PDC

How much difference would a rear diff. mod make to a W208 CLK 55? Stock ratio is 2.82. I note the new C55 and CLK55 (both naturally aspirated) post noticably better 0-60 times and 1/4 mile passes and they both have a 3.07 rear diff. Is this a mod worth pursuing in a W208 CLK55? I think Berg Werks sells upgraded diff's with deeper ratios, but I would like to hear from someone who has done this mod for some real world feedback. Thanks All!

Fast55

I believe E55Cent has made this mod or is planning it soon. It makes a big difference in any car or truck. That small change probably won't hurt mileage or top speed much. It is expensive however, and there is a trade off with the increased RPM's.

E55Cent

Hey Brad, whats up?
I did a some research on this project and I can get it done for $1800 and that includes the new 3.27 diff, new bearings and a new ECU for the tranny. The 3.27 is a 15% increase compared to the 2.82 stock. I have done this in other cars and it has made a huge difference. Diff swaping is very popular in the BMW world. Many M5 owners go from a stock 3.15 to a 3.45 or lower. Many say it's the best bang for the buck. Most say it makes more of a difference than CAI, SuperSprint headers, Powerchip and exhaust put together. I would love to go with something lower than a 3.27 maybe a 3.46 or someting but the problem is that nobody's ECU programming will raise the RPM limter. If I go with a 3.27 I will be able to hit 61 mph in second but I will have to go into 4th for the 1/4mile. I would guess the 3.27 will drop your 0-60 by 3 tenths and your 1/4 by .5 second or more. This would drop you 1/4 mile times into the 12's
I have an example for you. I have a buddy with a supercharged 540i and another friend with a regular 540i with some mods. When they would race the non-superchared 540i was 6 cars back but once he got gears he was only 1 1/2 cars behind. I was very impressed with this $2500 mod.
I hope this helps
Mario

Fast55

Mario what's up?? I thought you already made the change? I thought you were keeping it mild, like a 3.07? 3.27 shouldn't be too bad either unless you're flyin' down the freeway all the time. Was that Bergwerks? I wouldn't trust just anyone to put gears in anything, let alone my 55. Post results if/when you get it done. That should go along nicely with your mods.

E55Cent

I was going to do it a few months ago but, that is when I blew up my tranny and that cost me about 5k, so the gear fund kind of went out the window. Also I have been driving like crazy lately and with gas at almost $3.00 I'm not sure I want to lower my MPG even more. Maybe in a few months after I buy a couple houses in Arizona I will buy a used first generation HPS and add water injections to keep the heat temps down. It seems like the HPS first Gen had very few issues and I'm sure I could pick up one for $3k and the H2O injections is only about $400. I will also save on the labor, since I can do all the work myself. I would love to be able to sell my Powerchip software if possible once I get my S/C.

I'm glad to hear your 55 is running strong. I would love to take a ride in it one day and plus don't you owe me lunch. LoL.
Mario

RLS

Mario,
What you are doing is exactly what I want to do. Could you please tell me where you are getting the gears to put in, and also where it will be done at. $1800 sounds very reasonable for all that is included.
I also will be putting in a Kleeman LSD at the same time.
Thanks, Bob

E55Cent

There is a company close to me called RBtechla.com in Los Angeles. The guy Ralph is a Master MB mechanic and told me the diff swap was very straight forward the hardest thing would be the tranny ECU swap, but even that wouldn't be very hard. I'm not sure if he does LSD's but I'm sure it won't be a problem.
Mario

GTA23109a

Does he have a solution for the tranny computer reprogram or is that the holdup??

Ted Baldwin

.............I think Bergwerks is out of business. Where would you get a 3.45 diff for w208 or 3.27 diff for W210?

Ted

RLS

Mario,

You are always a help on here. The last time we spoke it was over doing the NOS on a C55. I decided to wait and have ordered the 2006 C55. It will be here in July sometime. Since I live in FL. and from everyone's help here, I found out that the bottle would have to be taken out everytime I parked it! That just would not fly for me.
The gearing was my next and with those prices, it is the best bang for your money. I was not aware that the tran. ECU had to be re-worked. Is this to get the speedometer right? what would rpm have to do with it? wouldn't it still shift at the normal shift points or rpms? Since the C55 has 3.07, do you think the 3.46 ratio might be better? You mention raising the rpm limiter, on the ECU, I do not understand why you want that. Is there a correlation between the speedometer and rpm limiter? Since I do not want to raise my rpm at all, would it be possible to go to the 3.46 gearing?

Thanks in advance for all the help everyone gives, Bob

E55Cent

Thank you for the nice words.
Since you have 3.07 already going to a 3.46 seems like the best bet. For some reason MB's have to have the tranny ECU changed out so the car can figure out the new RPM's and new shift points. In the BMW world all you do is swap the diff, no matter if it is an automatic or stick.
The reason I would like the RPM's raised is so I can still do a 1/4 mile in thrird instead of going to fourth for those last MPH's. Raising the RPM's with shorter gears kind of goes hand and hand. I'm only talking about maybe 400 more, so my car would shift at 6400. By doing this the car will drive and shift more like stock. Going with gears doesn't mean you have to mess with your RPM limiter but it would be nice for the car to retain its normal RPM range.
I was told by a few people that lowering the gears will put less strain on the tranny because the gears are helping the car get off the line, similar to a bicycle. You would never start in the hardest gear on a bike, it would be too much stress on you, the frame and the chain.
Hope this helped a little.
Mario

RLS

I see, you want to match your speed to rpm that you have now by increasing the rpm to get you through the the 1/4 without having to make that extra shift.
Yes, the gear change does lower the stress on the drivetrain up to but not including the axles. But than when you increase traction from an LSD, you end up putting more stress back on except the axles!
Now to find a Master MB mechanic in central Florida that will do it for around that price using 3.46 gears. Anyone that has an idea who to contact, I sure would appreciate the info.Also, anyone know where to get 3.46 gears at? Is it from MB?
Bob

RLS

Scratch 3.46 gearing! From what I have found out, there is no 3.46 gearing for a C55 diff. The only gears around that ratio are for the smaller diff. and would not take the stress. Back to the drawing board! lol

RLS

OK, Does anyone know if there is a higher gear available for the bigger diff. found in the AMG models other than the 3.06? Talking to Steve at Bergwerks, he thinks not!! The higher gears are in a smaller diff. and they would not take the stress. is what he is saying.

Anybody have some input on this?