M113k S55 AMG Project - Need recommendations for mods
Intended mods - I am planning on doing just a UPD 77mm clutched pulley upgrade & ECU tune. But I do have some questions regarding supporting mods.
First question - cooling.
I know a lot of 55k guys would usually do some cooling upgrades alongside my intended mod list, but if you guys didn't know the S55k and CL55k actually have a different and more robust intercooler system compared to other 55k models. There is a dual heat exchanger set up for the intercooler - one giant H/E the size of the radiator and a smaller secondary one behind the bumper. In comparison, the other 55k models only have one tiny H/E. With this in mind, is it even necessary to touch the cooling system at all in an S55k when doing power mods?
Also is splitting the cooling system from the main engine cooling even necessary or beneficial for my application?
Second question - belts and pulleys.
Is it necessary to install a belt wrap kit? Does it actually help reduce belt slippage and strengthen the supercharger drive for more reliability? And do those fancy looking metal idlers actually do anything or is it just for show?
Third question - spark plugs.
Is it necessary to run one step colder plugs (NGK LFR7AIX) with my intended mods? Or just leave the factory recommended Bosch ones?
Fourth question - fuel system.
Are the factory injectors perfectly fine for my intended application? Or should I upgrade to a bigger size? What about a looped fuel rail - does cylinder 8 starvation actually exist on these cars or is it just a myth? Should I just leave the fuel system alone?
Those are the major questions I have so far. Any help/recommendations from anyone more familiar with this platform will be very much appreciated. Thank you all!
1. No cooling mods done and don't think any are necessary, although I did install the upgraded Bosch 101 I/C pump.
2. No belt wrap kit and don't think it's necessary.
3. Stick with the OE plugs
4. I don't see any issues whatesoever with factory fuel delivery system
Last edited by 8899; Aug 30, 2021 at 11:17 AM.




maw
PS... the tuning scene was more active here before 2014...
Now, for a question you didn't ask, I'm told that a Quaife or Wavetrac LSD is a better spend for these cars than more power. But that part I cannot confirm. Pulleys, tunes and cooling, however, are well charted territory.
Last edited by maw1124; Aug 31, 2021 at 10:25 AM.
So what I've gathered is no BWK, keep oem fuel system, keep oem plugs, and basically not to touch the cooling system besides installing the upgraded 010 bosch pump and wire it to be always on. But the question still remains - is it necessary to split the intercooler system from the engine cooling?
For the LSD stuff, I can agree these cars absolutely need one and the fact it didn't come from the factory is really stupid. My S600tt really suffers from the open diff, it is an absolute mess when giving it any sort of throttle at low speeds. The S55 is similar but not as bad (stock) but I assume it will get worse after the upgrades.
As for the transmission stuff, I'm likely going to install a new valve body from the dealer before doing a TCU tune because the lockup clutch is acting up.
Speaking of TCU, has anyone figured out how to get rev matching downshifts on this platform all these years later? Or is it still impossible? This is the only thing I feel is really lacking with this car and keeping it from feeling like a modern sports car.




As for the TCU, I don't think anyone here actually wants their SClass to feel like a modern sports car. But your rev-matching question is probably better posed to the tuners (@zerocat and @raceIQ) themselves. The MKUltra TCU tune is likely the closest to that. There are built valve bodies available for this transmission from the Chrysler SRT cars that will get you some of that feeling. But again, most people don't want that in an S or CL class. Snobbery at its finest -- guilty.
I went 83mm with RaceIQ ECU and TCU tunes. Because it's an SClass, I have the Stage2 tune from RaceIQ. The car feels like Stock+ but nothing that's going to (1) annoy me; (2) cause reliability issues or lingering headaches; or (3) hurt resale value. Obviously (1) and (2) are most important there.
GL
maw
Last edited by maw1124; Aug 31, 2021 at 09:23 PM.
As for the sports car comment, let me clarify. This car is by all means a luxury saloon and rides like one when you want it to, but it also turns into an extremely impressive and capable "sports sedan" when you push it thanks to the amazing ABC suspension and AMG engine. It's the best of both worlds, and that is why I chose this car over the others

I still want the car to retain this dynamic of being a luxury car when you want it and a sports car when you want it, so I'm not going to be dropping in any built valve bodies or anything like that. I simply want the stock transmission feel with the smooth shifts, with the only addition being rev matching when downshifting. If a car has paddle shifters, it should also have rev matching. I will definitely give some tuners a call and see if its possible.
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As far as the TCU tune, you should ask the tuners (https://mkultra-electronics.company.site/). They answer questions.
GL
maw
Last edited by maw1124; Oct 13, 2021 at 11:10 AM.
The Best of Mercedes & AMG
I still have stock exhaust but will get headers soon. Not sure if headers are available for the S55. Yes definitely change supercharger oil if you do know history. Go with Mobil 387 oil and look up AMGMEISTER on you tube for his tutorial on this. Link below.




#flamesuit_on
maw
Last edited by maw1124; Oct 20, 2021 at 08:12 PM.






