Following the installation of my Budget Bilstein Setup (450/300, Maruha Top Hats, 4" Coilover Sleeve, HardS Billies) the Passenger side rear corner is .25" higher than the drivers side, without me sitting inside. I haven't gotten an alignment yet, trying to wait until I get my height situation solved. Both rear shocks rebound fine, tire pressures are the same, both collars are equally positioned on the Circlip, the coilover ring is at the exact same position, and the spring is centered on the isolator and the ring. With the rear end jacked up, my center of wheel hub to top of the quarter panel height is 16 3/8th Inches under full droop, with the exact same measurement on the other rear side. With the wheels on, the pinch weld height is .25" higher on the passengers side. I have loosened the lower shock mounting bolt, two nuts on the top of the top hat, and have tightened the shock rod nuts to show 5 threads at the top of the shock on both rear shocks. I have also ensured the Sway bar end links are tightened to spec, all bolts were tightened to spec with a jackstand compressing the setup under full load. The front two shocks are at identical heights with the collar adjusted at the same height.

Should I just adjust the passenger side shocks collar down a few turns til it equalizes? Am I missing something really obvious?

Pics of the rear collar adjustment on both sides
Stock everything except for the shock setup

 

Miatas aren't the stiffest car in existence, and pinch welds can be an imperfect measuring point depending on if the have been bent down at all. Have you driven it since putting everything back together? I think it's recommended because the suspension will settle. I think if you drive it and the difference remains, you are free to even it out if you want, a 1/4" isn't a lot though... Also when you get in the car that changes things too.

 

The difference remains after about a week of normal driving, the passenger side pinch weld is bent in a bit, but not enough to change the measurement of the height. I can fit two fingers in between the tire and rear quarter panel on the passenger side, while I can't even fit one in between the tire and quarter panel on the drivers side. If I didn't notice it there I wouldn't mind, but the difference is enough to bother me. That corner is also noticeably higher than the others when you circle the car on even ground. I will lower that side using the collar to even it out.

 

Yes. And that would be that adjustable spring perches are meant for corner balancing the car. And if you were to put the car on scales you will find that the pass rear is the lightest corner of the car. This is likely the reason why it's a 1/4" higher.

So you can lower the car on that side to even out your stance (no pun intended) but that may or may not make the handling any better. Or you could take it for a corner balance alignment and use your suspensions tunability and not worry about uneven wheel gaps. A 1/4" here or there is nothing. Even she says that.

 

Point received, as a vain individual I will choose style over functionality, and lose some suspension travel to even it out a bit

 

It's your car (and your money) so do what makes you happy.

Just in case, check the drivers front. If it's a little low, raise it to even it out with the other side. That might hep lower the rear.

Still won't make corner weights better but it will keep it more level with weight in drivers seat.

 

Also verify tire pressures are all even prior to measuring. Mazda put the battery in that corner because it was the lightest. That's also where they put the spare tire.

Consider maybe lowering the right front and left rear a thread or two and see where that gets you.

Edit- also check the alignment eccentrics on the lower control arms all the way around. It's not uncommon for our control arms to get bent. Even one on a different Corner could affect that right rear. If one was bent and the car had been aligned to compensate you may see some eccentrics with wildly different settings from left to right on one of the corners. Or it may be bent and nobody compensated for it yet with an alignment.

 

Spun the collar down one spin on the passenger side rear side, seems to have evened out the height. Will be bringing it in for an alignment with 949s Street Spec tomorrow morning. I will try to check the control arms to see if one is bent, I did overestimate my driving abilities and drove myself off into a ditch a few months ago.

 

my nb2 is the same way, if i set both rear coilovers identically, then the gap between the tire and fender is not even.

driver side would have barely a 1 finger gap, and passenger side a 2 finger gap.

i just lowered the shock with a few turns on the adjustable shock body to compensate and all is even now.

now when the car is on jack stands, one control arm has a slight angle downwards and other one is straight across.

but what ever, it handles great, did autox and hpde days, and car handles fairly neutral, with a slight hint of oversteer.

 

Not to steer the thread in another direction but if your car has control arms at different angles when off the ground, it's not because of the spring perch adjustment. You have more droop on one side as opposed to the other.

Either something is bent, something is binding, or the body length on your shocks are different, or.......

 

BC coilovers have adjustable body lengths to adjust ride height without messing with spring preload.

 

Just got it aligned pretty close to 949s daily numbers, -1.7 neg camber in the front, -1.3 neg camber in the rear, +.03 Front Toe, +.06 Rear Toe, and 4.5 degrees of caster. Measurements from middle of wheel hub to the fender/quarter panel all around was 315mm-319mm at all 4 corners, so I did pretty good eyeballing the ride height. The ride height is basically even if you adjust the front two collars to the exact same height, and adjust the passenger side rear to one full spin lower than the drivers side rear. Nothing was bent, all is well. Will need to drive a bit more to feel the difference.

 

This is perfectly normal.....but really you need to corner balance the car to do it correctly. You could have 50-100 lb's of crossweight depending on exactly why there is a mismatch. This is slippting hairs and unless you can tell a balance difference left to right then it's really not worth chasing down.

 

My MSM is like this too, although not as extreme. Passenger rear is a a slight smidge higher than the driver side rear. Haven't bothered to fix it since it's such a small difference and otherwise the car drives fine and aligns fine