GIdriver

Does anyone knows what is the max torque rating on the 7-speed SPEEDSHIFT MCT? I'm thinking of getting RENNtech's ECU upgrade and 839 lb-ft sounds like a lot . They do not mention anything about upgrading the transmission while getting this tune. Any input will be appreciated.

sdg1871

I have read but cannot confirm that the MCT is good until about 1000 lbs-ft. From my discussions with tuners, a MCT upgrade is not necessary if going with tune and bolt on mods but should be seriously considered if you are doing a turbo upgrade. Weistec offers such an upgrade. http://weistec.com/all/e/e-63/2014-present-4matic-w212-m157/7229-mct-transmission/722-9-mct-bullet-proof-transmission-awd.html

Renntech does as well for the 2012-13 RWD cars http://www.renntechmercedes.com/www/node/524 although I believe that Vasily is running one in Russia on his 2014 AWD E63 with turbo upgrade and all Renntech mods.

GIdriver

Thanks for the information. I'm probably going to stay away from modifications such as turbo upgrades. Most likely do "just" tuning, rear muffler and/or down pipes.


On a side note, Vasily's car is dope!!


Thanks again!!

sdg1871

Yes if I did not use my car as a daily driver and had other cars I would probably buy all of the same mods Vasily has from Renntech. But there really isn't any dispute that a mod as dramatic as a turbo upgrade has to shorten drivetrain life and engine life. Just not worth it for me.

That's why I went Renntech full tune and Renntech sport mufflers. For me I think 716 BHP and 859 lbs-Ft are more than adequate. If somehow the sound isn't enough for me I can always add the catted down pipes (would never go catless).

EVOII_Racer

I have heard the same

e65

I can tell you from experience, its nowhere near 1000 lb ft. You won't notice the clutch is slipping under normal driving or even acceleration in lower gears but if hold you a high gear in manual mode the MCT will show its true colors. There is a reason they don't use it in the S 65

https://youtu.be/7t97fJ6drdA

gaspam

i would think stock 722.9 is probably getting maxed out at around the 850 ft-lbs range (long term... can probably handle a bit more short term) and probably the reason weistec doesnt raise the torque limits on the TCU/valve body upgrade unless you get their bulletproof transmission upgrade which is rate at 1000 ft-lbs

and fyi, they do use the 722.9 MCT in the s65 since 2015

Minimization

Anyone know the power transfer efficiency gain from them going from regular 7G Tronic to MCT SpeedShift version? I am guessing the wet clutch packs transfer more power/torque, less lost to friction, versus the torque converter?

gaspam

havent seen any concrete numbers but The clutch pack is smaller in diameter and lighter than a torque converter. according to Mercedes, mct wet clutch has 60 percent less rotating inertia than the torque converter that was previously in the 7G tronic. That should make the powertrain more responsive, which, theoretically, should translate into better performance. The reduced inertia allowed the engineers to quicken shift speed by 20 percent

one caveat however, For wet clutch MCT, is it requires control system to control the clutch engagement and disengagement. This require transmission control calibration accurately because this will affect the vehicle driveability and performance.... so really all the improved efficiency of the MCT could be negated if the TCU calibration isnt great

PeterUbers

But on an S track where the mct rarely comes to a complete stop... The mct can shine ... Sux for us stop and go racers!

dav461

Brabus did E63 with 1300+ Nm of torque. so i think there are no limits unless you go with bigger turbo's for 850-900hp +

PeterUbers

"No limits"

Isn't it relative to short term vs long term lifespan of drivetrain?

Most people spending brabus money probably don't keep their car long enough to care about post-2 year reliability ... But for someone (like the e55 driver buying a 13 year old e55) I doubt the mct can reliably handle all that power long term

Just my $0.02, interesting discussion

gaspam

1300nm is about 950 ft lbs, but accord to Brabus for the e63 850 upgrade :

the sedan is powered by a biturbo, 6.0-liter, V-8 engine that received a displacement increase from the standard 5.5-liter found in V-8-powered AMGs. While the increase can be rated as significant, the power bump is plain staggering, with no less than 850 horsepower and 848 pound-feet of torque being pushed to the wheels. The engine is actually capable of delivering 1,069 pound-feet, but Brabus says it had to limit torque to prevent the drivetrain from enduring too much stress.

dav461

We were not talking about 13 year old E55
And, brabus provides 3 year warranty on cars bought directly from them or modified after left the dealer with possibility to extend it yearly ( Russia )

PeterUbers

Warranties don't guarantee problem free driving, but i trust you, problem free at 850lb-ft or less

Davidkuo0330

I think more than +750 hp. The TG didn't give me problems.

Hatake

Hi. And what do ? Who make flash mct ?