[94cobra69ss396]

Popular Hot Rodding did the same thing with their project Chevelle and saw a 28% loss at the wheels. Their 496 made 626hp at the flywheel but only put down 448 at the wheels through a TH400. It made me feel good when they only made 448rwhp because my Chevelle put down 461rwhp with the 454 and my cars drivetrain is set up almost identical to theirs. When I built the engine I figured it would make about 620hp so it looks like I made a little more. Plus their best time so far has been 11.30 at 117 and mine on the engine has been 11.07 at 121.

[Vettezuki]

Originally Posted by 94cobra69ss396

Popular Hot Rodding did the same thing with their project Chevelle and saw a 28% loss at the wheels. Their 496 made 626hp at the flywheel but only put down 448 at the wheels through a TH400. It made me feel good when they only made 448rwhp because my Chevelle put down 461rwhp with the 454 and my cars drivetrain is set up almost identical to theirs. When I built the engine I figured it would make about 620hp so it looks like I made a little more. Plus their best time so far has been 11.30 at 117 and mine on the engine has been 11.07 at 121.

That's AT though right? That would certainly be a bit higher.

[94cobra69ss396]

Originally Posted by Vettezuki

That's AT though right? That would certainly be a bit higher.

Yes. The TH400 is the turbo 400. It's stronger than the TH350 but also takes more hp to turn.

[jedhead]

Unless my STS-V is a factory freak or the dyno is reading high, I only had a 17.5% driveline loss based on rated 469hp with 387whp on the dyno. I had an 18% loss on my Taurus SHO with a manual.

Bob

[94cobra69ss396]

Originally Posted by jedhead

Unless my STS-V is a factory freak or the dyno is reading high, I only had a 17.5% driveline loss based on rated 469hp with 387whp on the dyno. I had an 18% loss on my Taurus SHO with a manual.

Bob

Yes but you have to remember that those flywheel numbers are SAE net numbers. That means the engine was tested with all belt-driven accessories, air cleaner, emission controls and a complete exhaust. Whereas the 496 for example was tested with open headers and an electric water pump only.

[Vettezuki]

Originally Posted by jedhead

Unless my STS-V is a factory freak or the dyno is reading high, I only had a 17.5% driveline loss based on rated 469hp with 387whp on the dyno. I had an 18% loss on my Taurus SHO with a manual.

Bob

This is more of what I typically expect. I wonder if the older cars have more loss through the old diffs and heavy axle/half shafts + u-joints.

[94cobra69ss396]

Possibly. I know that there is no way the Cobra is making 600+ at the flywheel which is what it would be with a 25% loss. I figure it to be closer to 520-540 which would be about 15% on the race gas tune.

[enkeivette]

Originally Posted by 94cobra69ss396

Popular Hot Rodding did the same thing with their project Chevelle and saw a 28% loss at the wheels. Their 496 made 626hp at the flywheel but only put down 448 at the wheels through a TH400. It made me feel good when they only made 448rwhp because my Chevelle put down 461rwhp with the 454 and my cars drivetrain is set up almost identical to theirs. When I built the engine I figured it would make about 620hp so it looks like I made a little more. Plus their best time so far has been 11.30 at 117 and mine on the engine has been 11.07 at 121.

That's pretty crazy, I wouldn't expect anymore than 20% with an auto through a solid axle. I can only imagine how much the Vettes eat up through a auto with the IRS. It must be in the 30% range.

[enkeivette]

But Ron brings up a good point. We are counting total loss of hp, not just drivetrain loss. If the motor was tested on the engine dyno with accessories and a full exhaust it wouldn't have lost that much just through just the drivetrain.

[Vettezuki]

Originally Posted by enkeivette

But Ron brings up a good point. We are counting total loss of hp, not just drivetrain loss. If the motor was tested on the engine dyno with accessories and a full exhaust it wouldn't have lost that much just through just the drivetrain.

Oh I misunderstood his test. I thought he had the engine fully dressed on the engine dyno and was measuring a 23% loss through the driveline alone basically. Let's say a more expected driveline loss is around 17% +- 1~%. That means there's something like an additional 5% from the accessories and exhaust. That's totally believable.