bpppp

HEy Everyone,

I bought my c63 back in June. From Calgary, Canada. Ive heard alot talk about the performance package and the LSD. I was one of the last people in Canada to receive the 08 model and belive it or not my car is equipped with an LSD. What tipped me off is that it stated in my owners manual that my car has a self locking differential that will will require an oil change at 3000km or 1900miles. I showed this to the dealership which they were puzzled by as they were under the assupmtion that only 09 c63 with the perfromance package should have the LSD. They asked if they could put it up on the hoist and for sure it has an LSD.

I asked them how this could be and they have no clue why some 08 were equipped with the LSD. I beleive there is one other member on this forum from Canada who also had this written in their owners manual.

Now I definately dont have the performance package my car is fully loaded with every other option.

My question is has anyone else run into this with an 08.

Oh yeah here are 2 pics of my car. Black on Black baby!!!!!

gsrjc

Very interesting... so the technicians at the dealership confirmed that you had an LSD. One way that you could confirm for yourself is to jack up the rear of the car, then move one of the rear wheels. If the wheel on the other side moves in the opposite direction, then BINGO, you do have an LSD.

bpppp

YEs, thats exactly what they did. They brought me into the service bay because i did not belive them. They spun the right rear wheel and the left rear wheel spun the opposite way.


They told me my car definately had an LSD. Thats why Im interested to see if any one else with an 08 has checked this and how may 08s did they put the LSD on.

I havent track the car but i have done some very aggressive accelerations and it will definately lay two patches of rubber.

MRAMG1

Ah, you have that backwards my friend. If you jack the rear off the ground and spin one, and the other goes in the opposite direction, you have a OPEN rear end. Thats the spider gear set causing that opposite direction. If they BOTH spin in the SAME direction, you have a LSD.
Note, the car would have to be in neutral to spin in the same direction, hence if you can't spin it, you have a LSD as well.

See yeah

PS: My custon Auborn I had you could actually change wheels with one wheel in the air. It would grip that tightly

MRAMG1

Hate to tell you my friend, but if they spun in opposite directions, you have the standard OPEN rear end. Those two patches of rubber you see, is from a straight line launch, and the ESP electronics. Try going around a tight radius right hander, and punch the gas. I'll bet it lights up the inside tire for a second, and then its ESP lights on baby and NO MORE FUN for you.

Sorry

See yeah

gsrjc

My IS300 had LSD and they spun in opposite directions.

MRAMG1

Don't see how that is possiable my friend. I don't have a picture of a diff handy, but lets think about it for a minute:

1. A diff works by using a set of spider gears to allow difference in corning speed. Most use four spider gears, one on each axle, and two inbetween, LIKE ALL MB diffs by the way.
2. ALL LSD, wether clucth style, gleason torsen, or cone type work by applying pressure to the spider gear that reside on the ends of the axles.
3. If there is NO pressure, ie open rear end, the spider gears are free to rotate. Hence spin one side clockwise, the opposite side MUST spin counter clockwise.
4. If there is pressure on the spider gears, it forces the ring gear to spin instead acting like a binder on one of the spider gears, hence they BOTH spin in the same direction.

Please keep in mind that I REALLY made this overly simplistic. Go to Auborns website, Gleason torsen, Quaifi, Phatom grip, etc and they will explain this in MUCH more detail.

If the rear wheels spin freely, with NO resistance, in opposite dircetions, you have a NON LSD rear my friend. Its simple physics of a differential.

Note: ALL LSD's besides lockers have a breaking point in the amount of pressure that they can apply. Some, like clucth packs can break free with about 40-50 ft/lbs of force. Actually that is the test for a FORD Posi set up, which you jack one wheel off the ground and place a torque wrench on it. If it takes more than 50 ft/lbs to spin the wheel, the posi is good. Some require severl hundreds of pounds of force such as racing units.

