[pmsteinm]

Because I'm weird this way I've compiled a bunch of data on several cars that I've owned or was interested in. I have put the engine load diagrams on one graph and also graphed the calculated torque at the rear wheels in various gears.

The cars I did this for:
F90 M5C
F90 M5
G30 M550 (latest N63)
E60 M5
22 Cadillac CT5-V Blackwing (I could only find a Z06 LT4 graph so I had to fudge some)
09 Cadillac CTS-V
04 Cadillac CTS-V
00 Cadillac STS

Most of the data came from BMW dealer technical guides and GM Powertrain media. I had to measure off of the printed-out graphs which may not have been to scale (like the S85 one looks like it came from some cheeseball Apple software). There is of course a decent margin of error here and some graphs seemed wrong (the calculated HP didn't match the graph at a given TQ and RPM). But for the most part things seem reasonable. Note my sample points which will cause some wiggles in the graph and straight lines which in real life are curved. But it is close enough to get an idea of things. I know BMW might overrate their engines but I don't have real data on that. Also I don't have real data on drivetrain loses so I didn't worry about that. This is just to give me an idea of how things compare.

Keep in mind that at least with the M5 1st gear doesn't seem to generate full boost (it seems obvious why when you see how far above any other car on this list the 1st gear graph is). It also doesn't account for weight, but all these cars are within 3900-4300lbs. Eventually I'd like to do some more math about total work done and so forth.

I found it very interesting that despite the different manufacturers and engine outputs all the cars are gears fairly close to each other in terms of RWTQ. This kind of makes sense since they all weight about the same and have the same performance targets.

This is an Excel file. I've attached some screen shots of the graphs but they are so busy it's better to filter in Excel.


gears.zip

[ResIpsaLoquitur]

Originally Posted by pmsteinm

Because I'm weird this way I've compiled a bunch of data on several cars that I've owned or was interested in. I have put the engine load diagrams on one graph and also graphed the calculated torque at the rear wheels in various gears.

The cars I did this for:
F90 M5C
F90 M5
G30 M550 (latest N63)
E60 M5
22 Cadillac CT5-V Blackwing (I could only find a Z06 LT4 graph so I had to fudge some)
09 Cadillac CTS-V
04 Cadillac CTS-V
00 Cadillac STS

Most of the data came from BMW dealer technical guides and GM Powertrain media. I had to measure off of the printed-out graphs which may not have been to scale (like the S85 one looks like it came from some cheeseball Apple software). There is of course a decent margin of error here and some graphs seemed wrong (the calculated HP didn't match the graph at a given TQ and RPM). But for the most part things seem reasonable. Note my sample points which will cause some wiggles in the graph and straight lines which in real life are curved. But it is close enough to get an idea of things. I know BMW might overrate their engines but I don't have real data on that. Also I don't have real data on drivetrain loses so I didn't worry about that. This is just to give me an idea of how things compare.

Keep in mind that at least with the M5 1st gear doesn't seem to generate full boost (it seems obvious why when you see how far above any other car on this list the 1st gear graph is). It also doesn't account for weight, but all these cars are within 3900-4300lbs. Eventually I'd like to do some more math about total work done and so forth.

I [...]

You actually shared it! You’re awesome. Can’t wait to pore over it.

[AP]

Sort of relevant, the m550 produces the same torque as the 540’s max torque at just 1000rpm

Find that quite amazing

[M550bernina]

Originally Posted by AP

Sort of relevant, the m550 produces the same torque as the 540’s max torque at just 1000rpm

Find that quite amazing

Yes, that's the problem with BMW V8's! They have these small twins scrolls. So you don't have turbo lag and get instant torque....Stock. The problem is when you go to tune them, The turbos are way too small and spool way too fast.

BMW V8's tuned, can hit anywhere from 700 to 900 plus wheel torque at 2000 RPM. Obviously you can see the problem there.

Ideally, with the V8 torque itself producing low end torque, It sure would be nice to have larger turbos. To move the torque band up the RPM band to help save rods.

I wish I could afford a single full frame Turbo for my 550.

[pmsteinm]

I've redone the whole things and made it better. I added acceleration and distance estimates and some fudge factors to align with test data. I've added the CT5V BW A10, F10 M5 DCT, and E39 M5. I've updated the tire revs per mile based on Tire Rack data since the normal math isn't quite right due to sidewall flex.

Couple interesting things:

The Blackwing A10 is gears very similar to the G30/F90 for the first few gears, then they tighten them up since they have 2 extra to play with. But notice the resulting acceleration estimates aren't that different than the M6.

LT4 has a lot more area under its curve than the S63 up to 6500rpm, but the extra 800 rpm the S63 gets ends up giving it more total area (Joules). And when you look at the gearing, the M5 has more area under the torque curve than the BW.

Based on how I fudged things to match test data, it validates the idea that the N63 and S63 are rated at the wheels and not crank. That didn't seem to be the case with the other cars and older M5's. It gets harder with the other cars because they are not AWD and are certainly traction limited in a lot of cases (I limited them to <1 G acceleration for some cars).


Automotive Power Curves.zip