RX-8Drifter

This spring i am going to enter my car into some auto cross events and i am wondering what modifications i should do to my 8. I know that racing beat has a suspension package out, but i was wondering what would make the most difference.

PUR NRG

What will make the most difference is not the car but you. Buy some books that teach racing techniques and car fundamentals. Learn what it is you're supposed to do and how to recognize what the car is telling you. Upgrading your car now can actually make you a worse driver in the long run because the upgrades may mask bad driving habits.

Stock the car can handle better than you can drive it. The most important upgrade is seat time.
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Motorcycle Tires

dannobre

iTrader: (3)

Recommended reading?

magixpuma

Mazda speed shocks and springs and sways and struts. i recomend rx8garage.net He gives rx8 club members discounts if you tell him your fromt eh club.

canaryrx8

iTrader: (3)

I second that, I'd fancy some better driving resources like books, links, or whatever, what good is a tricked out ride if your driving can't keep up?

Dark8

Here is a couple of good places to start:

http://www.tirerack.com/features/solo2/handbook.htm
http://www.sfrscca.com/solo2/faq/auto.htm

RX-8Drifter

thanks for the recomendation on reading and just having more time in the car...i got ahead of my self with all of the new parts coming out for the 8.

philodox

I've done a few mods to my 8 specifially for autocrossing. Look at my sig for the info.

I will say this about the Racing Beat suspension package. It really pushes the front end in high speed turns so there is a bit of understeer. I counter this with an offset in my wheels. I run 225's up front and 245's in the rear to give me a little bit of oversteer. With that setup the car handles like it's on guide rails.

A few tips. Turn the DSC and TSC off. Yes, even in the rain. I found that the RX-8 is more prone to a 4 wheel drift than spinning out in a high speed turn, especially in the rain. I tried running with them both on and off. I can say first hand that keeping the DSC and TSC off is good for a little over 1 second on your time.

Icemastr

If you are a beginner I would recommend leaving the car completely stock so you can compete in BS and save your money. Put your money into attending events, and replacing your tires/wear items. Then if you decide you want to be in a prepared class you can learn the rules of what modifications you can do. Once you learn the ropes a bit you can decide if you want to be serious or just want to have some fun, then you can determine what mods to buy. If you just go modding your car you might end up being in a class that has a lot of cars you can't even compete with. You can have a blast with the car even if it is stock.

swoope

iTrader: (5)

attend the newbee class. learn about tire pressure and chalk lines (on tires). and then burn, slow in fast out into your mind many times.

beers

philodox

Oh.. another tip.. street tires don't like to do more than 1 thing at a time.. for example: brake and turn at the same time.. a lot of new guys make that mistake and end up sliding into cones in the turns

RX-8Drifter

well when the weather gets better i am defninitly going to find an open parking lot to practice on...seems like the best way to make my car better.

philodox

Exactly.. nothing is a better performance mod than SEAT TIME. Experience is key

RX-8Drifter

i know the 8 is already such a great handling car, but i finally saved up some money to put into my car and i thought suspension was the best way to go if i was going to buy aftermarket parts.

Ophitoxaemia

cut the front bump stops down and/or replace the progressive rate springs with linear. i would get on the front bump stops too easily in stock even on street tires.

if you have less than a couple years experience (and even if you do) dont bother with car changes, just drive every event you can!

james

Dark8

Don't go cutting bump stops or anything till you read the rules. Cutting bump stops while using the OEM shocks will throw you out of stock. I don't think anyone would say anything if you are a novice, but if you beat them.......

Here is the link to the 2005 rules:
http://www.scca.org/Solo/Index.asp?IdS=02663A-B98E640&x=050|070&~=

Read the rules before you change anything on your car. If it doesn't say it is specifically allowed in the rule book, then it isn't allowed for that class. Heck, changing the gear **** can get you classed out of stock if someone wants to be an *** about it.

typerr

That seems the opposite of what I would expect. More grip in the rear should make the car understeer, not oversteer.

philodox

Larger tires in the rear put more power to the ground than there is weight when you are turning. Keep in mind that the weight is all in the front tires when braking. The extra increased power being delivered to the ground by the wider rear tires causes the rear tires to break loose since the weight is all up front. Does that make sense now?

PedalFaster

Um... no. More tire on one end of the car generally means more grip on that end of the car -- wider rear tires increases a car's propensity for understeer, and wider front tires increases its tendency to oversteer. Your car should be pushier with the 225/245 combo than it would be with 245s all around; if you're finding that that's not the case, the likely culprit is another setup change you made at the same time, or perhaps some difference between your front and rear tires.

Steve

philodox

Maybe i'm backwords in stating that the bigger front sway bar gives understeer.. oh well.. i know that i had to put wider rear tires on my 8 to counter what the larger front sway bar did. if i had my terminology backwords just shoot me

philodox

Oh boy, what's going to happen when I have a 245/275 setup next season

altiain

iTrader: (3)

In general, adding a larger front sway bar will increase the tendency of a car to understeer at steady-state cornering limits. Conversely, adding a larger rear sway bar will generally cause a car to be more prone to oversteer.

However, this is a general rule of thumb, and some cars have individual peculiarities that cause them to respond differently. In the case of the RX-8, which has relatively soft springs in the front, adding a larger front sway bar might decrease the tendency to understeer. How? Because when a stock RX-8 loads up its outside front tire to the point that the suspension compresses enough to contact the bumpstops, the effective spring rate at that wheel ramps up exponentially, causing a tendency to push. If the stiffer front swaybar prohibits that outside front wheel from getting that far onto the bumpstop, then it might indeed decrease the tendency of the car to push.

On the subject of tires - given the same tread depth and compound of tire front and rear, increasing rear tire sizes will almost always result in increased understeer, regardless of suspension geometry.

PUR NRG

Sorry, but this doesn't compute.

1. Larger tires in the rear put more power to the ground when you accelerate. This has nothing to do with when you are turning so adding that simply confuses the issue.
2. Yes, weight is primarily on the front tires when braking. However this has nothing to do with stepping on the gas. Are you saying you are braking and stepping on the gas at the same time?
3. "Extra power delivered to the ground by wider rear tires causes the rear tires to break loose" is backwards. Let me break this down:

a. We assume engine output (hp/torque) is the same regardless of tire width. Therefore power is constant.
b. Wider tires means more grip. More grip means more power is required to overcome that grip and spin the wheel.

This has nothing to do with how much power is "transferred" through grip and converted into the car's forward motion. From the above we can say two things:

1. A wider rear tire means more engine power is required to spin the wheel.
2. For a given engine a narrower tire will lose grip and spin sooner than a wider tire.
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Weed

ronbauer

Agreeing with the other recent posts....

We had the Racing Beat front swaybar on our car with 275/35/18s all the way around and the car handled extremely well. There is NO way that I would put bigger tires in the rear than the front on this car. As it is, with the big bar, it does push in slow turns, especially while trying to accelerate. The only way to stop this would be to increase the front grip.

So, if anything, you'd want to put the bigger size up front. However, I wouldn't recommend that.

Anyway, the car is a great autocross car. As a newbie, my only suggestion for car set up would be to get the Racing Beat front bar. You can upgrade tires too if you choose, but as noted, the biggest improvements will come from making the driver faster!

Ron Bauer
2003 DS National Champion

Sputnik

There are a handful of groups that hold "autocross classes". They might run from $150-$250 (last I checked), and not only do you get experienced drivers giving you tips, but you also get some 20 plus runs (much more than the three plus maybe extra runs on a normal autocross Sunday), so the runs are fresher in your mind , and you have a better idea of what mod/technique change did what.

---jps