See yeah:zoom

PS: Go here http://auto.howstuffworks.com/differential2.htm

gsrjc

hmmm.... so what is an advantage of an open rear end?

andy_meng1024

My W203 C280 4Matic does that, too. When I move one wheel in the front or back, the one on the other side moves in opposite direction. Does that mean my car has LSD on both front and back?

MRAMG1

In a word NONE

Its just cheaper to manufacture

Sorry for the bad news, see yeah

IwantA124

lol

whoover

An LSD has several drawbacks. Rear tire wear is higher and handling is not as predictable. It increases traction, but at the expense of less linear handling characteristics. Typically, there will be greater oversteer in the wet and greater understeer in the dry. The AMG LSD has different lock ratios under power and on underrun, which make the understeer/oversteer changes even more complicated. Not knowing any of this is a good formula for winding up off the road if you go all out with an LSD and no experience.

You can certainly lap faster with an LSD but the increased traction comes at the expense of some twitchiness that the driver must master. That, tire wear and increased maintenance (you have to change the diff oil regularly because the LSD works with friction surfaces that shed metal particles) are why AMG is conservative about their fitting.

Hans Delbruck

My 2008 owner's manual also discusses an LSD and the fluid change interval; doesn't mean the car has one though. There is an asterisk *in cars equipped with AMG Performance package. If your car has the LSD it would be listed on the window sticker....

Congrats on your new car! You made a great choice

MRAMG1

Okay, lets look at you statements a little bit my firned:

1."Rear tire wear is higher and handling is not as predictable." Yes and No, without a posi/LSD you will spin one wheel more often, making that tire usually right rear wear FASTER than then the left wheel. Handling, NO WAY is it less preedictable. By having BOTH rear wheels driven the car is WAY more predictable as the rear end will feel more planted. It could, and I use this word cautiously, cause the rear to want to come around, but ONLY under HARD accerleration. Note, this can also be a VERY enjoyable situation as well

2."Typically, there will be greater oversteer in the wet and greater understeer in the dry". While this is true, you are taking it to an extreme. Yes the rear end is tighter, hence more understeer during dry, but the differenece is VERY small. Oversteer in the wet could happen, but it will also allow you to go up a snowy hill, or get out of a ditch if you would slide because both wheels are driven. This SMALL difference in hadling is MORE than compensated for by being able to apply power SOONER when exiting a corner, and by having NO inner wheel spin during the exit. And of course the abilty to be driven in adverse weather is a HUGE plus.

3."That, tire wear and increased maintenance (you have to change the diff oil regularly because the LSD works with friction surfaces that shed metal particles) are why AMG is conservative about their fitting." Okay I already spoke about tire wear, so lets look at maintenace. Yes MB recomends changing the fluid, but do you not change your oil? The once at 3000 and then at 30,000 is a VERY small price to pay to ahve a better gripping, harder charging, able to drive in the snow vehicle IMHO.

Overall, I have NEVER had a car that made me MAD that it had a LSD/Posi. I can say that 3 vehicles in my last 25 years of driving that I had made me very mad that they did not have a LSD/Posi do to one wheel burn outs, or stcuk in snow.

The bottom line is there are NO real drawbacks, except for cost of the unit. The car is MORE predictable, as both wheels are driven. Drive ANY car with a LSD, and then drive the same car without one, and I can assure you which one you would want to own

Oh well, sorry for the long post, but ALL performance cars REQUIRE a LSD to enjoy, and SAFLY be driven IMHO.

See yeah

whoover

Excessive tire wear is inherent in the way an LSD works. An open differential allows the wheels to spin at the speeds they "want" to during turns (faster on the outside). An LSD constrains the outside wheel from turning as fast as it should because it senses it slipping. (The LSD can't tell the difference between the left wheel turning faster than the right because it's lost traction or because it's gripping fine during a right turn. In either case it diverts torque to the right wheel and slows down the left.) In a turn, the inside wheel scrubs with an LSD. Even if your grandmother drives the car for 10,000 milles, your rear tires will wear noticably faster.

