It should absolutely NOT effect your alignment. Simply replacing the 26mm bar with the larger one. The 31mm Mag Ride bar will fit the base or the FE3 Z51 mounting brackets with the use of the quoted bushings.

 

Theta - I think that in your case it would be fair to also mention that the reason for your massive oversteer appears to be the huge amounts of extra power and torque installed in your particular car. I'm surprised that you can keep any rubber on the wheels with that much power/torque .

 

If it's a auto transmission my guess would be the small plastic deverter under the rear center of car to cool transmission, it looks like scrapper. Sence you liked the rear your going to love the front!

 

Thanks for the information. I plan to autocross the car so neutral to oversteer is what I'm looking for.

 

Thanks, Savage, I will check under. Yes, I have the A8.

The fronts looks fine for a track setup. I forget what kind of driving you do but, the cambers look good for the track or even for autocross. For track, and particularly autocross, I tended to go with a small toe-out up front for better turn-in on my race cars but, they were not Vettes and not street cars.

Your rear toe-in is HUGE. What are you gaining with that as opposed to the "normal" 0.05 toe-in? I would think it would blunt the turn-in and promote understeer...?

My driving of the C7 is all street, almost fully winding mountain roads. The -1.3 cambers with factory toe and caster settings work super well. The car is now a pleasure to drive, thanks to you posting the rear bar solution.

 

This is about the wheel touching when hitting a road dip:

What I found is that the driver side rear wheel touches the wheel liner mouldings at the rear of the wheel well. On the passenger side it is fine but, on the driver side there is a small protrusion in the wheel liner that brings it within 0.5" from the back of the rear inside tire edge, about 1" higher than the centerline of the wheel. As the bump sends the wheel up it eventually touches the liner.

Now, what is interesting is if I place an instrument between the stationary tire surface and liner, a completely vertical wheel travel should not cause a contact with the liner. Only if the rear wheel is actually deflected backwards a good 0.25-0.5" when the contact occurs.

Not sure if that much horizontal deflection is acceptable in the rear lower A-arm? Not sure how hard the A-arm bushings are but, the A-arm is fairly long to allow for horizontal deflection.

Any ideas? I may have to check all suspension bolts tight and/or have the dealer check it out.

 

I hate that the widest rear tire I can fit is a 315/30/18 Hoosier a7 on my z51 car, I found I had way more oversteer with this tire compared to a 335/30/18 that I ran on a c5, long story short- tow in at the rear was the fix! The more I added the less oversteer I had, I stopped when oversteer was gone, I know I am scuffing some speed off in straight line but more than make up for it in the turns, I autocross mostly with small cars on tight courses and this works for me.

 

Sway bars reduce grip...you say it yourself "big rear sway= more oversteer"....what is oversteer? Its a loss of grip to the rear wheels before a loss of grip to the to the front wheels. I do not think you know how saybars work. Do you know how they control roll? They control roll by lifting the inside( to the turn) tire( see any well prepared FWD car lifting the inside rear wheel into the air). If down force creates more grip, what does up force create? I will give you a hint....its not more grip. Swaybars make independent suspensions less independent, its that simple. If you have any question of this, Take it to the extreem...how independent would your rear suspension be with a one foot diameter swaybar be?
You are talking "traction", I am talking grip...Grip follows the theory the only thing that keeps you car turning in a turn is 4 patches of rubber, those patches can only do 100% of work. You can brake up the work...IE 60% cornering 40% braking. On a Stingray the front tires have to turn the car and brake. On the rear , the tires have to do all the same and then put 400+hp to the ground, Using them to control body roll is not the best use your your suspension imo. Sway bars are used to fine tune suspensions, not offset poor spring rate for tire choices. Tuning suspensions starts with the tires, the tires set the spring rates, the spring rates set the damping of the shocks. Sways are used to fine tune everything.... If you upgrade the tires, you need to upgrade the springs to compensate for the added grip.....not the sways....

As far as just throwing factory parts at the car, I would be much more interested in throwing a set of Z06 07 springs and shocks at the car than the sways. I have not found out what the spring rates are yet but with the tires that come on the car, they have to be higher than the Z51 springs or everyone would be screaming about how much that thing rolled in turns.

 

you will be out of stock class...you can change front sways but not rear...just a fyi

 

Not necessarily. The 31mm swaybar is the stock bar for the Z51 Mag Ride version. Unless the rules specifically prohibit adjusting for the differences between the two Z51 models. I bet, most tech inspectors have no idea that two different sway bars are offered on the Z51.

