Misc RX-8 autocross questions
 

I’m another recent convert to the RX-8 after many years in FS. Forgive me if some of these noob questions may have been answered before, but I have searched around a bit and not found these answered.

I don’t want to reopen any of the set-up threads. I’m sure those are beat to death and full of different opinions anyway, but I am looking for advice on anything to watch for in autocrossing this car. Are there any quirks (ABS ice mode or wheel hop), maintenance items (wheel bearings, PS pumps and diffs on my Z-28), or other things to watch for?

Do you idle or spray down the car between runs?
Min fuel levels without starvation (¼ tank seems common)?

From what I have seen so far, the car seems to have no real vices (except maybe a lack of a torque).

Hope to see some of you around the Southeast and in September.

OK, that didn't get much response. I take it either:
1) Everyone is away for Christmas or
2) This car has no vices! :)

Hoping for #2, but let me try a different question. I didn't want to start another set-up thread, but I am getting ready to install a set of Konis (Thank's Santa). I havn't yet auto-xed the car, and knowing that the rears are a PITA to adjust, I want to get them close to start with. I was thinking about 1/3 to 1/2 stiff to begin with, to allow maximum adjustment of balance with the fronts. Does this seem in the ball park for those with more experience in this car? I will be starting with the stock FSB, and possibly going with something stiffer depending on how it feels.

TIA

I'm in the process of setting up an RX-8 for BS as well, and I was advised to set the rear konis to 1/2 stiff to begin with.

I can't answer any of the questions in your 1st post as I have zero experience autocrossing an RX-8. I was told that the fuel can be run low w/o starvation - like around a 1/4 tank or thereabouts.

Good luck!

I'll take a shot and welcome to B-stock !

ABS = the overall braking system is excellent, no major issues with ice mode.

Launch = can be challenging to hit just the right RPM's, but wheelhop has not been a major issue for me with Hoosier A6's. I tend to error on the side of too much wheelspin, versus bogging.

Items to watch for = some have reported issues with the trans after repeated hard launches. You will find a few threads on the subject by using search.

Post run routine = I tend to do a little of both, depending on how long it takes to get back to grid. I like to idle the car for awhile to bring down the oil temp and the n shut if off after maybe 5 mins.

Fuel level - varies with course design. 1/4 tank is "safe". The RX8 will drink fuel at a rapid rate on course, have some spare fuel with you.

Other "issues" - rotate tires often, the RX8 will eat the front shoulders quickly on aggressive surfaces. I rotate front to rear after every 8-12 runs.

Chris H

Between runs in hot climates we will let the car idle for a couple of minutes to keep the coolant and oil circulating, and we will spray tires/radiator/oil coolers/engine intake in the meantime. Pop the hood and remove the engine cover between runs in warmer weather - you'd be amazed how much heat gets trapped under there.

I've encountered "ice mode" once or twice with Axxis Ultimate pads on my car, but nothing nearly as severe as a 350Z or Elise (I can't stand the brakes in either of those cars). With OEM pads I've never had an issue.

On our car, the low fuel warning light (roughly 1/8th tank) was our "fuel starve indicator". If we went to the line with that light on, we would get fuel starvation on that run. We tried to keep it around 1/4 tank during competition, and brought spare fuel - on longer courses the '8 can guzzle a half gallon a run.

I know a well respected member (heh, heh...he said "member") of the RX8 autocross community suggests 1/2 stiff on the rear shocks, but many of us run them full stiff, including the Pro and Nationals winning cars ;)

There's something about the rear geometry on the '8...maybe having to do with the camber curve? Anyhow, the rear really wants to squat and load the outside tire on throttle, off turn which may be part of the reason why many of us feel the car suffers from understeer in those conditions. Stiffening the rear shocks seems to help with that effect...of course, as you can tell from the way I've written this, I'm no expert...just reporting what I've experienced!

Good advice Mike. I'll think I'll give that a try first - full stiff in the rear. We're installing the konis this Saturday, so that advice is very timely.

I have a few more set-up questions I'll ask you offline...

Keep in mind that the only car I absolutely am certain is at full stiff, rear, is mine! :o:

Understood. What kind of 60ft times did you and Braun cut during the Pro Finale this year?

^
Doh! Found my answer in the Pro Solo 60ft thread... :spank:

Any time I tried full stiff rear rebound either of our RX-8s have been too loose, and that's with stiffer front bars too. However, both are on DA Konis, not the off the shelf SAs, so the bump setting may be infuencing this behavior. As could the rear camber setting, which also comes into play for launching the car at a Pro.

