2020 Supra vs 2021 Supra Dyno Results

[65sohc]

The video in fact reinforces what I said. Despite being somewhat verbose, Richard Holdener knows what he's talking about. If you listen from 9:40 on you'll see he is saying exactly what I said.

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[Frosty]

LOL okay. Transmissions become more efficient the more power you throw at them or is it the fact you’re throwing more power at it and the losses are less obvious?

 

[65sohc]

A Powerglide takes 20 hp (Let's say, but I think that is pretty close). A mechanical water pump takes 5 hp to spin. A power steering pump takes maybe 5 hp. An alternator 5 hp. All hypothetical but close to reality. The effect is additive, ie. 20+5+5+5=35. They have a fixed amount of drag. If an engine makes 300 hp@6000 RPM it takes 35 hp to spin these accessories. If you add 15 lbs of boost and are suddenly making 600 hp at the same 6000 RPM the accessories are spinning at the same speed. Therefore they are creating the same amount of drag, ie. 35 hp. 35hp is a much lower percentage of 600 than it is of 300. The point I am making is that extrapolating from rear wheel horsepower to flywheel horsepower is not a simple calculation based on a fixed percentage. As the horsepower increases the percentage decreases.

 

[kona61]

A Powerglide takes 20 hp (Let's say, but I think that is pretty close). A mechanical water pump takes 5 hp to spin. A power steering pump takes maybe 5 hp. An alternator 5 hp. All hypothetical but close to reality. The effect is additive, ie. 20+5+5+5=35. They have a fixed amount of drag. If an engine makes 300 hp@6000 RPM it takes 35 hp to spin these accessories. If you add 15 lbs of boost and are suddenly making 600 hp at the same 6000 RPM the accessories are spinning at the same speed. Therefore they are creating the same amount of drag, ie. 35 hp. 35hp is a much lower percentage of 600 than it is of 300. The point I am making is that extrapolating from rear wheel horsepower to flywheel horsepower is not a simple calculation based on a fixed percentage. As the horsepower increases the percentage decreases.

I’m no engineer, but I think the transmission does vary on parasitic losses depending on how much power you put through it. I agree that pumps and whatnot likely have no change, and most modern cars disconnect the ancillaries under load anyways.

 

[HaiFrends]

A Powerglide takes 20 hp (Let's say, but I think that is pretty close). A mechanical water pump takes 5 hp to spin. A power steering pump takes maybe 5 hp. An alternator 5 hp. All hypothetical but close to reality. The effect is additive, ie. 20+5+5+5=35. They have a fixed amount of drag. If an engine makes 300 hp@6000 RPM it takes 35 hp to spin these accessories. If you add 15 lbs of boost and are suddenly making 600 hp at the same 6000 RPM the accessories are spinning at the same speed. Therefore they are creating the same amount of drag, ie. 35 hp. 35hp is a much lower percentage of 600 than it is of 300. The point I am making is that extrapolating from rear wheel horsepower to flywheel horsepower is not a simple calculation based on a fixed percentage. As the horsepower increases the percentage decreases.

Pretty interesting. Might be difficult but wonder if we could hone in on a generalized "sliding scale" power loss on higher power gains (if that makes sense)

 

[Supra Werty]

I have a feeling the whole gain is from a couple extra pounds of boost. That is just my assumption based on the lower compression and slightly better exhaust manifold for better higher rpm power. I still believe the ‘20 engine will feel a tad more responsive due to the higher compression. Nothing earth shattering but possibly even more noticeable during cruising.

It's not just the manifold, the cylinder head changed.

 

[Frosty]

It's not just the manifold, the cylinder head changed.

I know the exhaust manifold is integrated into the cylinder head. With that said, do you know it there are any additional changes in the valve train? Cams? Port size?

 

[Supra Werty]

I know the exhaust manifold is integrated into the cylinder head. With that said, do you know it there are any additional changes in the valve train? Cams? Port size?

I don't know

 

[MA617M]

I’m no engineer, but I think the transmission does vary on parasitic losses depending on how much power you put through it. I agree that pumps and whatnot likely have no change, and most modern cars disconnect the ancillaries under load anyways.

You are correct

The gear speed will affect torque, not to mention heat load. This all effects the losses from engine to wheels. Yes, it becomes less dramatic, but it's a function of power, not an offset.

 

[Supbrah]

I’ve been reading around on OpenFlash. It’s very cool that they are working on this platform.

Can’t wait to see what they announce!

 

[65sohc]

You are correct

The gear speed will affect torque, not to mention heat load. This all effects the losses from engine to wheels. Yes, it becomes less dramatic, but it's a function of power, not an offset.

As Holdener said, as you apply more torque to the drivetrain there is a nominal increase in heat generated through friction but the increase in drag is as measured on the dyno would be tiny.

 

[OpenFlash Performance]

I recall having this discussion with Richard 15yrs ago at Thunderhill Raceway during a USTCC race. I argued that drivetrain losses are *mostly* fixed. But there is also a loss component that is depending on power output. A car that pulls more power to the rollers will generate more heat (frictional loss) and tire carcass distortion than a car will less power. Even though they may both be tested in the same gear with the same min and max roller speed. It's an interesting discussion but every car will be a little different due to variance in transmission design/metalurgy/tire selection/oil viscosity/etc,. But basically, it's best to only talk about wheel hp measured on the same dyno since wheel-to-crank corrections are always going to be estimates/guesses.

 

[65sohc]

On a related note, how much fuel do you suppose a Supra consumes during two dyno runs? I am planning to dyno my car stock on 91 and then upload my e50 tune and add enough e85 to achieve e50.

 

[Marin@MarinTuned]

On a related note, how much fuel do you suppose a Supra consumes during two dyno runs? I am planning to dyno my car stock on 91 and then upload my e50 tune and add enough e85 to achieve e50.

This can vary on a lot of factors. Simply show up on pump gas with a half tank. Let the car sit for a few minutes and then check with logging the estimated fuel remaining and blend your fuel. Do a few partial throttle pulls to flush the fuel system out. I have no issues doing this on the regular.

 

[Marin@MarinTuned]

Welcome aboard Shiv. IMO a nice handheld would be nice to have on the market!

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