1/4 mile performance - 35i

[pete_z89]

All,

Just wanted to share with you my experience at the track last night...

Just two runs. Temperature was around 55 degrees. I did NOT use launch control.


Run #1 (I'm on the right, versus a stock automatic 2008 Pontiac G8 GT):





Run #2 (I'm on the right again, versus a modded/tuned manual 2011 Mustang 5.0 GT):





Cobb stage 1+FMIC tune; and Wagner Tuning FMIC. Everything else performance-wise is stock (including the stock rims and tires).

I didn't do any runs when I just had the Stage 1 tune by itself. But really couldn't tell much difference in driving power with and without the FMIC tune. Maybe just a little bit. I'm sure the Cobb Stage 1 by itself would break the 13 second barrier as well. But good to know the Stage 1+FMIC tune is a consistent 12.8 car!

I'm hoping that after downpipes, a re-flash of the tune to Stage 2+FMIC, and new rubber, I could possibly get down to breaking the 12.5 barrier.

I drive a 2011 sDrive35i with DCT, sport package, 23k miles.

[z4neb]

That is very nice!!

[Lambobimmer]

Did you run with DTC off and in Manual Mode? I am just curious.

Those are good times. I ran about the same when I had my 135i but it was a manual and I could never get any traction.

[pete_z89]

I ran with the suspension/shifting setting in Sport Plus, and the tranny in Sport.

Apparently, Sport Plus only removes about 50% of the traction control. And I found out that if I remove traction control completely, it does remove 100% of the traction control, but it reverts the suspension/shifting setting back to Normal/Comfort. So completely removing the traction control was not an option for me.

Also, I did not use the paddle shifters, I just let the car shift when it wanted to. I did go through and calculate the optimum shit points for each gear, so maybe next time I go to the track (if I ever go again -as I'm moving out of state in three weeks), I will try actually shifting manually.

[VailM3]

stock 35i?

[pete_z89]

Originally Posted by VailM3

stock 35i?

Please see my previous post...

Originally Posted by pete_z89

Cobb stage 1+FMIC tune; and Wagner Tuning FMIC. Everything else performance-wise is stock (including the stock rims and tires).

I drive a 2011 sDrive35i with DCT, sport package, 23k miles.

[Asbjorn]

Originally Posted by pete_z89

I ran with the suspension/shifting setting in Sport Plus, and the tranny in Sport.

Unless you press down the kick-down switch, in my experience the manual DCT mode is better than S (sequential?) mode.

In S mode the car up-shifts too early in first and second gear (6.5k instead of 7k), and sometimes even double up-shifts in case of excessive wheel-spin.

Also S-mode, in my personal opinion (some disagree), drops the clutch harder than in M-mode, and this would increase the risk of wheel-spin. With DSC=off you get slightly softer/better matched gear changes in both S and M mode compared to sport+. This might be a good thing especially when you start to run higher boost and all milliseconds count.

I know that with the adaptive suspension you loose the firmest setting with DSC=off, but avoiding wheel spin on gear-shifts alone might mean "DSC=off"&"DCT M mode" is a faster combination than "Sport+"&"DCT S/M mode". Not just because wheel spin in and by itself is a waste of energy, but because it might trigger the ECU to temporarily "limp" the engine even in sport+ mode. This is particularly unwanted in a turbo engine like the N54.

Finally you can consider dragging with the roof down to add weight over the rear wheels.

And btw, it is possible to let the DCT start in 2nd gear if you really feel like experimenting... personally I am out of warranty and I wouldn't dare to..!

[pete_z89]

Originally Posted by Asbjorn

Unless you press down the kick-down switch, in my experience the manual DCT mode is better than S (sequential?) mode.

I did not try it in manual mode, but next time (if I ever have the opportunity again), I will try that for sure.

Originally Posted by Asbjorn

In S mode the car up-shifts too early in first and second gear (6.5k instead of 7k), and sometimes even double up-shifts in case of excessive wheel-spin.

