Hello,

I’m having issues getting my 2017 C63 S Coupe to launch properly..
The wheel spin is much more than I anticipated and I’m losing Traffic Light Grand Prix’ left and right :’(
I often see posts of people with bone stock C63’s that run 1/4 in under 12 seconds which I assume needs a near perfect hook at launch.. which I can’t get for some reason.

Because of this lack of traction, I’m also hesitant to tune to vehicle since I’m not able to utilize all the initial power and torque anyways.

Am I able to swap my 285 Michelin PS4S to 295 on my stock rims?
I also often see articles about improving suspensions which could help.. but I’m very new to making mods to cars and even posting on forums.. so any and all help is greatly appreciated!

 

There are many topics/threads on this topic. Our cars have tons of torque and depending on tire setup and weight , you will spin and spin... learning to NOT just stomp it, and or having traction control off and feathering it..
Being that you have a coupe, it is lighter in the rear as well then the sedan, so you will spin more if you just stomp it.

 

Yes, I’ve come across a couple posts with my issue as well which people recommend changing the PSS to PS4 tires, which I’ve done, but still can’t get the desired results..

And over the years, I’ve been learning to accelerate just enough that it barely slips.. but it doesn’t seem to quite reach the usually advertised speeds of 0-60.. which if why I feel like I may do something wrong or missing something. I’ve recently come to see how drastic the difference was after driving an AWD car with a V6 twin turbo and the torque at launch felt like night and day.

I figured there must be other things I can change with the car to help me reach that perfect launch.. which maybe widening my rear 285’s to 295 may do if it’s safe to do so.
Is there any way to get more weight into the rear as well without the need to fill the trunk with sand bags? Or do I really need to light the tires up every time I want a good launch?

 

For starters, you need to get heat into your rear tires. If they are cold, especially now with winter temperatures they won't do you much good. Summer performance tires pretty much are crap below 40-45F, but even at 60F they don't have maximum grip. You'll hook up much better on a hot summer day and with the tires at proper temperature. I'm still trying to find what the recommended temperatures are for the PS4S for maximum grip. For example the Cup 2 needs to be at 180F for proper grip. You don't get that with just driving around. The PS4S is probably a bit lower, but still likely needs to be well over 100F. There's a noticeable grip difference once the tires get nice and hot on a summer day, compared to just driving around in cooler temperatures. A wider tire won't really help you much if they are still cold.

Tire pressure is also important to get maximum contact patch. The pressures on the door sticker are too high, and you essentially just end up rolling on the center of the tire, effectively narrowing your tire. The proper tire pressures are inside the fuel door. They are 32psi in the rear for my 2019 coupe. You may also get a better hookup if you put the suspension in comfort mode, so there is more weight shifting to the rear and the initial suspension compression softens the blow to the tires.

Lastly, AMG set the launch rpm too high for Race Start, and unfortunately in the PFL you can't change it. In the FL (2019+) you can adjust the launch rpm using the shift paddles in 100 rpm increments. The instructor at the AMG Driving Academy told us to lower it by 300 rpm, otherwise you'll just have wheel spin and it does work. He even lowered it when he demonstrated Race Start with a GT63S with 4 people in the car. Much better hookup at slightly lower rpm.

 

Wow, thanks for the informative reply! I only recently changed my tires in late fall, so it must be a matter of me being too impatient with my verdict.. I’ll have to wait until summer to see! I guess that’s why they call it summer performance tires.. haha.

One last thing is that I’ve noticed my vehicle is cambered a small bit which I’m not sure if it comes factory like this or if it’s from the previous owner since I got this certified pre-owned.
Because of this, I was told I couldn’t get warranty on my tires since it’ll be uneven wearing and it also made me wonder if this contributed to my lack of grip.
Should I angle it to make flat contact with the road? Or will that be a big mistake?

 

Camber and Toe have very little adjustment on our cars from factory (on purpose) ... our cars eat tires like there is NO TOMORROW, so get ready ...

 

If your tires are fairly new, then you need to break them in first. They need about 500 miles to wear off the lubricants from the mold, but also, performance tires don't develop their maximum grip until you've worn them down a bit. Usually they grip optimally around 6-7/32". Also wanted to add one more thing I forgot. When it comes to tire pressures and tire temperatures, the hot pressure also starts to become important. You actually need to lower the tire pressure once the tires are really hot. On a track for example. Again for the Cup 2 they say the optimal hot pressure is between 33 and 39 psi if I remember correctly. I also haven't found those numbers for the PS4S yet, but using the Cup 2 numbers is probably a good start.

Yes, camber is normal. There's more camber in the front than in the rear. It's for cornering and yes your tires will wear more on the inside as a result of it. They get pressed down as the suspension compresses in the rear, so with proper tire pressure you'll get full contact patch during a launch.

EDIT: But if the previous owner changed the suspension, then all bets are off. Most aftermarket suspension aren't really good. They throw off the balance of the car and are mainly done for aesthetics (lowering the car).

 

Yea.. I almost found out too late! I thought my tread was fine judging from the outside of the tire.. then I noticed my inside of the tires were down to the wire haha! It was a pain finding PS4S on such a short notice too since I only have one vehicle. I guess I’ll leave my camber.
Thanks!

 

I hadn’t even though about breaking the tires in. I appreciate the heads up!
I guess I really just need to wait for summer to really try them!
Sucks being in Southern Ontario so warmer temperatures don’t last too long.

Thanks for the help!

 

I've had my car for a year and I'm on my 3rd set of tires that don't spin like mad in temps under 50 degrees.

Trust me and just buy 305 30 20 ps4 all seasons. The compound is soft and sticky and will hook up(tuned) in 3rd gear in 35 degree temps. Second gear will hook around 55 and there is no street tire on the planet that will hook in first gear tuned.

 

Yea, maybe after Winter if it looks like it’s hooking well, I’ll be looking into wider tires and a tune after all.