996 major handling problem.

Hi everyone. I'm new on here and thought it might be a good place to get some help. Sorry that my first post is a problem thread. I recently bought a 2002 Carrera 2 and I was very pleased with it. I did a fair bit of research and thought I had a 'good un'. It's lapis blue with grey leather and it's in mint condition. It has 5 service stamps from Porsche and has covered a tiny 21000 miles. I've put about 700 miles on it since I bought it but it's mostly motorway. I recently came off the road after the back end stepping out quite violently after spinning up. I thought this was just me needing a wake up call to rear engined cars and was lucky to only damage an alloy wheel/tyre and need the geometry re-aligned. I decided to get an specialist independent (anonymous for now) to do the repair. This was all done without issue and the geometry was reset. However I had a call from the garage stating that the car is still having major lift off oversteer problems. It was so bad that one of their drivers almost crashed it. Three of them have driven it now and they are sure it's fairly serious. They have written on the report that the car handles like a 3.2 Carrera rather than a 996. I have experience of RWD cars. I had an S2000 and would consider myself a conservative driver on the road. I had put my accident down to too heavy a right leg but the garage have suggested this handling problem was likely the cause. They have spent a few hours looking at it and driven it back to back with other 996s but cannot find anything wrong. They suspension (non sports) is described as 'soft' but nothing is leaking and I wouldn't expect problems at only 21k I've contacted the dealer who I bought the car from. They are reputable but are insistent porche do an inspection. This I can understand but I expect all they will do it check the alignment which I know is correct. I am getting the impression that they are not taking this seriously. I have it booked in for a geometry check at East London Porsche but I have no prior dealings with them and have been told to 'leave a note in the car' to explain the problem. West London Porsche have not even returned my call. I'm wondering if anyone on here has had a similar experience. They specialist thinks it may be a problem since manufacture which has only come to light recently. I'd really like to resolve this amiably as I'm not a militant litigious type but I'm not wanting to throw my own money at problems which should be handled by the dealership/porsche. Does anyone know of a helpful porshe dealership close to London who can help? I can't enjoy the car. I'm wanting to do track days and nurburgring trips but without trusting the car I don't even want to drive it. I've funded all the repairs myself as I don't want to claim and ruin my full no claims record. The independant are suggesting replacing all the suspension to get rid of the problem.

Sorry to hear about your troubles. You can try Jaz in Wembley 0208-903-1118 or even better JZ Machtech in Kings Langley 01923 269788. Another way would be to get the 111 point Porsche inspection done (less than £200) , hope it passes and get the warranty. Then let them replace the suspension.

Thanks Rodney, the car was inside the scheme when I bought it. I extended it but they are saying suspension is not covered. Seems crazy to me on a 21k car but the suspension has not suddenly failed

[ ] Forget taking it to a Porsche centre, take it to a knowledgable specialist....I've heard nothing but great things about JZM and Jaz are also good. Give JZM a call first and talk to them about it. I've never heard of, or read about this problem before on a 996. Good luck!

I would be very dubious about using an independent who wants to replace all the suspension but cannot actually identify the specific faulty parts that may be causing the problem. I once had a 996C4 that had sports suspension fitted but the geometry was all slightly out, it was difficult to say specifically what was wrong with the handling, especially after my previous and idential C4, other than extremely nervous and with potential lift off oversteer feeling like it was on "tip toes"( I put it down to different tyres). In the end, I had it fully 4 wheel alligned by my local OPC and the printout confirmed onlyslight adjustments needed, but just about every where. It was the best £120/£150 spent, the car felt very planted ,stable and confidence inspiring afterwards, just like the previous one. They are obviously sensative to allignment. Does the independent have the same equipment as OPCs? Are you sure that a full camber, caster,toe and thrust angle allignment to Porsche specification has been done. If you have only done 700 miles in it, and it is covered by the extended warranty I would be pressing the OPC to sort the problem out as it should have be checked under the 111 point check to get the warranty in the first place. Good luck.

Thanks Rintoul. The car has not been inspected by Porsche as the warranty never lapsed. I have spoken to JZ as mentioned above and have it booked in there. I'm hesitant to use Porsche now as I think all they will do is check the alignment. The equiptment used was not the same as porshe but it was a high end full laser alignment rig. I have all the settings printed out and they are within Porsche's specified range. The main problem after the accident was the caster adjustment. (the suspension had moved back in layman's speak) and an adjustable part from a GT3 was fitted to bring it back into spec. As you say it was only out a small amount but the part corrected this. JZ are of the opinion that the whole localised area should have been replaced but without inspecting and driving the car they can't be sure. I'm considering putting fast/road nurburgring suspension on all round to be done with the problem altogether. I think the warranty porsche route might be more trouble than taking a hit in the wallet. I will still end up with a soft car without the sporty edge I am looking for.

First things first... 1. does it have the correct N spec tyres fitted ? 2. Are these correctly inflated ? 3. What is the tyre tread depth, and is wear even across the width ? Ans stating the obvious.. lift off mid bend and you transfer weight foward and off the driven wheels, therefore destabilising the car.

Hi there, tyres are all N rated contis. The fronts are brand new now. The rears are 40% worn. Tyre pressures are both fine. Very puzzling. I'm aware of the lift off oversteer principle but this is mostly designed out of the 996 compared to say an earlier 911. This car is dangerous according to the indies.