^That's a thought to possibly experiment with...less rear camber, but softer shock...that could be a way to get rid of the throttle on push, huh?

The other thing we were going to try was the big axx Whiteline bar, full stiff rear shocks, camber at -1.9r, but a little rear toe out...that, I would think, would really wake up the car off corners.

On the other hand, my car is a proven entity...it's the driver that needs work, at this point!!

2007 Pro Finale reaction times ....... special thanks to Darrin DiSimo for the info.

Despite my crappy finish (darn .490 redlight) I believe my 2.066 was the quickest 60 ft time for the class. I was unable to get close to it again so the planets must have aligned just right.

Fresh 285 A6's may have helped.

Interestingly, the 350z gap seemed to be less of an advantage at this event. Lee's one-flyer was a 2.106.

Chris H

Thanks, Chris.

Man, my memory was waaaaay off...I was sure Matthew had a 2.09, but not even close. I also was sure that there were some 2.0x RX8's...nope.

So, it was a low 2.1x to 2.2x range...maybe I was thinking of El Toro?

Matthew was fast enough everywhere else...he doesn't need a tenth advantage off the line too !
:o:

For those who were not there, it really was an epic B-stock battle that could have been won by any the 8 competitors in the class. Great Fun.

Ok, I'll bite. I have been autocrossing for two years in a 350Z with the smallest stock brakes they ever offered. (05' base model, I did change to HPS pads after the first year) I have no idea what you are talking about though.

Please enlighten me.

"Ice mode" happens when the abs senses one tire is decelerating too quickly...like it would if you hit the brakes on ice...and responds by cutting the braking power to all four wheels. In theory, this would help acheive maximum braking on a very low friction surface. In practice, it gives you roughly 50% of braking power and causes very...umm..."interesting" situations when racing or autocrossing.

Some cars are notorious for being overly sensitive. The Elise which I ran in 2006 was very bad, in this regard, going into ice mode in many different circumstances when autocrossing, with no real rhyme or reason. Most cars seem to need to have a combination of an unweighted corner, big steering input, high(er) speed and severe/threshold braking to trigger ice mode...

I've experienced it less than a handful of times in the RX8. Personally, I think braking is the RX8's best characteristic.

In my experience it takes two or more wheels that are locking up to trigger ice mode. We see this a lot in autox because of the strange dynamic things we ask a car to do, like change directions and brake at the same time. Often times this is made worse by a big front sway bar that takes weight off the inside tire if you are in a brake/turn situation, or poor brake pad choice, way to aggressive pad for low speed driving.

We have a guy here in Socal that every event complains about how ice mode in his Lotus caused him to blow a run.... But I never hear the other guys in the other Lotus that are kicking his @ss complain about it. You brake late enough and you can make any car screw up, only way to fix that is a better person working the pedal.

Here is how Chris Hammond fixed ice mode in his Z: http://www.my350z.com/forum/showthre...light=ice+mode

Ask Matthew about it, some time...although, being the only National champ in an Elise probably makes him less an authority than your local guys...:spank:

We have talked about it... Matthew is a trail braking fiend that loves to brake SUPER late, we saw that on the data from SD tour. You do that stuff in a car with no weight on the front and you are going to have issues, just a matter of adjusting the braking point, or live with the ice mode.

And is a guy who did not even trophy at natls an authority on RX-8 brakes? :pokeowned :lol:

I first heard of "ice mode" in the thread about the MS3 that got totaled on that road course.

I have never felt or heard of an "ice mode" on the Z and, over the last two years, have given the brakes a pretty good workout under various conditions. (good and bad)

Does the Z even have an "ice mode." Is it on all the models?

Nice recovery, but the fact is, the Elise is very easy to fool into ice mode, particularly with the lighter A6's and your first comment about the local guys "never complaining" means nothing, because the one guy who was able to get it done in the car complains about it to this day ;)

Hey, I was third at Nationals...on one day...besides, this isn't about me! :(

Any car with ABS will have some sort of mode like this, on some cars it shows up during an autox runs, in others you may never see it. In a non-ABS car you would just see brake lock up.

It felt like forever since I got to poke you, thought I was losing it. :evil_laug I still say if he broke in a normal place, like the rest of us mortals, he would not see it. Slow in, fast out. :boink: Fast in..... Well, you join Mike watching everyone else get the trophy.

True, Matthew does things with the car that most of us wouldn't try or be capable of pulling off...but, then, so do you (I must admit, as much as it hurts to do so...)

Signed,
Slow in, Slow out...One Day Mike...aka the only person in America still in their office "working" :wiggle: