No LSD... Please explain

kc_skyrider · 09-09-2009, 02:09 PM

So to start of let me calm everyone about to set me on fire.
1 I know the car doesn't line up with the skids because it was to dark when they were laid for a pic.
2 I know they are pointed at a house and cars I never exceeded 40kmph of actually speed moving foward
3 This was on a private paved section and the owner approved
4 The houses immediatly around the area recieve alot of low cost repairs from the shop I did this in front of so they do not mind when one of us occasionally does this, more often than not they come out with cameras and it's far more quite than the Lambos the shop owner drives.

With all that said the POINT is HOW is it that my car always lays two skids. I translate this into both tires getting enough power to spin. and judging by the rubber pretty close to equally! I have not added an LSD. In this instance I disabled all TC except E-LSD obviously started a lil spin in 1st as soon as they broke loose I threw it in 2nd and left the long skid you see here. The surface was dry and about 65-70F.

For those of you new on here I've always seen people discribe their "burnout" as one tire for approx 10ft then the other for the next 10ft or so. We've had extensive discussions on how this is the E-LSD doing it's best to distribute the power but being overloaded and unable to allow both wheels enough power to break traction. The thing is my car does this all the time. I've recently upgraded to direzza star specs so I have been having fun with the run craps and I ALWAYS get a identical burn out. BOTH TIRES are spinning. My question is why and is anyone else seeing this and I'm just nuts?

Oh and PS how cool is it that I appear to be getting the same launch as a LSD

MadMan77 · 09-09-2009, 02:33 PM

Go around a corner with the tires spinning. You will get a the single tire mark.

kc_skyrider · 09-09-2009, 02:37 PM

Quote:

Originally Posted by MadMan77

Go around a corner with the tires spinning. You will get a the single tire mark.

The closest I've come on that is a burn out in a sharp drift angle. but that probably isn't enough. However it is my understanding that even in a straight line I should only have one tire spinning at a time... And does this mean that if I primarily drag this car that I shouldn't need a LSD?

SlicktopTTZ · 09-09-2009, 02:39 PM

Quote:

Originally Posted by MadMan77

Go around a corner with the tires spinning. You will get a the single tire mark.

That makes me sad. One of my favorite things about owning my 300zx is that I can leave a nice track around any turn I choose, with a nice counter-steer to arc me through. Looks like I will have to throw some money down on one of those wavetrak diffs.

imported_mega · 09-09-2009, 03:44 PM

every sharp turn on tail of the dragon my car leaves black marks on the inside tire

My135 · 09-09-2009, 03:55 PM

This photo is fake. The skid marks did not line up with the rear wheels and no smoke was generated by the burn out???

DocSean · 09-09-2009, 04:01 PM

Quote:

Originally Posted by My135

This photo is fake. The skid marks did not line up with the rear wheels and no smoke was generated by the burn out???

Dude...take 10 seconds and read the post.

kc_skyrider · 09-09-2009, 04:03 PM

Quote:

Originally Posted by My135

This photo is fake. The skid marks did not line up with the rear wheels and no smoke was generated by the burn out???

Wow. you get the situational awareness award for the day. READ BEFORE YOU WRITE!!! I took the pic the day after the burn out and didn't bother trying to make a legit fake. If your the photo police then look at the tread pattern. the fact is the car pictured left the marks pictured. I know because they are both mine. If you still doubt this I invite you to come see for yourself. Then we can head to Oktoberfest where you can buy me a beer!

PS before I get called out by the next guy yes the parking lights are also on! lol

My135 · 09-09-2009, 07:50 PM

OK, I did not get it the first time since I paid too much attention to look at the photo.

This is what you said: "I know the car doesn't line up with the skids because it was to dark when they were laid for a pic."; and I am right too.

Next time, please post some real picture to prove your point:-):-):-)

MadMan77 · 09-09-2009, 08:24 PM

Quote:

Originally Posted by My135

OK, I did not get it the first time since I paid too much attention to look at the photo.

This is what you said: "I know the car doesn't line up with the skids because it was to dark when they were laid for a pic."; and I am right too.

Next time, please post some real picture to prove your point:-):-):-)

How is that pic not real and how are you right as well?

joeo · 09-09-2009, 09:12 PM

An open differential will apply torque to the wheel with the least amount of traction. If both tires have the same amount of traction, both will spin, and you'll leave two nice patch marks.
If you put one tire on ice, and the other on dry pavement - the one on ice will spin. In the case of the 135i, the computer will apply the brake to the wheel on ice, and hence transfer power to the other wheel, and off you go.

