azrael

are there any control arms that allow for adjustment of caster? I'd like to reduce the caster on my Z to the 7-7.5 degree range. I'm fairly confident that the caster plays into the irregular tire wear (and road noise) issue.. but I haven't seen any arms for sale that allow for the adjustment.

I've seen some references to the idea that the 350EVO arms might be capable of this, but BJ's (dwnshift) posts don't mention anything to this effect.

dwnshift

iTrader: (1)

We are looking into making this an option that can be added onto our arms. We just want to get these out now......but we do hear you and we are taking notes.
Provisions are in the works that could be added to the arms.
Cheers
BJ@350EVO.com

azrael

Thanks for the info, BJ.

What has your race team done about caster? Do you guys run the stock caster?

Stock caster is something like 8.1 degrees, where most other sports cars seem to run something between 7 and 7.5 degrees. Research into the "feathering" issue (which is actually the wrong name for this type of tire wear) shows that the heel-toe tire wear can be caused by excessively positive caster and/or incorrect shock valving.

I think we all agree the shock valving on the Z is a little bit off, and parts of the problem very well might be caused by this, but caster seems a little odd as well. I'd really like to run the 350EVO control arms, as they have gotten rave reviews.. but I don't want to invest money in this car if I can't fix the tire wear issues. If Nissan and/or the aftermarket comes up with a real fix, great.. otherwise, I'm trading this car in for a Z06.

Thanks again for the info BJ, you've been very helpful and your products seem top notch. Hopefully I'll have the opportunity to purchase a few in the coming months.

Matt

dwnshift

iTrader: (1)

No problem........
We have just run the OEM caster..never changed it on the race cars.
Cheers
BJ@350EVO.com

John

iTrader: (17)

The problem is inherit in the improper shock valving found in 2003 and early 2004 model 350Zs. There is not one reported incident of this reverse feathering on anyone with an aftermarket suspension or with a late model 2004 350Z.

johnlotusboy

iTrader: (1)

I have feathering and I have RS*R springs with Koni shocks and Cusco swaybars and the car has been in for alignment checks several times. I believe ther are others like myself with the problem that is persistent.

azrael

while it might contribute, I really don't think the shock valving is the true culprit.

I've yet to see anyone post definitive factual information (i.e. part numbers) showing a different set of shocks and/or springs for late 2004 cars.

Furthermore, several people with aftermarket suspensions have the heel-toe wear pattern, and I believe as the later 2004 cars begin to acquire mileage, you'll see the same data from them as well. I have an early 2004, and mine definitely shows the heel-toe wear pattern.

If Nissan had truly found a fix (i.e. different shock valving), then they would update/replace these rediculous TSBs that blame the issue on toe-out. My car has had nearly perfect alignment from day 1 (toe-in matching the updated specs), but still has the wear. According to the NNA rep I spoke to, Nissan engineers are aware that the alignment doesn't fix the problem and they are still searching for a permanent fix.

Matt

John

iTrader: (17)

Did this feathering occur on a new set of tires that were installed after the suspension? My car had an awful feathering problem, but at 12000 miles, I replaced the front tires and suspension, and after another 14000 miles, I have had no problem whatsoever.

azrael

interesting data point.

out of curiosity:

1. What all have you changed in the suspension?

2. How are your new tires wearing? I.e. even if the wear is no longer problematic, are the fronts still wearing faster than the rears? I've never seen a RWD car wear out the fronts before the rears.

3. What tires are you running?

Thanks,

Matt

John

iTrader: (17)

1) Suspension:
350Evo adj. sways
JIC coilovers

2) My new tires are wearing the exact same on the left and right side. Even with -1.7 degrees camber, no premature tire wear in the center. The rears are wearing twice as fast than the fronts, but other track junkies I know with the stock suspension are wearing the front much faster. Now, my rears do wear prematurely in the center, which is indicative of overinflation. However, my tire is actually underinflated when cold, and you can even see the concave shape of the tire. My previous set of tires did the same thing (before I swapped the suspension). I still haven't sorted this issue out...

3) S03s

azrael

Very interesting. that's good to know. it really seems the front suspension (shocks/springs) is very messed up (even more than I originally suspected). Every other sports car I've ever seen wears rears approximately twice as fast as fronts.. on my stock suspended '04, my fronts are slightly more worn than the rears, and will probably require replacement at 15K. I also have S03's, by the way.

I'm 99% sure I will be going the same suspension route you took -- JIC FLT-A2's and 350EVO sways, plus the 350EVO control arms as money allows. Hopefully I'll get fixed tire wear as well as the expected performance improvements.

Bring on the track!

GaryK

I agree with you on the caster. My car has 8.4 on one side and 8.0 on the other. Nissan's specs allow up to 9.0 IIRC. I'd be curious to see the caster numbers on cars that don't exhibit the heel-toe wear pattern, as compared to those that do. My car continues to have the problem, and I've noticed that it is a bit worse on the side with more caster....might mean something, might not. Most other modern cars run at the most 7 degrees caster, with a rare exception.

Damn I wish I would have bought that Z06 instead of this thing I have now...