CS: softer front sway bar?
#26
I realize I should just let this go but this is such a great shot by Karen I just had to share. This is me at the Atlanta tour, not understeering to the point that the inside right is off the ground. ![Big Grin](https://www.rx8club.com/images/smilies/biggrin.gif)
http://www.flickr.com/photos/11760021@N02/5706172758/http://www.flickr.com/photos/11760021@N02/5706172758/ by http://www.flickr.com/people/11760021@N02/, on Flickr
![Big Grin](https://www.rx8club.com/images/smilies/biggrin.gif)
http://www.flickr.com/photos/11760021@N02/5706172758/http://www.flickr.com/photos/11760021@N02/5706172758/ by http://www.flickr.com/people/11760021@N02/, on Flickr
Last edited by tpdrx8; 05-15-2011 at 07:22 PM.
#27
Registered
I know NOTHING about AutoX. I think I just saw rear toe OUT in the setup. Is that a common practice in AutoX? Pretty much everyone I know in the road racing market runs 1mm rear toe in total
#28
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Location: Seattle
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I was one of the early people to try out RX8's.
I fussed with alignment and bars. Only sorta liked the car when I had rear toe out.
I am not big on lots of rebound to "loosen" one end of a car.
I am big on lots of slow speed compression but without going $all out$, it wasn't going to happen.
Basically build a set of front shocks with almost no bleed on the compression side of the piston but blow off quickly to a middle of the road setting for bumps.
It will "act" like a big FSB in transitions.
I use whether of not I am lifting the inside rear at corner exit to size the FSB along with some rear rebound settings and rear droop allowances that exist in stock class. You don't want to lift an inside rear with the Torsen which everyone knows.
I like LOTS of front grip.
Big FSB's don't always allow that to happen on many cars.
As a side note: I think(never proved) that the RX8 and MX5 toe in in the rear under power or when leaning over.
When you toe in with a Torsen, it can cause understeer when on the throttle.
Has anyone modeled the rear? That doesn't take into effect bushing toe changes which Mazda loves to do.
Anyhoo. The 8 was a little bit of a disappointment compared to my RX7TTR1. I was hoping for a 4 seat FD.
I fussed with alignment and bars. Only sorta liked the car when I had rear toe out.
I am not big on lots of rebound to "loosen" one end of a car.
I am big on lots of slow speed compression but without going $all out$, it wasn't going to happen.
Basically build a set of front shocks with almost no bleed on the compression side of the piston but blow off quickly to a middle of the road setting for bumps.
It will "act" like a big FSB in transitions.
I use whether of not I am lifting the inside rear at corner exit to size the FSB along with some rear rebound settings and rear droop allowances that exist in stock class. You don't want to lift an inside rear with the Torsen which everyone knows.
I like LOTS of front grip.
Big FSB's don't always allow that to happen on many cars.
As a side note: I think(never proved) that the RX8 and MX5 toe in in the rear under power or when leaning over.
When you toe in with a Torsen, it can cause understeer when on the throttle.
Has anyone modeled the rear? That doesn't take into effect bushing toe changes which Mazda loves to do.
Anyhoo. The 8 was a little bit of a disappointment compared to my RX7TTR1. I was hoping for a 4 seat FD.
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
#31
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I stand corrected. It isn't a torsen but I use that term loosely.
Can I say "torque sensing?"
I still base FSB size wheelspin not lean. Don't even ask what I do in the wet with FSB's.
FM
#33
Your pic is golden to help your condition.
I can see that you have enough lean in the front so softer won't help.
Also, your inside rear should be up more (losing grip).
I'd start by running 40 psi hot in front 36 psi rear.
Then, I'd get more neg camber on the fronts(-.5 more like someone said), and zero to slight toe in in back.
If still understeering figure out how to stiffen rear with some shock that pushes with air like Bilstein.
J/K (maybe), but put a smaller tire on rears to get more pull and less traction.
I can see that you have enough lean in the front so softer won't help.
Also, your inside rear should be up more (losing grip).
I'd start by running 40 psi hot in front 36 psi rear.
Then, I'd get more neg camber on the fronts(-.5 more like someone said), and zero to slight toe in in back.
If still understeering figure out how to stiffen rear with some shock that pushes with air like Bilstein.
J/K (maybe), but put a smaller tire on rears to get more pull and less traction.
#36
A few comments, then I'll stay out of this and let the uninformed opinions fly.
Every nationaly competetive CS RX-8 is running 285 Hoosiers with basically the same setup you describe (including stock or slightly stiffer front bar).
Your camber settings sound low (i.e. should be more negative), but there is a lot of variation in alignment rack calibrations.
When we went from 245 Hoosiers to 285 Hoosiers we had to increase rear pressures more than front to maintain the balance. To me this means the rear gained more traction than the front increasing US, but the overall traction is greater with the 285s.
What you describe as SS push might be down to driving style and/or preference. If you want to change the balance, IMHO the best thing to do within CS rules is increase rear tire pressures.
Jim
Every nationaly competetive CS RX-8 is running 285 Hoosiers with basically the same setup you describe (including stock or slightly stiffer front bar).
Your camber settings sound low (i.e. should be more negative), but there is a lot of variation in alignment rack calibrations.
When we went from 245 Hoosiers to 285 Hoosiers we had to increase rear pressures more than front to maintain the balance. To me this means the rear gained more traction than the front increasing US, but the overall traction is greater with the 285s.
What you describe as SS push might be down to driving style and/or preference. If you want to change the balance, IMHO the best thing to do within CS rules is increase rear tire pressures.
Jim
#37
05-08 SCCA BS Natl Champ
iTrader: (1)
shocks: OTS Koni Sports. Almost (i.e., 1/4 turn off) full stiff in the rear; ~2/3 stiff in front, depending on the course (we use both a transition-heavy runway course and a sweeper-heavy parking lot). Tires: 285/30/18 A6s on required stock-size wheels. Pressures are typically ~34f/36r, but might change depending on how the car is working. Front bar is stock.
Alignment:
Front
Camber: max negative, which on my car is ~-1.2*
Caster: +6.5*
Toe: 1/16" out per side
Rear
Camber: -1*
Toe: 1/16" out per side
wow, thanks Mark.
![Roll Eyes (Sarcastic)](https://www.rx8club.com/images/smilies/rolleyes.gif)
Rear toe out, bet that is stable in a slalom.
![SHOCKED](https://www.rx8club.com/images/smilies/SHOCKED.gif)
#42
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
i tried running that caster and much lower caster (~+2); didn't affect static camber i could achieve at all. that was the first thing i tried when i was disappointed in my static camber range. i figured in that case i could at least take advantage of the negative camber gain while the wheel is turned.
#43
05-08 SCCA BS Natl Champ
iTrader: (1)
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
i tried running that caster and much lower caster (~+2); didn't affect static camber i could achieve at all. that was the first thing i tried when i was disappointed in my static camber range. i figured in that case i could at least take advantage of the negative camber gain while the wheel is turned.
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
Last edited by ULLLOSE; 05-26-2011 at 10:21 PM.
#45
![Eyetwitch](https://www.rx8club.com/images/smilies/eyetwitch.gif)
but in any event, available -camber didn't seem to change significantly whether caster was set at minimum or maximum; IIRC, the difference was ~.1*. i figured the negative gain while the wheel was turned would likely outweigh that tenth of a degree. i could be wrong. anyway, thanks for the input.
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