Horsepower question

[Bwana Bob]

According to the sales brochure, my '92 XLT with the manual transmission and 4.0 L OHV engine makes 145 hp and the automatic makes 155 hp. Why the difference?

Now I think the Ford Escape with the 2.3 L engine is probably underpowered, even with the manual trans, but the 2.3 is rated at 153 hp, more than my Explorer! The 3.0 L Ford engine is rated at 200 hp, lots more than my 4.0L OHV.

Granted, the Ex engine has lots more torque at the low end and an OHC engine squeezes out more hp than an OHV, but what does this all mean and what is the tradeoff?


Thanks.

Bob

 

[Interstate]

I think it's cause they're newer vehicles, the have very different powerbands, the rev higher, several other factors too. I think you'll have to wait for someone who knows the technical aspects of those engines for a detailed answer.

I know my 02 DOHC (I think that's what it is) is rated at 210hp, and close to 200lbft. Both below 4000 revs. I'd be willing to bet that those engines you listed make it at or just about 4000.

 

[monkeydude3]

yeah, pretty much as time goes on we get more and more horsepower and efficiency out of the same size block. I'm studying engines in my auto class, and the newer ones have more compression, improved valve timing, improved ignition timing, improved intake and exhaust manifolds, improved computers... the 4.0L overhead cam engines are interference engines which means very close and accurate valve timing that depends on the timing belt.... a direct comparison between the 4.0L OHV and the 4.0L OHC illustrates this, the ohc has more horsepower and fuel economy... take care