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I would wonder why, they would give you the choice of lowering, the car, if it could cause damage. I’ve driven it pretty hard, on the street, with no sign of rubbing or bottoming
GM's intent for the adjustable spring perches is for corner balancing, not lowering the car.
Coming from the powersports realm, the spring adjusters on the C8 adjust spring pre-load. Most of the time on cycles and snowmobiles you would adjust spring pre-load to adjust ride height for different weight rider(s). Proper ride height is determined by the manufacturer for full usage of the suspension geometry. Shock absorber compression and/or rebound damping should be adjusted to road conditions(mag rides purpose).
Reducing the Z51 spring pre-load would offer a more supple ride but without proper damping I would think body roll would increase. Just an observation on my part.
Yep, agreed. Magna ride relies on quite a bit of suspension travel, and major height drop will likely hinder its operation, as well as causing clearance issues at the track with sticky/wide rubber. If suspension is stock, I'd think stock ride height, or close to it, would be the best bet. The height adjustment should rather be used for changing the balance (rake) in my opinion.
Yep, agreed. Magna ride relies on quite a bit of suspension travel, and major height drop will likely hinder its operation, as well as causing clearance issues at the track with sticky/wide rubber. If suspension is stock, I'd think stock ride height, or close to it, would be the best bet. The height adjustment should rather be used for changing the balance (rake) in my opinion.
... Or just get aftermarket coilovers : )
i dissagree, I lowered my car, been driveing it on the streets, hard. Going to empty parking lots, doing autocross moves. The car works perfectly. I lowered mine maybe 3/4 in, that dos not affect the MAG ride at all. Sure it it a little lower, and you have to watch when you go up driveways, but that is the norm for Corvettes anyway.
i will be tracking it within the next couple of weeks, I’ll keep you posted
thx
Yep, agreed. Magna ride relies on quite a bit of suspension travel, and major height drop will likely hinder its operation, as well as causing clearance issues at the track with sticky/wide rubber. If suspension is stock, I'd think stock ride height, or close to it, would be the best bet. The height adjustment should rather be used for changing the balance (rake) in my opinion.
GM's intent for the adjustable spring perches is for corner balancing, not lowering the car.
Source? Not saying you are wrong, but am thinking that 1. Reports of cars leaving factory with (somewhat) significant differences in ride height, 2. Ability to drop almost 1" is more.than necessary for corner balancing alone -- I'm no expert but don't think there has ever been a situation where 1 corner needed to be dropped ..75", while another needed no drop, to balance?
Also, lower car = lower CG. Absent some other issue, this is undeniably better.
Your insight is appreciated. If everyone is just lowering their car based on a misconception, tha k you for brining it to attention.
Hi Guys, I am preparing my C8 Z51 MAG ride, for the track. I lowered it about 1in. One C8 owners told me he went to Ron Fellows driving school, and they were instructed not to lower the car, if you are going to track it, it’s ready to go, out of the box. Is this true, has anyone lowers their car and tracked it??
Before I spend $300 on a track alignment, I want to make sure, lowering the car, is ok.
thank you in ad My car lowered with 19x315s in rear and 18 265s in the front installed
vance
Are you going with the exact same "GM Track Alignment" specs after making the tire size changes? Curious how that effects alignment requirements (aside from fitment reqs). Apex recommends "at least" -2.5/-2 for similar tire sizes. Just looking to learn how tire width/sidewall height impacts alignment needs.
You can absolutely lower your car to whatever you want. We're merely stating as GM has stated in numerous occasions (engineer interviews at Carlisle events and some Savagegeese videos or Tadge at ask Tadge section on the forum) that this car is highly optimized for stock height for aero, cooling, and suspension (especially magna ride that leverages long stroke). If you switch to 4.8x stiffer MCS coilovers, though, you should absolutely lower it : )
Source? Not saying you are wrong, but am thinking that 1. Reports of cars leaving factory with (somewhat) significant differences in ride height, 2. Ability to drop almost 1" is more.than necessary for corner balancing alone -- I'm no expert but don't think there has ever been a situation where 1 corner needed to be dropped ..75", while another needed no drop, to balance?
Also, lower car = lower CG. Absent some other issue, this is undeniably better.
Your insight is appreciated. If everyone is just lowering their car based on a misconception, tha k you for brining it to attention.
There isn't one GM document that discusses using the adjustment collars to lower the vehicle. However the track preparation guide discusses using the adjustment collars for corner weights: https://www.gmspecialtyvehicles.com/...20Corvette.pdf
3. ADJUST FOUR CORNERS AND ALIGNMENT
SHOCK SPRING SEAT ADJUSTMENT, TIRE PRESSURES AND ALIGNMENT
The front shocks, on vehicles without hydraulic front lift and rear shocks, have threaded spring seats
that allow adjustment of the preload on the coil springs. The vehicle corner weights can be adjusted
for track use. If the vehicle trim height is modified, it should be returned to normal trim height before
street use.
