[ZDan]

Originally Posted by Jawnathin

There is a problem with your one dimensional approach to performance.

I develop vehicle performance models as part of my job. Currently doing all structural and drivetrain development for a vehicle for Daimler and am responsible for defining drivetrain performance characteristics and requirements for future projects.
I've also modeled the acceleration performance of my LS2 FD (including power curve, aero drag, rolling resistance, tire slip, tire growth, shift times, etc.) and predicted its standing 1-mile performance within 1mph (184 predicted, 184.8 actual).
I do not take a 1-d approach to vehicle performance modeling professionally or for my own personal vehicles.

I'm just pointing out in this thread that power/weight is not meaningless and does pretty well define basic vehicle performance, much better than misused/abused concepts like "power under the curve". For outright performance, the FA20 *is* inferior to the F20C (or F22C). Personally, for street usage, I don't find this to be a big deal, but for me the car *would* be cooler if its 2-liter engine revved to 9000rpm and made 240hp.

Peak power is just that, peak power. The amount of power the engine can make on its way to peak power is arguably more important than the peak number itself.

The way the f20c makes power is actually pretty similar to the way the FA20 does. They both have somewhat "peaky" powerbands, with peak power just short of redline. 7000/7400 for the FA, 8300/9000 for the f20c. What happens along the way is a little bit different, but not hugely so. The FA has the torque dip at 4000, the F20C has the VTEC discontinuity at 6000 (which would have been eliminated if they'd gotten the crossover rpm right, should have been set to the rpm where torque/power were the same on both sets of cam lobes, ~5000rpm).

There is a reason why people shit on peaky powerbands and prefer a flatter broader power curve. If you've ever driven a car with torque, maybe you'd understand that.

My daily FD makes more than 3x the torque of the FR-S/BRZ or the s2000. ~500 lb-ft/545hp. So yeah, I understand "moar torques".

And in my example, it wasn't about an FA20 or F20C, it was about the concept of power under the curve. So I'll ask again, do you prefer less power or more power at a given RPM?

What's with your fixation on "a given rpm"? You drive different engines differently. I don't shift my 2.0/9000rpm S2000 at the same points I shift in my 6.0/7000rpm RX-7, that would be absurd.

People act like there's something inherently difficult about revving out an engine that likes to rev. I don't get that.

A more appropriate question would be "do you prefer less power at a given *road speed*". To which I'd say "hell no!" And the S2000 will have more power on tap at any given road speed vs. the FR-S/BRZ.

If you can't see the benefit of having a stronger powerband earlier in the revs, you're only highlighting your inexperience.

I've been around a bunch of different tracks in dozens of different cars with very different drivetrains and won 6 time trial championships along the way. I'm not a professional race car driver or anything, but I do have more experience than most on road car forums. And probably ~half a million street miles? Something like that.

My current daily drivers are a totally stock S2000 and the aforementioned 6.0 liter 545hp FD RX-7. And you know what? On the street, I don't find the S2000's powerplant to be any less driveable.

There are plenty of situations where a downshift isn't going to be reasonable or the quickest way.

I don't usually put myself in positions where I have to go from low-rpm cruise to maximum acceleration in an instant.

Downshifts and upshifts take time. If you have a flexible powerband, you can stay in gear. If you can stay in gear, time can be saved. The fact of the matter is, more power is better than less power at a given RPM and that is why the power under the curve is very important.

Get over "at a given rpm". You drive different engines differently. If you can't drive a 9000rpm 240hp differently than you drive a 7400rpm 200hp engine, then you are doing it wrong.

It is irrelevant that the FA makes more torque "at a given rpm", because I'm generally going to be keeping the F20C spinning ~20% higher and hence have greater torque available *at the drive wheels* (you know, where it COUNTS) *at all times*.

This is ironic. You bash the dip (in which the FA20 still has greater output) yet justify the lack of low end on the F20C due to your driving style. Fair enough.
But hey, guess what? I could argue the very same exact point that the dip is avoided in regular driving and when driving competitively because you're either down low or revving it out.

