Swaybars vs Coilovers for the track?
 

Need some feedback for those with rx8 track tuning experience. My 04 Gt is used for street and track days/hpde events. The oem suspension was shot when I got the car so I never had much experience stock. I took a chance on Bilstein PSS coilovers due to their overall value. Set the ride height to 13.75” and a streetish alignment at -1.5 camber, 6.5 caster and 0 toe front. Rear at -2.0 camber and .2 deg toe.

On the street this setup is great. Good ride, balance and control. On the track roll is excessive even on 225 500tw tires. Front tires are rolling over the edge. Obviously some more camber in the front will help but need to keep it streetable. However the body control in transitions is underwhelming. Pitch control under heavy braking is fine... at least with the tires I have. Overall the car feels ok, I just need more grip and lateral control. My plan is some 200tw 245s.

I have plenty of experience with better coilovers as I had ohlins dfv on my s2k. Usually I am an advocate of spring and damping changes rather than sways. There are some differences with the rx8 though. First it’s a long travel car and I have to get used to more body movement, 2nd it has little issues with pitch control. 3rd I am pretty happy with the damping and balance now, I just need more grip and roll control.

options...

1). Go with a stiffer set of front rear sways. Nothing super crazy like hotchkis. Thinking whiteline or pt Miata bars by good win. Put more camber, bolt on stickier tires and be done.

2). Ditch the bilsteins and go full ohlins. I know the damping can be tuned for ride and control with the near magical valving. Sways are just a band aid and won’t get me where I need to be.


As always it always comes down to money. $400 sounds better than $2k. I will make some money back on the pss, but still expensive.

I noticed a bigger difference in cornering/handling with sway bars and end links than i did with coilovers. You already have pretty good coilovers, now just do sway bars, end links, and tires.

Im running a progress tech front sway bar and for my rear sway bar im actually running a "orange dot" R3 Rx8 rear bar, with evo-r endlinks all around.

Tires I have 245/40 Federal 595RS-RR's on a set of Motegi MR135 Traklite 3.0's in 18x9.5+35. I couldnt get my hands on some 265/35's or 275/35's at the time but thats what I plan to usually run. Granted, I benefit from more tire due to having a turbocharged setup and needing extra grip. You will probably do better on a set of 245's due to less drag

You already have decent coilovers. The springs can be upgraded to something stiffer if you'd like to down the road.

I'd do swaybars right now too. I will say, the Hotchkis set isn't nearly as stiff as they sound because they're fairly thin wall. I have a set on my car and I might need to switch to the PT RX-8 bars.

Thanks for the feedback. That was kind of the direction I was leaning in. My complaint is so focused on roll control that is what I will attack. Overall I have been pretty impressed with the PSS. They seem to match the character of the RX8 well. I am not sure they can take much more spring rate without stiffer valving but it could just be that I am used to overly firm damping from the S2k.

Alright, so help me pick some sway bars. I would prefer adjustable front and rear. I would also prefer hollow bars to save on weight. Some thoughts...

Whiteline RX8 bars (solid front though)
PT Miata bars (Good-Win)
PT RX8 bars
Hotchkis RX8 bars
Racing Beat RX8 bars

My thought was to stay on the softer side. I am guessing new links and bushings alone will add a little control. The whiteline bars on the softest setting will be stiffer than what I have. The PT RX8 bars are a good deal, I just thought they would be too stiff.

So my understanding regarding PT rear bar is that while it lets you push the car a little bit harder, people have reported that transitioning feels significantly more abrupt. While something like the R3 orange dot bar for example is a bit more gradual and controllable when paired with good links and the PT Rx8 front bar, which is exactly my reason for running that combination. As mentioned before, I am extremely happy with the combination. The R3 orange dot rear bar might be a solid bar, but it will fit in the brackets and bushings of the OEM yellow dot "sport" bar and can be purchased brand new from Mazda for approximately $100.

Interesting...

any idea what what the sway bar rate ratio is on the yellow dot front to rear bar compared to the setup you are running? Pt front / orange dot rear

right now the ratio seems ok but I would like to be able to dial in some more rotation as I become more familiar with the car.

Theres a chart somewhere online with a little bit if data and a little bit of speculation, but its been a while since I saw it and I dont recall where it was

you need to swap your camber alignment numbers, more negative Front camber than Rear by 0.5 degree. 200tw tires.

I run hotchkis bars and like them:

DESCRIPTION

Benefits:
* Dramatically improves cornering potential due to increased front/rear roll stiffness
* Offers definite track and autocross advantage over stock sway bar package
* Adjustable front/rear sway bars offer 9 roll stiffness adjustment possibilities for fine tuned balanced handling
* Speed robbing understeer is eliminated allowing power to be applied earlier during corner exit
* Durable and reliable in road or competition environments due to our extensive street and track testingFeatures:
Front Sway Bar THREE POSITION
* Lightweight, durable and adjustable 1-5/16" (33mm) hollow
* 110% stiffer than the stock sway bar with a rate of 970 lbs/in,
*150% stiffer than the stock sway bar with a rate of 1150 lbs/in,
* 195% stiffer than the stock sway bar with a rate of 1370 lbs/in.

