N54Tech.com - International Turbo Racing Discussion
(#1)
Old
Taron's Avatar
Taron Taron is offline
Senior Member
 
Posts: 584
Join Date: Jan 2013
Car: 2008 BMW 335XI
Default launching XI models. - 06-13-2013, 11:20 AM

Hi all,

I would like to collect some experince on launching with xi models. I know some of AT users are revving till 2.5-2.8k and pushing pedal on 2nd gear. However my experince show that launching XI is better on first gear. We recently got timing system in my country and I will be able to test both ways however i would like those of you who tried with kickdown blocker on 2nd gear please share your timing experince.

Thanks
Taron


2008 335XI(E92) AT/ garrett gtx3582r with jpworks manifold 1.06AR housing/ tial mv-s 38mm wgs(13.5 psi springs)/ tial bov/ fuel it level1 upgrade/ index 12 injectors/ N20 Map sensor/JB4 ST TS BEF with MHD/ Alpina Flash for now.
Reply With Quote
(#2)
Old
Martinw2579's Avatar
Martinw2579 Martinw2579 is offline
Junior Member
 
Posts: 38
Join Date: Apr 2012
Car: 11 335is DCT
Default 06-13-2013, 11:36 AM

My butt dyno tells me 1st gear launches. 2nd gear launch was a little messy and felt slow when I was at the track.
Reply With Quote
(#3)
Old
Taron's Avatar
Taron Taron is offline
Senior Member
 
Posts: 584
Join Date: Jan 2013
Car: 2008 BMW 335XI
Default 06-13-2013, 11:49 AM

Yup. I fill the same. Seems that rwd users doing this to not spin on start. However 1st gear is to short and maybe loosing time on shifting might be even worse.


2008 335XI(E92) AT/ garrett gtx3582r with jpworks manifold 1.06AR housing/ tial mv-s 38mm wgs(13.5 psi springs)/ tial bov/ fuel it level1 upgrade/ index 12 injectors/ N20 Map sensor/JB4 ST TS BEF with MHD/ Alpina Flash for now.
Reply With Quote
(#4)
Old
mykal335xi mykal335xi is offline
boom
 
Posts: 83
Join Date: Oct 2011
Car: BMW
Default 06-13-2013, 04:33 PM

2nd gear launches on the XI will kill your trans, ask me how I know


2011 335i m-sport
2008 335xi (Sold)
Reply With Quote
(#5)
Old
LQQKOUT's Avatar
LQQKOUT LQQKOUT is offline
Junior Member
 
Posts: 127
Join Date: Jul 2011
Car: 335XI
Default 06-13-2013, 05:25 PM

How do you know?
I usually start in 1st @ about 2K RPM. 1.7 60' is the norm for me.
It all depends on the track prep even with an AWD vehicle.
Last weekend I had to abort about 4 runs due too wheel spin.
Reply With Quote
(#6)
Old
08n54 08n54 is offline
Junior Member
 
Posts: 79
Join Date: Sep 2012
Car: 2008 535xi
Default 06-13-2013, 09:18 PM

I rev'd to about 2800rpms in 1st gear. Never tired 2nd gear launch as XI's don't have traction issues.
Reply With Quote
(#7)
Old
themyst themyst is offline
Super Demigod
 
Posts: 247
Join Date: Feb 2009
Car: 335i
Send a message via AIM to themyst
Default 06-14-2013, 07:40 AM

if you have the traction for it 1st gear will launch your car like a bat out of hell. 2nd gear launches are more for those who are traction limited e.g. street tires.


E90 LCI N54 6AT
Reply With Quote
(#8)
Old
mykal335xi mykal335xi is offline
boom
 
Posts: 83
Join Date: Oct 2011
Car: BMW
Default 06-14-2013, 08:15 AM

2nd gear was only good for ~50 launches before the trans started acting up, rough shifts into 2nd and would go into default mode on me under hard acceleration. I think 2nd gear launches in the 335i/135i will eventually do the same thing, just take a lot longer.

1st gear launches at over 400whp on street tires will spin all 4 pretty easy in my experience, but this is good as it's less stress on the drivetrain than just a straight hook with all that torque. Spin or not you'll need to try and grab 2nd gear yourself, takes practice to work out the timing so you don't hit the rev limiter. The car will not want to upshift on it's own to 2nd gear because the sensors think the tires are spinning from the very rapid launch, because DTC is off it is OK with the spinning, but it upshift logic is suspended with wheelspin. Trick here is if this is happening to you, try shifting right around 5k, the delay in the paddle is enough to make the trans actually shift 6500-6700 if you do it right.


2011 335i m-sport
2008 335xi (Sold)
Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump




vBulletin Skin developed by: vBStyles.com
Copyright 2007 - 2018, N54tech.com