[ZDan]

Originally Posted by Jawnathin

Power under the curve represents of the engine output over the entirety of its operating range.

F20C average from 2500-9000rpm = 135rwhp (using the 202 peak rwhp curve above). FA20 average from 2500-7400rpm = 121rwhp (using the 173 peak rwhp curve above).

y your definition the engine with less peak power is inferior despite romping on the other everywhere else in the power band because only peak power matters.

I have never said or implied that.

Of course the power curve matters. But the FA20 and F20C power curves are *similar enough* that peak power does a good job of indicating performance.

Ancient equation for peak hp from 1/4-mile trap speed (aka "ricer math" in recent decades...):
hp = (trap speed/234)^3 * weight
FRS/BRZ: (95/234)^3 * (2750 lb. +200 lb.) = 197 hp
AP1 S2k: (100/234)^3 * (2800 lb. +200 lb.) = 234hp

Is your car always at a MPH/RPM where it makes peak power? No?

Of course not. But my S2000 *is* always at a much higher rpm range toodling around town than the LS2 car. I drive in the rpm range that gives me the oomph I need for what I'm doing. In the S2000, that rpm range would be a bit higher than in the FR-S/BRZ. I don't see the big deal here.

A broader power band gives the engine and driver flexibility.

FA20 powerband is not broader than F20C's. F20C engine is supremely flexible, btw. Totally happy ~2000-6000rpm around town, totally happy 6000-9000rpm at the track.

The fact the F20C needs to be revved out to get anywhere is why it has such poor fuel economy.

It is geared lower overall, and they kept 6th low as well. It could have handled taller gearing, but that didn't fit with its mission. FRZ twins get better mileage primarily due to DI and far better aero, though.

There is no way an F20C is as driveable around the street as a 545hp LS2.

It is MORE driveable, but that's partly due to a tuning issue. Cam surge makes it lurch at low rpm low load, total PITA. Also, the clutch is much heavier and shifting is more of a chore. The S2000 is a much easier car to drive around town.

I've got a 560~whp C6Z and even with its crazy tall gearing, it can pull strongly from nearly any rpm in every gear. You can do something silly and try to go WOT at 800rpm in 6th, but anything reasonable and it pulls quite well. Even if I never taking it above 3k RPM I can accelerate quicker than most traffic.

I know the feeling But still, when I know I need to accelerate in the S2000, I keep the revs up. No biggie. I am practically never in a situation where I go from just cruising to WOT randomly, and in any case downshifting the s2k trans is more of a snick-snick joy than a CHUNK-CHUNK chore.

And because of that torque, the car can be geared super tall and have excellent fuel economy. I get close to 30mpg on the highway vs 24mpg for the AP1 S2000. under the same conditions in the S2000. Hell, its even better in the city too. Who would have guessed that a 7.0L V8 would be more fuel efficient than a 2.0L 4 cylinder?

I've gotten 29mpg max highway in the LS2 RX-7. Usually more like 25. And in town, 15 or less. With vastly inferior aero, I've gotten 31-32mpg max hwy in the S2k, usually more like 27, and easily get 20-22 in town. I don't know how or why some people manage to get crappy mileage in the S2000...

So you never exit a corner at an RPM less than peak power?

Where'd I ever say/imply that?

I find that interesting, I hear S2000s fall in and out of VTEC all the time at the local autocrosses. Clearly they're doing it wrong and you should come teach them how its done.

Must be stock AP2s. Big difference between 6000-8000rpm powerband vs. 6000-9000. Anyway, autoX bores me, never done one in the s2000.

For the 10th time, my position is about power under the curve in general, a 'misused concept'. Not specific to FA20 vs F20C. And even then, that is not true. There are certain speeds that despite the shorter gearing and higher revs, the F20C doesn't make as much torque to the wheels as an FA20. Look at 25~mph @ 2nd gear for both cars as an example. BRZ should be around 3000rpm and the AP1 @ 3200rpm.

And by the time you reach 30, they're even again as the FA20 goes into its midrange hole.

This pretty much happens in any gear/mph with the FA20 @ 3k rpm, which is where the car likes to sit and cruise around in. Pretty much where the car sits 90% of the time.

On the street, driving semi-speedily, I find myself around 4000, and cruise at 75mph on the highway is 4100rpm. If you drove an S2000 every day, you would be driving it at higher revs more of the time, and you'd do this without even thinking about it. Key difference: if I get on it from 4000, I basically never lose torque. If you get on it in the FR-S/BRZ from 3000, you get decent torque, then it drops off significantly, then comes back. Not ideal, possibly annoying, would either get used to it or hate it more and more over time, I think.

Uh, just look at the dyno plot? At what point under 6000rpm is the F20C making more power?

If we're limiting both engines to less than 6000rpm, yeah, the FA20 has "more power under the curve". But that's an odd stipulation to make when the real power from both engines is somewhat north of 6000rpm... Power under the curve: F20C has a TON more, but tie one hand behind its back, and yeah, it loses.

Both motors are peaky. The FA20 is just stronger down low and in RPMs suited for street driving.

"RPMs suited for street driving" is not a constant from car to car.

The point is that despite whatever bickering that goes on in this thread, is that they're not worlds apart. Neither car is slow but neither are quick.

OK, agreed

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