Rear Differential Question
06-22-2008, 06:59 PM
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'09 C63 Performance Package - Steel Grey/Sahara Biege
Rear Differential Question
Anyone know the rear gear ratio for the c63? Do we know if it stays the same if we upgrade to the LSD in the performance package?
Not sure with this car, but with other cars, you often get a more aggressive rear gear ratio when you get a LSD or posi-type rear.
Not sure with this car, but with other cars, you often get a more aggressive rear gear ratio when you get a LSD or posi-type rear.
06-22-2008, 10:25 PM
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'09 C63 Performance Package - Steel Grey/Sahara Biege
Thanks for the info. Given the low 2.85 number, those looking for performance increases may be well served to look at their rears [insert joke here]
06-23-2008, 11:31 AM
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'09 C63 Performance Package - Steel Grey/Sahara Biege
As I listen to all of the videos of this car, I have (seemingly) noticed that it sounds a few hundred RPMs too low at the bottom of the next gear at each wide open throttle up-shift. Anyone else notice this?
It would be interesting if someone could tell us where that RPM needle drops to between each up-shift, then we could match that up to the hp/torque curve of the engine.
I'm not in my '09 yet and am talking purely from theory, so just my opinion.
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06-23-2008, 11:53 AM
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a quarter mile at a time
Agree completely with the first gear comment, but 2.85 is a low number for a performance car. A steeper gear (higher number) will help across the other 6 gears by keeping the RPMs a few hundred higher at the bottom of each up-shift.
As I listen to all of the videos of this car, I have (seemingly) noticed that it sounds a few hundred RPMs too low at the bottom of the next gear at each wide open throttle up-shift. Anyone else notice this?
It would be interesting if someone could tell us where that RPM needle drops to between each up-shift, then we could match that up to the hp/torque curve of the engine.
I'm not in my '09 yet and am talking purely from theory, so just my opinion.
As I listen to all of the videos of this car, I have (seemingly) noticed that it sounds a few hundred RPMs too low at the bottom of the next gear at each wide open throttle up-shift. Anyone else notice this?
It would be interesting if someone could tell us where that RPM needle drops to between each up-shift, then we could match that up to the hp/torque curve of the engine.
I'm not in my '09 yet and am talking purely from theory, so just my opinion.
06-23-2008, 12:16 PM
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2003 E55 & 2014 GL550
Wanna make sure our newer Benz family members are aware of the evil that is the Benz ECU. I say the word evil in that the ECU has been the hold back on much of the modding on these cars that have soooo much potential for higher hp. Talked to several tuners that all say the same thing, the Benz ECU is very hard to crack and mod, thus not a lot of tuners doing it.
Car is wonderful granted but it's just jam packed with electronics that Benz has all talking to each other.
If anyone of you C63'rs wants to tinker with the rear end in the future, just know that you will need a complete new tranny TCU program to go with it.
If the tranny senses the new rear diff ratio, it sends the car into limp mode as a safetly measure.
Just a heads up as this discussion came up.
Carry on.
Car is wonderful granted but it's just jam packed with electronics that Benz has all talking to each other.
If anyone of you C63'rs wants to tinker with the rear end in the future, just know that you will need a complete new tranny TCU program to go with it.
If the tranny senses the new rear diff ratio, it sends the car into limp mode as a safetly measure.
Just a heads up as this discussion came up.
Carry on.
06-23-2008, 12:18 PM
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It's an academic question. In the days of ECUs, TCUs, ESP, BAS, etc., you can't just change the ring and pinion to change the final ratio. You'll start throwing codes when the electronics detect rpms don't match expected mph. There are probably tuners who could modify the appropriate programming, but it's not trivial.
06-23-2008, 12:41 PM
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a quarter mile at a time
It's an academic question. In the days of ECUs, TCUs, ESP, BAS, etc., you can't just change the ring and pinion to change the final ratio. You'll start throwing codes when the electronics detect rpms don't match expected mph. There are probably tuners who could modify the appropriate programming, but it's not trivial.
06-26-2008, 09:18 PM
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'09 C63 Performance Package - Steel Grey/Sahara Biege
It's an academic question. In the days of ECUs, TCUs, ESP, BAS, etc., you can't just change the ring and pinion to change the final ratio. You'll start throwing codes when the electronics detect rpms don't match expected mph. There are probably tuners who could modify the appropriate programming, but it's not trivial.
I know, I'm preaching to the choir when I complain about ECU and tuning prices here...
