Coilover ride quality?

[RHanselman]

I have two Z's with Coil Overs and a unmodified car as well. The Stock Ruby I drive all the time and she's a pleasure to drive around town. My Coil Over Ruby is another story. While a great car on the track she leave a little to be desired around town. She has a performance FX-3 computer and chip with the Morocco upgrade. She'll rattle your teeth on performance mode for sure... She also has a roll bar and x brace that stiffens the ride even more... Outstanding on the track but that's what it was built for. The wife will ride along but she doesn't much care for it.

My Turbo Car on the other hand is somewhere in between. I don't know what the spring rates are but I think Corey Henderson got it right. I'll have to ask if he remembers what he sold me. I actually installed them with Corey's help. Wasn't that bad at all. I believe Demps has some brackets that make the install even easier.

If I was starting out again and wasn't planning on tracking my car at a Spring Mountain or Miller Motorsport type track I'd just do a few minor upgrades. New Poly, new sway bar and maybe the Morocco FX-3 upgrade. I'd defiantly keep the stock springs...

One thing I've never heard of before riding in Roberts car is a mix of both. I believe he has coil overs on the front and the stock spring in the back. The car seemed to ride just fine...

Cheers,

[mike100]

Originally Posted by RHanselman

...

One thing I've never heard of before riding in Roberts car is a mix of both. I believe he has coil overs on the front and the stock spring in the back. The car seemed to ride just fine...

I've been considering such a modification.

My FX3 shocks were revalved, but only a little bit more aggressive than stock. I already have a VB&P aftermarket rear spring so all that really needs to be done is to get a little more spring rate on the front to offset the weight of the LT5 block.
Another reason would be to regain a little bit of ride height (if at all possible to get full height on coilvers) since my front spring had the rubber bushings shaved and has those lowering wedges instead. I absolutely hate that because taking out the bushing material actually un-tensions the spring effectively lowering the spring rate.

[batchman]

Originally Posted by mike100

I've been considering such a modification.

My FX3 shocks were revalved, but only a little bit more aggressive than stock. I already have a VB&P aftermarket rear spring so all that really needs to be done is to get a little more spring rate on the front to offset the weight of the LT5 block.
Another reason would be to regain a little bit of ride height (if at all possible to get full height on coilvers) since my front spring had the rubber bushings shaved and has those lowering wedges instead. I absolutely hate that because taking out the bushing material actually un-tensions the spring effectively lowering the spring rate.

Here's another possibility - it's what's on our car and it is not a bad street/handling compromise.

VB&P Sport front spring, I think ours is 770 lbs, with Bilstiens to match.
Hypercoil Rear Z51 spring, which I think is 375lbs, again Bilsteins to match. It's not enough for balls-out autocross but it did not kill the ride.

With the bolt kit in back and c5 style adjusters in front (available if you order the front spring that way) you're all adjustable.

I can't go coil-over due to class rules, but wouldn't in the rear anyway - I know everybody does it but I just can't get past putting all the force on a single-shear mount.

Cheers,
- Jeff

[rkreigh]

yes, the angle of the shocks, close clearances to the half shafts and single bolt "shear point" mount on the rear shock is a bit scarey

seems to be holding up well and I pound the car (and me) with runcrap EMT supercrud tires and 19 rims

not seeing any cracks yet.

might go back to a stock buggy spring eventually, but for now I'm content to just get better tires. car rides quite a bit better on the amolds, although the look of the ccw 505s is killer

first thing I'm going to try is rebuilding the shocks and raising the ride height up a bit. it's a bit too low in front and on really high speed dips I'm rubbing the tire on the inner fender

285/30/19s up front and in the weeds stance looks great, but not the best for the mean streets of DC

seems that as I put more miles on the car the shocks are freeing up too and the ride is a bit better. other odd thing is that with the top off and the R&D brace on it, I think the car rides better too. maybe just a bit more flex without being "floppy"

like to hear any tips you guys have to get the best of both worlds (handling and ride) which are typically a bit at odds

one thing for sure, the GM engineers are smarter than I am....

[Fully Vetted]

Originally Posted by batchman

... I just can't get past putting all the force on a single-shear mount.

Bingo. That's why I haven't done it. That and I don't want to lose the ride quality. And since I don't track my car I think CO's are not the right choice for me.

We could always go the Brett Henderson route and just fill up the wheel well with the largest tire known to man that will fit

[XfireZ51]

Originally Posted by batchman
... I just can't get past putting all the force on a single-shear mount.


Has anyone run into this issue? This is the first concern I have heard of it.

[Daniel_Mc]

Originally Posted by XfireZ51

Originally Posted by batchman
... I just can't get past putting all the force on a single-shear mount.


Has anyone run into this issue? This is the first concern I have heard of it.

I hear people talk about this all the time and have NEVER heard or seen an actual failure in this way. Now I have heard of the shafts on the rear shocks breaking where the shaft mounts to the frame on the Callaway coilover kits.

FWIW I have been running DRM coilovers for YEARS on our 89. This car is tracked in HPDE's and TT's 90% of the time and have zero issues.

-Daniel

[batchman]

Originally Posted by XfireZ51

Originally Posted by batchman
... I just can't get past putting all the force on a single-shear mount.


Has anyone run into this issue? This is the first concern I have heard of it.

I have not seen an issue but haven't seen much real test of something done this way. As a guy who spends his free time with folks that beat the snot out of things it looks like a failure point to me. The mount is pretty stout so it may take a long time/big event but still, the middle or end of a lever is not a first choice to put all the load of a corner of a car. And that lever is seated in aluminum. It was designed for, and apparently sufficient for, damping forces - as the load path, not to my eye.

Your mileage may vary,
- Jeff

[batchman]

Originally Posted by Daniel_Mc

FWIW I have been running DRM coilovers for YEARS on our 89. This car is tracked in HPDE's and TT's 90% of the time and have zero issues.

Glad to hear. Continued good fortune to you,
- Jeff

[rkreigh]

I agree with you jeff, it's an area of concern and it just wasn't designed for this kind of pounding. I'm wondering about using the van steel mount with bilstein shocks. they sell it separately and it looks like it could help (but still just one bolt on the knuckle ear) so it's not a solution.

the shock towers in front are also a problem area. I talked at length with Dave M about this and he mentioned that even though it wasn't designed for coil overs, the stampings are beefy and although they might eventually stress crack, he hasn't seen the problem

honestly I'm more worried about the back. aluminum would be more likely to fail from the duty cycles

kinda like alum rods in a street motor, they let go in spectacular fashion!

so far, no worries. if anyone has the van steel setup and can measure the "gap" for the bottom shock mount please let me know.

looks like it's too narrow for the bilsteins, but it could likely be machined to open it up and make it work. machine work gets expensive in a hurry though!