BRZ / FR-S Boxer Engine Dyno Powerband revealed

[old greg]

Originally Posted by ahausheer

why do F1 cars have basically no torque...?

Because they are required to be 2.4L, duh.

In torque-centric terms, the high rpms at which F1 motors operate allow a relatively large gear reduction and fairly significant torque at the wheels.

Please ignore the fact that I'm saying Torque x RPM is what matters.

[Dimman]

Anyone want to overlay some rpm drop by gear over this graph? Throw in some wheel torque figures by gear too?

[old greg]

Did we get gear ratio info while I wasn't looking?

[Dimman]

Originally Posted by old greg

Did we get gear ratio info while I wasn't looking?

Japanese brochures I thought. I remember seeing for sure the two different diff ratios (stripper JDM gets like a 3.73:1, while the rest are 4.10:1, I think...).

Edit:

[serialk11r]

Yea, I almost have them memorized already rofl. 4.1f/d (or 3.727 non-lsd), 3.626, 2.188, 1.541, 1.213 (had to look these two up), 1.000, 0.767. Wheel is 24.6 inches I think. Okay 24.61 or 625mm.

[SUB-FT86]

Originally Posted by Exage

This was already answered with the bike question I believe.

Power = Force X Distance / Time

HP is roughly calculated with: Torque x Rpm / 5252

5252 is some conversion factor I don't have the heart to research right now.

Speed of the engine torque is applied at gives you the amount of power the engine is producing at RPM.

Something like 10m (~33ft) cable with a 10kg (~22lbs) weight attached, and you have a spool/drum to do a vertical lift. I'm in metric sorry for those who use the imperial.

The force is 10kg x 9.81m/s2 (gravity), distance 10m. Two electric motors lift the weight up vertically. One motor takes 20 seconds the other 30 seconds. They didn't do the same work despite delivering the same force:

(98.1N X 10m / 20s) = 49.1W : In 1 minute this motor can lift 10kg 3 times.
(98.1N X 10m / 30s) = 32.7W: In 1 minute this motor can lift 10kg twice.

Also the RPM of the spool will be different: I'm sure you can figure out which is faster. It's hard to explain, I hoped going liner (strait line) helped.

____________

People try to keep RPM low. Fuel economy, engine wear, noise etc... The way to counter lack of power at daily driving speeds is an increase in torque. This is achieved through drive-train design. Hence when SUB says his RSX is gutless because it has little torque, what he means is it develops insufficient power for his liking at low rpm (or the whole range).

[old greg]

Originally Posted by serialk11r

Wheel is 24.6 inches I think.

Bling bling.... can we get spinners from the factory, or are they a dealer installed option?

[old greg]

Originally Posted by Dimman

Anyone want to overlay some rpm drop by gear over this graph? Throw in some wheel torque figures by gear too?

Manual = Blue
Auto = Red
Purple = Manual 5th and Auto 4th




It looks like the car would benefit from a few more rpm up top, even without any mods.

[Homemade WRX]

Originally Posted by ahausheer

Ok, for all you smarty pants, if torque is what moves you and is also what you ''feel'' why do F1 cars have basically no torque and super high Hp? I still argue that, in the end, HP is more important. That's why we see power to weight, not torque to weight metrics.

It's a 2.4L so more RPM = more air = power but because it's power at RPM, Torque is comparatively seem lower. Then take into account that they gear the shit out of them, which is a torque multiplier.

Originally Posted by Dimman

Anyone want to overlay some rpm drop by gear over this graph? Throw in some wheel torque figures by gear too?

I see Greg posted some. I have mine with lines drawn back to gear drop from redline but otherwise the same...and it isn't on this computer but now you get the point.

[Deslock]

Here it is with 15% drivetrain loss.

[Ryephile]

Thanks for sharing the graphs guys, that helps a bunch.

[Mr.Jay]

I love it when you guys get technical

I get to learn something new all the time

[bw1235]

Based on Subau's history of horrible tunes on the STI, I wouldn't be surprised if the torque dip is due to emissions/economy, but time will tell. If it's anything like their turbo tunes, the dip would be where the AFRs drop from too lean to too rich...
That would certainly be a good thing- it would be straightforward to tune out.

Found a quick example here with AFR: http://www.iwsti.com/forums/2731193-post16.html

[Deslock]

Here's a rough estimate for comparing acceleration of the BRZ and WRX. As expected, once the WRX hits boost the BRZ never matches it. Still, I was a little surprised to see that:

• The BRZ in 6th gear has more pull than the WRX in 5th until 70 MPH.
• The BRZ has more pull than the WRX when both are in 5th.
• The BRZ has more pull than the WRX when both are in 4th until 55 MPH.

This doesn't account for traction and of course it doesn't take much to increase the WRX's output. Even stock, it'll be 1.2-1.5 sec faster just to 60 MPH.