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-   -   Twisted chassis? (https://www.ft86club.com/forums/showthread.php?t=79566)

lukey86 12-21-2014 05:20 PM

Twisted chassis?
 
I ran a search on this but couldn't find anything...

I've had my coilovers/wheels installed for a while now but it's only recently that I've lowered the car to where I want it after pulling the rear guards etc.

I have the rears and the fronts measured to perfection (spring length at 0 preload and ride height) but I've noticed that the left rear sits low and the left front sits a little higher and the right rear is high and the right front a little low, overall there's a difference of around 10mm.

Obviously I could adjust the ride heights to equal everything out but first I thought I would get some opinions on what may be causing this, twisted chassis maybe?

wparsons 12-21-2014 06:02 PM

Chances are much better that it's unequal weight distribution than a twisted chassis.

That said, how are you measuring ride height? It's highly unlikely that the LR and RF would be lower than the RR and LF. Bent or not, that's a very improbable way for it to ride.

lukey86 12-21-2014 06:13 PM

Quote:

Originally Posted by wparsons (Post 2064353)
Chances are much better that it's unequal weight distribution than a twisted chassis.

That said, how are you measuring ride height? It's highly unlikely that the LR and RF would be lower than the RR and LF. Bent or not, that's a very improbable way for it to ride.

With the car up on jack stands the RR/RL measurements are equal both by measuring hub to fender and measuring the coil dimensions as well, same story for FR/FL, but when the car sits on the ground (perfectly level concrete slab btw) the R/L sits lower than R/R by around 10mm and F/R sits lower than F/L by the same measurement

Weight distribution in these cars is pretty good, and theres no aftermarket parts that would put it off by that much

Turdinator 12-21-2014 07:32 PM

1 Attachment(s)
It could just be tolerances in the springs or top mounts putting things out. I highly doubt you have a twisted chassis.

Or maybe you are just making so much torque the chassis twisted coming off the line.

Poodles 12-21-2014 07:36 PM

I'd be more inclined to think a fender is out of alignment than the chassis being twisted.

lukey86 12-21-2014 07:45 PM

Quote:

Originally Posted by Poodles (Post 2064445)
I'd be more inclined to think a fender is out of alignment than the chassis being twisted.

Front is possible maybe but rear fenders are static and its happening font and rear, plus 10mm is way too much not to be noticed at the fender gaps

I just figured with the skin and bones style chassis these cars have coupled with the rough roads we have down here (and my driving lol) it could be a possiblitity

It doesn't really matter either way, I was just probing to see if anyone has faced a similar issue before. The car still handles like a champ so I'll just make the necessary adjustments to even things out.

Fizz 12-21-2014 08:40 PM

Same experience here. When I installed my Bilstein coilovers I noticed that the actual ride height was uneven between left and right (by about 8-10mm), even though the spring preloads were all matched perfectly prior to install. So I just leveled everything out on the height adjusters and have not had any issues whatsoever.

In fact, the "proper" way to adjust would have been for me to use weight scales, and in doing so would probably end up having different preloads on all 4 corners anyways. But I don't have scales and I don't really care about corner balancing.

wparsons 12-21-2014 09:34 PM

Quote:

Originally Posted by lukey86 (Post 2064368)
With the car up on jack stands the RR/RL measurements are equal both by measuring hub to fender and measuring the coil dimensions as well, same story for FR/FL, but when the car sits on the ground (perfectly level concrete slab btw) the R/L sits lower than R/R by around 10mm and F/R sits lower than F/L by the same measurement

Weight distribution in these cars is pretty good, and theres no aftermarket parts that would put it off by that much

Up on jack stands meaning the body resting on jackstands, or the control arms resting on jackstands?

You'd probably be surprised how off the weight balance could be even with the springs measuring level in the air.

What coilovers do you have? It's entirely possible there is some inconsistency with the spring rates causing this as well.

The proper way to do this is to adjust until the car is level (or balanced if corner balancing), not by setting the perches to the same measurements.

redlined600 12-21-2014 09:36 PM

Setting by static ride height will get you close but the car needs to be corner weighed.

If you have separate ride height and preload and you are pre setting it off the car then I'm not surprised at all that the ride heights are off.

It's like getting high performance tires then never checking the air pressure.

lukey86 12-21-2014 09:43 PM

Quote:

Originally Posted by wparsons (Post 2064550)
Up on jack stands meaning the body resting on jackstands, or the control arms resting on jackstands?

You'd probably be surprised how off the weight balance could be even with the springs measuring level in the air.

What coilovers do you have? It's entirely possible there is some inconsistency with the spring rates causing this as well.

The proper way to do this is to adjust until the car is level (or balanced if corner balancing), not by setting the perches to the same measurements.

Sweet as, I won't be corner balancing, I'll just adjust until it sits level

Thanks for the input :thumbup:


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