I do two wheel burnouts?

grunyon · 10-02-2013, 05:38 PM

2008 135i here with 6 speed MT

When I launch hard enough to burn rubber, I leave two streaks perfectly even. Do I have a limited slip? I thought our cars didn't have one. Of course this is with traction control off.

marc@x-ph.com · 10-02-2013, 05:45 PM

You don't have a limited slip. but If you're going off in straight line, and grip on both sides is almost the same then power will go to both not favoring (in big manner) one over the other.

Try to do it on water, or exiting a corner (be safe!!) and you'll definitely notice that only one wheel is spinning.

Freon · 10-02-2013, 05:52 PM

Even if grip is almost perfectly a car without any sort of LSD should spin only one tire. This is because grip is ever exactly even, the drivetrain isn't perfect, so once one wheel starts to spin even just slightly more than the other "it's over" and you have one wheel peel. It's a positive feedback loop--a runaway condition.

The real reason you lay two strips down in a modern non-M BMW is the car has an "eLSD" which uses the brakes to keep you from spinning just one tire. Once one tire starts to spin more than the other the brakes are applied which transfers torque back to the non-spinning wheel.

Dackelone · 10-02-2013, 06:05 PM

...jack your car up in the air (both rear wheels off the ground)... AND with the trans in neutral... now spin one of the rear wheels forward... IF your car has a LSD the "other" side wheel will rotate in the same direction. This will mean your LSD is working.

But most likely the other wheel will spin in the opposite direction, which means your car does NOT have a LSD, but a open diff.

The e-diff (which is part of bmw's DTC system), uses the ABS system rear brakes to control wheel spin actually does a pretty good job when launching the car. But I would think you turned off the DSC when doing a "burn out".

Davyhay · 10-02-2013, 07:43 PM

Mine lays down rubber with both wheels as well. decided to try this out, yesterday on a deserted road. Yes, at nearly 40, I am still a child.

alexmtl_135i · 10-02-2013, 10:41 PM

Quote:

Originally Posted by Dackelone

The e-diff (which is part of bmw's DTC system), uses the ABS system rear brakes to control wheel spin actually does a pretty good job when launching the car. But I would think you turned off the DSC when doing a "burn out".

Dackel (or someone else), can you confirm whether the e-diff only works when DSC is fully off? I thought I read somewhere that in normal and DTC mode there is no e-diff but only traction control, which means that it would cut power rather than braking the other wheel.

froop · 10-03-2013, 12:28 AM

Quite sure that the e-diff is active at all times wether with DSC, DTC or TIMYOYO.

NORAGRETS · 10-03-2013, 12:55 AM

Only thing holding me back from
Drifting my rear tires to the bone: MPSS $$. Wahhhh

Freon · 10-03-2013, 10:00 AM

Quote:

Originally Posted by froop

Quite sure that the e-diff is active at all times wether with DSC, DTC or TIMYOYO.

Correct. Even with "happy mode" engaged, you'll still spin both tires.

It's not perfect, but its better than nothing.

3002 tii · 10-03-2013, 12:06 PM

Best way is to enter an underground drift contest to find out

brusk · 10-03-2013, 09:15 PM

It will always be on, if you only spin one wheel slightly that's not enough for traction control to kick in. If both wheels start to spin too much then traction control kicks in.

As for the spinning the tires in the air recommendation that doesn't work with most LSD's. Most allow the rear diff to basically act open until there's enough of a wheel speed difference to lock the LSD portion whether it be viscous, clutch, helical or locker styles. I've tried this on every car i've had on the lift.

