bellwilliam

looking to purchase a RX8. would love to do some track days with it.

I am experienced with HPDE, wondering what is needed to run a stock RX8 on track. Every car I've taken to track days have a weakness. one need bigger brakes, others overheat unless going to big radiator, another won't run w/o adding rear sway bar (because it understeers a lot in stock configuration).

of course I would do the basics:

1. R-compound tires (RA1 or NT01), btw: what is the fastest size for a stock RX8 ?
2. track brake pads
3. Motul brake fluid

basically does RX8 have any reliability weakness for track days? also is there a must performance upgrade for track days ? thanks.

SouthFL

No outright weakness. This is why I purchased this car.
I've just run a half dozen track events over this calendar year on a completely stock (except ATE brake fluid and HP Plus brake pads) RX-8.
Even the OEM tires are trackable. The OEM brakes are superb and won't fade with the use of a decent pad a fluid (generous rotor diameter from the factory is partly to do with this).

Eventually, you may want to mod the car. I found (as do many) that the car is underdamped and rolls somewhat, so Koni's and springs went on this week. But this is simply an upgrade to a very stellar handling base which the stock car provides. For starters, a performance alignment points you (literally) in the right direction.

bellwilliam

forgot one more question. any particular model I should look for? I am open to new or used RX8. All models have limited slip? any particular model I should look at? thanks.

SouthFL

I run a base 6speed manual, no options, cloth interior. Limited slip is standard. No Traction Control on my car. No sunroof to impede head room.
Just pick a non Automatic transmission model and you've got pretty much a similarly suspensioned/braked car no matter what the options are.

expo1

1. 245/40/18 fit on the stock rim and you can get Hoosier R6 in that size.
I put on THESE rotors this year and noticed about a 60 Deg. decrease in temps.

Otherwise the only weekness I would say is always keep the gas above 1/4. Dip below that on a track and funny things can happen. I once did a track day that involved 8 20-25 minute runs and the 8 lived to tell about it.

imput1234

iTrader: (6)

IMO you shouldn't do anything except for the basics first, you have to learn how to drive the rx8 the way Mazda intended to drive it, after that do as you please, IMO spending money on mods is useless if you don't know the capacities of the stock car.

G3tR3DDY2GR3DDY

iTrader: (8)

i love your thinking- best advice you can give! so i agree with him... do the little tire/brake pad and fluid mods.... then once youve experienced the real feel, step up to some nice sways and struts then springs and shocks after that. Yes, the no sunroof thing is a good idea for helmet clearance ( so i hear) and obviously no AT model... and get a white one they are more appealing on the track! lol jk but good luck!

bellwilliam

thanks all. I wasn't planning on any mods. my question was if there are any obvious mods that need to be addressed before taking to track. example: another car I took to track needs a rear sway bar to correct the bad understeer.

I have done a ton of track days, so I am not worried about pushing the envelope. I already have a track car, but I still want to be able to enjoy RX8 on track if possible.

SouthFL

It really is this simple....

Let's recap w/ Cliff notes.

1) Trackable pad
2) Trackable brake fluid

This is all you need.

Nothing else is necessary.

I'd begin with a performance alignment to dial in better turn-in and rotation.

altiain

iTrader: (3)

Any 6-speed RX-8 will have the limited slip, 18" wheels, larger brakes, and "sport" suspension. I would second the recommendation to avoid a sunroof car unless you're a midget, as the sunroof eats up a significant amount of headroom in this car.

I'd recommend a performance alignment (a must start on any car that will see track time), a set of track worthy brake pads, and a good brake fluid as the first steps to tracking the car. From there I'd probably reocmmend a good set of shocks, as the stock ones are severely underdamped for anything but street driving.

Regarding tires, I've heard from my track day buddies that the NT01 is a bit faster than the old RA1 (which is going away anyway, to be replaced with the R888). They're both slightly slower than a C50 Hankook or an R6 Hoosier, which are in turn slower than an A6 Hoosier or a Kumho V710. How fast do you want to go, and how often do you want to replace tires?

Why would you buy struts for a car that uses shocks?

bellwilliam

thanks guys, just don't think it could be that easy

every car I've taken to track has some issues need to be addressed. even stock Miata have overheating issue if you push it hard in hot weather.

I've done some searches on the forum. there are a lot of fan and radiator mods. is this for tracked stock RX8 ? or only for highly modified track RX8 ?

btw, I am in SOCAL, so I run in 100F + weather all the time.


what is the best tires sizes to stuff in RX8 (using either stock or aftermarket) ? I've seen GRM's article on running 285/30-18 or 295/30-18. how about 17" ? does 17" clear stock brakes ? I would think smaller diameter wheel would be better. or is RX8 different is this aspect ? running 285 on stock 8" rim sounds strange, in Miata world, hot setup is 15x8 running 225/45-15. can't imagine 8" will fit 285/295. if going aftermarket wheels, what is the optimum size ?

shaunv74

I haven't had overheating issues at the track. I think it's more in stop/go traffic. If you want to keep an eye on it to see if it's a problem pick up Racing Beat's gauge kit. The stock oil pressure and temp gauges aren't much more than idiot lights. The water temp. gauge won't even move off of center until it gets to 230F!

