jerbroo

Hey guys,
My 97 C2 Targa was, until yesterday, a predicable driver and I've gotten better at driving fast at the track and quickly on the street in the twisties. I know, for the most part, what the car's going to do. I've felt under and over steer in various situations on the track and street and it's not big deal - manageable.

Yesterday however, she dealt me a scary surprise.

Turning wide left and much slower than I might when driving quickly, there was enough sudden understeer to almost feel like I had popped a tire or that the font left wheel was coming off.

By understeer, I mean turning the wheels did not change the direction of the car. (just clarifying)

I nearly hit the outer curb with the front right. It felt as though something other than minor traction loss was happening. It felt wrong - really wrong. I had to slow to about 10mph to regain significant traction. If I got on the gas at all, understeer started again immediately until I was pointed straight again.

After exiting the turn and continuing straight I didn't feel anything unusual.

There was no indication of a flat tire or any issue prior to that turn.

near my neighborhood at that point...

I then took a right turn with no problem. Then another left and got massive understeer at about 10mph. I've taken that same turn at 30 with not so much as a squeak from the tires.

For now, she's parked and not moving until I know what's wrong or the flat bed is called. I'll be looking the car over this weekend.

I think the obvious first checks are:

1. tire pressure or tire damage
2. Maybe a sticking caliper?? ...seems like I would have felt that.
3. something really loose in the front end - something cracked.
4. lugs
5. bearings

...What else should I check?

Thanks in advance,
JB

jscott82

My money is on a flat/low tire... If not that, rear toe link.

jerbroo

thanks!

jstyer

If nothing is obviously broken in front or rear suspension members, I'd go for an alignment check.

Mike J

You can do a quick check by going to each wheel (while the car is parked) and really pulling on it from the top and sides to check for looseness.

Definitely check tires pressures.

Check underneath for anything broken or loose.

Its not like all of a sudden the alignment changed, so something must of broken/shifter/gotten loose, so you need to find that first.

Cheers,

Mike

jscott82

Bump + rear toe not tightened by the hand of god = rear end that is not happy being behind the rest of the car....

Happened to a previous 993 of mine in the rain... Had a 2 hour drive where the slightest movement of the steering wheel had to be followed be immediate counter steer to catch the rear as it tried to pass....

Toe was so far out, the drivers rear tire was worn to the cords by the time I got home... Needless to say a stiff drink was in order the moment I got home alive.

race911

Understeer at 10MPH on a paved surface? And only in one direction. Got me, other than the right front tire.

We were pounding on some new Michelin all season mounted on base Cadillac CTS's for a tire test last Friday at Fontana. (Sadly, only autcross + braking tests in the parking lot.) As low end as that tire was, we weren't THAT much slower than a sports car on decent street tires. Anything not in full failure mode on a 993 should get you around a corner as well as that.

Mechanically? Tough for a press fit wheel bearing to fail without oddities happening just going up and down the road. Ditto for ball joint or tie rod failure.

So whatever you find, I'm curious to hear.

element

Subscribed

Im really interested in what would cause such a dramatic difference.. even a flat would give you some traction at those low speeds.. unless it was ice raining only on one side of the car? Come to think of it.. do you have an oil leak at the cooler in the front right corner? that would explain the slipperiness and only one corner.. did you take a good look at the front tire? pressure? check the threads for anything wet or oily (compare both sides).. then get it up in the air and check everything!

stay safe! phil.

race911

^^^^ Yeah, or gas. Had that happen with overfilled cars on track. But you still had to be pretty on-pace.

AOW162435

I vote tire pressure.



Andreas

Quadcammer

I can't imagine even extraordinary tire pressures would cause 10mph understeer.

I have to think you have a damaged drivers side tierod or similar.

bcameron59

+1

race911

Scratching my head, too.

Thing is, if it's on a tie rod toe will self-equalize with some measure of toe out. (It won't get longer, thus damage can't cause toe in.) Even 1/4" will make itself known to all but the most comatose driver. And then, if nothing else gains your attention, your steering wheel will be off center.

87 944 C

sway link snapped? other than tire pressure I can't think of much else. does the car lean when parked? perhaps collapsed spring or shock, but even still having to drop 20mph to correct the car through a turn, pressures.

NYC993

+1...but wouldn't it be passenger side. Turning left transfers weight to the right side causing right wheel with more grip to give up?

10mph seems over exaggerated, i can take turn on a bicycle at that speed without loss of traction.