10-02-2013, 05:38 PM	#1
grunyon Enlisted Member 16 Rep 36 Posts Drives: 2008 BMW 135i Join Date: Apr 2012 Location: Flemington, NJ iTrader: (1)	I do two wheel burnouts? 2008 135i here with 6 speed MT When I launch hard enough to burn rubber, I leave two streaks perfectly even. Do I have a limited slip? I thought our cars didn't have one. Of course this is with traction control off.
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10-02-2013, 05:45 PM	#2
marc@x-ph.com Captain 15 Rep 678 Posts Drives: 2010 e92 335i Join Date: Sep 2013 Location: USA iTrader: (0)	You don't have a limited slip. but If you're going off in straight line, and grip on both sides is almost the same then power will go to both not favoring (in big manner) one over the other. Try to do it on water, or exiting a corner (be safe!!) and you'll definitely notice that only one wheel is spinning.
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10-02-2013, 05:52 PM	#3
Freon Major 81 Rep 1,051 Posts Drives: 2009 135i Join Date: Nov 2007 Location: Indianapolis iTrader: (3)	Even if grip is almost perfectly a car without any sort of LSD should spin only one tire. This is because grip is ever exactly even, the drivetrain isn't perfect, so once one wheel starts to spin even just slightly more than the other "it's over" and you have one wheel peel. It's a positive feedback loop--a runaway condition. The real reason you lay two strips down in a modern non-M BMW is the car has an "eLSD" which uses the brakes to keep you from spinning just one tire. Once one tire starts to spin more than the other the brakes are applied which transfers torque back to the non-spinning wheel. __________________ 2009 BMW 135i 6MT Sport, AFE intake, Cobb AP, Apex 18x8.5+9.5, 255/275 PSS Last edited by Freon; 10-02-2013 at 06:00 PM..
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10-02-2013, 06:05 PM	#4
Dackelone European Editor 10532 Rep 22,992 Posts Drives: N54 e82 Join Date: Feb 2010 Location: Bayern, Germany iTrader: (1)	...jack your car up in the air (both rear wheels off the ground)... AND with the trans in neutral... now spin one of the rear wheels forward... IF your car has a LSD the "other" side wheel will rotate in the same direction. This will mean your LSD is working. But most likely the other wheel will spin in the opposite direction, which means your car does NOT have a LSD, but a open diff. The e-diff (which is part of bmw's DTC system), uses the ABS system rear brakes to control wheel spin actually does a pretty good job when launching the car. But I would think you turned off the DSC when doing a "burn out". __________________ Dackel's European Delivery Museum Guide
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10-02-2013, 07:43 PM	#5
Davyhay First Lieutenant 33 Rep 316 Posts Drives: 2008 135i Join Date: Aug 2013 Location: Montgomery, AL. iTrader: (1)	Mine lays down rubber with both wheels as well. decided to try this out, yesterday on a deserted road. Yes, at nearly 40, I am still a child.
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10-03-2013, 12:28 AM	#7
froop Colonel 171 Rep 2,682 Posts Drives: 08 AW 6MT E82 Join Date: Jul 2012 Location: Sydney, Australia iTrader: (3)	Quite sure that the e-diff is active at all times wether with DSC, DTC or TIMYOYO. __________________ froop's AW 135i Build Thread
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10-03-2013, 12:55 AM	#8
NORAGRETS Colonel 441 Rep 2,036 Posts Drives: 2017 F80 M3 ZCP BSM 2012 E82 1 Join Date: May 2012 Location: Boston, MA iTrader: (0) Garage List 2017 BMW M3 ZCP LCI [0.00]	Only thing holding me back from Drifting my rear tires to the bone: MPSS $$. Wahhhh __________________ 2017 F80 ZCP BSM - Klein Innovation. ActiveAutowerkes. AR Design. BootMod3 Paul Johnson. EvRw. Project Gamma. RW Carbon. UCP. UUC. Hawk. Dinan. NGK. Macht Schnell. TMS. VR. aFe. RIP - E82 135i - 7/7/2021
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10-03-2013, 12:06 PM	#10
3002 tii Lieutenant General 2282 Rep 12,565 Posts Drives: Z4 M, X5, GX460 Join Date: Apr 2008 Location: CT iTrader: (99) Garage List F15 X5 xDrive35i [8.75] E86 Z4 M [10.00] F10 550i (Retired) [9.17] F25 X3 xDrive35i (R ... [9.43] E82 135is (Retired) [9.50] E85 Z4 M (Retired) [9.41] E90 328i xDrive (Re ... [9.25] E86 Z4 3.0si (Retired) [9.22]	Best way is to enter an underground drift contest to find out __________________ Follow for latest mods
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10-03-2013, 09:15 PM	#11
brusk Lieutenant 33 Rep 578 Posts Drives: 2008 135i Coupe Join Date: Jan 2012 Location: Cleveland, TN iTrader: (1)	It will always be on, if you only spin one wheel slightly that's not enough for traction control to kick in. If both wheels start to spin too much then traction control kicks in. As for the spinning the tires in the air recommendation that doesn't work with most LSD's. Most allow the rear diff to basically act open until there's enough of a wheel speed difference to lock the LSD portion whether it be viscous, clutch, helical or locker styles. I've tried this on every car i've had on the lift. __________________ 2008 135i - MHD/JB4, MS DP's, AMS IC, UI CAI, CDV delete, M3 control arms/Links, RE Toe Link, ECS Trailing Arm, M3 rear SF & Trans bushings, SS brake lines, Michelin PSS.
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