Cito

I know there are many opinions about whether it makes sense to go to STX from BS, but what I am wondering is what others think about a low-buck approach in transitioning from BS to STX.

At this point, I will probably stick to BS, but I was thinking about what it would take to transition to STX. These are the parts I was thinking about:

17x9 lightweight rims with corresponding 255/40 tires probably Dunlops or Kumhos to keep the cost low

Keep Koni sports and replace the springs with something a bit more stiff...but I have no idea what rates to consider. Any thoughts would be appreciated. The idea here is that the minimum double adjustable coilover set worth buying is going to run at least 1700+, and the other coilovers out there seem to provide little benefit beyond what you would get from lowering springs and stock shocks (aside from adjustability in height).

Replace swaybars with aftermarket set. I was thinking about the progress bars.

And, that's about it.

chiketkd

iTrader: (5)

For the low-buck approach, everything you mentioned seems on. You'll need at least 2 sets of custom springs made (maybe 450 & 500 Front, 350 & 400 Rear). Sipe could probably give some better input on some good rates to use. I also wouldn't have them drop the car too low - maybe 1.0-1.5" lower than stock.

Also as money allows add power mods such as a full exhaust (w/ high flow cat) and a Cobb AP.

shinronin

550/325 or 500/275. i started my STU setup at 700/400.

i wouldn't go with DAs unless you run on concrete. also if you run DAs prepare to tweak the bump valving to get it right. i ran moton DAs and even when i finally dialed in the spring rates (550/325) the bump valving was still too strong.

i have the PT front/rear set (and other ST goodies) if you'd like to go that way. the trick to the front sway setting is to achieve good high speed transitional balance without inducing massive low-speed understeer. prepare to tweak the front sway setting a lot. ;-)

learycd

iTrader: (1)

yeah right now im sitting in STX with my mods, havent yet competed tho as this work was down after the last season was over

idk, i feel like im gonna be sitting in the back of the pack regardless lol

Mr. Pockets

That's really close to what I ended up with on the Stance coilovers: 10k front, 6k rear. That's 560f, 336r.

I'm using the stock bars, though.

Cito

Anyone have any ideas on pre-existing springs out there with similar rates, I have been looking for about 9kg/mm f, 5kg/mm rears as a WAG, but don't find anything like that outside of coilover setups.

If I need custom springs, anyone have any ideas regarding such (i.e., who, where, how much)?

Thanks.

BRODA

iTrader: (7)

FWIW, I am running 8kg (450) F / 5kg (281) R with RB bars.

shinronin

right, it's the front sway and shock tuning that'll getcha. ;-) i'd start with stock sways and see how it goes. in fact, with hindsight i think i'd stick with the stock rear sway or even go with the stock auto rear sway which is allegedly a touch softer.

i mention the front sway tuning difficulties, but it's very course dependent obviously. a fast open course with a pin turn is the devil's work. that corner alone will cost you a win vs. a WRX.

bingo

interesting, subscribed

shinronin

hmm, dunno. that might take some searching. all the OTS stock replacement springs i have data on (MazdaSpeed, Tein S.Tech, H&R Sport, Tanabe GF, Racing Beat, Eiback Pro, Tein, H.Tech, Tanabe NF) are much softer than 550/325 or 500/275. i've only dealt with coilovers solutions. mebbe someone else can chime in. there's also Sprint, Drop Zone, SpringTech, RE-AMEMIYA, ICR, Pettit, Espelir, Intrax, Autoexe, and FEED Sport but i don't have data on them.

Cito

I am not seeming to find any off-the-shelf springs that are stiff enough in rates, but maybe I am looking in the wrong place. I guess I might just need to buy some coilovers or convert the konis I have to coilovers.

Or, just stay in BS....

Mr. Pockets

Are you suggesting that you've had problems with understeer in tighter corners? I have been able to do pretty much what I want with the front of the car throughout all the changes I've made, and I'm still just using the stock bars. The limiting factor has always been the rear. The changes I made to my alignment, and then the softer spring from Stance, helped make the car much more neutral. I can't wait to get back on course and pick up where I left off.