Rear Sway Bar THREE POSITION:
* 390% stiffer than the stock sway bar with a rate of 195 lbs/in,
* 470% stiffer than the stock sway bar with a rate of 250lbs/in,
* 580% stiffer than the stock sway bar with a rate of 340 lbs/in

Easy to lubricate polyurethane bushings and heavy duty brackets with zerk fittings included. Designed and manufactured by Hotchkis Sport Suspension specifically for the 2004-11 Mazda RX-8.

Our street, autocross and track ready Sway Bar package features our extensively tested 33mm 3 position adjustable front bar and our 21mm 3 position adjustable rear bar for drivers looking for a distinct street, track and autocross handling advantage. Polyurethane bushings and heavy duty bushing brackets are also included along with zerk fittings for easy lubrication.

The Mazda RX8 in stock form is limited by excessive body roll and understeer. For ultimate speed, and due to the limited Rotary engine torque, cornering momentum must be maintained. Bolt on a set of Hotchkis Sport Sway Bars and gain true handling performance and increased cornering momentum.

ENDLINK NOTE! The front bar at the stiffest setting when used with endlinks that have a protruding top bolt that connects to the bar (in my case the Agency Power front links) may contact the dampers.

I have the same coilovers as you and got a Progress NC Miata sway bar to help balance it out w/ stock OEM rear sway. copied the setup Steve Dallas used to run in his RX-8.

I had it initially set to the middlemost setting and it tended to push on my old PS4S, so switched it over to the softest setting and the car feels more neutral now. There's still a decent bit of roll, as the spring rates are pretty soft, but the car feels much better controlled vs. OEM.

I'm thinking of a coilover upgrade down the line, but need to get more seat time and continue trying to find the limits on these.

Still not sure what bar I will be going with. I am worried the PT RX8 front bar or the Hotchkis bar will be too much. Thinking Whiteline or PT MX5 NC bars. I am pretty happy with the balance now, but agree the camber can use a change. Not sure why going to -1.5 on the rear would help. Though I do agree -2 on the front would.

The PT RX-8 bar is a LOT stiffer than the Hotchkis RX-8 bar.

Thanks for the feedback. Thinking whiteline or the pt good-win nc bars at this point.

Did you replace your worn out stock suspension mentioned in the original post? You refer to sway bars as bandaids (the first time I've ever heard sway bars referred to like that), but worn out suspension is where you seem to have an actual injury. Everything is a bandaid until you get that under control.

Yes suspension is working fine with new bilstein pss coilovers. Original springs and dampers are in the trash.

I contacted good-win to see if they recommended their Miata nc bars. They did not and actually suggested the rx8 pt bars. Their thought is the rx8 is heavy and can actually take a lot more bar with little penalty to ride quality.

In your estimation, how much more roll stiffness do the hotchkis bars have over stock? How much do you expect the pt rx8 bars to have?

Tires make a difference. Set the tires with a slight stretch on wheel. Means the tire beads are located beyond the tread width of tire. 10” tread width run a 10.5” wheel or 11”.

the spring rates I like are 600 front 10.7 and 336 rear 6.

I use an eibach front bar on softest setting to balance car and stock rear. Has slight understeer at corner exit under throttle. Balance of car is great and slaloms fantastic. I run 285/30/18 on 18x11 wheels +40 offset hypergram.

use sways to balance the car. Car is fantastic. I have -2.25 degree camber front and -2.0 degree rear.

My math correlates pretty nicely with what's seen in this thread: https://www.rx8club.com/series-i-whe...ummary-242324/

PT Rx8 front bar with the R3 Rx8 rear bar with good endlinks like I mentioned.. You'll be quite happy with the results.

Appreciate all the advice. I think I am leaning to hotchkis. Almost as stiff as the pt bars but should be a little lighter. I also like they come with greaseable brackets and are cheaper. I really don’t want to overbar the car, as other than roll feels like it can do no wrong. However once I get a new set of tires, I will wish I didn’t go too soft. Not ruling out the pt bars either, may just look for the best deal. Bottom line is I have to pull the trigger in something.

thanks all

If you go for end links, post if you like what you found. Powergrid closed shop from what I read.

Karcepts ND OEM front swaybar endlinks work perfectly at least for the front swaybar. I was using Whiteline rear endlinks and they worked fine but I *hate* the internal hex style balljoint especially with such grossly oversized studs that take ages to spin the nut off.

Thanks for the tip doc!

I usually go with a high quality oem style. They are better for street driving. Maybe moog. Will do some research when I pick bars.

Got rb sways front rear with the original oem end links that came with the car. Had my eyes on Powergrid ones but hesitated because front rear would cost me around 400 dollars to my door.

Tried ordering Hotchkis... forever backorder. Probably try pt next. Either rx8 or nc mx5.