Torque rating for newer vs older engines

[jlshields]

Newer V8s their max torque measured as high as 4600 rpm. My old ('96) Ford 5.8 has it's torque measured at 2800 rpm.<br />Would the Old Darlin' show higher torque if measured at 4600? She does fine the way she is, I was just wondering.

 

[bandit86]

Re: Torque rating for newer vs older engines

stroker engines, as in engines where the bore is smaller then the piston overall travel, like to rev lower, but because the extra leverage, they tend to produce more torque. The opposite, engines with large bore pistons, they like to rev to high rpms, but produce less torque. It's a different engine design all together<br /><br />In the end, torque is what is important, I like mine nice and low and constant. Horsepower is a formula of HP=(TxRPM)/5252 so you would get higher hp at higher rpm, but generally the manufacturer listed the peak torque availible at the rpm they posted, higher rpm will just have it taper off

 

[TilliamWe]

Re: Torque rating for newer vs older engines

Originally posted by jlshields:<br /> Newer V8s their max torque measured as high as 4600 rpm. My old ('96) Ford 5.8 has it's torque measured at 2800 rpm.<br />Would the Old Darlin' show higher torque if measured at 4600? She does fine the way she is, I was just wondering.

No that torque was measured at it's peak. So at 4600rpm the torque is almost certainly much lower. Just like the newer engine, if you measure it's torque at 5000rpm, it'll be lower than it is at that 4600 you mention.<br />But you have touched upon my biggest gripe about 4.6 & 5.4 Fords and 5.3 & 6.0 Chevies, the torque number is a "big" one, but you have to scream them. Not my idea of a good way to run an engine.

 

[KM2]

Re: Torque rating for newer vs older engines

What a second, the 5.4 Ford triton motor is rated a 350ft lbs at 2500 rpms.

 

[KM2]

Re: Torque rating for newer vs older engines

The new Fords with 3 valves peak torque is at 3200 rpms. (5.4l 365ftlbs) So it's a little higher but not screaming. I would love to see a chart, I bet it's fairly flat curve.

 

[TilliamWe]

Re: Torque rating for newer vs older engines

I may have unfairly lumped the 5.4 in there. My Ford knowledge is not high, as I have never owned, nor will own one, at least not with a 4.6 or a 5.4. I'll bet the curve on the 3 valve is "less flat" than it was on the 2 valve engines. But you can make any graph look peaky or flat, just change the numbers on the side and the bottom!

 

[JB]

Re: Torque rating for newer vs older engines

Actually, TW, modern engines have remarkably flat torque curves compared to most flathead and pushrod engines.<br /><br />Advanced tuning of intake and exhaust paths, OHCs, multivalves, computer control of EFI and ignition and even variable valve timing all contribute to optimizing torque at a wide range of rpm.<br /><br />My 4.3 liter V8 peaks torque at 3500rpm but has 80% of that torque from about 1500 to about 5000rpm. About 300hp from 262 cubic inches. Sounds sweet at 6800rpm.

 

[QC]

Re: Torque rating for newer vs older engines

Every number matters, torque, RPM, horsepower etc. You cannot seperate them and you shouldn't. If geared correctly an engine that makes 300 lb/ft. @ 2500 RPM and one that makes 150 lb/ft. @ 5000 RPM could have the same torque at the wheels (and those examples both make exactly the same horsepower, 142).<br /><br />There is no good way or bad way to run all engines. There are good ways and bad ways to run each engine. They are all different and all designed to accomplish different things . . . <br /><br />High torque rise engines "feel" the strongest, but are not necessarily so. Torque rise is the difference between torque at peak torque and torque at max rated RPM and is expressed as a percentage. Soooo that old engine with a high number at low RPM and comparably lower horsepower at the highest RPM (corresponding low torque number) would have the highest torque rise percentage. When you hit a hill and don't downshift, the higher peak torque engine will feel stronger as it maintains horspeower better as RPM drops. However, JB's example with a "flatter" torque curve would actually get more work done if geared properly. With a simple downshift it could walk away from the other example . . .