Engine Performance

[RockyBob]

I know I'll start a firestorm of controversy, but I gotta say it: The only engine performance parameter that matters is horsepower, and specifically maximum horsepower available for any specific vehicle speed. Torque, which is often mentioned, is irrelevant. (Wait for the uproar to die down). Torque at the crankshaft is different than torque on the other side of a torque-converter, is different at the output of the transmission (and selected gear), and is different than torque out of the differential. Maximum horsepower is suggestive of better performance, but horsepower available at any vehicle speed is the best measure of pulling power. 400 horsepower at 4400 rpm isn't very useful when starting out from a stop if all that is available at 1500 rpm is 130 hp. 500 ft-lbs of torque from the crankshaft isn't useful if the final gear ratio through the differential 2.2 to 1. Automatic torque converters help startup primarily because they allow an engine to rev up to higher rpm = more horsepower.

All the talk about V6 vs. V8 and crankshaft torque misses the real point: given two vehicles of same weight with different engines, the vehicle with more pulling power at any given speed will be the one producing more horsepower at that speed. Torque alone, rpm alone, gear ratios are related but in the end it's available horsepower for a given vehicle speed.

Let the arguing begin.

[mmeyer]

So the 2018 2500 Dodge truck with a 5.7 l hemi at 383 hp is a better tug than the 370 hp Cummins turbo diesel?

[Steve L.]

Originally Posted by RockyBob

Let the arguing begin.

Let's not.

[FRED SMAILES]

Please state your knowledge base, where can I read that will confirm what you say?

[Justus C]

Originally Posted by Steve L.

Let's not.

Nothing to see here folks! Don't take the bait that has been clearly identified as bait.

[Raspy]

Originally Posted by Steve L.

Let's not.

Exactly.

I don't see the point of the original premise, much less want to argue about it.

[Glenn Baglo]

Originally Posted by Raspy

Exactly.

I don't see the point of the original premise, much less want to argue about it.

And so it starts.

[Raspy]

Originally Posted by Glenn Baglo

And so it starts.

And gets ramped up further.

[Iowa Dave]

Can’t fix stupid
Iowa Dave

[Raspy]

I'm busy holding my tongue as the horsepower "experts" share their views.

Now, I'm biting it to keep quiet! Chomp chomp, ouch!

[Cliff Hotchkiss]

Originally Posted by Iowa Dave

Can’t fix stupid
Iowa Dave

👍 Yah think😂

[Alf S.]

Originally Posted by Iowa Dave

Can’t fix stupid
Iowa Dave

Hi: Iowa Dave... FWIW...Thork's thowe thare whou phull thep howl aphter whou phit tit!!! (Thounge in phcheque)
Alf S. North shore of Lake Erie

[steve dunham]

Originally Posted by Alf S.

Hi: Iowa Dave... FWIW...Thork's thowe thare whou phull thep howl aphter whou phit tit!!! (Thounge in phcheque)
Alf S. North shore of Lake Erie

Thank you ; finally a post that makes sense

[Jon in AZ]

https://www.youtube.com/watch?v=XaWU1CmrJNc

[Johnny M]

Tell this to the farmers gathered around the feed n seed any Saturday morning and you will be laughed out of the town. Tractors of relatively low hp can pull far more times in weight than much higher horsepower auto tows, albeit the tractor will be relatively slow in comparison it will out pull the auto all day long.

[Civilguy]

HP = Torque x RPM ÷ 5252

There, that's settled.

What else have we got on the menu for this morning?

[Alf S.]

Originally Posted by Civilguy

HP = Torque x RPM ÷ 5252

There, that's settled.

What else have we got on the menu for this morning?

Hi: Civilguy... As the "Clown of Denmark" would say " Phitts~~~ pubt, pubt, pubt.
Alf S. North shore of Lake Erie

[Len S]

Originally Posted by Johnny M

Tell this to the farmers gathered around the feed n seed any Saturday morning and you will be laughed out of the town. Tractors of relatively low hp can pull far more times in weight than much higher horsepower auto tows, albeit the tractor will be relatively slow in comparison it will out pull the auto all day long.

Love the answer and the best comparison yet. The big thing on selecting a motor for the job is looking at the hp, torque and at what revs. The higher the torque at the lower the revs is going to be the better “stump puller”.

[FlyGuy]

Horsepower gets you up to speed.



Torque keeps you at that speed.



Using statistics, you can game any number.

[Losthwy]

"Torque, which is often mentioned, is irrelevant".

A quick Goggle search and a little reading will show that statement is incorrect.