I actually created a Microsoft Excel sheet (based on the Cobb Stage 1 tune numbers), to show where the optimum shift points are in each gear. Turns out (at least for Cobb stage 1), the optimum shift points are: 1st gear- ~6400 rpms; 2nd gear- ~6100 rpms; 3rd gear- ~5650 rpms; 4th gear- ~5350rpms. Again, this is just rounded to the nearest 50 rpms. I didn't get a computer to do these calculations either, but just from my own math and info I gained from Cobb's power curve given on their site, that's where I got these numbers.

I left the tranny in Sport mode the whole time just to see how the computer would do on it's own. Next time, I will try to memorize these shift points, and see if I can't go a little faster shifting on my own!

Originally Posted by Asbjorn

I know that with the adaptive suspension you loose the firmest setting with DSC=off, but avoiding wheel spin on gear-shifts alone might mean "DSC=off"&"DCT M mode" is a faster combination than "Sport+"&"DCT S/M mode". Not just because wheel spin in and by itself is a waste of energy, but because it might trigger the ECU to temporarily "limp" the engine even in sport+ mode. This is particularly unwanted in a turbo engine like the N54.

Not only does DSC=off put the suspension in the softest setting, but it also doubles the shift speed of the tranny. I didn't realize this until about a month after owning the car, but a little research and personal observation has convinced me that when the "suspension" is put in Sport or Sport+ modes, the shift times are literally cut in half. This is why I was forced to leave it in Sport+ mode, instead of just completely DSC=off.

Luckily, I only had slight wheel spin at the end of 1st gear, but the engine did not enter limp mode! Both times this happened. No power was cut and the engine shifted into second gear on its own both times perfectly.

Originally Posted by Asbjorn

Finally you can consider dragging with the roof down to add weight over the rear wheels.

I agree! Haha, but the track I'm at doesn't allow even the windows to be rolled down, let alone the convertible top down But I definitely thought of that!

Originally Posted by Asbjorn

And btw, it is possible to let the DCT start in 2nd gear if you really feel like experimenting... personally I am out of warranty and I wouldn't dare to..!

It is indeed possible...but I think the performance times would be quite a bit worse.

[ManiacGT]

From memory.. I read bmw stated the fastest shift times were only available in manual mode so perhaps experiment with doing the shifts yourself also.

[nicknaz]

Nice times OP! Congrats

I came across this post where an N54 335 owner shared his dynos for each modification and the FMIC was the 2nd biggest gain after the chip. I think based on these dynos and your trap speed the FMIC is a nice gain over just the stage 1 tune

http://www.extremeturbosystems.com/E...p-Dyno-Sheets/

[Asbjorn]

Originally Posted by pete_z89

Not only does DSC=off put the suspension in the softest setting, but it also doubles the shift speed of the tranny. I didn't realize this until about a month after owning the car, but a little research and personal observation has convinced me that when the "suspension" is put in Sport or Sport+ modes, the shift times are literally cut in half. This is why I was forced to leave it in Sport+ mode, instead of just completely DSC=off.

I totally agree. And I should add that I only ever had "problems" with temporary hesitation(limp) and double up-shifts due to wheel spin when running ESS stage two (which is a 15psi tune if I remember correctly). It would depend on the tires and road condition as well. If wheel spin isn't a problem when combining sport+ and DCT S-mode, then that would be the fastest shifting program, closely followed by sport+ combined with DCT M-mode according to my butt-dyno. Some would say they are the same... and bmw says DCT M mode is the fastest...
I guess my main point was that If wheel spin becomes a problem as you add more torque you can try DSC=off + DCT M-mode.

BTW I am surprised that you need to upshift before red line in 1st with any N54 tune, but I believe DCT S-mode up-shifts at 6.5k by default in any gear unless you press the kick down switch. In any case, revving to 7k is another way to reduce wheel spin caused by gear shifts - if present.