| Author | Message | ||
| Rob Schermerhorn (Rexrcr)
Junior Member Username: Rexrcr Post Number: 160 Registered: 11-2002 |
A dead shock can induce this behavior. A shock absorber can be viewed as a timing device for managing the mass of the vehicle. If one is dead, you will get "diagonal" weight transfer, that is, unbalanced transfer relative to the left and right side. This is very much like having too much cross weight in the chassis due to messed up spring collar settings. What you describe is exactly what circle track racers want to achieve with their set-up because they're only turning one direction. They desire this type of reaction to engine torque inputs. Inspect your shocks, look for a broken spring or spring collar, too. These are definite possibilities. Alignment and tires can do this, too. | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 22 Registered: 10-2002 |
Yep,thats exactly what i got JRV | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 705 Registered: 11-2002 |
>>Why would bad LSD be a possible cause?<< Billy, The car I'm working on feels like it's torgue steering from the rear in a striaght line not corners. The car can be made to wag from side to side with throttle going on or off and downshifting. Because it feels like the rear causeing the effect and the tires are the same, there is not alot of other things in the rear that can cause it to force steer the front end using the throttle. If it was alignment one would likely feel the effects all the time. All that said, I'm not quite working on it yet so I haven't had a chance to fully and carefully inspect everything. Someone mentioned shocks, could be, I'm going to investigate that possibility also. | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 21 Registered: 10-2002 |
Right!Thanks for all the suggestions , i have a couple of days off so i'll get on with eliminating one thing at a time.Hopefully i'll be posting good news by Wednesday , if the answer is later than that .....You can bet it was expensive! I have a 911 & previosly owned a Testa so i don't think it's the LHD trouble (Mind you the Porsche did end up in a field at a recent track visit - best place for it, maybe !!!!) | ||
| Najib Amanullah (Najib)
Junior Member Username: Najib Post Number: 237 Registered: 4-2001 |
Steve possibly the symptoms you have described are similar to a thread I started a couple of months back. I felt the car used to twitch under acceleration and pulled to the right. The car would correct itself if I came off the gas. Had the car checked and all was OK. Basically it was put down to lack of experience of driving a mid-engined car, a heavy right foot, a far more sensitive steering wheel than I am normally used to and the exceptionally hard (slippery) compound they use on roads here to prevent them melting in the summer. I plan to resolve some of the iisues by switching to wider tyres. Several people recommended Kumho 275 (rear) and 245 (front). Hope your problem is not too serious or expensive. | ||
| billy bob (Fatbillybob)
Junior Member Username: Fatbillybob Post Number: 164 Registered: 8-2002 |
"Can you confirm the rims are on the correct side - I think the 348 rim are not interchangeable side to side" Tom, 348 rims not interchageable side to side but for cosmetic reasons and very slight brake cool reasons. Does not effect drive of car. JRV, Why would bad LSD be a possible cause? There are many cars with 1 wheel drive without this torque steer phenomenon. If one side pulls more than another I do not see a problem. However, best performance comes with proper working of the LSD. I would think that if you lost the LSD to 1 wheel drive the worst case is oversteer when you come out of turns under power since you do not have two driven wheels applying power right? Steve, To a "certain degree" this is correct as many LHD people unknowingly brace to the drivers door more so hit the right turn harder causing oversteer then countersteer to correct or off the gas the back on to correct. Most LHD people can't make as good a turn turning left because there is only air to support them. Therefore the reason for the challenge seat. Huge difference! OTOH you could have a broken piece of suspension. Check for crushed rollbar pieces and check for nuts on the U shaped upper rollbar attachments just behind the shock towers. | ||
| Jens Haller (Jh280774)
Junior Member Username: Jh280774 Post Number: 206 Registered: 9-2001 |
Steve, Eibach springs are standard for a 348. My tb (1990) has them as well. You can see that the rims are mounted properly by looking at the different star parts of the wheel. The parts of the rim which are not plain should always point backwards (to the end of the car) and not to the front. Sorry about my poor description but my english is not good enough for such a technical description. You should always mount the rims right because only that way it is ensured that that the brakes get enough air. Through an aerodynamic trick (underpressure) air is sucked to the brakes when wheels are mounted correctly. Otherwise this is not the case. My mechanic also told me that it would be the best decision to always change all four wheels because of balance problems. Think your problem could be solved with new wheels or by surveying the front axle (Hope you understand, sorry for the poor english) The pitching can surely be erased by using new shocks by the way! Con saluti cordialissimi, Jens Haller P.S. Hope you are up for our meeting in june! Looking forward to see some other 348 owners  | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 20 Registered: 10-2002 |
Thanks , i'd appreciate that .The diff crossed my mind but i was praying it may be something cheaper!!I'll keep an eye out for the results.My car has also covered 30k miles now. | ||
| Jeff B. (Miltonian)
Junior Member Username: Miltonian Post Number: 82 Registered: 12-2002 |
Steve: If only one tire was replaced, it isn't likely that it was put on the wrong side, but you should still check the arrows for direction of rotation. And hopefully your new tire is the correct size, matching brand and model - are you sure you don't have mismatched tires (different rolling circumference?). And of course set tire pressures to specs. Is there a "clunk" associated with getting on and off power, when the pitch/pull is most noticeable? Is there an abnormal wear pattern on any of the tires? I would jack up the car and put it onto jackstands (follow safety precautions) or put it onto a lift, and check for something loose in the suspension or steering. HOPEFULLY this problem is not due to poor repair of accident damage, but your symptoms could reflect this. Is this a new problem, it was OK when you got the car 9 months ago? By the way, I see that my 348 has Eibach springs, I always wondered if it came new with them - I don't know. Each rim should fit onto its own corner, but I don't think this would have any bearing on a problem such as you describe. Good luck, keep us informed! | ||
| JRV (Jrvall)
Member Username: Jrvall Post Number: 696 Registered: 11-2002 |
Steve, I'm just about to do a 30K service and updates on a 94 Mondial T and road testing the car last week I noticed the exact issue you describe with this car. To me it felt like a Lmtd Slip Diff issue, ie: torque steer. As power is applied and removed it felt like the back end was steering the car. So, in the course of the service this is one of the issues I'll be looking to solve. If I can find the cause and draw some relivent conclusions I'll post my findings here. Regards, JRV | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 19 Registered: 10-2002 |
good question, how can you tell, i know the tyres are ok and directions are right but no idea about the rims , i have only had the car 9 months | ||
| TomD (Tifosi)
Intermediate Member Username: Tifosi Post Number: 2449 Registered: 9-2001 |
if you only put one new tire on and the others are well worn that could be your problem. Can you confirm the rims are on the correct side - I think the 348 rim are not interchangeable side to side | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 18 Registered: 10-2002 |
Yes , i had a new rear tyre fitted about 200 miles ago everything was checked then , apart from the usual road bumps i know they haven,t been kerbed or bumped | ||
| TomD (Tifosi)
Intermediate Member Username: Tifosi Post Number: 2448 Registered: 9-2001 |
are your wheels correctly aligned and are they on the correct side of the car? | ||
| Steve Holden (Sf_348)
New member Username: Sf_348 Post Number: 17 Registered: 10-2002 |
My 348 ('93 LHD) piches up (normal i'd expect)under acceleration, but also pulls to the right , strong enough that i have to counter steer slightly.When i come off the gas it pulls back right. Also i looked at the rear shocks and they are eibach - is that standard ????? |