Dyno Numbers

[Baldeagle]

Originally Posted by Tracer29

I get the whp but is the torque also to the wheel?

Sent from my SM-G781W using Tapatalk

Short answer: Yes

Longer answer: You cannot measure HP. It is impossible. You can only measure the amount of twist the wheels apply to the drum roller at every rpm. That twisting force is wheel torque. With that data, you then calculate HP. In concept, HP is torque multiplied by a time component. RPM has that component built into it (minutes). The formula for HP is:

Horsepower = (Torque X RPM) / 5252.

If you wonder about the number 5252, James Watt defined one horsepower as the ability to lift 550 pounds one foot in one second. That translates to the ability to lift 33,000 pounds one foot per minute. Because the crankshaft of an engine spins, we must convert linear motion to angular motion. To accomplish that we divide 33,000 by 360° or 2pi. 33,000 ÷ 6.2830 = 5,252. Anyway, that’s the 5,252 in the formula.

To create a HP curve, a computer simply plugs the measured torque for each rpm into this formula and plots a graph. That is your HP curve. By default, because these dynos can only measure wheel torque, the HP graph reflects wheel horsepower.

In the lab, they can connect an engine, just the engine to a dyno. The flywheel directly spins the dyno. Because the engine has very little parasitic loss from pullies, exhaust systems, intake systems, transmissions, driveshafts, etc., it spins the dyno with more force. That calculation becomes the engine’s “crank HP” numbers.

[Stonehorsw]

https://www.delicioustuning.com/2022...k_Dyno_Results

[Stonehorsw]

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[Jianlun]

Thanks Stonehorsw.

The peaks and valleys seem exactly like that the Japanese are getting.

I can't help but wonder what that little peak in the AFR is and whether it correlates with the torque dip. And of cause what riching that out will do....

[Lantanafrs2]

That's almost a forced induction delta. They clearly got the message before designing the new motor.

[Blighty]

I'm most impressed with the honesty I am seeing in these dyno runs.

From Australia where dynapack is often the one used, my OG car pulled 150hp at the hubs, which I think looks decent against the 140 WHP run shown.

Its probably the first time I have seen such similar reporting out of the US.

[Lantanafrs2]

I think there's more behind the improvement than just a displacement increase

[Blighty]

Originally Posted by Lantanafrs2

I think there's more behind the improvement than just a displacement increase

Lightened driveshaft.
Internal friction reduction.
New fuel injection strategy (port is used up high for better top end air/fuel mixing).
Possibly more?

[Lantanafrs2]

Originally Posted by Blighty

Lightened driveshaft.
Internal friction reduction.
New fuel injection strategy (port is used up high for better top end air/fuel mixing).
Possibly more?

Cams and better port/valve sizes

[DarkSunrise]

Nice, was waiting to see the Delicious dyno.

2022 BRZ (top chart) vs. a stock 2013 FR-S with just E85 tune (bottom chart) on the same dyno. About 14 whp difference. Looks like the 2022 makes ~10 lbs-ft more starting at 5000 RPM and up, and a good amount more below that. Easy to see why people say the 2022 engine feels strong/torquey. Also looks like a header/full exhaust first gen on E85 would be pretty close on the top end.

[PulsarBeeerz]

Originally Posted by Blighty

Lightened driveshaft.
Internal friction reduction.
New fuel injection strategy (port is used up high for better top end air/fuel mixing).
Possibly more?

Originally Posted by Lantanafrs2

Cams and better port/valve sizes

I think its the new engine as a whole mostly.

[rawpoly]

Can someone ELI5 the graph to me?
Good/Bad?
Lines up with what savagegeese was talking about?

[Kona61]

Originally Posted by rawpoly

Can someone ELI5 the graph to me?
Good/Bad?
Lines up with what savagegeese was talking about?

Good for us lol. Around 35% gain of peak power and similar torque curve to what we had seen before.

It’s hard to compare dyno to dyno, better to draw comparisons from deltas on the same dyno with different cars as they did here.

[ZDan]

I am not buying those curves showing 188hp vs. 140hp as the actual delta between 1st gen and 2nd gen, it's gonna be more like +20% rather than +34%.

1/4-mile speeds are a good indicator of horsepower, particularly between similar cars (and gen 1 & gen 2 are largely the same car).
2013 BRZ and 2017 BRZ both tested 95mph in the 1/4 by Car and Driver, and they tested the 2022 at 101mph. !/4-mile speed scales with the cube of power, so the actual power increase should be about (101/95)^3 = 1.20X (1.21x accounting for +30 lb. weight gain)

My stock '17 dyno'd 179hp at the wheels on Dynojet, I expect the 2022 to put up 215hp. A big increase and more than rated power would suggest, but +34%? No... If it really made that much more, it would be trapping ~105mph.