Has anyone installed any of the C-ONE Performance Bars for Gen II?

[blueumbrella]

I would like to find out if anyone has any experience with any of the C-ONE Performance bars for Gen II, sold by Sigma?

I have a BT Stiffening plate installed and was looking at the front and center C-ONE performance bars. I wondered how difficult the install was and whether modifications were required.

I would appreciate any information you could share.

Thanks-

[autocross72]

I installed the C-One front sway bar on my 2008 about 2 weeks ago. I was dissapointed at first since I couldn't really tell any difference. Then I realized I could exit corners faster without the traction control kicking in. I think I would have noticed a much larger difference if I had already up graded from the lame stock tires.

Installation was very straight forward, even though the directions are in Japanese. The pictures tell the story well. Be sure to unbolt the steering rack from the sub frame before you lower it or you could risk damaging the steering.

Pete

[Dobey]

I'm seriously considering the following right now - install the C-One front and rear sway bars, keeping the shocks and springs the same on my base 2009.

I've still got doubts whether I'll be over-doing it or not, because:
1. the C-One sway bars are 24mm F, 23mm R
2. the base bars are 21mm F, 19.1mm R
3. according to this site Sway Bar Rate Chart, my front sway bar will have about 75% increase in stiffness, and rear will have about 90-95% increase in stiffness. This may cause an oversteer issue because the rear will have an increase in stiffness greater than the front, but I also have the Tom's front strut brace, which may add to the front stiffness somewhat. I'm thinking that it should all balance out, but I can't be sure until I try it.

Has anyone got any experience in sway bar mods to offer some guidance? At $780 for both C-One bars incl shipping, it ain't exactly cheap to experiment with...

[Rokeby]

FWIW, lots of discussion of sway bars and at least one report on using
after-market 22mm rear bars in this thread:

Rear Sway Bar

[turnerdhr]

i think lowering springs should be done first.... it will be a cheaper alternative that will lead to better handling, improved fuel consumption (due to less drag coefficient) etc...

[Dobey]

Not sure about that, someone correct me if wrong, I think lower springs need new shocks - the spring/damper ratio might not be matched otherwise. The way I look at it, sway bar mod will be like stiffening the springs when cornering (since both springs will be engaged on the turn). My concern really is the front to rear spring rate ratio that will be changed by the sway bars - will these provide the right balance to prevent excessive oversteer/understeer; I think I will just need to try it out.

[turnerdhr]

Originally Posted by Dobey

Not sure about that, someone correct me if wrong, I think lower springs need new shocks - the spring/damper ratio might not be matched otherwise. The way I look at it, sway bar mod will be like stiffening the springs when cornering (since both springs will be engaged on the turn). My concern really is the front to rear spring rate ratio that will be changed by the sway bars - will these provide the right balance to prevent excessive oversteer/understeer; I think I will just need to try it out.

no, you don't need new shocks.... you can read a good discussion on springs here:-
B&G Suspension S2 Sports springs now available for the 04-09 Prius

[Dobey]

I've read through that thread and it seems to me that most of the people who bought the shorter springs did end up changing their shocks as well for a better match. Changing the springs/shocks is obviously one of the options for better handling, but I wonder if changing the sway bars is more effective...

[autocross72]

I have both the TRD rear sway bar and the C-One front sway bar in my 2008. It still has the stock springs, shocks and tires (base model). I reinforced the stock sub frame brace by welding in 5/16" steel on both sides (I had the scrap steel laying around and I didn't want to spend $165 for a mod that I don't think really does anything) and a strut tower brace that I haven't had time to install.

I have experienced NO oversteer at all! In fact, the understeer is still so bad that I am fabricating mounts for a 1" external sway rear swaybar.

I used to have a 1995 Chevy Beretta (a front wheel drive car with a rear axle design almost identical to the Prius) that was set up for autocrossing. to get it to handle neutrally, I had to install a 22mm swaybar in the axle (it didn't have any sway bar in stock form), install a 1" solid external bar, Eibach lowering springs (all 4 corners) KYB shocks, and 1000 lb coil overload springs that went over the rear shocks. It also had a rear sub frame brace, and rear shock tower brace. Of course, it had a front strut tower brace, 30mm front sway bar, and 225/50/17 tires too. That car handled like you can't imagine and I could set top time of day in the rain. My point is that you have to go WAY beyond stock before you even have to begin thinking about oversteer with a front wheel drive car.

Pete

[Dobey]

Originally Posted by autocross72

I reinforced the stock sub frame brace by welding in 5/16" steel on both sides (I had the scrap steel laying around and I didn't want to spend $165 for a mod that I don't think really does anything)

By sub frame brace, do you mean the rear stiffening plate that bolts on to the frame?

What is the diameter of the TRD rear sway bar? I've got the Tom's front strut brace installed, I'm wondering if you install your front strut brace, and with your thicker front and rear sway bars, whether you would solve your understeer problem. I know that the front strut brace by itself significantly improved the understeer.