The same happens around a turn. If you're going around a left hand turn quickly, the inside tire (driver's side in this case), get's light, and will spin if you're under power. Again, the computer will apply the brake to that wheel to transfer more power to the outside wheel.

-Joe
http://www.lovehorsepower.com

My135 · 09-09-2009, 09:22 PM

Hey, guys, plesae relax.

I wasn't saying anything negative. I've just simply pointed out something wrong with the photo.

As the original poster admitted, the skid mark was made prior this photo was taken. The photo only showed the car driving over the skid marks.

I thought picture is worth more than a 1000 words. I was looking at the photo and I was wondering how the skid marks were generated as shown in the photo. That is all.

MadMan77 · 09-09-2009, 10:15 PM

Just wondering where you were going with all that since everything was explained in the OP.

kc_skyrider · 09-10-2009, 12:57 AM

I understand how the open differential works. but I've never had traction so equally distributed that I can lay 10ft of skid on both tires. This is the first open differential I've owned that did this. My question is Are all 135i owners seeing this or is there something different in my car? And if I drag race can I depend on both tires getting near equal power every launch if so I might not spend ALOT of money on a LSD.

MadMan77 · 09-10-2009, 06:15 AM

In a straight line mine does the exact same thing. There is no need to worry.

kc_skyrider · 09-10-2009, 06:35 AM

Quote:

Originally Posted by MadMan77

In a straight line mine does the exact same thing. There is no need to worry.

So if I built this geared toward occasional drag racing an LSD would probably be a useless investment till I started to auto-x or tried drifting it.

imported_mega · 09-10-2009, 06:36 AM

Quote:

Originally Posted by kc_skyrider

So if I built this geared toward occasional drag racing an LSD would probably be a useless investment till I started to auto-x or tried drifting it.

bad choice for drag racing, that said, the odds of both wheels hooking up like that every time, are low

larryn · 09-10-2009, 07:53 AM

Simple. E-LSD. It simulates (as best as it can) a true limited slip diff. Going around a corner will let you also leave two patches. When you have the car in eLSD mode (DSC and DTC defeated), then the engine will not be throttled back.

Just like with an LSD, the car doesn't know it is nearly at a standstill, and just tries to keep both wheels consistently spinning. With eLSD, it uses the rear brakes on the faster spinning wheel (supposedly breaking loose). With both wheels spinning, as long as they are spinning at the same rate, which eLSD tries to make it keep doing, the system is functioning as designed. Remember it does not retard throttle...

imported_mega · 09-10-2009, 07:56 AM

Quote:

Originally Posted by larryn

Simple. E-LSD. It simulates (as best as it can) a true limited slip diff. Going around a corner will let you also leave two patches. When you have the car in eLSD mode (DSC and DTC defeated), then the engine will not be throttled back.

Just like with an LSD, the car doesn't know it is nearly at a standstill, and just tries to keep both wheels consistently spinning. With eLSD, it uses the rear brakes on the faster spinning wheel (supposedly breaking loose). With both wheels spinning, as long as they are spinning at the same rate, which eLSD tries to make it keep doing, the system is functioning as designed. Remember it does not retard throttle...

does not do that for me, I only ever get inside wheel screeching

it's a good idea, but it does not seem to work when pushed hard

larryn · 09-10-2009, 07:57 AM

Dunno what to tell you. I autocross all the time, and it works that way for me. Are you holding the traction control button for >3seconds beforehand? That puts you into eLSD mode.

imported_mega · 09-10-2009, 07:58 AM

Quote:

Originally Posted by larryn

Dunno what to tell you. I autocross all the time, and it works that way for me.

same, autocross, mountain runs, tail of the dragon, mine does not do that at all

inside wheel will spin sooo easy, soon as the body roll starts the weight transfers and it's spin city

there really is no excuse for not offering an LSD on these cars from the factory, RWD need them

larryn · 09-10-2009, 08:02 AM

Not arguing with wanting a true LSD... Usually reserved for ///M cars only though (right or wrong). Once BMW started adding traction control (of any sort), they reduced the application of locking diffs on their cars.

