[Landshark92]

I kind of love and hate the way my car drives. I love how it has such a hard midrange punch but I hate how it drops off so hard in the top end. I guess that is just the way the stock motor is and I've learned to live with it.

But with such a large drop off, that got me thinking that maybe I shouldn't run it out to redline like I enjoy doing, like I have done with all the other NA cars I have had in the past. So I got a few logs and converted them into dyno runs using Virtual Dyno. The graph in red is my car in kill mode, 19 psi peak tapering to 15 psi at redline. The graph in blue is a 14 psi flat boost curve all the way to redline. Here are the gear ratios for our N54 6MT:

335i E92 Coupe manual
1st 4.06
2nd 2.40
3rd 1.58
4th 1.19
5th 1.00
6th 0.87

For the shift rpm in 1st gear, I just took an educated guess of what rpm to shift at and multiplied that by 2.40/4.06 to get the rpm I would get in 2nd gear. I then compared the horsepower in 1st compared to the horsepower in 2nd. Then through trial and error, I found the shift rpm where the horsepower in 2nd gear would be equal to the horsepower in 1st or very close to it. This keeps me as close to peak horsepower as much as possible.

Then I repeated that for every gear until I found my final 5th gear shift rpm.

Disclaimer: This is all assuming that I have perfect traction. We all know that is not likely in first gear at least. So boost limiters by gear in 1st and 2nd gear and available traction play a very big part in when I would shift in the lower gears for the best acceleration.

The results:
In kill mode (red graph), with a big boost taper at redline, I should never redline the car and should short shift lower and lower in every subsequent gear.
Shift rpm: kill mode stock flash E35 map 5 19 psi peak 15 psi at redline 411whp on virtual dyno
1st 6,700 rpm
2nd 6,570
3rd 6,400
4th 6,100
5th 6,000

The flat boost curve (blue graph) is interesting. The car rewards me for holding onto gears a little bit longer. I actually should redline the car in 1st, 2nd and 3rd gear. You can see the slope of the torque curve dropping off at the higher rpms is not as severe in this run.
Shift rpm: E85 flash E35 14 psi flat boost curve 370whp on virtual dyno
1st 7,000 rpm
2nd 7,000
3rd 7,000
4th 6,450
5th 6,400

Well, it was bugging me that it felt like I was losing time redlining the car but I didn't know how much and what to do about it. Many people here know from experience and their timeslips that these cars don't like to be revved all the way out with stock hardware, even if it is fun to do so.

It is pretty clear that it's best to shift sooner and ride that fat torque curve for the best times. Let me know what you guys think. If anybody wants to do the same for their setup, post a log and lets take a look.