95gsrturbo

Ive had my car only a few months.
My VIN breakdown doesn't show LSD as an option.
Neither does my window sticker options sheet.

But i was playing with Race Start mode after work and i noticed the pic below

If i dont have n LSD.... Can i still lay tracks like this?

BLKROKT

Yes it is still possible without an LSD.

DiscoBandit

The only difference is, with LSD the tracks might change shapes and turn more vibrant colors

95gsrturbo

Please elaborate.

My understanding is without an LSD only one wheel is being driven by the driveshaft.

If this is the case, then the other wheel is a follower just like the front wheels. So how did i lay tread with both wheels

_Ryan

Put your car up on a lift or jackstands and CAREFULLY put it into gear. Notice how both tires spin the same speed? This is because traction) or in this case, lack of traction) is equal on both tires. As long as the forces on each tire are the same, both will receive 50% of the power. An open differential allows power to be transferred when the forces on each tire differ. In the case of the photo above, the forces on each tire were near enough to allow both to receive enough power to spin.

This doesn't mean that whenever you are on pavement they will both spin. There are other forces at work like weight shift when launching, temperatures, etc. Sometimes you may only get one to spin but it is possible, when conditions are right, to spin both equally. An LSD will equalize the forces when they are not identical.

95gsrturbo

So the Differential DOES apply power to both wheels, but not always....

While the LSD ensures equal force to each at all times?

jptaylor

Ok, let's dive into this.....
An open differential is NO different than a fully locked differential-----so long as there is equal traction available to both wheels. Once that traction shifts bias to one tire however an open diff will send more and more power to THAT wheel, path of least resistance. Now a limited will help with traction but keep in mind that in order for the limited slip to begin working it MUST see slip to start the LIMITING....if the less tractive tire is spinning TOO quickly then no limited slip on the planet will reel it back in. A locker on the otherhand does just that, it mechanically locks the rear axles together so they spin the same speed, all the time, ALWAYS....GREAT for traction, sucks for handling.

Now to check for limited slip in any rear wheel drive vehicle do the following......

Jack up the rear end and put the car in neutral
Spin one rear tire, either one, doesn't matter
Look at the OTHER tire---
if the other tire is spinning in the OPPOSITE direction then you have an OPEN differential
if the other tire is spinning in the SAME direction then you have a LIMITED SLIP differential

Jasonoff

Open diff

zcct04

Cars without a LSD use traction control to try to accomplish a similar feat. If the car senses one wheel spinning faster than the other, it applies brake to the one spinning fastest. The upside is that you get equal power delivered to both wheels (and two matching black tire marks). The downside is that the car accomplishes that by applying brakes, slowing your acceleration.

chrisridebike8

Don't forget that even with ESP off, the car still brakes the wheel that is spinning faster to try and act like an LSD. In a straight line, it works ok. Coming out of a tight corner on a track...not so much.

jptaylor

With ESP off it does not brake to control wheelspin, that is what ESP is for.....

Mort

Yes it does or at least that is what it says in the Operator's Manual.

ETS/4ETS(Electronic Traction Control)
The traction control is part of ESP.
Traction control brakes the drive wheels individually if they spin. Etc......
Traction control remains active if you deactivate ESP.

jptaylor

Mort I have seen that and have questioned it ever since given the fact that if you matte the throttle in c63 from a dig it will spin the rear tire/tires uninterrupted until you let off, also if you are in a drift with ESC off you find you and you alone in control of the attitude of the car. If any part of the abs/ESC/traction control stayed active it SHOULD step in under those conditions, and it does not. I have owned other vehicles where you could disable the ESC as well but they would all step in and pull the car back under control. But you are 100% correct in that it does say that in the manual

Jasonoff

If you have ESC off and activate ABS it does kick back in temporarily. This is easy to demonstrate in the snow.

jptaylor

Ok, THAT would make sense if it is front abs only, as in if it detects a front skid.....but with the rear end on jackstands and ESC in the off position there is NO interference from the safety systems no matter what you do with the throttle.

Additionally, we have a dyno mode accessible through the engineering menu BUT how many of you guys have had to use dyno mode for the dyno? I know that I never have, just ESC off, but I've also always been on 4 wheel dyno with the front rollers in the locked position. If ESC or ABS did step in while in OFF mode then a dyno run would be impossible.....and trust me guys, I'm not arguing with ANYONE here, just trying to think out loud through our different experiences (like the snow comment)

BLKROKT

You also haven't mentioned that doing big smokey burnouts at the dragstrip (or anywhere else for that matter), wouldn't be possible either with just ESC off.

jptaylor

That's what makes me now think any safety intervention when ESC is off must come from front wheel input....

Mort

Maybe when both wheels get spinning ETS shuts off or is not activated. It only works when just one wheel is spinning.

QWKSNKE

Interesting to note that this design with some clutch packs underneath the driver side spider gear is what the American cars call a limited slip. I would be willing to bet that the C63 is designed the same way. My 2008 manual states that all c63's come with LSD even though my vin breakdown does not carry 'the code'. I would love to see pics of a carrier out of a base c63 to confirm.

However just like in the mustang/camaro/ 4wd truck world, the aftermarket units are much 'tighter' in the amount of slip allowed as compared to the oem units and rarely will wear out enough to develop the 1 wheel peel as my mustang oem LSD units have done after many beating at the track

zcct04

Partially correct: the ABS will still function even if the ESC is off. However, what 'kicks in' is just the ABS, not the traction control.

jptaylor

It cant be ABS, at least not unless it is only in relation to the front wheels

95gsrturbo

Now I'm more confused

Jasonoff

Your car must be different than mine then.

Try throttle lift OS in the snow then slam on the brakes mid way. The nannies help keep the rear in check. It's nearly identical to ESP on throttle lift OS without touching the brakes. It suggests the systems are tied together.

chrisridebike8

Yeah. When you are driving with ESP off and engage ABS, the car essentially says "you told me you could handle this. But clearly you cannot, so I'll help you out so you don't kill yourself..."

jptaylor

But what I'm saying is that this abs intervention NEVER happens as long as just the rear is involved in the slip/skid, ie drifting, burnouts, dyno runs.....think about it-if it did step back in you would never be able to break the rear end loose without it throwing out the anchor to reel you back in