The engine is still hanging out the back of the rear axle, but you would have to drive a 996 like a total pr*t to experience what you describe. The caster isn't adjustable on the 996 Carrera, hence an adjustable arm has been fitted to correct the problem. My concern would be what else is out of line. Iain is absolutely right that small corrections for alignment can transform the feel of the car, but I have never heard of a severe handling problem like you are describing. The camber, caster and toe can all be within limits on a car that has the 'chassis' out of line. I'm probably being pessimistic, and maybe it's something simple, like the dampers are shot. Keep us posted on what JZ say.

Hi Richard, I think your bang on the money there. Yes a GT3 adjustor has been fitted to the front right side only. I'm hoping it's something like the damping that just needs swapped out. I'd be very suprised if the chassis is out of allignment from my accident. It was relatively minor and the suspension should bear most of the force of impact. Whether the chassis was out of line from manufacture is something I'm more worried about. Anyway - I feel confident JZ will sort it out.

Neil - The problem was there prior to your spin, so I wasn't suggesting it was as a result of that. Let's hope it is something straightforward and not too expensive. Unless you DO drive like a pr*t, of course! [ ][ ]

Porsche say that the wear between the tyres on each axle can cause a "marked difference in vehicle handling" (see your manual) FWIW, I had a BMW 330 Sport and I changed the rear tyres and left the fronts which had a bit of tread left. After this the car handled like an absolute camel- I could not believe what a difference it made. Just an idea- see if the garage can put a new set of front tyres on, this may solve the prob if everything else checks out.

Richard [The caster isn't adjustable on the 996 Carrera, hence an adjustable arm has been fitted to correct the problem.quote] I do not doubt your knowledge, but out of curiousity how does the caster come back into Porsche perameters if it is not individually adjustable? My last 2000 C4 was fully alligned by my OPC and out of 14 measurements only 4 were green before adjustment. All were adjusted to be mid point. The caster figures were 7o 06' left and 7o 27' right (against Porsche perameters of 8o 30' to 7o 30') ie red on the printout. After adjustment they were both 7o 58' ie green on the printout. Iain

On the standard C2 and C4 there is only adjustment for Toe and Camber, both front and rear. A special adjuster to allow Caster correction can be fitted to the front In the event of repairs (accident repairs, I assume). This is what it says in the workshop manual: Wheel-alignment corrections Rear axle: The kinematic toe-in is not adjustable. Camber and toe can be adjusted via eccentrics. Front axle: The caster is not adjustable on standard vehicles. In the event of repairs, a caster adjustment facility can be installed if necessary (as with the Boxster). The camber is adjusted by moving the spring strut transversely. For this purpose, loosen the three fastening nuts of the spring-strut mount.

Update.. I decided to take the car on Andy Walsh's carlimits day yesterday ( www.carlimits.com ) I explained the problem and asked if he could give an opinion. He instantly looked at the rear tyres and gouged it with his thumb. It's rock solid. He said thats likely to be my problem. I was very relieved to hear that. Throughout the day he test drove the car at the limits and I think it's handling as it should with bad tyres. The oversteer is predicatable and consistant. It was a lof of fun as Andy said most of the Porches suffered from understeer there rather than oversteer. It was still quick enough round the course to match the lotus elises so I'm pretty sure that the 'major handling flaw' is just tyres that have gone off. The car is a 2002 and has only 21k on the clock. My hunch is the tyres have been on there since the car was new. They still have a fair bit of tread but the grip is terrible!! So a positive outcome I think. I'll get new tyres fitted this week and hopefully this will sort the problem out. I'm not really happy with the garage that sold me the car though. I'm wondering if I should ask for some sort of goodwill gesture.

You can easily find out the age of the tyres. If you look at the tyres you will find 4 small numbers in a group (as in 0205 )- this is the week number and year the tyres were manufactured. Tyres do only last a few years before they "go off" - I recall being advised by Pirelli that this would be about 5 years. Edit - to correct!

I think you'll find that they show Week Number and Year on the side wall. Porsche say that the tyres should be changed after 5 years no matter what.

Hmm.. I just phoned JZ Machtech and let them know I might be cancelling the inspection. However he got me thinking. The dealers put a different set of wheels on the car for the testing. Therefore the rear tyres were possibly not part of the equation. I think there may still be a problem after all. Thanks for the tip on the sidewall. I'll take a look tonight and check.

You are quite correct - I don't know where my head is today. [8|] I've corrected my post! Thanks Richard![ ]

Hi Richard

Hi Iain The difference between M030 Sport Suspension and standard is Shock Absorbers, Springs, and Anti-roll bars. They don't change any of the suspension arms. To adjust the camber, they fit a special lower control arm (see pic). I can't explain why they were able to adjust yours - Sorry.

I think I've found some numbers which are 4904. So the tyres are in theory still good.

Don't suppose anyone can post a data sheet showing what settings my 996 C4 should be running? Or where I could find this data? TIA.

I can take a look later. if I remember it has a range which the geometry should fall between. I have a printout.

Would appreciate it Rawhide. Re. Tyre pressures I'm sure I read somewhere that for the UK rears should be set to 36 psi?!

Geometry settings depend on whether the car is C2/C4, C4S, Standard suspension or M030. I'll dig out the settings over the weekend and post them in the Technical Section. Tyre pressures depend on wheel diameter. Check your owners manual for the correct pressures for your wheels.

I'll dig out my geometry check sheet over the weekend too, it was done along with the major service before I took delivery. The state of UK roads, I'm sure it's been knocked out of alignment. P.

Alignment settings are now shown on the TA page, or you can get them from here: <Suspension Alignment - C2 and C4> (95Kb) <Suspension Alignment - C4S> (77Kb)

Thanks Richard.