Chets LS3

have read a few threads but its mainly the z06 vs Z07 suspension or MSRC vs base.

Even when I'm running on the track on stock michelin tires in track mode, I am rolling the car enough to scrape a z06 stage 1 splitter. much less the air deflectors (those are about shaved to nothing)

I have lowered the car on stock bolts and added hotchkis swaybars, other than that the car is stock.

after looking at some pictures on stickier tires. This car REALLY rolls hard. it seems a solid inch plus of tire is inside the fender well. I see that Tadge stated you can't get the stiffer calibration for shocks on a z06, so I'm sure any calibration tuning to stiffen the shocks it out for the z51.

I ask this to see what other solutions people have done with wheel/tire combos. I just added 295 michelins on the car (it is lowered on stock bolts) and my drivers side tire rubs just driving to town.

This car seems to be a real headache when it comes to tires and offsets with what works.

NTMD8R

My '14 Z51 with Mag ride M7:

I put Rennen M5S Forged monoblock wheels on it
10x19 front with stock 56mm offset
11x20 rear with stock 79 mm offset
It has Toyo R888 tires
295x30x19 front
315x30x20 rear

I originally had lowered the car on the stock bolts.
But, with this wheel/tire combination, I was getting fender lip rub...
not while cornering, but while driving on the highway, over the undulations in the road.

So I put it back to stock height.

I also installed LG G7 sway bars, front and rear.
I have since replaced the rear bar with the OEM rear bar, to address oversteer,
I am still working on this setup, to continue to address oversteer.

Alignment is
-2.5 camber front, with 1/8" tow out each wheel.
-2.0 camber rear, with zero toe each wheel.

To get this amount of rear camber I removed ALL the A-arm washers front and rear.

I am going to try rear toe IN of 1/8" to further address the remaining oversteer.

Note: we Autocross this car.... 25 events last year (2 drivers, 6-8 runs each driver per event)

No rub, and all is great (except the remaining oversteer).

I hope this helps.

Chets LS3

Thanks that's good Info.

I'm at -2.3/-1.4 camber and I will autocross this car as well.

How are the rennens. I read some bad reviews and were concerned about them for track wheels

NTMD8R

The wheels are great, and (IMO) look great (Mine are chrome).
Lightweight, forged, monoblock.

Matt_27

Stiffer shocks won't do anything. They only help in transients. When you are in steady state cornering your springs and sway bars are what determine your body roll. So you need more spring rate if you want to reduce it.

0Anthony @ LGMotorsports

AutoX guys are going to be a little different from road racers as you have to focus more on low speed grip, which can be harder to do in these cars vs a road racer that might only have a 40-50mph "slow" corner.

Either way, with a stock rubber bushing I would never do zero toe at the back of the unless I just could not get it to rotate. Even with bearings in the control arms we typically run 3/16 to 1/4" toe in at the back of the race cars to keep them stable at speed.

Have you checked tire temps/wear on the back of the car? Sure it needs that much rear camber on it? If you get to much in it, you are going to loose contact patch. Again...do this depending on what you see and the courses you run.

0Anthony @ LGMotorsports

Sway bars first....as NTMD8R stated he has ours on the car (changing it a bit on the rear for his use). I am sure he can tell you it will make the car a bit more neutral/over steer vs the stock push they tend to have at speed on track. This will also solve a lot of your body roll concerns too.

froggy47

NTMD8R

Yup, those sway bars, along with the much wider and stickier tires has induced oversteer.

Anthony, I had to put that much camber in the rear so the whole tire tread was touching
the pavement. Otherwise the inner 1/3 of the tread was not being used.
And the only way I could get that much camber in was to remove the A-Arm washers.
I am going to put 1/8" toe in each wheel at the rear, and see how that goes now.

0Anthony @ LGMotorsports

Think about it like driving a fork truck, deflection in the assembly is giving you rear steer. If your rear wheels are pointing out the car is going to follow that path. Regardless of what parts and tires on are the car, if the wheels are not pointing in the right direction the car is going to be almost impossible to drive quickly.

I think you could dial a lot of your issues out with alignment changes myself, or at least I would do that before throwing parts at it. We had tried running 0 to 1/16" toe in at the back of the car to try and gain straight away speed before and Lou almost couldn't drive it.


The camber...if the car likes it, then go for it. Just shocked it liked that much.

See how much things move....

NTMD8R

Well, I've got zero Toe at the rear now.
And we still have some oversteer.

So I'm going to try a little bit of Toe In at the rear.

We do have 1/8" Toe Out at the front.

I understand another option might be to have no swaybar in the rear.

0Anthony @ LGMotorsports

No bar at the back would cause a lot of weight transfer at the back of the car, and for slow speed grip that might help it.

However...still doesn't change the angle of the rear tire. I know it is 0 static but probably not zero under load.

seamus2154

I have found this to be true. Guys forget to don't document how many heat cycles a tire has. Then when these issues come up they are chasing suspension. When I put fresh rubber on it is a whole different animal. Not using my car often then tracking it occasionally I had not realized my tires still had meat on them but were cycled out. New rubber was the cure!

Chets LS3

thanks for all the input, this is an auto and track car as well, so its nice to see these discussions. I might brake down and go with LG bars. I'm just unsure if that will help much coming from an already upgraded (hotchkis) bar. not saying its the best, but it is better than the stock bars.

GTB/ZR-1

No wonder...

It will become a totally different car with 1/4" total toe in, as compared to zero. You'll be able to really throw it around with confidence. Try it, you'll like it ;-)