solocus

iTrader: (8)

Some info on the car:

2001 Camaro
Stock Ride Height
Stock Springs
Stock Front Shocks
M6
OZ 700 Clutch
Prothane Motor Mounts
Full UMI Suspension
BMR Trans Brace TA Relocation
LCA Relocation Bkts (LCAs in second hole)
S60
Strange SA Rear Shocks (Both Set to 5)
Angles with me in the car
1/3 tank Gas

Only my rear shocks are adjustable, everything else is non-adjustable. This combination finally ended my severe wheel hop (Thank God!) It now spins the stock Eagle F1s smooth on the street and second gear spin is smooth as well. I do seem to get a little vibration only in fith gear (weird, any thoughts on this?) Also, I figure the angle finder is only accurate to a half degree or so.

Since nothing is really adjustable is a -3.8 pinion angle a big deal and should I buy an adjustable TA before racing it at the track? Could the strange minor vibration in 5th gear be related to the angle, the vibration is not speed or RPM dependant, but seems to lesson when the clutch is depressed. What do you all think? All comments welcome.

Manic Mechanic

iTrader: (3)

That's very similar to what I had to do to get rid of driveshaft vibration. I had to space the rear of the tranny up a good bit to get cancelling angles on each end with an adjustable torque arm. Mine has a slight vibration in 3rd now (A4), especially when coasting down. I didn't have wheel hop, just vibration with speed. What did you do to acheive this? Just bolt on the parts and measured? And what was the combination that had wheel hop previous to this one. What were the prior angles?

Vernon

solocus

iTrader: (8)

Yes I did just bolt on parts and measure them. Since it was stock height and all I hoped it would work out, which looking back now was kind of stupid. But initially I did not really give much thought to suspension setup. I believe it was the LCA relocation brackets that took care of the wheel hop. Cheapest of all the parts. The shocks may have played a part in eliminating the wheel hop as well. Rear shocks, S60 and Reloc Bkts all went in at the same time.

I didn't do the math or take previous measurements of the LCA angle or other angles, but with the LCA being a inch or so higher on the rearend side it had to be sloping the wrong direction, even with stock ride height. So you think the vibration in 5th may be the 1 to 1.5 degree excessive pinion angle? I thought it weird only in 5th.

Manic Mechanic

iTrader: (3)

I'm not so sure about why we have our vibrations in one gear only. From what I've read from U-joint and driveshaft tech the opposing angles should cancel out driveshaft vibrations as long as they are within the u-joints capability and both of ours are. I have been thinking mine had more to do with the stiff poly trans mount and the driveline all traveling at the same speed in drive. Yours does it in OD so the single rate of rotation theory doesn't apply. What kind of tranny mount are you using? I see you have poly motor mounts.

LCA lowering brackets will definately help plant the rear but I'm about to take mine off because I think that these along with a tunnel mount torque arm like the one I'm using actually sets up too much anti-squat. My instant center is really far back. If I hit the tires too hard the sidewalls get crushed and it will just spin though I can still leave harder than before if I step into the throttle instead of just flooring it. One or the other is good but both a short torque arm and upward angled lower control arms is too much. At least for a mostly stock car on street radials.

Vernon

solocus

iTrader: (8)

I'm still kind of new at this suspension setup thing, but I'm learning all I can. I would say with 2.5 degrees on my LCAs and a longer TA My instant center is pretty far up front. I also know I need front shocks soon for better weight transfer.

Yes the vibration in one gear is puzzeling. I wonder if its some form of resonance. My trans mount is factory, I hear the poly trans mounts often cause additional vibrations. Heck, I may just be over critical about the 5th gear vibration. I seem to forget about it or just not notice it when its in 5th for a while. I guess expecting the car to remain perfictly stock feeling with Poly MM and TA relocation is unrealistic anyway.

solocus

iTrader: (8)

Anyone have any other thoughts on this? I guess it just makes sense to get an adjustable TA and lower the pinion angle to a more reasonable 2 to 2.5 range. It sure would be sweet to get rid of what feels to me to be a slight vibration in 5th gear. It still kills me that it is only in 5th and not MPH or RPM related (in 6th gear at same MPH or RPM it is fine.....WTF).