Scion FR-S dyno by Insideline = 173 whp @ 7000 RPM, 143 lb-ft @ 2800 RPM

[ZDan]

Copying what I wrote in the FR-S thread:

Dip is a function of cam and tuning for max power at 7000. Tune for 7000 rpm peak and apparently you get anti-tuning at ~half that. I have (had) the same dip on my tweaked 240z 3.1. Doesn't matter what you do with the fuel maps and ignition timing if the engine simiply isn't breathing well at that rpm.

[OrbitalEllipses]

Originally Posted by Hanzo

Cayman R has the same dip on the curve wonder if it's something to do with the flat engine. Here is the chart, it's on page 17: http://files.porsche.com/filestore.a...ault&version=3

On NASIOC, the dip was attributed to intake manifold design. Wonder if people are replacing intake manifolds on their Caymans to any effect. Likely a combination of that and what ZDan is saying, though I can't claim any verity on the intake manifold statement.

[Spaceywilly]

Originally Posted by Lighting Red

Yeah, that dip between 3500 and 4500 (roughly) is going to feel like quite a pause during acceleration.

It will be easy to avoid it. You will be above or below it most of the time. In normal driving you would shift around 3000RPMS so you wouldn't reach the dip, and when you're trying to accelerate you would be shifting close to redline so you will stay above the dip.



I like this comment on the Insideline article:

firstwagon says:
08:58 PM, 04/10/12
If you're buying an engine... GTI
If you're buying a car... FR-S

[tripjammer]

Sounds like the torque in this engine is underrated. Nice!

[tripjammer]

Originally Posted by Hanzo

Cayman R has the same dip on the curve wonder if it's something to do with the flat engine. Here is the chart, it's on page 17: http://files.porsche.com/filestore.a...ault&version=3

that is not much of a dip in the Cayman R...but yeah, it could have something to do with the flat engine or more likely the DI\and port injected heads...

[BMWDavid]

Remember that Porsche has variable cam timing as well as a second set of cam lobes that give greater lift at some higher rpm transistion point. So they could tune the base cam lobes for a smoother torque curve at lower rpm.

[brianbot5000]

Two things... I'm sure they dyno'd the engine during development - why didn't they fix the dip in the torque curve?

Also, this looks great, and it's nice to know the BRZ will have about +5 on both of those curves, just due to the Subaru badges and more realistic looking fender vent.

[Draco-REX]

If the dip is due to the manifold tuning, then it would make sense. Intake manifolds are designed to resonate like a musical instrument. The goal is, at the target RPM, the air vibrating back and forth in the runners is timed perfectly to force more air into the engine. If the FA20's intake manifold is designed that way, then it's conceivable that at half the frequency the resonance would be on the back swing, which would hinder air from entering the engine.

Granted, this is with just an armchair engineer's understanding of vibrational frequencies in a moving fluid. But the theory makes sense.

[Longhorn248]

Originally Posted by brianbot5000

Two things... I'm sure they dyno'd the engine during development - why didn't they fix the dip in the torque curve?

Also, this looks great, and it's nice to know the BRZ will have about +5 on both of those curves, just due to the Subaru badges and more realistic looking fender vent.

Haha

Don't forget the color of the car has a direct impact on horsepower as well.

[SUB-FT86]

Damn that Cayman R has a shitty torque band below 5k. I thought it was going to be nice and flat.

[ZDan]

Originally Posted by SUB-FT86

Damn that Cayman R has a shitty torque band below 5k. I thought it was going to be nice and flat.

It's not as bad as it looks, the torque scale starts at 147, not 0.
Worth noting, where the curve starts at 1500rpm, the Cayman is making ~25% more than FR-S/BRZ *PEAK* torque.

I want a Cayman R, in that snot green color...

[linkwpc]

I wonder what would a turbo do for this motor. It would it get over 250hp?

[Hanzo]

Originally Posted by ZDan

It's not as bad as it looks, the torque scale starts at 147, not 0.
Worth noting, where the curve starts at 1500rpm, the Cayman is making ~25% more than FR-S/BRZ *PEAK* torque.

I want a Cayman R, in that snot green color...

Also keep in mind that Cayman R's chart is based on fly wheel not at the wheels.

[Spaceywilly]

Originally Posted by ZDan

It's not as bad as it looks, the torque scale starts at 147, not 0.
Worth noting, where the curve starts at 1500rpm, the Cayman is making ~25% more than FR-S/BRZ *PEAK* torque.

I want a Cayman R, in that snot green color...

25% more torque for 160% more dollars