tpdrx8

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.


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

EricMeyer

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

fastmike

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.

dmitrik4

iTrader: (5)

totally different world. autoX cars are usually set up really loose in the rear; some of the Civics I know of are so loose they would likely be almost undriveable at road course speeds.

TeamRX8

iTrader: (25)

the RX-8 does not have a Torsen, that said if the front bar is too soft it will spin the inside tire like mad and do more crazy **** than a 1-legged wh0re with an unlimited life time supply of blow and booze

fastmike

Where do I meet up with her?!?!?
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

TeamRX8

iTrader: (25)

It's called "theory" for a reason .....

40w8

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.

tpdrx8

Mark, stop me, please!

TeamRX8

iTrader: (25)

I vote for more body roll

not

fossumja

iTrader: (4)

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

ULLLOSE

iTrader: (1)

You planning on doing a little drifting? Can't see any other reason to run all that caster. Then there is the reduction in -camber that goes along with it.


Rear toe out, bet that is stable in a slalom.

olddragger

iTrader: (3)

is this understeer balanced? Same for right and left turns?
Yes-- i do mean if your corner weights are as good as you can get them?
Probably are, but since everything else has been covered i thought I would mention it.

TopGear8

iTrader: (3)

^You can't corner weight a car if he's not on coilovers...

TeamRX8

iTrader: (25)

Sure you can, but swapping spring spacers in/out is a major pita ....

olddragger

iTrader: (3)

and you can stratigically shift weight in and on car. Staying within the rules of course.
OD

dmitrik4

iTrader: (5)

slaloms just fine.

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.

ULLLOSE

iTrader: (1)

Your doing it wrong. I have not seen an RX-8, or MX-5, that did not gain -camber when reducing caster. I have also never seen an RX-8 achieve +2 caster, typical minimum is around +4, I think your equipment/tech is suspect.

TeamRX8

iTrader: (25)

in this case I'd say "everything" is suspect

dmitrik4

iTrader: (5)

yeah, i'm a real shady character.

it could have been +4; it was almost two years ago that i tried it and i didn't have my notes around. i could have that number in my head from my previous car.

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.

TeamRX8

iTrader: (25)

I only meant to question everything, probably the most valuable tool for not overlooking something ....

dmitrik4

iTrader: (5)

true enough.