Topic: ZOK Rear vs. Front Bar

[wspohn]

I have seen opinions that the front of these cars does not need increased roll stiffness, while the rear definitely improves by adding the ZOK bar at that end.

Is this in accord with the experience of those that have fitted the rear only to their GXP chassis?

[LatinVenom]

Read snaponbob comments on this thread.
Here is the link.
http://kappaperformance.com/forum/index.php?topic=2683.msg32260;topicseen#new

[snaponbob]

I have seen opinions that the front of these cars does not need increased roll stiffness, while the rear definitely improves by adding the ZOK bar at that end.

Is this in accord with the experience of those that have fitted the rear only to their GXP chassis?

It depends. On what? It depends on what you want your car to do and how you are using it. So .................. what do you plan on doing with the suspension mods and what results are you looking for?

[wspohn]

It depends. On what? It depends on what you want your car to do and how you are using it. So .................. what do you plan on doing with the suspension mods and what results are you looking for?

I do not slalom cars (any more) so that isn't a consideration.  Nonetheless I found a mild understeer situation even on competition setting and so didn't think any added front roll stiffness was called for, and that somewhat increased rear roll stiffness was probably worth a try.

I will simply use the car for fast cross country (winding roads, mountains etc.) miles.  What does your experience suggest for that sort of situation?  I am a racer and so value crisp handling on the road as well.

[snaponbob]

I do not slalom cars (any more) so that isn't a consideration.  Nonetheless I found a mild understeer situation even on competition setting and so didn't think any added front roll stiffness was called for, and that somewhat increased rear roll stiffness was probably worth a try.

I will simply use the car for fast cross country (winding roads, mountains etc.) miles.  What does your experience suggest for that sort of situation?  I am a racer and so value crisp handling on the road as well.

Understeer is when you hit the wall with the headlights while oversteer is when you hit the wall with the tail lights !!!!!!!!!!! Neutral means if you make a mistake results are a surprise !!!!!!!

If you use only a GXP/Z0K rear bar and do NOTHING else to the car it will certainly become less pushy. If you want "crisp" handling;
1) Ditch the Goodyears and get some decent rubber
2) Konis with GXP/Z0K, BC coilovers with 5K (~280 pound) springs, or KW V3 coilovers
3) DDM ProBeam and Backbone
4) BOTH Z0K bars and switch the front back to the FE3 if needed.
5) Get some negative camber in that car!!!

The bars can be had for no more than $115 so "playing" with the front is not too expensive. The current challenge is the backorder status of the rear bar. Current spring rates are 175f/220r so the 285 pound spring on the BC and KW coilovers will provide more roll resistance. The preferred sequence of suspension tuning is spring first, and THEN bars to "tune. (That's what every race car builder told me to do, and it worked.) My Redline is well north of those 285 pound rates and really is not nearly as harsh as I thought it might be, even with a bunch of rebound dialed in and poly control arm bushings.

Did THAT help?

[wspohn]

Thanks Bob.

I am no stranger to setting up suspensions but each car is different, and if i can take advantage of what others have learned by trial and error, so much the better.

To me those spring rates seem very soft, but then the car I race runs 950 lb springs on the front and I remove a leaf from the rear to soften them!  Problem is that while I don't mind playing with springs, I do not want to lower the car - I am sick of dealing with cars that have clearances that mandate driving around a cigarette pack if you see one lying on the road and I actually had to raise another car I built awhile ago just to get it into my driveway (it was pretty low with only 4" clearance)


Many after market springs are simply the same wire diameter but made with fewer coils and normally less length, which lowers the car even if you didn't want to.  I haven't got into researching the situation for the Sol yet

Having just bought the car, I will endure the Eagle F1s until they wear out and then look for something better to replace them.

BTW, the GM list price for the bars isn't $120, it is $350 each in Canada!!  Which is why I will source them 'below the line' as the shipping doesn't eat up half the difference. I am just trying to decide if I should get just the rear or both at once.  From what you say, it might be worth getting both to play around with.

May I impose on your good graces one more time and ask you what springs, if any, you would recommend for minimal lowering?

[snaponbob]

Thanks Bob.

I am no stranger to setting up suspensions but each car is different, and if i can take advantage of what others have learned by trial and error, so much the better.

To me those spring rates seem very soft, but then the car I race runs 950 lb springs on the front and I remove a leaf from the rear to soften them!  Problem is that while I don't mind playing with springs, I do not want to lower the car - I am sick of dealing with cars that have clearances that mandate driving around a cigarette pack if you see one lying on the road and I actually had to raise another car I built awhile ago just to get it into my driveway (it was pretty low with only 4" clearance)


Many after market springs are simply the same wire diameter but made with fewer coils and normally less length, which lowers the car even if you didn't want to.  I haven't got into researching the situation for the Sol yet

Having just bought the car, I will endure the Eagle F1s until they wear out and then look for something better to replace them.

BTW, the GM list price for the bars isn't $120, it is $350 each in Canada!!  Which is why I will source them 'below the line' as the shipping doesn't eat up half the difference. I am just trying to decide if I should get just the rear or both at once.  From what you say, it might be worth getting both to play around with.

May I impose on your good graces one more time and ask you what springs, if any, you would recommend for minimal lowering?

PM coming after this post.

If you want to maintain ride height, first you need to decide on shocks. Frankly, the FE3 Bilstiens are fine for a daily driver. When pressed the car feels underdamped (VERY typical of GM cars from econo-boxes to everything up to Z06's!!). I have single adjustable Konis with threaded sleeves. Since I already owned the Konis, this was the cheap route. Had I not, I would have purchased the BC coilovers ~ a grand USD and have adjustable preload and separate ride height. Single adjustable but the adjuster brings the compression up about 30/70 with the rebound. For street that would be fine, but for Solo not so much. The BC's come with springs so that's a good deal. KW V3s come with 285 pound springs and are double adjustable at ~ 2 grand USD. If you want to keep the Bilstiens you can get the adjustable spring hardware and upper spring seat adapters and play with 2.5" springs.

