it is really frustrating ot me that this has all happened. We wanted it 2 years ago and they said 30 units. Now they may do less, but at a higher cost. Really frustrates me a great deal!

You would think they would jump to sell ten units!

Regardless, we are alos looking into another option using a very well known diff builder.

Thanks

Brad

 

AaronC,

Count me in as somebody who would be interested in the LSD. Can it be built to our specifications? Will they examine the components and come up with an optimal? Will it be 1.5 or 2? will they have to do any ESP tweaks? I know ESP is supposed to be our makeshift electronic LSD right now. How does AMG do it when they install their LSD in Germany.

Has anybody done the LSD install in germany - maybe I should post this question in the amg-owners board to see what they say and what AMG had to do to make it all happen.

Thanks for doing some good investigation and hope this pans out.

Prasith

 

lets see some prices.... i know I will have to pay more but if MKB sells for over a grand and they can get the price down to just a few hundred bucks and still acheive the same function just as well then im in!!!!

 

Pricing will be minimum $1500 for the LSD and $500 for the install, that would be my guess. So if anyone won't spend the minimum 2 grand then they might as well forget it.

Also, who is going to send there Diff to Europe for a month or two while they prototype a unit?

 

I have at least 4 people from the r170 forum on b e n z w o r l d interested and hopefully a few more, depending on price. What is the total count? Surely we passed 10 and are approaching 20. If it was in the same price range as there other diffs, I would hope most people would go for it.

 

You don't have to spell benzworld like that. We do not block the word like they do over there for us.

FYI... From what we were told, it will be nearly $2000 for just the diff without installation in this quantity. If we could get 30 ordered, it would be 1/2 the price. As such, we are looking at another source. If you can get them to do it for the non-quantity price, I think that I could get a few customers immediately to be interested, and I know we would take some.

Thanks

Brad

 

Brad or Vadim, can you comment on how the LSD from any manufacturer will work with the C32's electronic programing that has been of concern and debate in other threads. I just makes no sense that some of the MB tuners would go out of their way to make a custom LSD that needs software programming when they could have made a turn key unit from Quaife or the like at a significant reduction in price. Will the Quaife or your other source be a direct bolt on and work flawlessly with the stock C32 software?

 

smgc32: there is a set of final gear for our C32... but you gotta get them in germany from AMG.

"...Toss out the computer chip that restricts its top speed (something AMG does quietly for customers who insist on running with 911s on the autobahns), and the C32 tops out at 175 mph. Change the final drive, as some clients demand, and the engineers whisper that it's closer to 190 mph. "

i suppose that will be a taller/smaller final gear?

 

OK, so what kind of effect a Limited Slip Differential will have on ESP?

First, let's establish ESP's function. ESP uses ABS sensors at all 4-wheels to monitor wheels' speed. When speed at rear wheel or wheels exceed speed of front wheels by certain percentage, ESP interferces by either applying rear brakes or reducing throttle plate angle, thus reducing power.

Since, factory differential is open, i.e. if one rear wheel looses traction there is not power transfer to other rear wheel, ESP is used to control the wheel that looses traction.

Quaife or more typical clutch-type limited slip differential will try to spread power to both wheels thus reducing speed differential between rear and front wheels.

So in theory should be no adverse affect on ESP function. AMG offers LSD as an option in Germany, but it has to be retrofitted at the factory. Now whether they reprogramm ESP or not is the question for German C32 owners.

For now only experience with one will tell.

Personally watching our C32 with over 400 RWHP smoke right rear tire half way around the track gets tiring very quickly. All that smoke is wasted seconds that could off put our C32 ahead of all-wheel drive Audis in this years EuroTuner GP.

 

Thanks Vadim for some insight into the operation of ESP as it relates to the LSD. How do you think this affects my brake issue at the track? Could the reverse be true: If the front wheels are spinning faster than the rears, ESP/ABS applies force to the brake on the wheel that is spinning faster which in this case is on the front axle? But in a left hand turn the drivers side wheel should be the one spinning faster as it is lighter and may even lift off the ground, but it is the passenger side that is interviening. Very troubling situation to think about. Your input in the other thread on track day failure would be greatly appreaciated.

 

https://mbworld.org/forums/showthrea...516#post804516

 

So what is this: A post from some guy named TwinTurbo who "thinks" that software is not required and "thinks" that Kleeman makes an LSD and he does not even own a Benz. Then he says "Don't quote me on this".

This is not an answer

 

Can we rehash this?

Suppose in a stock C32 the right wheel has less traction than the left wheel. The open differential transmits equal torque to the right and left wheels, with the amount of torque limited to amount of traction possible of the wheel with the least amount of traction, in this example, the right one.

At some threshold of spin rate difference between the two rear wheels, lets call this T1, doesn't ESP brake the wheel with the the highest spin rate (i.e., least traction) to reduce the spin rate differential? Presumably this in a function with some sort of hysteresis. In any event, if ESP does this, the brake system is now interfering with (i.e., reducing) power delivery. In the stock car this is advantageous since you need to be able to apply more torque to the wheel with good traction.

Suppose we replace the open differential with a limited slip. Absent ESP, the limited slip will allow torque to be distributed to both wheels, within a limit. This limit corresponds to a certain wheel spin rate difference, lets call this T2.

Now suppose T2 just happens to be greater than T1. If my assumptions are correct, then ESP will cause brake the least traction wheel when the threshold reaches T1. But one of the goals of replacing the open diff with a LSD is to permit power delivery up to a spin differential of T2, so ESP at least partially defeats the advantages of having an LSD under this scenario right?