Btw, you responded before my edit... but wanted to post something from BMW's internal tech docs about eLSD... (in case some have not seen them - and it is directly relevant)

09-09-2009, 02:09 PM	#1
kc_skyrider Second Lieutenant 13 Rep 231 Posts Drives: 2009 135i M-Sport Join Date: Jun 2009 Location: Kindsbach, Germany iTrader: (1)	No LSD... Please explain So to start of let me calm everyone about to set me on fire. 1 I know the car doesn't line up with the skids because it was to dark when they were laid for a pic. 2 I know they are pointed at a house and cars I never exceeded 40kmph of actually speed moving foward 3 This was on a private paved section and the owner approved 4 The houses immediatly around the area recieve alot of low cost repairs from the shop I did this in front of so they do not mind when one of us occasionally does this, more often than not they come out with cameras and it's far more quite than the Lambos the shop owner drives. With all that said the POINT is HOW is it that my car always lays two skids. I translate this into both tires getting enough power to spin. and judging by the rubber pretty close to equally! I have not added an LSD. In this instance I disabled all TC except E-LSD obviously started a lil spin in 1st as soon as they broke loose I threw it in 2nd and left the long skid you see here. The surface was dry and about 65-70F. For those of you new on here I've always seen people discribe their "burnout" as one tire for approx 10ft then the other for the next 10ft or so. We've had extensive discussions on how this is the E-LSD doing it's best to distribute the power but being overloaded and unable to allow both wheels enough power to break traction. The thing is my car does this all the time. I've recently upgraded to direzza star specs so I have been having fun with the run craps and I ALWAYS get a identical burn out. BOTH TIRES are spinning. My question is why and is anyone else seeing this and I'm just nuts? Oh and PS how cool is it that I appear to be getting the same launch as a LSD
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09-09-2009, 02:33 PM	#2
MadMan77 ↓↓↓ Ex-Con ↓↓↓ 34 Rep 1,874 Posts Drives: Jet Black '08 135i Join Date: Apr 2008 Location: Yigo iTrader: (1)	Go around a corner with the tires spinning. You will get a the single tire mark. __________________
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09-09-2009, 03:44 PM	#5
imported_mega Colonel 122 Rep 2,199 Posts Drives: various bmw's Join Date: Jul 2007 Location: neverland iTrader: (0)	every sharp turn on tail of the dragon my car leaves black marks on the inside tire __________________ You only need two tools in life - WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape. Driving e82, e72, e85, R53 Gone but not forgotten.. 1974 2002, many various 3s.
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09-09-2009, 03:55 PM	#6
My135 Lieutenant Colonel 85 Rep 1,609 Posts Drives: Join Date: Mar 2008 iTrader: (0)	This photo is fake. The skid marks did not line up with the rear wheels and no smoke was generated by the burn out??? __________________ 7/08 135 Coupe, Crimson Red, 6 SP, Sport, Taupe Lette/Aluminum. Performance Mods: JB4 on Map 5, BMS DP Fix V3, Injen polished intake, AR Catless DP, Maddad resonated mid-pipes, aFe exhaust polished tips, ST Suspension Coil Over and Hotchkis front sway bar. Others: BMS OCC, BT Scanner, Mud Flap. Next Mods: AA Front Strut Brace.
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09-09-2009, 07:50 PM	#9
My135 Lieutenant Colonel 85 Rep 1,609 Posts Drives: Join Date: Mar 2008 iTrader: (0)	OK, I did not get it the first time since I paid too much attention to look at the photo. This is what you said: "I know the car doesn't line up with the skids because it was to dark when they were laid for a pic."; and I am right too. Next time, please post some real picture to prove your point:-):-):-) __________________ 7/08 135 Coupe, Crimson Red, 6 SP, Sport, Taupe Lette/Aluminum. Performance Mods: JB4 on Map 5, BMS DP Fix V3, Injen polished intake, AR Catless DP, Maddad resonated mid-pipes, aFe exhaust polished tips, ST Suspension Coil Over and Hotchkis front sway bar. Others: BMS OCC, BT Scanner, Mud Flap. Next Mods: AA Front Strut Brace.
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09-09-2009, 09:12 PM	#11