It *is* "fair enough". The dip *is* an annoying feature, just like the VTEC bump is an annoying feature on the F20C. If I'm tooling around town, I'd honestly probably never encounter either on a regular basis, so really, for a street car, not a huge deal. At the track, I'm over 6000rpm in the S2000 100% of the time, so the VTEC crossover is nonexistent. In the FR-S/BRZ, I'm sure I'd be above 4500 (or whatever) most of the time as well, so no biggie there either.

The undesirable points of either powertrain are avoidable, but if I do need to speed up on the street, I can go all the way to 6000rpm with the S2000 without running into any weirdness, and above that it only pulls harder. whereas in the FR-S/BRZ I'm going to get a big lull right where I would like for it to start pulling.

But I'm not going to make excuses for the dip. Why? Because I understand the value of a broad powerband and the engine would be better with out it. Just like how an F20C would be much better if it had a flatter and broader powerband.

Neither the FA20 nor the f20C have broad/flat POWERbands. In fact, having a flat powerband just means your engine can't breathe at elevated rpm.
What you must be talking about is a flat TORQUE curve. Which *IS* very nice. The F20C has two of these, one from ~3k to 6k, another from 6k-9k (it does trail off a bit above 8k, but peak power is at 8300 and it's still making useful torque and more importantly POWER at 9000).

For the record, comparing an FA20 vs F20C is irrelevant to the point being made. My position is that a broader powerband is better and you seem to have a hard time understanding that.

I fully appreciate a broad TORQUE band. A broad POWERband just means torque is falling off as quickly as rpm is rising. A RISING powerband is what you get with a broad flat TORQUE curve.

And if we were to compare engines, I'm not trying to say one engine is better than the other. I see both sides of the coin for both engines, both have their strengths and weaknesses.

As do I...

I respect the F20C for its high revs, but in actuality it doesn't make much power up top and it is lethargic down low. By somehow suggesting a narrow powerband isn't an issue because only peak power matters reeks of typical S2000/JDM fanboyism.

It makes good power up top, and if you find it "lethargic" down low it's because you aren't driving it properly. It does make less torque below 6000rpm than the FR-S/BRZ, but all you have to do is keep the revs ~10-20% higher and this is MORE than compensated for.

FWIW, I like the S2000, a few close friends own one or have owned one. I've driven many on multiple occasions. I crossed shopped an S2000 before buying the BRZ (just last week). I decided that while an S2000 would be a better performance car stock, it wasn't fast enough to make up for the rest of its compromises.

Same here. I would prefer a 2+2 coupe and would have bought an RX-8 but for its abysmal fuel mileage.

Your statement doesn't make any sense here. One statement says it doesn't make more power under the curve (in which it does), then you say it makes more torque. Which is it? lol

Look at the power curves for both engines. Then tell me with a straight face which one has more area under the power curve. It's not even close.
Torque is not power. Torque is a means to make power, but power is more important than torque because torque by itself doesn't tell the whole story.
FA20 makes more torque down low, yes. But this is not the same as "more power under the curve".

The funny thing is that as much as you're touting the FA20 as some kind of low-end stump-puller, it actually is pretty peaky. The nice broad/flat torque curve above 4500 gives peak power at 7000rpm, just 400 short of redline/rev limit. Similarly, the F20C's broad/flat torque curve above 6000 gives it peak power at 8300rpm, 700rpm short of its redline.

The engines are pretty similar in terms of how they make power vs their rev limits, the MAJOR difference being the F20C's huge rpm advantage, which gives it a big power advantage.

A high 14 vs a low 14 isn't 'significantly' different. That kind of delta in a low ET would be great (10s, 11s), but with such high ETs, it is pretty minor. The fact that both cars trap in the mid-90s suggests that they aren't that far off.

S2000 traps in the 100/101 range, FR-S/BRZ ~94/95. That's a pretty big difference.

Both are slow but one is far better to live with.

I'm pretty jaded, but to me 14-flat/100mph is not what I'd call "slow" for a street car. But 14.5/95mph is :P (j/k)