Hi Y'all,
Have a '97 4-RNR, 2.7 L, modified air box, headers, 33" BFGs, 4.88 rear end gears and 2" lift.
Had the truck dyno'd the other day and it came back with 118 HP
and 145 torque. From what I was able to dig up, original horsepower
was 150. My question is... was that at the crank or the rear wheels?
If it was at the rear wheels, where did 32 horses go? The vehicle has
been well maintained and well used off road. Any comments or
suggestions would be greatly appreciated.

Art

 

What was your stock tire size and gear ratio?

 

Your numbers sound about right, manufacturer's numbers pretty much always refer to hp at the crank as opposed to the rear wheels. This is the case w/ Toyota, so the truck never had 150hp at the rear wheels.

 

Yes the HP numbers always refer to crank HP not RWHP, which is real world numbers. It is likely that your drivetrain might be eating up alot of the HP to drive those big 33" tires of yours (esp at higher RPMs). I'd bet going down in tire size, you'd see some of that HP return.

 

Thanks for all your responses. I don't feel too bad now knowing the HP rating
is off the crank and not the rear wheels. Yes, I know that the big tires and
possibly the gear change contributed to it, but the tires are a must in the
sand... Thanks again.
Art