Engine ratings....bhp or whp?

Brake horse power.

By the time you pay the transmission, alternator, water pump etc etc etc wheel HP will be less.

Generally for a 500 it comes out to 280 or so HP at the tire. More or less.

 

Yep, always flywheel horse power. It's never wheel end due to all the different driveline combinations.

 

A lot higher than that. We dyno'd a DDEC 4 rated at 500 hp and it was throwing 410 to the ground.

 

That's pretty good.

I wonder if it maintained or increased the HP at torque and high horse on the curve somewhere in there or did you measure it at high horse?

 

A good running 550 cat will put down 480-490 on the wheels stock.

So yes. Factory ratings are fwhp.

When you get a tune then that' is differnt .A lot guys base there horse power at the wheels. My Haney tuned 2ws is at 620rwhp.
My rebel tuned 14L ddec4 is about the same maybe a touch more.

 

No idea. This was back in '99 or 2000. All I remember was its peak HP was 410 at the wheels.

 

Electronic engines may have changed things, but Cat used to fuel you up til your 425 put 425 to the tire as soon as you had your first valve set. That's why a 3406 325hp fuel saver would walk away from a 400 Cummins. The best running NTC 400 i ever had put 318 to the tire and Cummins wouldn't touch it. Said it was in spec. Macks were rwhp rated too.

 

Cummins is a one RPM engine. I bet it will burn less fuel for a given distance than that kitty if all is equal.

Ultimately the more horse you have availible at the wheel at cruise somewhere between torque and high horse will burn less fuel. It's hard to explain.

A 350 Mack made in the 90's would run Town Hill loaded upgrade (Near breezewood PA) at about 43 or so while a 350 cummins carried about 21 mph on the same hill. (Mack transmission had shorter legs where you could sort of step into the higher gears and stay in them...) So it's worth the time savings.