AlexMercedes

Hello all! I recently purchased a 2004 S55 AMG. I've sorted out a few issues with the car already and I am getting ready to do some common M113k mods to it and I need your help. The M113k modding scene is really robust and active, but unfortunately not for the S55k / CL55k guys. This post will also serve to help any S55k / CL55k guys out there since our cars actually have some important differences from the other 55k models.

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!

8899

I just installed a 83mm fixed SC pulley from UPD along with a stage 2 ECU tune from RaceIQ as well a MKUltra TCU and am very happy with the results. Some answers from my perspective:
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

maw1124

OP, you'll likely downsize the belt when you go to 77mm, which in my mind eliminates the need for a BWK. As @8899 mentions, you'll upgrade the inter cooler pump, but the updated MB pump is likely sufficient, given the added cooling capacity stock with this car. Most tunes these days will set the intercooler to always on, which is not a bad thing. You run into lean condition when you start messing with the throttle body, it seems to me. As you review the E55 crowd, that throttle body is what tips you into a never ending science project around air to fuel Mia tire, cooler plugs, looped rails and what not. But a simple pulley and tune don't require any more than a proper functioning intercooler pump. You should change the supercharger fluid before doing any of this, if you haven't already; as well as the transmission fluid if you plan on a TCU, which most do and I recommend. Pretty standard fare for these and SLs.

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.

AlexMercedes

Thanks for the responses guys. The plan was not to go crazy with this build - I was more worried about the reliability of the car by going with the 77mm pulley as I know that is basically pushing the blower to its limits. Last thing I would want is a blown engine due to poor cooling, fuel, etc.

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.

maw1124

Don't forget to change the belt size (Tavarish) and change the supercharger fluid. I haven't met anyone who thought split cooling was necessary for cars with two intercoolers stock. Back in the day there was a lot of discussion about some pumps moving the coolant with flow rates that were TOO HIGH for the liquid to cool; but again, that was on the single radiator EClass chassis.

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

AlexMercedes

Got it, just going to leave the cooling alone then. Definitely going to change supercharger oil before doing any of the mods, in addition to new coil packs, plug wires, plugs, and injectors. Car has 200k miles and it needs that refresh, but otherwise runs surprisingly well for the mileage and still has its full power!

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.

Shax Shux

Hi there, I'm also planning all those mods discussed above on my S55k, my question is, if I do TCU tuning wil that change open differential? Also, if I go with 77mm pulley, what size will be the belt to replace? Thanks!!

maw1124

https://mbworld.org/forums/market/823531 I’m pretty sure you want the shorter one, 80505HD but do your own research to verify that.

As far as the TCU tune, you should ask the tuners (https://mkultra-electronics.company.site/). They answer questions.

GL

maw

CDC55AMG

Hello congrats on the S55! I have a CLS55 with UPD 83mm pulley with BWK and pulley idler set. Before I did these I went with the MKUltra TCU and the shifts are so quick in Agilty mode (A) that the supercharger belt would squeal on a upshift because the supercharger was having to slow very quickly so the BWK eliminated that entirely. I think you are good with Bosch 010 intercooler pump upgrade if you have not already. I also went with RaceIQ stage 2 when I upgraded the to 83mm pulley. Tony was great to deal with!
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.

maw1124

For clarity, I think the right (shorter) belt eliminates the need for a belt wrap kit. Key words = I think. But I think it's simple arithmetic. There might be an issue with underdriving the alternator (is what I would expect the belt wrap kit guys to say) but I haven't experienced such. But I went with 83mm not 77mm, so I cannot advise as to whether the extra mm of alternator under drive matters or is worth the extra weight and complexity of the BWK. I know, I know, I know, no one asks such questions before going for the BWK bling.

#flamesuit_on

maw