breastroker

Has anyone swaped their rear end on their W203 C class. This is the quickest way to get better performance out of almost any car. If I had a C32 this would be the first mod I would do.

My 2003 C230K Coupe has a 3.27 rear end, around town in drive the car is lazy unless I floor it and it downshifts. At 65 on the freeway it is below it's torque curve. The CLK 230 uses a 3.46 rear end that explains why it is faster (also lighter).

The one problem that makes the rear end swap is the transmission computer gets inputs from an ASR unit that tells the transmission how fast it is going.

Their may be a way around it using a devive to convert the 3.46 signals into 3.27 signals. Their is a nice article at:

http://www.mercedesshop.com/shopforu...5&pagenumber=1

He swapped the 2.24 rear end in his E420 for a 2.82.

It amazes me that people spend thousands of dollars on engine mods to get a few horsepower and lose some gas mileage. The rear engine swap will get the car much faster. His E420 went almost a half a second quicker in the 1/4 mile.

Lynn

renncpe put a 3.67 in his coupe. Search both this forum and csportcoupe.com

AMGDood

bergwerks has been doing this conversion for awhile. Check out www.bergwerks.com.

breastroker

Lynn,
Randy (renncpe)is the source of my hope that this can work. His was a 6 speed, mine an Auto. But he listed Potomac as the source and the price was reasonable.

There is the electronic speed converter that will input the axel speed correctly to the trans computer. This relative difference between true speed and the speed indicated on the speedometer is called the Variance Ratio, and it is corrected using the Abbott Electronic Ratio Adapter.

Hopefull the sensors at the rear wheels work only tell when one is not at the same speed as the other.

I will be calling Berg Werks, maybe even going by their shop to see if they have done this for an auto c class.

hobie

I've seen the whole pumpkin advertised at $3k+. It think it was being imported by Evosport. It might be worth a call.

breastroker

Randy got his for $500, and if I really searched around could probably get one for a little less. There is not a large call for these as they typically don't wear out for 200,000 miles or more. They are usually not damaged in crashes either.

I would expect to pay less than $2500 for a new pumpkin and a limited slip differential together. More than I want to pay right now.

mctwin2kman

I just noticed that the 2004 C-Coupe has a 3.46 rear end. I am wondering now if the 2003 I have is the same way. I do not remember the specs now.

breastroker

It was a smart move by Mercedes to raise the rear end ratio on the coupe. The smaller engine revs nice and still gets great gas mileage.

I am now walking the walk, ordered a 3.67 rear end carrier for my 2003 Coupe. Should cut 0-60 time by half a second, equilavent to 30 HP Should be almost or as fast as the C320 Coupe and get slightly better gas mileage.

I can't understand the C240 having the 3.46 rear end, no wonder the C320 sedan gets close to the same gas mileage using a 3.27 rear end.

Will post pics when the rear end is installed. They have to ship it to me so it may take a while.

preyx

Where did you obtain the differential from? I checked bergwerks but they didn't have anyting for the W203. Details would be appreciated.

breastroker

Great news,
Contact Richard Jaques at Potomac German Parts for the same rear end, 3.67!!!

He has a couple more in stock, price is right
Call 1-800-831-7686

Buellwinkle

How do you really know it's a 3.67? Is there a tag on the pumpkin? Is there a part number you can verify with MB? I checked around a year ago and the only W203 made by MB with that rear end ration is the automatic C180 sedan in Australia. Did they take it off a different model MB?

mctwin2kman

Does the 2003 have the 3.46 rear end gears? I would assume so since the 2004 does and the 0-60 times are the same for both years. But I can no longer find that info on MBUSA as the new 2004 is on there now.

breastroker

mctwin2kman,
You need to be more specific when you mention 2003 MBs, the Coupe and sedans use different gears as did the stick and automatic. I also believe different parts of the USA may have received different rear ends.

The first C230K Coupes used 3.47 for the 6 speed and 3.27 for the automatic. The C240 sedan used 3.27 and 3.47 rear ends, and apparently on the East coast some came with 3.67s.

All the C320s came with 3.27s and the C32 with 3.06

breastroker

I did not ask, but last year Randy (renncpe) was able to get the same ratio from a C240, and he confirmed it was a 3.67.. See:
https://mbworld.org/forums/c-class-w203/4509-new-3-69-differential.html


Are you thinking about it? The way you car pulls I bet you have a 3.47 rear end and not the 3.27. For $550 plus shipping ~$50 a nice upgrade on my little engined car. Now you might look for a 4.11, they must produce one somewhere in the world for a MB

Figure a 20% increase in torque in your Coupe would make it fly real nice.

trench

I think it was determined later that the 3.67 was out of a different car, not the C240. (An MB pumpkin will fit almost any model.)

Buellwinkle

I think that's what it is, don't think they would publish a gear ratio on the web or in their brochure and change it for certain areas. Maybe it's from an SLK which uses some of the old W202 running gear and chassis.

Harris

The idea of changing the rear diff came across my mind last year and I did a little bit of research to it. I was told although its possible to swap the rear diff, your ECU and ATM will f**ked up big time. Almost everything that is controlled by the computer has to be re-programmed. And no one can do that super complex re-programming job. Forget about it. Too much of a hassle.

shaft

Harris,

there wouldn't be any problems with a manny, would there? I don't think RennCPE mentioned anything about modifications to the ECU etc.

I called Potomac, Richard was gone for the day, but another guy couldn't find a 3.67. Would the differential be the same for auto and manual?

Harris

Based on what I was told and the info that I gathered, its not as easy as just a swap. Randy didnt say doesnt mean there is no ECU mods. But I have not tried it, so I cant say for sure, better PM him and find out the truth. I am just telling what I know. Good luck!!

breastroker

Harris,
Supposedly BergWerks does this all the time. In one of the forums there is a "black box" that converts the pulses recieved from the higher ratio rear end to an equivalent number of pulses as if you still had the old lower ration rear end. tricks the computers. It can also be adjusted for different tire sizes etc.

AMG, Brabus all change the rear end ratios. BMW uses the same type of ESP and electronics.

Harris

DONT get me start thinking of swapping the rear diff again!!! You DEVIL!!! Are you sure Potomac has 3.47s????? Hahahahaha!!!

breastroker

Harris, YOU REALLY want this admit it. :p

Take the plunge and order that 3.47 rear end. For you an additional 8% torque is worth 10 HP.

If you don't you will always regret it

Harris

Well, I already have my own in-house pulley kit installed on my car. Changing the rear diff will give me more than 8% gain vs. stock 32!!!

breastroker

Harris,
You are so right. The 3.47 will cut your 1/4 mile time by more than 0.5 seconds. You would have the fastest C32 in Canada

nukblazi

quafe