Mr. Pockets

If I already had Konis, and the option was there to convert them with an adjustable sleeve (ie, ground control), I would do it.

shinronin

yep, i ended up using either the soft or medium setting on the PT front sway (32mm), but it was usually understeer city in the slow stuff, but brilliant in fast transitions and sweepers. in the majority of the philly region autoxs where i drove the rx-8 in STU it was at warminster (an old airfield) where it was great once i had it dialed in. but at boeing helicopter plant, a small parking lot, it was usually brutal as there almost always a pin turn involved.

TeamRX8

iTrader: (25)

My mistake was going too stiff. I never fully realized it until my somebody I trusted recommended running ultra-stiff rates from the Koni Challenge series (800/400), which was a major disaster on street tires. Only then was I aware looking back what the one defining problem was.

I wouldn't go over 450# front and 275-300# rear for street tire racing. For general use and grippy racing surfaces you may get away with higher, but you'll have compounded issues racing on slippery surfaces.

As for your desire to do it on a budget, my recommendation is the KW Variant3 coilover setup, which fits the rates mentioned above.

Team

shinronin

true, kw v3 spring rates are 455/285 and ohlins pcv are 450/280. ohlins are likely more expensive, but i believe are rebound only instead of the combo bump/rebound (ick) of the kw's. i haven't checked prices.

re: sway bars what does your hindsight tell you team? stock? PT? other? i advocated for stock rear or stock auto rear and possibly PT front.

TeamRX8

iTrader: (25)

the KWs have separate compression and rebound adjustments

they buy many of their internal parts from Koni

http://www.kw-suspension.com/en/30_P.../30_Variant_3/

chiketkd

iTrader: (5)

Perhaps we can do a group buy for springs that fit the stock-style shocks (stock, koni, etc.)?

We'd have to agree on rates and the drop in ride height though. Looking at the suggestions in this thread, how about the following:

Option 1
Front Springs: 420lbs/in
Rear Springs: 280lbs/in
Drop: 1.0" (from stock ride height)

Option 2
Front Springs: 450lbs/in
Rear Springs: 300lbs/in
Drop: 1.25" (from stock ride height)

These should be a good compromise and still be daily driver friendly as the car won't be riding super low.

If you like I can talk to Fluid Motorsports. They should have the ability to get custom springs fabricated at a reasonable price.

P.S. I'll be willing to go into the group buy for at least one set of these springs.

shinronin

huh. my buddy has the kw v3s for his STU evo 8 and they don't have separate bump and rebound adjustment. mebbe his coilovers have previous generation dampers.

Mr. Pockets

The KWs look like a great package, and if it hadn't been for the exciting changes in exchange rates (well, and the deal I got from Rishie for the Stance parts) those would have been my choice.

In the end, I was happy with my purchase because Stance supported their product so well.

MilesJ

Question. Would it be crazy to run the hotchkis adjustable MX5 sway bars in STX? 27mm front (claimed stiffness range of 520-735 lbs/in) and 21mm rear (Hotchkis claimed stiffness range from 390 - 580 lbs/in) would be a huge change from stock. It would be a slightly stiffer front bar and a radically stiffer rear bar. I see some people recommeding a softer than stock rear bar which seems counter intuitive to me. Why would a softer rear sway help the car turn?

TeamRX8

iTrader: (25)

it's not a huge change

the only reason to run a softer rear bar is because the spring rates are too high, this assumes that alignment, air pressures, etc. are all proper ... the responsiveness of the RX-8 chassis with high rates will overload street tires easily. Moreso at the rear as the Renesis throttle response increases.

That was another thing that caused me a lot of grief; living at 5000 ft elevation. A balanced setup at that elevation would become loose as a goose at sea level and vice versa. Very frustrating ... but again, much of that all had to do with running too much spring rate in the first place. You need to maintain some compliance for street tires on an RX-8.

MilesJ

So my theoretical suspension set up with the Hotchkis MX5 bars, Bilstein HD's, threaded perches and hypercoil springs (350/300 F/R) isn't crazy? I'm hoping that my low budget BS to STX conversion will be ok to start off the season.

TeamRX8

iTrader: (25)

sure, if you're goal is to drift with that rear spring rate relative to the front

I have a set of KW V3's coming for my Honduh Ridgeline

More_Revs

I'm doing local events and the index is better for STX, especially since I don't use R tire, so that's where I'm going. I'll be slowly converting to STX and already have Koni yellows. What would be the better first step for the suspension? Getting those slightly stiffer OTS lowering springs for more camber, or stiffer sway bars?