I have 21K miles on the OEM Goodyear with plenty of life left in them. Damn it !!!!! They are good for only ONE thing -------------- keeping the rims off of the pavement. All of my car money is going into Solo prep for Street Prepared, but I really want to replace them in the spring with almost anything !!!

[Graywolf]

My vote would be to get both front and back,  I put the complete zok package on my car and I use it for high speed driving events but still drive it on the road.  most important is to change toe /camber etc to improve handling  Graywolf

[snaponbob]

The latest is NOT good for the rear bar. Best bet is to order it and wait/hope.

[LatinVenom]

I have a GM person that has been helping me with the rear Z0K sway bar.
My dealer after talking with (PAC spelling) cancelled my order, although it was already paid. The GM person called the dealer with me on the other line and made the Dealer re enter the part using the original order and to make sure to tell (PAC spelling) not to canceled again, but rather wait until the part becomes available.
If you want the Z0K rear sway bar I would suggest you call GM and request assistance.
So far my experience has been very positive, the GM person is working very hard to make sure that the new GM works hard to make this happen.
A lot of the problem as was explain to me has to do with the suppliers that have gone away, and now the new GM needs to find new suppliers to make the parts.
It is going to be a fairly long wait but hopefully at the end the Z0K rear sway bar will once again be made available to us.

[lil goat]

I have the HKS coilovers, they are similar to the BC's, a bit more expensive. Nolanb has the Z0K springs front and rear, they are still available as far as I know, I have my HKS's as high as they will go and the car is lower than Nolanb's by close to an inch. The Z0K springs look to have a pretty decent ride height, better than cars I have seen with the Eibach springs if that helps at all.

[kennysabarese]

Any specific phone numbers you recommend calling LV?

[kwtoxman]

It all depends on personal setup of an individual's car (including the mods) and preferences. I have an aggressive street alignment, KW V3's, extreme backbone, probeam and I have tweaked the PSI, compression and rebound to lessen the front end push..... but it is still there a little more than I'd like on the car. At least enough so that I want to lessen it further. The addition of only the rear ZOK sway bar will help and I'd expect to be enough. At least enough to be able to adjust the coilovers and PSI to fine tune it to where I want it.

This is my experience with my setup....

[spartan]

I've been reading the various posts on sway bars and it seems to me that if you want to go all the way, why not go with one of the solid sway bar options.  I just saw an "AADCO" solid front way bar (28.5mm) on ebay for $148.  They show it weighs about twice the stock (vice ZoK) one at 15 lbs.  Thoughts?  Overkill?

[snaponbob]

It all depends on personal setup of an individual's car (including the mods) and preferences. I have an aggressive street alignment, KW V3's, extreme backbone, probeam and I have tweaked the PSI, compression and rebound to lessen the front end push..... but it is still there a little more than I'd like on the car. At least enough so that I want to lessen it further. The addition of only the rear ZOK sway bar will help and I'd expect to be enough. At least enough to be able to adjust the coilovers and PSI to fine tune it to where I want it.

This is my experience with my setup....

There two (simple) ways to affect roll resistance. Springs and bar. The KWs come with 285 pound springs (at least that is what I was to by the US distributor), so you may want to jump the rears to 350 or so. Additionally, in speaking with some of the go-fasters that have been coming to Licoln and on the sccaforums.com, raising the rear roll center can loosen the rear some. At a 2 day SCCA run event last weekend in Lincoln I ran day 1 with the rear raised 1/2" higher than normal, and day 2 set the rear back down. For Nationals the rear is going back up as day 1 was tossable and day 2 was tight (pushy). Also, try reducing the front compression and increase the rear rebound. The increased compression WILL cause a bit better bite  on turn in but induce push (this from Lee Grimes at Koni) and the increased rear rebound will induce transitional roll resistance thus helping the rear move a bit more easily. As you make these adjustments it may be best to reset your tire pressures equal f&r as to not mask the effect of the changes and then fine tune them again. HTH.

[snaponbob]

I've been reading the various posts on sway bars and it seems to me that if you want to go all the way, why not go with one of the solid sway bar options.  I just saw an "AADCO" solid front way bar (28.5mm) on ebay for $148.  They show it weighs about twice the stock (vice ZoK) one at 15 lbs.  Thoughts?  Overkill?

Copied from the auction listing --
Application:
06-09 Pontiac Solstice
07-09 Saturn Sky

Not sure if it will fit the turbo models or not.  We did our test fitting on the nonTurbo model.  Should fit though...

Front Anti Sway Bar
1.125" - 28.5mm Diameter Solid Bar @ 15lbs

Stock sway bar = 1.06" Hollow @ 8lbs

This tells the story of that item. Basically, it will just about equal to the FE3 bar.

I have a 32mm solid bar from (the now closed) Saner in Florida. It's about 40-60% stiffer than the FE3 bar and found it too stiff without a much bigger rear bar. I now have both GXP/Z0K bars mounted. If I could get a bigger rear bar I would try that with the Saner again. Currently I have a call into Addco as the Kappas are not listed in their catalog. Maybe some discussion could lead to bars for the FE3 cars.

[LatinVenom]

Any specific phone numbers you recommend calling LV?

1-800-762-2737 and ask them you want to get help in getting the Z0K rear sway bar and give them the part number 25919110. You must have an order with a dealer.
I have another phone number but that one is the direct number to the GM person that took up my case.

[kennysabarese]

Great, I'll definitely be calling, thanks