I am both a newbie to the B-Stock class and a newbie to RX-8. I have got my cars a few months ago. It is totally stock with 710s (245 widths) as the only change for autox. I have autoxed a few years with a FWD car in GS. With the RX-8, I am always feeling that I am leaving something on the table by not getting the setup correct. So, I have a few questions:

1) What tire pressures do you guys think I should run or start with? There has been many discussions about tire pressures on cars with konis, swaybar, etc... What about a completely stock car with 710s? I have been running ~ 40psi fronts and ~35 psi rears. We have pretty tight courses around here because of venue limitations, hence the high front pressures... I have gone as high as 42 just to avoid roll over. I am assuming I can lower the pressures with more wide open courses. With the front pressures set at a certain psi, what would bumping up or down the rear pressure do to the car?

2) I just found out that holding the TCS/DSC button for ~7s shuts off the system completely. Before that, I just pressed the button once to turn it off (at least I thought). Is it right that completely shutting off the system would yield faster times? I tried both and couldn't really feel a big difference... but I did find that I can make the back end kick out easier with the system completely off. Note to self: resist the urge to drift the car while autoxing.

3) What rpm does people launch at to avoid excessive wheelspin or bogging down at the start? I have tried between 4000 - 5000 rpm... but have yet to perfect it.

Any other tips would be welcomed. Thanks guys.

 

Do an alignment. Max camber up front (happens at minimum caster), Front toe at 0 or a little toe out. Do your own research for the back, everyone has a different opinion.

 

When you get an alignment see how much camber you can get up front and then change the caster to see how much it affects it. I was able to get another 4-5 degrees of caster while only losing .1 degrees of negative camber.

If your car happens to be one that is camber challenged you might need to go with min caster, but check the numbers before you decide on anything.

 

You've gotten good advice on the alignment, I think.

On pressures, I might increase the rear at least to 37 psi, but you're close to where most seem to be with the V710.

Launch will depend on surface and, on most autocross courses, isn't critical. I like to bring rpms up just high enough that I will spin the rear tires a bit, just to kind of clean them off and get the run going.

Have fun!

 

thanks for all the advice... I have one more question that I can think of.... If the course is wet but with no standing water, what pressures (v710) should I run? I am guessing lower pressures to get more grip as there is no chance for the tires to roll over. And should I leave the TCS/DSC on partly by only pressing the button once? Well, I guess that's 2 questions... haha

 

I would lower the pressures in the 710's for wet, but don't know if that is unanimous.

It is my belief that you should always, ALWAYS, turn off the traction control and DSC for autocross.

 

We had a very very wet autocross yesterday. I tried running with and without. The runs with the traction control on were quicker because I spent less time going sideways. I was on street tires yesterday.

 

i find that 40 in front and 37 in rear feels GREAT.

still on stock suspension, gonna get a good track alignment before upgrading.

 

Even in the snow, I would turn off the Traction Control and DSC.

 

I don't mean to hijack, but since we're on the topic...I tried using 40psi front and 38psi back, the car felt good, but I have a good 1/4 of tire I was not using on the front so I started lowering the pressure. It wasn't until I got to the mid to low 30's before I start using all the tread surface on the front. Since everybody seems to be using 40psi at the front, am I missing something?

I'm using 710's. They must have close to 100 runs on them now. they felt slippery on Sunday, but I don't know if it was me or the tires, since this is my first season on R compound and I bought them used.

 

We had a standing water/pouring rain autocross late last season. David Hedderick (much better drive than I) was co-driving my car. With standing water and a heavy rain, we were both 1-1.5 seconds faster with the DSC and traction control on versus off.

 

I was saying that tongue in cheek. There are situations in which it might make sense, and you have the data to prove it. I was just being an opinionated *** about it for no good reason.

Its a moot point for me since I have a base model. This could be something that comes into play at Nationals if it rains.

 

i run 36/34 F/R for what it's worth (245 710s, stock sways, stock shocks), and seem to get good wear out to the shoulders.

 

Congrats for the class win at the Cdn. nats.....that was you was'nt it?
only 2 RX8' there.

 

might be a little off subject, but with tcs/dsc off does that help the 8 quicker ie. drag, or better for drift cause i cant tell a difference with it off

 

Yes, that was me. Hehe... I was definitely more at home at the larger, more wide open course that they had at national... our local courses are relatively tight and doesn't flow that well... on top of that, there are hazards at our local venue that is always on the back of your mind when driving.

The organizing club for the Canadian National (CAC) put on a first class event. I was really impressed. I have never been to an event with better organization. Kudos for all the competitors as well. I was glad to see a few US National champs at the event as well.

 

was the Cdn Nationals held at Pitt Meadows, BC? I missed that! It was so near my home!!!

 

Yes, that was where it was held.

 

I have to echo the same as others have said.
DRIVER DRIVER DRIVER.

My 05 Sport touring model does just fine as it is. Our courses are a bit quick and long which allows to stretch the legs of the Mazda. I am finishing 1st or a very close 2nd in B stock each local event. Just about finished off the Potenza 040 tires the car came with.

Only complaint is it does not turn in well for slow speed stuff. Probably could be fixed with an alignment. But this is my wife's daily driver so I will leave it alone and learn to drive around it.

 

Sport touring model eh? That must be the best of both worlds in performance and ultimate luxury.

P.S. this car has RAZOR sharp turn in and I don't even run with any front toe out, maybe the nut behind the wheel is just a bit loose. C&D tested it to have even faster turn in than the S2000 and that's definetely making a point there.

 

Huh? What test measures turn-in?

I've driven multiple S2000s and RX-8s, and let me tell you, the RX-8's turn-in is nowhere as good as a properly set up S2000's.

 

 

The S2k makes the RX-8 look like a truck on turn in.

 

http://www.motortrend.com/roadtests/...rformance.html



"While steering feel is subjective, responsiveness can be measured. One of the best ways to do this is via a step-steer test. The concept is simple enough: Suddenly snap a predetermined amount of steering angle into the wheel and measure the time (hence, distance) the car travels before it attains its final lateral-g cornering rate. Here, we premeasured the steering angle each car needed to achieve 0.6 g at 30 mph and monitored the lateral-g forces via an accelerometer. Our trio's report card: All three are quick responders, but the RX-8 has the fastest reflexes, trailed by the S2000 and the heavier-feeling 350Z. The Honda seems to match the Mazda, but we suspect its quicker steering ratio contributes to that illusion/"

I drive both on a regular basis, the S2000 has a quicker ratio for sure but the actual turn in feels about even to me.

 

Perception vs. Reality. S2k gives the illusion that it is the sharper handling car with noise, quick steering, open top feel. But nothing beats an objective calculated test.