Riccardo

Hello All,

I don't know if its just me, but I could swear that recently my car has been feeling a bit more skittish than it did a few months ago. It could just be driving on roads I am not used to, or that I'm generally driving more quickly and thus there are more forces happening, but I get the following symptoms:

- under heavy braking yesterday it kind of 'jumped' to the right, very weird
- at speeds over 80mph it feels like it wanders round a bit
- at speeds over 100mph (not on public roads, you understand...) it definitely wanders a bit

In the nearly 2 years I've had it the following have been done:

- replaced both front suspension arms
- 2 alignments

I've also got the pressures at 36 all round (17 Cups) and the tyres are half worn Bridgestones SO2s. My undertray is on.

The only thing I can think of is the broken spoiler wall, but could this be having such an effect on the car?

Any feedback welcome!

Jeff Curtis

Broken spoiler wall affecting handling??

NOPE, no way, notta.

Wandering sounds like a toe out condition with the 'ol alignment or mis-matched tires.

I have changed my wheels lately to the Sport Classics, the tires that came on the Sport Classics were Pirelli P-Zeros that were worn to the cord on the rears, fronts were about 75%

I had the rears changed to my Bridgestone Potenza 730s and haven't gotten the fronts changed out yet...my car wanders and tramlines BAD on certain roads - but I'm used to it.

The only other thing I could say is check your front tire pressures as they are suspect due to your car darting to the right under braking, this can also be caused by deposits on one rotor but not the other - causing an uneven braking scenario.

Just guesses and speculation at this point, but hopefully those are a few items that you find valid to checkout.

John Boggiano

I got some wandering sensations when my dampers were getting tired (around 65k miles).

New dampers sorted it, but then I did get the geometry reset at the same time.

I also find I get some wandering under hard braking if I don't keep my rear pressures up to about 40psi (fronts at 36).

Christer

Riccardo

Could be worn shocks after all this time. Might as well do springs and anti roll bars as well. <img border="0" title="" alt="[Wink]" src="wink.gif" />

Riccardo

Jeff,

I would be very annoyed if there are deposits (of what by the way, brake dust?) on the rotors as I had new front pads and discs only about 2k miles ago! Plus I had the front calipers rebuilt too. Having said that, the brakes have been feeling a bit weird too recently, they seem to not have as much 'bite' as they did just after the refurbishment. I've only done a small track day (6 laps) and a driver's Ed, so can't see that they should have gone down so much.

John and Christer,

Could this be the time to finally get that lowered suspension I've wanted for 2 years? The current shocks have 65k miles on them and 10 years...

DaveK

I think the "10 years" probably means YES.

Although I wouldn't follow Christers example - what you need is a nice RUF kit......

Adrian

Dear Riccardo,
I would follow the advice given by Jeff and check the tyre pressures. I find that when it is really hot the tyre pressure goes up too much. Just today I reduced them 4 psi and the C4 feels much better. I would also check the wear on the tyres. Is it even or showing excessive wear on the sidewalls or in the centre.
6 laps by the way can easily do a set of brake pads in plus overheat your brake fluid and runi it. I would recommend a brake fluid change and a brake bleed.
The rear spoiler wall will not impact on handling at the speeds you mention. It will only possibly have an impact if the rear spoiler start vibrating because it has lost its rigidity at really high speed.
Ciao,
Adrian
911C4

Randall G.

Back around '95 or so, I could feel a strange vibration coming from the rear of the car. I also had a weird, intermittent twitchiness at freeway speed. I found that one of the upper bolts securing the rear spoiler had fallen out (allowing it to sag slightly), and the wall was torn. After replacing the wall and bolt, both the vibration and twitchiness went away. To this day, I'm still amazed that the missing bolt could cause a vibration that could be felt at the driver's seat, and that the missing bolt/torn wall caused the car to handle funny at freeway (+) speeds. I imagine the spoiler was bouncing up and down some ~0.25" (on one side) at freeway speeds because of the missing bolt, which translated to the vibration and quirky handling.

All that said, I would look closely at new shocks. Good chance they'll make a huge improvement.

Riccardo

Christer and Dave,

You guys have, respectively, the Rook and the RUF setups right? How much did these cost (inc fitting, alignment and vat)?

Did you guys ever drive each other's cars? What are the differences?

Dave, what does the RUF kit comprise?

If I do need to replace my shocks I have been thinking of going for the FVD Eibach/Bilstein setup. Cost is about £700 + fitting and alignment.

DaveK

The RUF kit was about £2.5K including fitting, vat, alignment - although the alignment was pretty cheap since it had been done not long before that anyway. This included about £150 for a RUF strut brace as well.

We haven't driven each others cars, but I think we should the next time we meet up.

I can't actually remember what I did get with the RUF kit. I'll see whether I have details at home tonight. I know it was dampers + rear springs, but it kept the original front springs. I think it included anti-roll bars or something as well but I'll need to check.

Christer

Riccardo, I have H&R coilovers with RS roll bars from Gert @Carnewal. The kit includes 4 springs, 4 shocks and all the RS droplinks stuff.

I can't remember the price now, and anyway the Euro has got stronger since I purchased mine, just check on <a href="http://www.carnewal.com" target="_blank">www.carnewal.com</a>

Dave, we will have to compare cars next time I totally agree.

Tony Davis

Hi Ricco

After replacing the suspension, I realised just how s*****d my dampers were, the instability at speed has gone completely.

I'm really pleased with my Eibach/Bilstein set up, go for it. The car is more comfortable for normal driving but handles a lot better when pushed. In fact I think this is how it should have come out of the factory. The price you quote is about right. Further, your coupe could take a bit more lowering than my cab, especially as its not your every day car.

Regards

DaveK

Riccardo,
Took a look last night, but I don't have any other details on what the RUF kit included so if you need to know more you may have to mail RUF.

It was actually a bit depressing looking through the stack of receipts I have for the car. There are some BIG bills in there!

Tony Davis

Dear Dave

Depressed ? try doing what I do, record all bills on a spreadsheet identifying miles and date. You can then determine runing costs per year/to date, miles between services/tyre change etc. When you know to the penny how much you have actually spent, you can justify your depression......or think of it as an investment.

Regards

DaveK

I think "to the penny" would definitely depress me! I know roughly what I've spent in the last 18 months (and it's a scary amount).

I don't want to work it out properly and find it's even more.....

Still - car is well sorted now and I don't regret any of it.