway, making similar power to their identical corvette powerplants.
This.
I really wish the whole "% power loss" would go away. Drivetrain loss can not be measured as a percentage... it is a static figure, more or less. Think about it, you have a stock car making 300hp. It puts down 240hp to the wheels, for a 20% drivetrain loss. Ok, fine. Now double the horsepower to 600, and suddenly the drivetrain is now losing 120hp? The drivetrain didn't change. Only the engine output did. The drivetrain didn't suddenly become less efficient at putting the power down, or gain weight.
Drivetrain losses are basically a set number, that fluctuates a bit from friction in the transmission by about 10-20hp.
Another point that wasn't mentioned is a dyno is totally worthless without a baseline dyno. You have an idea as to what this dyno is now producing, but if you wanted to remove any question, you'd have to see your car (stock) on the dyno....then you could compare the figures stock vs modified, which would answer your question...the only other option is to find a similar 98-02 f-body with the same transmission and rear axle ratio as you, and have that car dyno'd as well. It wouldn't be perfect, but might get you a better idea...some dyno's are considerably more "liberal" in their results than others...
STD correction. Have them put the run file into SAE and your numbers will drop in line. SAE is the accepted standard. Also having the mph as the X axis shows different numbers then having RPM. That shops WINPEP7 settings are all whacked out.
Shops that want to show people higher numbers give printouts in STD.
I really wish the whole "% power loss" would go away. Drivetrain loss can not be measured as a percentage... it is a static figure, more or less. Think about it, you have a stock car making 300hp. It puts down 240hp to the wheels, for a 20% drivetrain loss. Ok, fine. Now double the horsepower to 600, and suddenly the drivetrain is now losing 120hp? The drivetrain didn't change. Only the engine output did. The drivetrain didn't suddenly become less efficient at putting the power down, or gain weight.
Drivetrain losses are basically a set number, that fluctuates a bit from friction in the transmission by about 10-20hp.
Drivetrain loss is parasitic, the more power you make the more you will lose, it's not a set number. Look at the ZR1, makes 638 HP and puts maybe 530 down to the wheels, a stock LS1 makes 350HP and puts 300 down to the wheels. Over a 100HP difference in crank to wheels for the ZR1 and only a 50HP difference in crank to the wheels for an LS1.
Drivetrain loss is parasitic, the more power you make the more you will lose, it's not a set number. Look at the ZR1, makes 638 HP and puts maybe 530 down to the wheels, a stock LS1 makes 350HP and puts 300 down to the wheels. Over a 100HP difference in crank to wheels for the ZR1 and only a 50HP difference in crank to the wheels for an LS1.
You are incorrect. I did not say it was a set number, it's a range centered around a set number. That range is dependent upon the tires, wheels, drivetrain weight, reciprocal mass, and friction in the transmission and gears.
Your example is flawed. You're comparing a stock LS1 vs a ZR1 which has different heads, exhaust, and supercharger, which is making the drivetrain losses completely different. The drivetrain losses for any sc'd car will be higher than an NA car.
Stick with the SAME car and start with stock and then mod it. You'll learn quickly that drivetrain loss is NOT a simple percentage.
As a certified Dynojet dyno operator, I should mention that it's pretty easy to "fudge" numbers once you get the hang of it (by imputing temp, humidity and altitude incorrectly/inaccurately). A lot of dyno operators do this on purpose by a little bit, Especially when they're running the dyno after performing an "upgrade" of some sort (I know, not exactly moral ethics, but it's rampant). Every "freak" engine I've seen and retested turned out to be perfectly normal.
There's ALSO a difference with the different Brands of dynos.
Dynos are good for two things (when you have a trustworthy operator), that's to identify gains or losses from changes made when you have a before/after and to help work on jetting (for carbbed engines) through the RPM band, under load (though only when combined with an EGA).
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