Very Unstable C63 Coupe.

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Active Member
May 11, 2014
Maserati Ghibli
Gentlemen I desperately need your help here as I am now baffled - read on!
I have a 2011 reg C63 Coupe which has only covered 25k miles, right from the start the car has never felt stable at very high speed (*removed*), but I put this down to the rear tyres, as they were worn and getting ready to be replaced, based on this I gave the high speed runs a miss.
In February I fitted 2 brand new Goodyear Eagle Assymetric 2 to the rears, and decided to go wider fitting 265 x 30 x R19.
Thinking this should have cured the problem I went out for my usual favourite blast which ends with a motorway drive, as soon as I accelerated hard at around *removed*, the car feels as though it is on ice, the back end goes very light, and I am having to correct the steering no end, not a nice feeling at all and bloody baffling. High speed runs are again deleted.
At the end of Feb I go to MSL and have an ECU remap and IPE exhaust fitted, now producing 525BHP - well pleased!
I now take the car along to JCT Porsche at Sheffield as I trust their mechanics and we check the car out for full 4 wheel alignment, after an hour the report comes back all clear, everything is either **** on or well within allowed tolerance, mmmmm??, car still feels unstable on the motorway at *removed* or very, very hard acceleration.
Fast forward to tonight, and to be honest me and the wife are lucky to be alive. Coming back home from Sheffield I rose to the bait with a Golf R.
Still in comfort mode I hit the pedal and go for it, at around 140+ we come to a slight motorway curve / bend, at this point the car starts to loose control, and I am having to seriously correct the wheel, the back end is moving from side to side as is the front, the same feeling as " aquaplanning", at one point I have moved from the 3rd lane back into the middle lane!!!!.
I slowly ease off and at around , well god knows what speed, the car is back in control, lets say *removed*
Putting everything aside,( I know the high speed is foolish, especially at my age!) the standard car should be rock solid at up to *removed* - agree?
Anybody any idea.
I have 38 psi all round in the tyres?, they seem to have been fitted correctly, I have Michelins PSS on the fronts by the way at the standard Merc size.
Looks like a trip to Wakefield MB I think?
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+1 on this issue I've noticed the same the car seems to float about at higher speeds and can be very worrying at times.
Don't take this the wrong way - I'm making no judgement regarding the speeds you mention attaining - but I'd strongly advise that you edit the locations you mention for fairly obvious reasons.
You can normally take that slight curve on the M1 at around 175mph :)
As above and also there's a few posts/threads on here in regards to C63 feeling and getting light at high speeds.
Can't help you with why your C-Class can't handle high speeds but I want to know did you beat the Golf?
is 38psi the correct tyre pressure for one of these?
If i had a car like that which didnt feel right, the last thing id be doing is that sort of speed on a road especially
Can't help you with why your C-Class can't handle high speeds but I want to know did you beat the Golf?

he would had done, had his car been working as it should.
best take it to acid at msl...all my 3 C63s have been fine and have all been driven at high speed, the 4 door saloon was not as good as the last two that are coupes ( 507 and 125 ) that are fine, saying that I am fitting Kw3s soon to improve damping on Scottish roads.
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I have heard of them feeling light at higher speeds.......but not as bad as you describe.
The fix for the "light" feeling is normally to replace springs with H&R or KW ones.
No... :fail

Immortalising someone's post has nothing to do with the law, and that's what makes you a c0ck, not "abiding by the law".

How you're making that connection, I don't know... :confused: :doh:
Very sad.....
The OP shouldn't have mentioned places etc let alone high speeds on UK roads but to then copy/paste his comments knowing that he then couldn't edit and retract any incriminating evidence is pure evil
Anyone that drives over 79mph (Police Approved 10% + 2mph before NIP issued) on a UK Motorway is deemed a C0ck in your eyes then?
What a sad man you are!
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I disapprove of inappropriate speeding on the public highway, It was already in the public domain.
I disapprove of all speeders, go fast go to a track.

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