Back in my day we rated our gas motor hp at the flywheel.

Everything we do with our diesels seems to be rwhp. When our trucks are new it has a rating of say 325/610. Is this also a rwhp?

If we measure our trucks at rwhp, what does that make flywheel hp rating at?

Also, I was talking to a high hp diesel builder the other day and he said he won't do dyno runs anymore, as he always blows head gaskets on the dyne but not the track. I didn't want to ask him why and sound like an idiot, so I thought I'd ask here and sound like an idiot. LOL

1 more question, when we add our performance dl's or boxes etc, are they rating the hp increase as a rwhp?

Thanks to all.

Always remember 9/11.

 

they are rated at the motor ,Stock they are around 265 rwh-for the 600.

 

At one point this was something that was debated a lot!

Here is the simple truth and you can make what you want of it.

The fact is that what we should all be quoting is a horsepower gain. It does not matter where it is measured at. A 100hp gain is a 100hp gain. You can play all of the driveline loss games you want but a 100hp is 100hp. So if you buy something that makes a 100hp gain and your truck makes 325 stock then you should have 425 engine horsepower. IF that truck make 260 as measure at the rear wheel then it should also make 370hp at the wheel with the power adder.

You cannot take a 100hp gain and add 10-20% for drivetrain loss and then figure you added 120hp to the engine. A gain is a gain no matter where it is measured.

 

The new vehicle mfrs measure at the flywheel because it makes it sound like more power. The diesel aftermarket pretty much all measure their gains at the wheels. As Qzilla said, it's what you make at the wheels that matters. Mine made around 190 rwhp when it was stock. Now I'm at 500 rwhp. I guess factoring in drivetrain losses probably puts me at around 600hp at the flywheel but it's what's on the dyno sheet that matters. Kind of like the difference between saying your truck will run a 12 second 1/4 mile and having a timeslip to prove it..