Low Torque @ High RPM VS High Torque @ Low RPM
 

The FRS has


151 ft/lb @ 6400 RPM






How would you compare this if we had a 200 ft/lb @ 3000 RPM


In other words, Low Torque @ High RPM VS High Torque @ Low RPM

HP = (Tq * RPM) / 5252

You'd have 114HP there.

Then BMW has 241hp
The frs has 200 hp


BMW has 200 Ft-lb @ 3500 rpm
Whereas frs has 151 @ 7000 rpm


I'm confused

Those are peak values.

The BMW doesn't produce 241hp at 3500, it produces 133 hp when you hit peak torque at 3500

High torque at all rpm, thanks.

and high RPM range

Your FRS only has 200 HP at around 7000 RPM, it has less anywhere else.

Torque is how much rotational force the engine is outputting.

This changes drastically along the RPM range of any engine. Mainly because of how quickly the air can enter the engine and how quick the combustion burns.

If you want to have an engine with high RPM power, you want to try to keep the torque output good near the redline, if you want the engine to have "low end torque", you try to make the torque curve fat in the low RPM (long stroke specs. gives good torque, but limits the high RPM potential due to piston speeds). If you want good torque in the low and the high RPM, that's where you start needing variable cam timing, ignition timing, and everything else that is "variable".

Or you can do it the american way, and just make a very big displacement engine, then you have gobs of torque everywhere even with 2 valves per cylinder.

Take a look at this stock FR-S dyno:

http://www.tune86.com/sites/default/...n-frs-dyno.jpg

The solid red line is torque (in lbs-ft) and the dotted line is horsepower to the wheels.

Let's take it in 1000 RPM increments.

At 3000 RPM, you have 140 tq. Using the formula LuisGT posted [HP = (Tq * RPM) / 5252], you have: 140 lbs-ft x 3000 rpm / 5252 = 80 hp.

RPM - TQ - HP
3000 - 140 - 80
4000 - 122 - 93
5000 - 139 - 132
6000 - 140 - 160
7000 - 130 - 173

You can see that peak hp is 173 hp (to the wheels) at 7000 rpm. Assume 13.5% drivetrain loss and you have the manufacturer's rating of 200 hp to the crank (200 hp - [.135 x 200] = 173 whp)

High torque at low rpm is for trucks and drag cars.

High revving cars are for twisties.

To each their own.

:burnrubber:

Drag cars spend little time at low RPM. You've got to rev them pretty high to get the most out of those big lift, big overlap cams they put in them.

:threadjacked:
What's the point in having high end torque? Would'nt you rather have low end torque for quicker starts?

Why would one say high revving engines be better for twisties?

Sorry for the noob questions

fcuking Newtonian physics, how does it work?

Drag racing engines are revvers optimized for max power up top, even more so than roadracing engines which have to be tractable over a broader rpm range.

High end torque means more max power lol.

I don't think there's a really good reason for high revving engines in twisties, they tend to have higher power density but for most people I think it's the fact that an engine that can spin faster than the engines in most cars on the road is cooler, and makes it have better noises.