Author Topic: GXP/Z0K front sway bar (Read 11264 times)

Brazen17 · « **on:** November 15, 2009, 11:20:05 AM »

I have installed the rear sway bar and love how flat the car stays in turns. I have the front bar but have not installed it yet. I am wondering now if I really need to install it. How much would it help and might it even be detrimental to the way it is now performing? I know I could always install it and remove it if I don't like it but wanted to get some opinions before I go to the trouble.

Imaj · « **Reply #1 on:** November 15, 2009, 12:02:18 PM »

I have installed both bars on my GXP and it feels a lot better all around.

kennysabarese · « **Reply #2 on:** November 15, 2009, 02:46:02 PM »

try it. you can always switch back. it's easy

snaponbob · « **Reply #3 on:** November 15, 2009, 05:33:35 PM »

I have been swapping around FE3 bars and GXP/Z0K bars. For general street and "fun" driving, the Z0K pair are great. For Solo, FE3 front and Z0K rear is sweet.

Brazen17 · « **Reply #4 on:** November 15, 2009, 06:34:55 PM »

I think I just might go ahead and swap it out. Maybe tomorrow. Also, why would it not be advantageous to run it in auto-X?

snaponbob · « **Reply #5 on:** November 15, 2009, 06:43:05 PM »

Quote from: roadstersol on November 15, 2009, 06:34:55 PM

I think I just might go ahead and swap it out. Maybe tomorrow. Also, why would it not be advantageous to run it in auto-X?

Z0K bars front and rear = general understeer. Fe3 front and Z0K rear = neutral. Neutral is better.

Brazen17 · « **Reply #6 on:** November 15, 2009, 08:20:14 PM »

Not sure I understand. Wouldn't neutral be better for the street also?

snaponbob · « **Reply #7 on:** November 15, 2009, 10:04:12 PM »

Quote from: roadstersol on November 15, 2009, 08:20:14 PM

Not sure I understand. Wouldn't neutral be better for the street also?

It can be. But if a car is REALLY neutral, it can be "edgy". What can this mean? one has to "drive" the car all the time, and that is not always relaxing. A car that is tuned just a bit towards understeer will track straighter better. A really neutral car can get a bet darty. Fun, but needs more concentration.

Brazen17 · « **Reply #8 on:** November 15, 2009, 11:10:30 PM »

I have just the rear Z0K bar now, been on for about two weeks, and I don't think I noticed any difference in straight line behavior. Certainly noticed a difference in the twisties.

I will install the front Z0K bar tomorrow and see how it behaves. Maybe I'm just not as attuned to my car as I should be?

kennysabarese · « **Reply #9 on:** November 16, 2009, 07:45:38 AM »

The only difference you would notice in the straight might be a rougher ride, but the back would probably not be noticed as much as the front.

Imaj · « **Reply #10 on:** November 16, 2009, 10:21:39 AM »

where is all the data showing that the back ZOK bar is the way to go for anything other then a straight line?

kennysabarese · « **Reply #11 on:** November 16, 2009, 10:55:17 AM »

there's tons of other discussion around here about it.

snaponbob · « **Reply #12 on:** November 16, 2009, 02:42:40 PM »

Multiple BUTT DYNOs !!!!!!!!!

Plus, there have been lost of discussions on the two BB's. Additionally, at the last two Solo Nationals most, if not all, the GXP Z0K A/S cars were equipped with FE3 front and Z0K rear bars. In Solo there is a significant difference in the handling of the Kappa LNF platform. I could not do that in A/S as I have a Redline, but , B/SP I am free to do what I like with bars, and even with 450# f&r springs the same changes can be felt.

wspohn · « **Reply #13 on:** November 16, 2009, 05:50:43 PM »

Quote from: roadstersol on November 15, 2009, 11:10:30 PM

I have just the rear Z0K bar now, been on for about two weeks, and I don't think I noticed any difference in straight line behavior.

You wouldn't. No sway bar has any effect on straight line handling unless you have one wheel that experiences elevation change relative to the other. I suppose you would get this on a street full of potholes, but the normal situation is in a turn where one wheel tries to go up more than the other.

Sway bars aren't for straights, they are for cornering!

