Hey all,

I have a 99 FRC (Z51 Obviously) without the ride selection option. I have a few suspension upgrades including lowered on stock bolts and brand new 2011 C6 Z06 shocks (which feel amazing when hitting the loop type off/on ramps BTW for those who are considering buying these shocks, DO IT).

My question to you guys is should I invest in the C6 Z06 sway bars? I understand they are slightly thicker and stiffen up the front in cornering especially, but since I have the C5 Z51 sways do I really need the upgrade? I have always put Hotchkis on every car I have owned, and saving money on suspension isnt a big deal to me because I know the quality of Hotchkis will always be great.

Do any of you currently have the C6Z sways and what are your thoughts? Any noticeable differences?

 

Most here have used the C6 Z06 shocks in conjunction with the C6 Z51 bars with metal end links. That's what's on mine-works very well ('99 FRC).

 

If you run the Z51 sways, whats the largest tire size you can run?

Is there a considerable difference in size between the Z51 and Z06?

 

Tire size is dictated by wheel size and offset, not the bars. I forgot my fronts-2.85x35x18 (I think) and the rears are 305x30x19. Here"s a chart from Pfadt that will give your relative stiffness for various C6 bars:
http://www.pfadtracing.com/photos/da...Comparison.jpg

 

Okay sweet thanks. I know ive heard people running into rubbing issues but I guess that would be with a larger rim size over 10" wide. Right now I have C6 18x9 and 19x10 running 285's in the rear and planning on running 305 PS2's in the next few months. With that said i may just go with the C6Z06 sways since they are slightly stiffer and basically the same price as the Z51's. Im sure GM parts house will be giving me a good deal

 

EERRRRRRRRRRRRRTTTTTTTTTT As they say on the game shows,,

Sorry Phil, but that's a wrong answer....

You need to match sway bars with the wheel and tire sizes you intend to use to optimize the handling. While the tires have to fit the wheels, there's a big variation in what tires you can put on a given set of wheels.

For instance, the C6Z has bigger rear tires relative to the fronts and uses more rear roll stiffness to balance it. Conversely, lots of guys running track days or racing go to a square setup with equal size tires front and rear. I you do that on a C5 you need to increase the front roll stiffness to keep the balance. Otherwise the car will be really tail happy.

If you upsize tires on both ends of the car pretty close to equally you will retain your balance. If you increase the amount of tire relative to one end or the other, you need to also look at the roll stiffness distribution to get the car back into balance.

 

So for wider tires such as 305's would you recommend a stiffer or softer sway bar?

 

I had my shop install C6Z shocks and sways, I chose the C6Z sways over the Z51 because I am doing a mini tub and 345s!

If you chose the Z sways, you need a 325 tire in the back or wider to compensate for the thicker bars!

If you have 305s, you should choose the Z51 sways! This will work best for your setup!

This is a 345/19 Drag radial! They are Huge!

 

Not to hijack the thread, Blitzkreg- did those center caps come with those rims? Been looking for the same type for mine, I have the same style rims..........

 

Yes they came with the wheels, Factory Reproduction from Discount Tires! I wanted the plain ones but they sent me these! Oh well.

 

Ok- I will check out my local Discount Tire and see if I can order some caps. Man those are some HUGE tires.

 

I'm running Bilstein Sport shocks with C6 Z51 sways. My rear tires are 11.5 wide so I could have also gone with Z06 bars but decided on the Z51 in case I change wheels and end up with a narrower rear tire. For now my combo works GREAT!

 

I was trying to give him a quick (generic) answer as opposed to a tutorial on chassis setup. Agreed, the bigger the tire, and the more the offset (think tubbing or widebody), the more leverage the suspension generates against the chassis and bars, and a larger bar is indicated. That being said, if he's going with 3.05s and staying within the confines of the factory fenders, I think, as stated above, the Z51s will work. Tubbing, flared fenders-not so much. And it really depends on what he's doing with the car-street or race. My $.02.

 

Point taken and agreed, if he is only going to 305's the bigger rear bar probably is unwaranted. I was just making the point that you have to look at everything as a package. If you are putting bigger tires at one end and not increasing the tire size at the other a similar amount, then, to keep it balanced, you might want to go with a bit more bar, or stiffer bar bushings at the end where you put the bigger tires.

 

 

OK i have a 2001 coupe,heads cam intake, full exhaust. I don't trackthe car much but i do autocross it and i live in the twisties and am quite particular about my cars feel.

I put on c6z06 sways first thing off... rear bar was way too much, certain bumps and turns it felt like the tail was wagging the dog. added c6z06 shocks, it was better, added wider tires on heavier wheels, it wasn't too bad. handled well but felt unsettled at certain spots, I added c5z06 springs and it all came together. very nicely.

so if i had to do it again, i'd definitely go with a C6 front bar, and probabally a c6z51 rear bar, i think the z06 is too much like many folks reccomended when i got mine, but i got a great price on it.

that said, I'llbe selling my entire setup socks springs and sway bars, in the near future going with pfadt coil overs, and either johnny oconnel sway bars from PFADT or their adjustable light race bar.

make sure you use the metal end links and polyurethane bushings, and have good alignment settings for your driving style, not the generic factory grandpa ones.