Info on RX-8 and autocross
 

First, I would like to start off by saying that I do understand how to use the "search" mode, but due to my limited time that I'm able to use the computer, I can't devote time to look thru all that's available ~ at this time.

........that said, please refrain from any crass remarks and thanks in advance to those who will be responding with info.

Now as for my questions:

What is a competitive set up for these cars ?
Obviously tires, Konis, alignment....... but is there a need for a larger or adjustable front bar (?) ~ and what beyond that (barring weight reductions ie exhaust, spare delete, etc)

Second, what (if any) known problems arise from autocross use on these cars ?
(ie wheel bearings, rear, power steering unit)

I am not new to autocross but new to the RX-8
.......just contemplating where I can deal with the torque ~ or lack there of
(I'm use to 340-400 RWTQ) :)

Tires - Kumho V710 R

Pressure - 4+ PSI higher than recommended, 2psi higher in rear (36f 38r for instance)

Shocks - adjustable all around. Set front, 70% stiff, rear 90-100% stiff

Sway bar - front, as stiff as possible. TeamRX8, MS, etc...

Alignment - slight toe-in increase front, slight toe-out increase rear, as much camber as possible all around.

Fluids - switch to full synthetic for tranny and diff (Royal Purple is best recommendation from most folks).

Don't run under 1/2 tank of gas, due to some fuel delivery issues.

Thats about all you can do for class BS.

No real autocross-related problems should be encountered. Brakes hold up fine, clutch, tranny, diff hold up fine. Keep it close to rev limiter, and torque not a problem.

Oh yeah... Turn off DSC, A/C, and Radio before runs. DSC/traction control can mess you up, and A/C and Radio use power, that would be better used on the rear tires!

Oh Yeah 2 - some folks turn off car between runs, I prefer to leave mine running, with hood open. I have a feeling (unproven) that heat cycling off and on is harder on engine than being slighty hot with a gradual cooldown.

Have fun!

I've just started autocrossing a RX8, after running a Z06 the last two years. I also have spoken with what I consider the two best in BS regarding car set up and have started to set my car up in a similar way to their's.

Tires: Kumho V710 245 section
Shocks: ots Koni yellows, full stiff front and rear (springs are too soft, typical stock class car)
Sway bar: stock
Alignment: max camber front (we got -1.6), very slight toe out to help turn in (1/16-1/8), caster ends up at about 6. Rear camber is set at -1.8 and toe is zero. Goeke runs some rear toe out, but he likes a loose car.

Interesting comment on the fuel pickup issue. I've run as low as 1/4 tank with no problems. Maybe this one varies from year to year or car to car?

We have ran with low fuel warning light on, say less than 1/8 full, and still be fine. Then again, I don't pull crazy Gs on my 2nd season V710.

About alignment, my car does not rotate at all with 82% rear stiff (out of 990deg range), zero toe, and Tanabe front sway (116% stiff over stock). This is a problem for tight hairpin and round-about. Thinking of going back to stock front bar, more camber in rear (-.3 less than front now), rather than messing with rear shocks (pain in !@^).

Additionally, I need to learn LFB to help with hard sweeping turn.

YMMV

(good to have a good benchmark like mwood in my future region)

Thanks for the responses thus far.....,

MWOOD
~ what is your opinion of the car so far ?
.....cosidering we're coming from basically the background.

Interesting -- I found Joe's car to be frustratingly pushy. Agree with your setup, though.

I never had a chance to test a BS RX8, because I had too many mods on my car when I entered the sport. BSP allows me the opportunity to run the 285 V710's...and it is heaven. I have the full MS suspension and think it works beautifully together. Very happy with the turn in, and controllable loose rear.

I've only run it a couple of times, but am really enjoying it. The Z06 required lots of patience and finesse, whereas the RX8 allows very aggressive driving...at least that's my impression so far...get back to me after I have a chance to run against some of the fast guys and determine how far off the pace I am :rollingla

I know NOTHING ....
http://www.nndb.com/people/181/000032085/schultz.jpg

Yeah because you're driving a car with 1/2 the whp and 1/3 the wtq :) That's how the miata guys feel about us

LOL

Damn, I haven't seen THAT in a LONG time!

:yelrotflm :lol: :rofl:

Just curious, Mark...why don't you share more of your thoughts? Been there, seen that, done that, got the t-shirt (too many newbie discussions on the ol' RX8 club forum)? or, is it something more mysterious? ;)

sorry for my ignorance... but why do you increase the air pressure.? doesnt that create less grip? thanks just curious. and so what would you set your air pressure for "spirited" street driving? i have xexius 245/40/18 tires. thanks guys

I never ran satggered air pressure...but having more grip in the front (less air pressure), it would help with understear....right guys?

There's no set rule for pressures; every tire/car combination is different. People run street tires at higher pressures for autox to reduce sidewall flex which prevents rollover and keeps the contact patch flat. R compounds are a different animal all together because sidewall stiffness is built into the construction. You just have to find the optimum pressure for best grip. Since the RX-8 in stock form is traction limited up front, we go for optimum pressures in front and then adjust the rear for balance. Either increasing or decreasing pressure from the optimum point decreases grip, but it does it in different ways. Decreasing pressure allows for rollover and makes for a forgiving breakaway characteristic but reduces repsonsiveness. Increasing pressure reduces the contact patch which makes for a sharper breakaway that is more difficult to manage for an inexperienced driver because traction drops away more quickly after you exceed optimum slip angle, but for a good driver it makes for a more linear and quicker response at the limit. Most top level drivers decrease grip by increasing pressure.

Tire pressures are the last step in the setup process and can change from week to week due to course conditions. Different alignments, shock setting and swaybars all effect optimum tire pressures. Just because someone else runs a certain pressure doesn't mean it's correct for your car and driving style.

For autoX I run with 48#s in the front and 45#s in the back for tire pressure. This seems to work the best for me. Normal driving I run about 33#s all around.

That seems pretty high even for street tires on an RX-8. Because of the camber curve it just doesn't require pressures that high. On the OEM tires I was at 39F/35R. Try decreasing pressures 2psi per run until you see the tire starting to rollover on you via the wear pattern on the tire. There are small triangles on the sidewall that show the edge of the contact patch. You want it to wear all the way to the triangles for maximum grip.

yah, 48 and 45 is very high...must be pushing a lot.

I watch the tread wear and I am staying just above the nobbies. I could run a few pounds less but do not want to roll over. I have the whiteline sway bars and they are stiff.