 

I can assure you that I raced long enough in SCCA and won a good number of Championships while contructing much of my racing cars, including the suspensions. So, yes, I do have a pretty good idea how sway bars work in combinations with all other suspension components.

Not sure what you are attempting to argue, particularly when I bolded the condition, "if it sized correctly". So, I don't want to talk about swaybars with 1 foot diameter. As I said, suspension design is full of compromises and you are doing your best to find the best combinations of compromises that work on your particular car.

In this case there is really nothing to argue since the bar I recommended is the factory stock rear sway bar for the top C7 models. Per most track tests and reports with those bars the C7 is considered one of the best handling cars on the road and track. What was not known before is that Chevy decided to put the smaller bar on the "base" Z51, likely expecting that the people who wanted the fastest, most neutral setup would chose the Mag Ride Z51 and the non Mag Ride would be for the wax and coffee crowds.

The 31mm bar is what should have been installed on all Z51s and the 26mm should have been put on the base, non-Z51 models. BTW - not sure if you know that; the front bars are the same on both Z51s, as well as on ZO6. If you are an enthusiast driver I can not imagine that you would not prefer the handling of the Z51 with the 31mm bar.

 

OK, do you know the spring rates of the sport and the ride/handling leaf springs(manual trans)? I have read that the Mag ride springs are softer to allow the customer a more noticeable feel when adjusting the suspension, that would explain the bigger sways... Again, I do not think bigger is better with sways.

 

No, I have not seen any info on spring rates.

No one said that bigger is always better. In this case, IMHO, the larger rear bar does justice to the car. Notice that it is the ratio between the front and rear bar that is changing between the Z51 models. The front bars are the same on all models, except the very base model which has 26mm front bars vs the 28mm for the Z51 and ZO6 versions. So, to everyone who is thinking of getting the 31mm rear bar, be sure you start with the 28mm front bar setup for proper handling balance.

 

Sooo the sport( Z51 with out the mag shocks), the ride/handling(MAG SHOCK z51) and Z06 AND Z06 07 springs all have different part numbers for the springs...and then the auto's have another set of part numbers in each trim....and noone knows the the spring rates? The car has been out for 3 model years...wow ....guess I will have to look around

OP....good luck with your sway....

 

I want to do the same for my base C7 and for the C7 without going to coil overs, it looks like very expensive Penske's or the aFE Pfadt Johnny O'Connell shocks which are much less expensive. Here is AFE's answer to my inquiry:

"The aFe CONTROL JOC shocks were built around the racers Johnny O'Connell's specifications as far as dampening and valving is concerned, along with using OEM quality seals, shock body and pistons. aFe aquired PFADT and addressed many of the concerns and issues others had with quality. We certainly don't want to put our name on something, that is no good or fails. So we have address the quality issues in the past.

Now the Z51 shocks will handle better than the base C7 shocks, but if you are looking for comfort, while maintaining a flatter cornering ability the JOC shocks will meet your requirements. The base shocks are very soft in low speeds, tending to be mushy and unrefined, while you drive on higher speeds and hit bumps that are bigger they really tend to be harsh. The Z51 shocks are a level better over the base C7 shocks, but still hold the same characteristics as the base shocks.

We adjusted the dampening to be soft, yet precise in low speeds. While we removed the harsh ride during higher speed bumps. We are confident you will feel the improvement over your current setup."

I was at Corvettes at Carlise last weekend and found nothing for suspension on C7's. Ride Tech was there but told me they are still working on shocks for C7. We're on the third model year so I hope so. Rather disappointing. Now if you wanted an exhaust system you had a large choice of manufacturers.

 

Pretty sure I will be going with the aFe set-up. As far as the 31mm rear bar, I have the luxury of having Paul Koerner working on my car, so it sounds like a consult is in order.

Thanks again for all responding and creating great debate!

 

FYI.
Just got off phone with Paul. He stated that the car would perform better with BOTH Z bars installed on the car.

Will be doing that when time allows.

 

Joe, why did you start a 2nd thread on the exact same theme?


The 2nd thread has been deleted.

 

Neglected to put the word "shocks" in the title and thought I would limit responses. I tried to edit but it wasn't letting me insert that word into the title.

Thank you for deleting that one.

 

I think I'm going to try the aFE Pfadt JOC shocks with the base C7 front only sway bar and see how that feels. I don't have much problem with sway in my mountain road antics but the mushy shock action is bothersome. I definitely don't want to compromise rear traction or increase oversteer with guard rails right beside me on most mountain roads. And when I "floor it" the back settles/front rises noticeably which isn't really a problem but annoying.