johnc Posted December 9, 2007 Share Posted December 9, 2007 This is an interesting problem... After a 4 hours of track time at California Speedway a week ago my 2006 350Z now steers hard left under power. I haven't spent a lot of time figuring this out but I have some ideas. Here's the basic setup: 2006 350Z. Nismo R-Tune clutch pack LSD - 51lbs preload and 100% lock. Koni Sport Shocks. Nissan Motorsports ARBs. Rear shock settings and tire pressures are eqaul. ARB links are symetric. Noticed no problems on the track all day and something like this would have been VERY noticable. We did get the diff hot and it puked little bit of fluid out the breather, but not much. Pulled the car off the trailer, switched back to street tires, and didn't notice anything unusual driving around the shop business complex. Car sat for a week. Now it pulls to the left under power and pulls slightly right under decel with the clutch engaged. Car goes perfectly striaght coasting in neutral or cruising at neutral throttle. Your ideas and suggestions welcome. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted December 9, 2007 Share Posted December 9, 2007 John, I'd get it up in the air and check for rear suspension link or bushing failure somewhere. I had a similar situation on my C5 Vette when I had a lower ball joint that was not torques properly. The nut for the ball join was holding it on finger tight and had been missed upon reinstallation of the suspension after one of many repairs. Under throttle it would pull hard to that side (right side for me) and under braking would pull in the opposite direction. Also look to see if you've got a spot weld that gave way on the suspension pickup points... just some thoughts... Mike Mike Quote Link to comment Share on other sites More sharing options...
buZy Posted December 9, 2007 Share Posted December 9, 2007 chassis flex? Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 9, 2007 Share Posted December 9, 2007 The rear pickup points sound like a reasonable place to start with. I almost sounds like one side has toe issues caused by torque (accel and decel). Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 10, 2007 Share Posted December 10, 2007 My guess was also something loose in the suspension causing the wheels to toe in and out. Damn noobs wanting to be spoon fed. Quote Link to comment Share on other sites More sharing options...
Forrest Posted December 10, 2007 Share Posted December 10, 2007 You should see what John Coffey thinks...oh. Quote Link to comment Share on other sites More sharing options...
G.I.jonas Posted December 10, 2007 Share Posted December 10, 2007 Sounds to me like you have a car with one wheel drive,steering you one way under power and the other under decel..kind of like a paddle on one side of a canoe. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 10, 2007 Share Posted December 10, 2007 Is the LSD set up tight enough to not break away under hard acceleration if by chance on side (stub or internal issue with the differential) was severed? Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted December 10, 2007 Share Posted December 10, 2007 My guess was also something loose in the suspension causing the wheels to toe in and out. Damn noobs wanting to be spoon fed. I Agree with Pop. No clunking or anything? Quote Link to comment Share on other sites More sharing options...
badjuju Posted December 10, 2007 Share Posted December 10, 2007 Damn noobs wanting to be spoon fed. http://forums.hybridz.org/showthread.php?p=807988#post807988 lmao, I couldn't help myself, please don't smite me. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 10, 2007 Author Share Posted December 10, 2007 Everyone's a comedian... It will be a month before I get a chance to put the car on the lift and check things out. It was on the lift after the event but all I was doing was swapping tires and brake pads. I gave everything a quick look-over but didn't check nuts, bolts, bushings, etc. I usually do that before I go out racing. I'm pretty sure the car is one wheel drive (right side). I drove it around up in La Habra Heights and can get the rear end to snap loose very easily in turns, either under power or on hard decel. Its kind of fun. It would make a great skid pad training car right now. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 10, 2007 Author Share Posted December 10, 2007 Is the LSD set up tight enough to not break away under hard acceleration if by chance on side (stub or internal issue with the differential) was severed? The diff is very tight. 100% lock under load. I've been wanting to tear it down and reduce the lock to about 80% and this may be my excuse. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 11, 2007 Share Posted December 11, 2007 Is the back end subframe mounted like the S130 or Z32? If so, one of more of the big bushings that mount to the unitbody may be deflecting due to damage or wear. Whole back end can move around and send you off in all sorts of directions under power. If you had wrinklewalls, that would be different...JeffP's car wants to change lanes when he romps it...flexy sidewalls do that... Good Luck! Keep us posted on what you find!!! Quote Link to comment Share on other sites More sharing options...
bjhines Posted December 13, 2007 Share Posted December 13, 2007 OK... This kind of thing always needs a "tricked out" answer. It is due to trash in a wheel sensor causing the computer to brainfart into the stability control system. Is one rear wheel getting hot due to the brake being applied. It is probably a mechanical problem. Get a friend to watch the rear wheel for any visible shifting while you drive in reverse and jab the E-brake. Quote Link to comment Share on other sites More sharing options...
260DET Posted December 14, 2007 Share Posted December 14, 2007 Is the back end subframe mounted like the S130 or Z32? If so, one of more of the big bushings that mount to the unitbody may be deflecting due to damage or wear. Whole back end can move around and send you off in all sorts of directions under power.If you had wrinklewalls, that would be different...JeffP's car wants to change lanes when he romps it...flexy sidewalls do that... Good Luck! Keep us posted on what you find!!! What he said ^ If it is similar to the Z32 et al multilink subframe setup, a set of poly mounting bushes is in order, solid (aluminium) if you are really serious. And don't mind a bit of vibration Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 14, 2007 Share Posted December 14, 2007 OK... This kind of thing always needs a "tricked out" answer. It is due to trash in a wheel sensor causing the computer to brainfart into the stability control system. Is one rear wheel getting hot due to the brake being applied. Doubtful - all of the stability control systems on the oem market have pretty sophisticated failsafe and plausibility algorithms, and wheel speed failures have been well understood since the early days of ABS. Any sensor failure that would cause the car to have a constant, repeatable oversteer problem would have long ago caused a system fault, shutting the system down and lighting a light on the dash. BTW, I realize that this was kind of a tongue-in-cheek answer, but thought I'd answer it anyway. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 14, 2007 Author Share Posted December 14, 2007 I bought a base model 350Z. I doesn't have VDC or TC. Just brake force distribution as part of the ABS. Quote Link to comment Share on other sites More sharing options...
jeromio Posted December 15, 2007 Share Posted December 15, 2007 I had this exact same problem on my s30. Accel it would turn one way, deccel it would turn the other. And even mild accel would peel one wheel. Hard deccel would skid one wheel. I thought it was the diff. Turned out to be a loose bolt on the front of the driver's side rear arm. Well, loose as in no longer there. Bushings were still on, but obviously the arm was no longer tightly secured. JT1 mailed me his spare boltand washer (not available for order anymore) and I was on my way. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 15, 2007 Author Share Posted December 15, 2007 I'm hoping its a suspension problem becuase that's easy enough for me to fix. The Cal Speedway Roval course uses the NASCAR front stright and turns 1 & 2. My car spent about 30 seconds per lap turning left at 135 to 150 mph with two people on board and the right rear suspension pretty close to fully compressed. Quote Link to comment Share on other sites More sharing options...
woldson Posted December 16, 2007 Share Posted December 16, 2007 For what it is worth, steves ac corbra kit car would head to the right under load. He got a four weel alingment and the car habeen straight as an arrow ever since. Quote Link to comment Share on other sites More sharing options...
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