joeo Lieutenant 120 Rep 475 Posts Drives: 2009 Crimson Red 135i Join Date: Mar 2008 Location: Sterling, Va iTrader: (0) Garage List 2009 BMM 135i [9.50]	An open differential will apply torque to the wheel with the least amount of traction. If both tires have the same amount of traction, both will spin, and you'll leave two nice patch marks. If you put one tire on ice, and the other on dry pavement - the one on ice will spin. In the case of the 135i, the computer will apply the brake to the wheel on ice, and hence transfer power to the other wheel, and off you go. The same happens around a turn. If you're going around a left hand turn quickly, the inside tire (driver's side in this case), get's light, and will spin if you're under power. Again, the computer will apply the brake to that wheel to transfer more power to the outside wheel. -Joe http://www.lovehorsepower.com
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09-09-2009, 09:22 PM	#12
My135 Lieutenant Colonel 85 Rep 1,609 Posts Drives: Join Date: Mar 2008 iTrader: (0)	Hey, guys, plesae relax. I wasn't saying anything negative. I've just simply pointed out something wrong with the photo. As the original poster admitted, the skid mark was made prior this photo was taken. The photo only showed the car driving over the skid marks. I thought picture is worth more than a 1000 words. I was looking at the photo and I was wondering how the skid marks were generated as shown in the photo. That is all. __________________ 7/08 135 Coupe, Crimson Red, 6 SP, Sport, Taupe Lette/Aluminum. Performance Mods: JB4 on Map 5, BMS DP Fix V3, Injen polished intake, AR Catless DP, Maddad resonated mid-pipes, aFe exhaust polished tips, ST Suspension Coil Over and Hotchkis front sway bar. Others: BMS OCC, BT Scanner, Mud Flap. Next Mods: AA Front Strut Brace.
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09-09-2009, 10:15 PM	#13
MadMan77 ↓↓↓ Ex-Con ↓↓↓ 34 Rep 1,874 Posts Drives: Jet Black '08 135i Join Date: Apr 2008 Location: Yigo iTrader: (1)	Just wondering where you were going with all that since everything was explained in the OP. __________________
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09-10-2009, 12:57 AM	#14
kc_skyrider Second Lieutenant 13 Rep 231 Posts Drives: 2009 135i M-Sport Join Date: Jun 2009 Location: Kindsbach, Germany iTrader: (1)	I understand how the open differential works. but I've never had traction so equally distributed that I can lay 10ft of skid on both tires. This is the first open differential I've owned that did this. My question is Are all 135i owners seeing this or is there something different in my car? And if I drag race can I depend on both tires getting near equal power every launch if so I might not spend ALOT of money on a LSD. Last edited by kc_skyrider; 09-10-2009 at 03:21 AM..
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09-10-2009, 06:15 AM	#15
MadMan77 ↓↓↓ Ex-Con ↓↓↓ 34 Rep 1,874 Posts Drives: Jet Black '08 135i Join Date: Apr 2008 Location: Yigo iTrader: (1)	In a straight line mine does the exact same thing. There is no need to worry. __________________
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09-10-2009, 07:53 AM	#18
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	Simple. E-LSD. It simulates (as best as it can) a true limited slip diff. Going around a corner will let you also leave two patches. When you have the car in eLSD mode (DSC and DTC defeated), then the engine will not be throttled back. Just like with an LSD, the car doesn't know it is nearly at a standstill, and just tries to keep both wheels consistently spinning. With eLSD, it uses the rear brakes on the faster spinning wheel (supposedly breaking loose). With both wheels spinning, as long as they are spinning at the same rate, which eLSD tries to make it keep doing, the system is functioning as designed. Remember it does not retard throttle...
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09-10-2009, 07:57 AM	#20
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	Dunno what to tell you. I autocross all the time, and it works that way for me. Are you holding the traction control button for >3seconds beforehand? That puts you into eLSD mode.
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09-10-2009, 08:02 AM	#22
larryn Lieutenant General 2148 Rep 10,176 Posts Drives: '97 332ti, '21 X5 45e, '16 GT4 Join Date: May 2005 Location: Seattle iTrader: (2)	Not arguing with wanting a true LSD... Usually reserved for ///M cars only though (right or wrong). Once BMW started adding traction control (of any sort), they reduced the application of locking diffs on their cars. Btw, you responded before my edit... but wanted to post something from BMW's internal tech docs about eLSD... (in case some have not seen them - and it is directly relevant) Attached Images
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