I have a 2017 Base Stingray, I want to add sway bar to the rear. I Found a Z51 kit front and rear complete GM but its for Mag Ride. I don't see how it would affect the car if I went this route. I am not installing mag ride. The difference is 26 mm non and 31 mm with.
Any thoughts ?

 

I put the wrong year sorry , it is a C7

 

NP ,

Cant answer what the thicker bars will handle or ride like
I just bought a set of non mag Z51 bars off of EBAY , came with end links and grommets , just had to buy the rear caps and bolts .

 

In general I would go w/ the thinner rear bar. I say that because I believe that the thicker rear bar would be a better match for a thicker front bar.

 

The complete Z51 Mag ride setup will include the thicker front bar and 31mm rear bar. So they would be "matched" if that makes a difference to you. I have had the 31mm rear bar and the smaller front base bar on my car for over a year. It drives fine even at the limit during autocross.

 

I heartily recommend the standard shock Z51 kit available from Cultrag here at the Forum. It comes with everything and has the correctly matched bars.

(btw, I suggest topping off your differential before putting on the rear-bar... much easier then; most C7s were shipped low despite what the dif manufacturer CEO claimed some years ago)

 

Not sure what correctly matched bars means. In no case did GM ever match a rear bar to the smaller base Stingray front bar (26.2 mm bar). That bar was only used on base Stingrays and only with no rear bar at all. For all other the non-Mag Ride C7s, GM matched the bigger front bar (28mm) with a 26.5 rear bar. For all Mag Ride C7s (Z51s, Grand Sports and Z06s), GM matched the same front bar (28mm) with a 31mm rear bar. So what does correctly matched mean within this context?

The most important function of the sway bars is to balance the chassis for mid corner performance. I know some will disagree saying the most important function is to prevent body roll, but body roll in and of itself is not as much of a contributor to how fast the car can lap a track. Allegedly, GM chose the bigger rear bar for Mag Ride C7s because the Mag Ride shocks would compensate for softer springs used on those platforms and the softer springs then required stiffer sway bars to get the balance correct. However, GM did not change the sway bars as it increased spring rates on the heavier (and higher down force) Grandsport or Z06 models, so something seems wrong about that theory.

Keep in mind that shocks have very little affect on mid corner balance (unless you have damping rates so stiff the tires skip off the pavement at every little bump). Spring rates, tire sizes, corner weights, downforce and finally sway bars do determine mid corner balance.

In general, wider tires have more lateral grip so the ratio of front to rear widths could affect mid corner balance which would then need to be addressed with sway bay sizes, but again the Z51 and wide bodies get the same bars so the tire widths must not be the reason.

Spring rates do effect mid corner balance but to a lesser degree than sway bars. I find the whole concept of why GM chose the sway bar sizes they did to be confusing. Perhaps they chose these bar sizes because of expected performance levels for the various models. A car that is balanced for mid corner handling will be faster when driven to the limits of tire grip. It will also be more dangerous because the car is less stable (more likely to spin) than a car that is balanced towards understeer like the base Stingray setup. Since the Mag Ride versions of the car were touted to be the best for performance, it makes sense they would balance them for the fastest possible lap times.

Just some thoughts to promote further discussion. Not trying to star a flame war here.