Hi guys,

Got myself a new to me 2012 991 Carrera S Cab. Coming from a 981 Cayman S, there is definitely a significant difference in power as well as weight. I've tracked my Cayman and preparing to do the same with the 991. Just trying to get used to the PDK as I've never owned one before. The car has been great so far and it's PPI when I got it was fine. It had ~14,000mi when I got it and after having driven it for ~500mi, I've noticed that it seems to be sliding to the Right side when I hit a bump or if there's mild camber on the road. I brought it to my local dealer and they did notice that the steering seems to turn a little to the right. It's very mild but very disconcerting that I feel I'm trying to correct it or trying to catch the car. They checked the alignment and it was off and brought the alignment back to stock. Apparently the suspension seems to be in order. There was really no significant change in the cars handling after the alignment and still feel the slide. It occurs randomly be it at low or high speed or braking. I'm bringing it back to the dealer but just want to see if anyone had a similar situation or if any one has thoughts on what the problem may be. Thanks in advance. Obviously won't take it to the track until the problem is solved.

 

What are the condition of the tires?

Sport Chrono? Have them check your dynamic motor mounts.

Make sure tire pressures are fine.

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Tires are new, yes has sports chrono --> will have them check the mounts, tire pressures are as per Porsche recommendations

I've googled about it but no info regarding Porsches. Other car makes mentioned tie rods, bushings, etc but like I said, my dealer said the suspension and other parts seem to be in order.

 

Are the new tires all matched? If directional, are they correct?

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Porsches don't just go out of alignment, and alignment problems are fixed by what you did, realignment. Since that didn't work then most likely a prior owner hit something hard enough to do some suspension damage somewhere. Evidently not visually obvious damage, but it doesn't take a lot to noticeably affect handling on an otherwise impeccably handling car. An impact of this magnitude would likely damage a wheel, so I would be curious to know if the car has all its original wheels. In any case, I'd want them to be looking a lot more closely at the suspension.

 

Interesting problem, but hard to make an accurate diagnosis without an in person view. But since I'm in my arm chair and quarterbacking, my thoughts are 1) considering what you have already eliminated, you may have a strut or strut mount issue on the right side or 2) you have a tire issue.

Since you say it happens after a bump or on an off camber surface, you might try testing it at various PASM or SPASM settings and see if you get the same effect at all settings. Are you actually losing traction or just an internal sway feeling?

If you have a bad tire(s) sidewall, you can test it pretty quickly by swapping right for left on front and similarly for the rear and test drive over a known surface the causes the problem. If the problem is still there, tires are not the problem.

Interested to hear what ultimately is the solution.

 

So for the first 500 mi was fine then it started acting that way?

 

I'm not sure if it only happened after 500mi. This is my first 911 so initially wasn't sure what to expect from it in terms of handling. But having been in the trackI slowly started feeling that hey I don't think that's normal. It's very mild sensation of a sway. The car doesn't really lose traction and PSM doesn't turn on. If at all I'm guessing it only moves a couple of inches. Just worried what it would do at speed at the track. Thanks for all the suggestions.

 

Have you had a full geo done by a specialist? It is possible for the geo to be out of Porsche tolerance so it does not drive in a straight line or follow the camber of the road naturally. My Boxster did this from 10 months old when I got it and after a proper geo it has driven spot on for the past 5.5 years.

 

Pardon my ignorance but what's a "geo" in relation to a 911 suspension/handling?

 

you sure you are not experiencing "tramlining" ... what type of tyres do you have mounted?

 

He's talking about a full suspension alignment... caster, toe etc.... corner balance if that was possible on a regular 911

 

Yeah, and no corner balance adjustment on the 991.

Since whatever is happening has now been described as sliding, swaying, steering, and having to catch it, I'm totally lost. The only consistent part is its on the right. Time for a thorough suspension inspection and alignment.

 

ditto ... +1

 

Great minds, Larry, etc, etc.

Long shot but…. does the car have mismatched tires? Or one tire that was replaced and has a lot more tread than the one on the other side?