I agree with Bob - solo = slow corners where you don't want any push and can't always induce oversteer with the throttle. Open road will take more front roll stiffness. I have both ZOK bars on my GXP and find it just great for the street.

Critterman · « **Reply #14 on:** November 17, 2009, 01:59:50 PM »

I have the stock N/A bar on the front, and the FE3 on the back now. I have to dial a lot more front shock into my setup to settle the rear down under throttle than I did with the stock N/A bar in the back before.

The FE3 is the ZOK bar for the N/A. I will be getting a front FE3 bar as well. If that doesn't make me happy and able to avoid cones in a single bound, then I will be looking at the GXP ZOK bars.

snaponbob · « **Reply #15 on:** November 17, 2009, 03:01:06 PM »

Quote from: Cone crusher on November 17, 2009, 01:59:50 PM

I have the stock N/A bar on the front, and the FE3 on the back now. I have to dial a lot more front shock into my setup to settle the rear down under throttle than I did with the stock N/A bar in the back before.

The FE3 is the ZOK bar for the N/A. I will be getting a front FE3 bar as well. If that doesn't make me happy and able to avoid cones in a single bound, then I will be looking at the GXP ZOK bars.

All this business about FE3 front and GXP/Z0K rear bars really applies to the LNF Kappas. The 2.0's weigh about 200 pounds more than the 2.4 and that is all up front. The 2.4s (even the SC ones) really benefit from "paired" bars. The FE3 front bar should settle down your car.

You list HKS coilovers on your car. What spring rates do you have?

Brazen17 · « **Reply #16 on:** November 17, 2009, 03:06:00 PM »

I realize that sway bars are not for straight line performance. I was just responding to a comment that with the Z0K rear bar and stock front bar the car could be "edgy" as it would be more neutral. I haven't noticed any "edginess" while going straight as compared to having the stock GXP setup. I didn't get the chance to install the front bar yet but hope to in the very near future.

snaponbob · « **Reply #17 on:** November 17, 2009, 05:32:09 PM »

Quote from: roadstersol on November 17, 2009, 03:06:00 PM

I realize that sway bars are not for straight line performance. I was just responding to a comment that with the Z0K rear bar and stock front bar the car could be "edgy" as it would be more neutral. I haven't noticed any "edginess" while going straight as compared to having the stock GXP setup. I didn't get the chance to install the front bar yet but hope to in the very near future.

The advantage of a basic understeer set up is straight line stability and when going of the straight line. An example would be when fast action in traffic is called for a neutral car could react more then might be ready for, and the result could be having the shase the ass end of the car !!!

Critterman · « **Reply #18 on:** November 17, 2009, 09:03:51 PM »

From the site:
HKS hipermax III
80140-BA001 PONTIAC Solstice 2006-2008 ; Fits GXP and Base Model
Spring
Rate Front (kgf/mm) 8
Spring
Rate Rear (kgf/mm) 6

Here is the conversion

Spring Rate
kg/mm 6 8
lb/in 337 450

in plain English = hard

snaponbob · « **Reply #19 on:** November 17, 2009, 09:45:43 PM »

Oh, good lord, that is SO backwards. Right now I am running 450's f&r, and for Solo that may not be best. When I had 400f & 450r with FE3 front and GXP/Z0K rear bars my Redline was at its best on concrete. Asphalt needed the stiffer (GXP/Z0K) front bar. Why some of the coilover companies settled of 8f/6r is really a mystery. Apparently they never DROVE a Kappa.

Critterman · « **Reply #20 on:** November 17, 2009, 10:14:23 PM »

So you are saying the rears are too soft?

snaponbob · « **Reply #21 on:** November 17, 2009, 10:19:39 PM »

Yup. And so do a lot of chassis dynamics spreadsheets.

Critterman · « **Reply #22 on:** November 17, 2009, 10:21:20 PM »

Probably a good thing I don't know what I am doing then

snaponbob · « **Reply #23 on:** November 18, 2009, 09:59:52 AM »

C.C. Good morning. Check you PMs. Thanks.

wspohn · « **Reply #24 on:** November 18, 2009, 10:22:27 AM »

Quote from: Cone crusher on November 17, 2009, 10:14:23 PM

So you are saying the rears are too soft?

I'd have put it the other way - the fronts are too stiff.

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Author Topic: GXP/Z0K front sway bar (Read 11264 times)