An easy cooling mod that works is listed here.

https://www.rx8club.com/series-i-do-yourself-forum-73/diy-hood-ventilation-mod-123524/

mwood

If all you want is track dependability, like others have suggested, I'd focus on the brakes. The rest of the car seems pretty good. Of course, as altiain said, a track alignment is a neccessity, if you don't want to destroy tires while having no fun

Besides temp range appropriate pads and Motul or other quality fluid, I'd invest in a set of spindle ducts. Many of the RX8 "brake duct" kits I've seen are basically worthless, make sure to use a properly engineered kit or build your own!

bellwilliam

wow, you guys are helpful. within minutes, got 2 answers. love this forum.

what is the best track tires sizes to stuff in RX8 (using either stock or aftermarket) ? I've seen GRM's article on running 285/30-18 or 295/30-18. how about 17" ? does 17" clear stock brakes ? I would think smaller diameter wheel would be better. or is RX8 different is this aspect ? running 285 on stock 8" rim sounds strange, in Miata world, hot setup is 15x8 running 225/45-15. can't imagine 8" will fit 285/295. if going aftermarket wheels, what is the optimum size ?

2k4_8

There was someone I remember reading about not too long back that made some brake coolers using a simple ducting to blow air onto the brakes. IMO, if I was going to be tracking the car much, a mod like that would be cheap insurance.

mwood

The fat boy tires, 285 section, will fit on the 8" rim and work well for autocross (some of us believe ), but would be (I would guess) poor for track use, because of squirm under the rim, compromised sidewall profile and overheating of the outside shoulder.

If you are going to do a set of dedicated track tires, I'd just go with the Kumho V710 in the 245/35-18 size. They stick like crazy, fit the 8" rim perfectly and will last longer than other DOT R tires in this application.

altiain

iTrader: (3)

Keep in mind when reading the GRM article that they were specifically testing tires on an SCCA Stock class autocross car. In Stock you must run OEM wheel size and diameter, which is why you'll see people trying to stick 285/295s on 8" wide wheels.

For reference, the hot setup for years on a Stock class '99+ Miata was 225s on a 6" wide wheel.

If it were me and I wasn't constrained by classing rules, I'd opt for a set of 18"x9.5" RPF1s and add your favorite flavor 245 tires. The 245s will also work fine on an OEM 8" wide wheel, but if you're buying a dedicated track set of wheels you can pick up the RPF1s for the same price as a decent set of lightweight 18"x8" wheels.

I have no experience with 17s, but there are a few posters on this board who use 17" track wheels. olddragger comes to mind.

bellwilliam

wow, V710 in narrower size for track day !! sorry that goes against stuff I know. I thought 3,000 LB car would be better in much wider size in wider wheels. V710 is also known to overheat quickly (may be only here in 110F desert weather) after a few laps. always thought smallest diameter rim (that clears brakes) is the fastest setup (and cheapst).

I want to be clear I was talking about track days. thanks again.

shaunv74

17" rims will clear the stock sport brakes.

SouthFL

Too wide a tire in relationship with the wheel width creates too much curvature of the sidewall. You want the sidewall to be in an optimal relation to the wheel width for the proper stifness to occur, otherwise, as mentioned, you will get too much squirm. So, yes, a smaller contact patch with a better (straighter) sidewall profile is desired for track days. http://www.dunloptire.com/care/widthRatio.html
Try tracking the car on stock tires. You will see that there's plenty of performance to get acquainted with the car. I'd only step up to a 235 width tire myself for lapping days.
Also, the car is equipped with oil coolers and the radiator does an OK job on the naturally aspirated stock engine. I've been running all summer in Florida heat and humidity with no issue. Up to 50 minute on-track sessions with no issue.

bellwilliam

if I am running R-compound tires, that would mean I will be purchasing some aftermark rim. so I have a choice in wider and smaller diameter rim.

if rim sizes is not stock, what is the optimal size for both RIM and tires, for maximum grip on track days?

sorry for many many questions.

altiain

iTrader: (3)

Maybe 3000 lbs with driver, unless you opt for every option in the book.

FWIW, at SCCA Solo Nationals the B Stock RX-8s (think Base or Sport models with ~1/4 tank of fuel, lightweight 18"x8" wheels, lightweight axleback exhausts, factory a/c, radio, etc. still intact) ranged from 2790-2860 pounds. The RX-8 is lighter than you think.

costello

For non-competition track days, it becomes more of preference and budget when looking for rims and tires. I have a set of Enkei RPF1 18x9.5 mounted with Toyo Proxies RA1s 275/35-18. These are relatively light and inexpensive rims for the size and they work well with the wider tires since they're 9.5 inches wide. The RA1s are a good track tire and last a while (algthough they may not be as sticky as a Hoosier A6 or similar). Plus they have some tread and I can drive to and from the track with them.

mwood

Directing air to the general rotor area has very limited effect. In order to acheive any significant brake cooling, the ducting really needs to be attached at the spindle, directing air into the center of the rotor and taking advantage of the rotor venting.

Back to tires/rims, I'm so used to thinking about being limited to stock rim dimensions that I forgot that, for track use, you have no limitations!!

I think the idea of 17" rims could make lots of sense, not for gearing or cg reasons or any other "technical" consideration, but simply for $$$. 17" tires are quite a bit less money than 18" and, seeing as tires are a primary wear item in tracking a car, the savings would be big.

bellwilliam

in theory, 17" RIM should be faster. they are usually lighter (combo with tires), plus weight is towards the middle, so it is easier to accelerate and decelerate. oh, and the pricing thing of course.

anybody running 17" for track setup ? how wide of a RIM ? what size tires ? it seems 245/45-17 and 275/40-17 tires is perfect (in diameter), and are a very popular sizes. there are a tons of choices for this size r-compound tires. I believe every r-compound manufacture in these 2 sizes, as they are Camaro/Mustang/Corvette sizes.