If the above is true, then the question is where is T1? If T1 is non-zero and reasonably high, then the LSD is advantageous because you can apply more power below T1 with the LSD. If T1 is zero or very low, I don't really see a benefit to the LSD absent changing the parameters in the ESP program. If T1 = T2, that would seem ideal.

Is my analysis wrong?

 

estimate gains you guys think this will produce??

 

i'm sorry guys... i still can't see anything ESP gotta do with a faster differential with better accurate traction?
i can only see ESP is now do less... correct me if i'm wrong...

what do we gain? faster in the corners i suppose. the only AMG car has LSD is the CLK DTM AMG, its real fast, and indeed, the weakest part of our car is lacking a LSD...

 

One thing to remember is that ASR which is the traction control of the ESP system only operates below 40kph. So this artificial LSD called ASR does no good above 40kph (about 25mph).

 

So why can't we order the LSD units that are already engineered by AMG? I can't imagine why it must be installed at the factory. I can not believe they sell this car without an LSD. That is the weakest part about my girlfriends C32. No LSD plus the ridiculous traction control settings make for not much fun at the track or even spirited driving on the street.

I'm not sure I would even go with a Quaife on this car. Quaife's require a different suspension setup to work well and you must insure the wheels are always in contact with the pavement. I imagine that a clutch type LSD might work better and possibly be cheaper. What kind of LSD does AMG use?

Juan Bruce
VP BMW CCA GGC
'95 M3
'85 M635CSi
'02 C32 (girlfriends car)

 

You no more need a different suspension with the Quaife than you do with any other LSD.

The statement about always having to keep both wheels in contact with the pavement is not true. It is a wives tale that the Diff will explode if one wheel looses contact.

While a clutch type does have some advantages there are a number of disadvantages, 1) Noise, 2) Break in Period, 3) Special Diff Fluid, 4) Clutches wear out, 5) Getting the Diff properly set-up can be time consuming and require taking the Diff apart a number of times.

A clutch type is probably a littel better for the drag strip, but the Quaife is a better all around choice.

 

Lets examine the statement about keeping both wheels in contact with the pavement. The Quaife provides a multiple of the torque sent to the lower traction tire to the higher traction tire. So multiplying zero at one side times say 4-5 and you get still zero. Whereas with clutch type you always get something (including when you don't want LS action such as at turn-in).

In terms of the other things you mention.
1 Noise - they can be more noisy but they don't have to be if you use the correct fluid. BMWs have used clutch type diffs for years without noise being a problem.
2. Break in - true
3. Special Fluid - fine but no big deal since its widely available, many cars use it from the factory and you are installing a whole new diff anyway.
4. Clutches wear out - true but they can last a long time very effectively. Again see the BMW LSDs as an example.
5). Diff set-up - you also need to do some with a Quaife as it has belleville washers (dished) inside of it that provide an initial clutch type action side to side.

You also typically set up the car differently, with a Quaife ideally with much less rear bar, and different damper settings.

Don't get me wrong, a Quaife can work very well. I've experienced it in some front drive cars and rear engined cars but its not guarantee to work better out of the box than a clutch type LSD. Either one can require some tuning to get the set-up right. I'm simply suggesting that if AMG already did their homework on creating an LSD set-up for the car it my be worth trying first. Odds are it already works well with the stock suspension set-up. No need to sink lots an time and money to reinvent the wheel (or ideal suspension set up). My hunch is that they are using a clutch type diff. Lets find out more about what they use. Anyone know?

Of course if you look at there traction control tuning maybe MB/AMG does not really want you to get into a situation where you would find out how well the LSD helps you put the power down out of a corner.

 

Juan - hey nice to see you here!

 

Thanks Brad. My new girlfriend's C32 has gotten me curious about the MB world. She's anxious to get out on the track but already thinking about trading the C32 in for an M3 after a few laps around Thunderhill a few weeks ago.

 

car can be fast, but needs a diff and more camber!

We were only a few seconds behind Stasis (Lambert) in their World Challenge a4 at the streets of willow. If we would have had the above things, we would have rocked it!

Thanks

Brad

 

Agreed but no one seems to be able to source AMG factory only modificaton parts. They treat their European customers differently. That or MB USA gets in the way. AMG has a lot of great stuff for customers who can bring their cars to Germany but us NA customers have to try this route.

 

Here is some pricing I have found for the various LSD's available in Europe:

AMG: 3.800,00 EUR (including fitting and VAT) 30% with ESP adjustment
MKB: 5.318,60 EUR (including fitting & VAT) for a CLK 55 (45%, but no ESP-adjustment)
Brabus: 6.310,40 EUR (including fitting & VAT) for a CLK 500 / E55 (40%, but no ESP-adjustment)

When it says including fitting they do not mean it includes install, they mean installation is extra. So these are way to pricey and the AMG one is only available to be installed at the factory, therefore no U.S. installs.

 

Ok I will base my responses on my experiences.

1) I have been in & driven cars with clutch type Diffs that are very noisy even using correct break in & fluid. The noise was very noticeble both in and out of the car.

3) The fluids might be readily available but they require more frequent fluid changes and the fluid can be expsensive.

4) True they can last a very long time. Only problems I have really seen with their longevity is when they are improperly installed, not properly broken in, or very much abused.

5) My experience with the Quafie is it was basically plug & play. No setup required, no washers to set no nothing. All you have to do is install it properly and replace the appropriate bearings. Compare that to the clutch type which you can add or remove the clutches and change their oreintation. I have seen guys take apart and reassemble their Diffs 5, 8, 10 times to get the setting correct.

I agree I would love to try the AMG LSD. But I am willing to bet that wont be an option for us in the states.