tri-star tech

I've read bits and pieces about a swap to the larger CLK55 rear diff, but is there any information out there from someone who has actually done the swap?

DRBC43AMG

It seems that you need to modify the floor pan. See Wikipedia

cm60k

........

stockC43

This may have some good info https://mbworld.org/forums/c36-amg-c...-almost-4.html

I may do the 220mm housing swap as well in the future. my car needs a lsd and with a supercharged 55 engine I don't want to put the money into the stock diff to then blow it up

DRBC43AMG

Hi stockC43,

Perhaps but if you swapped the 43 for a s/c 55, how did your conversion go. Could you give us some details (start a specific thread perhaps)? This is a subject which has been put on the table many times, but it seems the solution is not simple at all.

c55m8o

Not clear why you'd want to go with longer gearing? I'd choose to go shorter if I could ... but aside from that, a thing I learned when I researched doing so (installing shorter gearing) was your ECU is programmed for the existing gearing. It expects a specific number of wheel revolutions from the sensors on the wheels for a particular engine RPM in a specific gear. If you change the gearing (longer in this case), there will be less revolutions of the rear wheel for the same speed in every gear at every RPM. And what I was told is that will do anything from constantly activate to slip control to putting the car into limp-home mode. So the folks who I was talking to were also going to send my ECU to Germany to code in the change in gearing.

nd4spd13

Woah. They were going to send it to Germany for that?! Hopefully I'm not way wrong, but I think you should be able to change those parameters pretty simply. I believe maybe even through STAR. I just bought an E55 TCU to attempt a Tiptronic retrofit and I'm counting on it being relatively simple to change the rear end parameters.

And also I believe that's only the TCU that knows those numbers and such. I don't think the ECU has too much to do with that

EDIT: Just remembered, I won't have a problem messing with the TCU because 2000+ plus models (tiptronic onwards) used the updated EGS52 software, which can be reflashed and edited etc. The stock TCU is EGS51 and cannot be reflashed, so I could see why one might try sending it to Germany to get it messed with

503C43 ////AMG

If you want to avoid the issues listed above just swap the C43 ECU for an E55 or CLK55 ECU as both have the 2.82 gearing.

Unless you are looking to get better gas mileage or make a run at the Texas mile I would stick with the stock ratio or go with the shorter gearing. Sure the 2.82 will allow you to run a higher top speed but the stock 3.07 will get you to 185 MPH and how many of us are going to go that fast??

cm60k

Good Input........

importfan21

This.

And this.

cm60k

I believe nothing to do with ECU for a TCU tune or ratio reprogramme,,

we can’t swap E55 or CLK55 ECU, it won’t work, cause the 55s has a different starter security signal programmed to the ECU itself, it may works for

early models "98 to the middle of the 99" to starting only, but no any relation with a TCU.......


ZAYED,,

cm60k

If go with 2.82, well losing some tenth, no one need this......!!,

100% agreed,, its soo risky to go more than 180km, soo many fools crossing the road with half Eye & can’t tell where’s a monster Cops hiding.......

ZAYED,,

nd4spd13

Naw, 180km is easily attainable. Thats just a fun run
He's talking about 180mph which is 300km. That's unnecessary.

cm60k

Your lucky to have a many highways, here we have a few, that’s why Cops can hide easily behind the TREES.......

ZAYED,,

blackbenzz

I might be selling my Clk55 diff with quaife LSD in it in a couple months

c55m8o

You're right on all accounts. I remember now it was the TCU, not ECU. And was the older model.

c55m8o

Before you do this you may want to see what this does to your 1/4 mile ETA by using CarTest2000; Amazing hard-core simulation software. Where it really gets clever is you can enter readings from "at the wheel power" from a dyno test with your present gearing, play with the shift speeds and tire traction's static and dynamic co-efficients, other parasitic losses of the drivetraina and air, plus much more, so that the simulation is giving you the same ETA as you may have measured at the track ... After you get all that set-up, then change only the rear-end's gearing and re-run the 1/4 mile simulation. My guess is your eta will have went down. (see the image below)

CarTest2000 also has an "optimization mode". Where given all those custom config parameters cited above, you hold all the parameters constant but you allow it to vary just the rear gearing. It will run a series of simulations and find the optimal gearing. It determined somewhere under 1:3.25 was optimal for my C43 w/an E55 engine transplant, and ECU flash,and nothing else that will affect power to the wheels of any merit.


If you click the image you will be taken to my Fotki site where I shared other images detaining other parameters that factor into the simulation. But not the actual interface where you add all the parameter goodies. If you tend towards geekiness and are not scared off by screens with 100 parameter entry fields, CarTest2000 is a must have.

cm60k

Good find & Thankss for info.......

ZAYED,,

stockC43

Will do when I get the chance its a 208 55 motor though with a bolt on hps, however I may do the 211 55 engine swap soon though, I have a few ideas on how to make that set up actually work properly then by by 43 diff

DRBC43AMG

We are looking forward then