A discussion of the safety vs. traction issue of 2-way or 1.5-way LSDs (like AMG's) is found in the wikipedia article:

http://en.wikipedia.org/wiki/Limited_slip_differential

Most people would consider higher maintenance cost (tires and regular diff oil changes) a drawback. Very possibly worth it to you, but a cost is a cost.

MRAMG1

I agree if you drive like your grandmother, a LSD will cause tires to wear quicker. Now if you drive like any normal AMG owner

Go look at ANY AMG, including yours, and you will see that the passenger side rear wears QUICKER than the drivers side. Why, because of one wheel spin, aka NO LSD. Long and the short of it, I think we can simply agree to disagree. You will never convince me that there are ANY advantages to owning a open differential my friend, as there are simply way too many drawbacks IMHO. Good luck and enjoy.

See yeah

whoover

Actually, while I drive very hard my tires always wear very evenly. Very fast, but evenly. If I had greater wear on one side I'd check my alignment since I keep close tabs on my tire pressure.

MRAMG1

LSD use:

I guess Porche S's, BMW M's, Lambos, F cars, GM, Ford, Chrysler, Dodge, Toyota, Acura, etc, etc, are all wrong when using LSD's in ALL of their sport cars and should switch back to open diffs with electronics then since they are are better than a LSD

Okay NOT

I siad once, and I will say it again ANY sports car REQUIRES a LSD to maximize its driving capabilities. Sorry, but its true.

See yeah

whoover

You seem to think I said LSDs aren't good things to have. Especially in a performance car, they're very useful. I'd take one in a minute.

But you 're also insisting that they have no drawbacks or costs. That was the question I was answering, and I maintain they do. I've cited authorities discussing the handling inconsistencies that can get the inexperienced driver in trouble, and the additional maintenance costs involved. And AMG's product managers have said that it was these considerations, not the relatively modest cost, that prevent them from using them more widely.

To respond "I guess Porche S's, BMW M's, Lambos, F cars, GM, Ford, Chrysler, Dodge, Toyota, Acura, etc, etc, are all wrong" as proof that there is no downside is not compelling. You might as well say "there are no downsides to LSDs because I say so," which is essentially what you're saying. That's cool. Opinions are good too.

MRAMG1

I will agree that a simple oil change, can be a pain in the, well you know. But for all the advantages that a LSD gives you, I can only say "YES, it is a must item on my list"

The argument about tire wear, and problamatic handling are just not valid, and I beleive that I have explained that quite well enough my friend. It is not my opinion, it is Car 101, Facts that every reputable enthusiast knows, and trusts. I won't waste anymore posts on this subject as the message is VERY clear. I will leave you with one last idea, " To each his own" Have fun.

See yeah

Star & Laurel

LSD or Open diff you can get the wheels to do either or. If the car is in Park meaning the shaft from trans to diff is locked your wheels will always turn opposite due to the simple fact that the driveshaft can't turn. The LSD will be harder to spin compared to the open due to the friction that is in the diff. But that is a matter of the technician being able to feel the difference.

Now if the car is in neutral meaning the driveshaft can spin freely and you perform the same test of spinning one wheel. With an open diff you will most likely see the other side spin opposite since there isn't enough friction in there to spin the driveshaft going to trans and with an LSD typically the friction is enough that both wheels will spin the same direction and the shaft up to the trans will spin.

Ultimately to know if you have an LSD the end all be all is open the diff cover and see what you have. Otherwise it is all guessing.

1Lop2K5C

On another note, not all of the Porsche cars have LSD (996-997), the only P cars that have LSD are the GT3, GT3RS, GT2.

SuperCover

I had a 944 turbo SE back in 1990 with a L.S.D.

Made a big difference in handling compared to the standard 944 turbo...IMO! Insofar as you felt more confident around corners....

Mark.