You can absolutely lower your car to whatever you want. We're merely stating as GM has stated in numerous occasions (engineer interviews at Carlisle events and some Savagegeese videos or Tadge at ask Tadge section on the forum) that this car is highly optimized for stock height for aero, cooling, and suspension (especially magna ride that leverages long stroke). If you switch to 4.8x stiffer MCS coilovers, though, you should absolutely lower it : )
Have fun!
Do you have a link to an official GM document that discusses using the collars to lower the vehicle? I'm not saying that it does any harm or anything, just that I haven't seen a GM document that officially endorses it. The track preparation guide says to make sure to return the vehicle to normal trim height before street use. And the service manual only has settings for the normal trim (ride) height and says to check for the trim height being within specification when troubleshooting problems. If you modify the suspension then GM's recommendations don't matter anymore.
Are you going with the exact same "GM Track Alignment" specs after making the tire size changes? Curious how that effects alignment requirements (aside from fitment reqs). Apex recommends "at least" -2.5/-2 for similar tire sizes. Just looking to learn how tire width/sidewall height impacts alignment needs.
Thanks so much. Car looks great 👍
im going with the factory track alignment, this was also recommended by Apex.
I lowered my car on z51 factory coilovers to the max (3/4ths inch)
I got smaller wheels (18s)
I added 3deg of camber.
My car is now so low i have to avoid certain bumps. However, the functionality of the car/suspension (even on sticky 200s) remained great. Car def felt a little stiffer (shorter travel, maybe magride compensating, placebo, idk). Maybe i also just got used to it as in a way it feels really comfortable.
Either way, i'm just about as low as practically viable (especially with no front lift) and everything runs great. I won't recommend going as low as me though, i don't drive impromptu as much because i'm thinking about how i'm gonna navigate the choppy terrain that is CA roads.
I'd say pick 2. (lower, smaller wheels and/or camber)
I lowered my car on z51 factory coilovers to the max (3/4ths inch)
I got smaller wheels (18s)
I added 3deg of camber.
My car is now so low i have to avoid certain bumps. However, the functionality of the car/suspension (even on sticky 200s) remained great. Car def felt a little stiffer (shorter travel, maybe magride compensating, placebo, idk). Maybe i also just got used to it as in a way it feels really comfortable.
Either way, i'm just about as low as practically viable (especially with no front lift) and everything runs great. I won't recommend going as low as me though, i don't drive impromptu as much because i'm thinking about how i'm gonna navigate the choppy terrain that is CA roads.
I'd say pick 2. (lower, smaller wheels and/or camber)
I lowered mine only 3/4in. It is hardly noticeable, ride-wise, but in turn the bar feels more stable and less leaning in turns. I think it will be fine on the track. Tomorrow I go for track alignment.
thx for input
I haven't lowered my car nor looked at this in detail but I'm pretty sure adjusting the collar neither stiffens or softens the spring. You are adjusting the bottom perch, the top of the spring remains in a fixed position but the bottom of the spring moves in relation the lower control arm attach point. Calling it preload is a little misleading since you are only adjusting the preload when the shock is in a fully extended position. Once the weight of the car starts compressing the spring then the preload is overcome. I.e., the compressed length of the spring compressed by the weight of the vehicle doesn't change no matter what the collar is adjusted to. What does happen is you loose upward travel if the car is lowered because you are starting from a lower position and have less travel (and less spring compression) before you hit the bump stop.
+1, the sitting spring's force applying to the car is same, since car's weight is same, and your car is in balance. The biggest impact is in available suspension travel as well as center of gravity, and higher preload will also mean it'll land harsher (will hit the ground starting from a higher wheel rate) if any tire ever gets airborne.
+1, the sitting spring's force applying to the car is same, since car's weight is same, and your car is in balance. The biggest impact is in available suspension travel as well as center of gravity, and higher preload will also mean it'll land harsher (will hit the ground starting from a higher wheel rate) if any tire ever gets airborne.
I will find out soon, when I take it to the track, will keep everyone informed
I wanted to thank you guys for kindly correcting my thought on preload. I just read some articles and have a better understanding of preload and spring rate now.
Jeffrey
I wanted to thank you guys for kindly correcting my thought on preload. I just read some articles and have a better understanding of preload and spring rate now.
Jeffrey
Thats what this forum is about, to help each other, and share knowledge and experience!!
I haven't lowered my car nor looked at this in detail but I'm pretty sure adjusting the collar neither stiffens or softens the spring. You are adjusting the bottom perch, the top of the spring remains in a fixed position but the bottom of the spring moves in relation the lower control arm attach point. Calling it preload is a little misleading since you are only adjusting the preload when the shock is in a fully extended position. Once the weight of the car starts compressing the spring then the preload is overcome. I.e., the compressed length of the spring compressed by the weight of the vehicle doesn't change no matter what the collar is adjusted to. What does happen is you loose upward travel if the car is lowered because you are starting from a lower position and have less travel (and less spring compression) before you hit the bump stop.
Think about this for a minute ....this is not true.
