allenk4

I found this article on drivetrain loss from Super Street interesting:

Drivetrain Power Loss - The 15% "Rule"- Modified Magazine.

It seems that the percentages that have traditionally been used to calculate drivetrain loss may not be valid.

The fact that dyno pulls are done in the gear ratio that’s closest to 1:1 throws the math off.

i wonder is the SAE numbers are achieved with accessories on the motor, although those losses are minor compared to drivetrain.

arthursc2

iTrader: (5)

Sae is done with acc on motor, under varying conditions too. The J spec they test to has changed but it's not a static water braked dyno

bhp or "brake hp" is done with 0 acc; unfamiliar with the test conditions tho

got a grudge race and you think every last hp counts? Pop off the belt. Hotter motors make more power and you won't lose power spinning silly things like the w/p or p/s. If you can, run shorter tires on lighter wheels. Generally speaking disc brakes "make" more power than drums: less mass to spin up and eat up energy to spin

dyno= time. Reduce the time to accelerate the wheels=more power

1FastBrick

iTrader: (17)

On a Mustang Dyno, My Bone Stock 2000 5.3L put down a consistent 240 HP at the wheels with 120K Hard miles on it. The shop that dyno'd it, was also within 80 ft of sea level too.
On a DTS dyno I think it was 250 at the wheels.

I would think just about every dyno operator has dyno'd a similar stock vehicle for comparison at some point. Especially if they tune them for a living. If not, I would think they would at least want to show what it was putting down when it came in Vs what it was making after the changes.

letitsnow

This is what I would focus on...