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2Addicts | BMW 2-Series forum Technical Topics N55 (M235i) Engine, Transmission, Exhaust, Tuning What's the optimal launch rpm and psi for drags ?

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      08-19-2014, 05:21 PM   #1
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What's the optimal launch rpm and psi for drags ?

Was wondering what's the optimal launch rpm, shift points and tire psi for the drag strip?
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      08-19-2014, 05:45 PM   #2
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Originally Posted by pikcachu View Post
Was wondering what's the optimal launch rpm, shift points and tire psi for the drag strip?
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      08-20-2014, 01:23 AM   #3
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Originally Posted by pikcachu View Post
Was wondering what's the optimal launch rpm, shift points and tire psi for the drag strip?
I find launching at 2200rpm and 40psi tire pressure gave me the quickest time on my stock auto m235i, with the transmission on auto and in sports+, the best run I did was 12.8sec with 2 sex flat for the 60 footer.
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      08-20-2014, 12:19 PM   #4
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cool.

yeah i was thinking around 2000rpm.....
mmm 40psi sonunds pretty high I would think you would want like 34-36 to get better traction... no?

what about shift points? should it be better to shift around 5500-6000 instead of letting it go to 7k with the sport+ auto program?
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      08-20-2014, 12:41 PM   #5
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It depends if you are tuned or not .
If so , it depends which map and how much boost you are making on each RPM.
Best way to know is to do a dyno pull and analyze your power curve.
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      08-20-2014, 01:03 PM   #6
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let's say completely stock. any tips ?

heading to the track with some friends on a 550ix and a 09 cayman s so want to know what my chances are
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      08-20-2014, 05:25 PM   #7
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so let it shift in auto or shift at 5500-6000 rpm?
also start on 1st or 2nd?

I have 2hrs for an answer
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      08-21-2014, 12:44 AM   #8
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This was my best and first run

Screwed up my rt but even my rt went down to .200 my 60' never got below 2 :-(
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      08-21-2014, 12:46 AM   #9
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      08-21-2014, 01:00 AM   #10
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That's pretty good 60 footer what rpm did u launch in and what tire pressure?
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      08-21-2014, 01:14 AM   #11
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2000rpm and 38psi

then i dropped it to 30psi but time didn't get any better... 13.3 13.4 even though my reaction time went down to .250

maybe I'm getting wheel spin but was kind of loud so couldn't really tell.... also after the first run i started shifting at 6krpm ... maybe i should have left the computer do its thing...
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      08-21-2014, 07:29 AM   #12
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That's not bad at all. Looks like you have some good benchmark numbers now.

What did the Cayman S do for it's best run?
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      08-21-2014, 10:32 AM   #13
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well.... he kind of rode the clutch through 3rd gear and quit the run so was like 16 or so and didn't run again...

the 550x did around 13.4-13.6 but I beat it every time....

what surprises me is that I would pull away at the start.... you would think that him with x drive would have a better launch... then at the end is when he starts to catch up as his trap speeds where always 2mph faster or so than mine..
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      08-27-2014, 10:20 PM   #14
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thought I would post this here as well.
Car is definitely running strong even in 2972+DA!!
Always traps fastest off the highway(112.5-corrects to 114-116) then trap starts to go down hill.
chassis was in comfort.Foot braking to 2000 rpm as lights start to drop(told if done earlier would "blow off boost" by my "mustang trainer" lol-seemed to work for 1.91 60 ft.)
I will need to try Terrys suggestion to launch in 2nd and use kick down blocker-would have to shift manually but may work since peak power is at 5500-6000 and auto shifts higher than that.Overall I am pleased as achieved goal of running low 12's with just JB4- no other mods other than MPE exhaust.In cooler weather and with better 60 ft it could run high 11's.Will definitely run that with down pipe but not sure I want the car loud and smelly-I have a mustang for that! lol

Best run of the night was 12.40(corrects to 11.9-12.2)- with chassis setting in sport.I was able to back it up once but car has started slowing by then.
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Last edited by olaosunt; 08-27-2014 at 11:09 PM.. Reason: wrong DA
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