Yesterday I tried autocrossing in my convertible for the first time at a local track meet. My Buddy has been doing it for a while in his Porsche 924 and is itching SOOO bad for me to join in!! We'd run in the same class, see. I actually got fairly close to him timewise on my second run, my crappy street tires against his racing rubber! He also said the smoke and wailing coming from the tires was pretty awesome - only running the stock pressures as the whole thing was unplanned in the first place...

Anyway, my question is simply this; what issues might arise from autocrossing an rx-7 convertible in particular and what things should I keep an eye on? I'm a bit worried of tearing something up. My buddy can afford to replace stuff on his car, but I can't right now. I'm mainly thinking of axles, suspension bushings, brakes, overheating, and so forth. Any thoughts?

Thanks!

 

get the best brake pads and tires you can afford. As far as suspension and other changes, what class you race in will determine what you can or can not use.

Also the Verts are stiffer with the roof up and the the targa section locked in, so make sure you can fit with the roof up and a helmet on.

 

Break pads are a must. I found that running 46psi in the front and 43psi in the rear tires seam to work real good. As for tires if if you run a nice set up front and crappy cheapos in the rear it will get rid of the terible push you probably felt as you were going into the corner hot. This alows the back to drift very controlled. I just had my vert out this weakend at the autocross and i place a fourth over all. I was very impressed. I think it was a lot of luck. I am running stock every thing. I havnt had any problems out on the track and its my second year. If you have any more ? just fire me a email. I picked up a lot tricks driving that heavy vert on the track.

Scooter@uplogon.com
Lake Superior Region SCCA

 

Thanks for the advice Mark! I've been thinking of the Bridgestone Potenza S0-3's. Have heard they are quite sticky for a street tire.

I'm allowed to change the suspension components, replace the stock parts with equivalent, replace the brakes as long as the rotors are the same dimension (I think), but no strut braces, lightened flywheels, or competition clutches. I would like to stay stock as long as possible as the rx-7 is a very nice stock performer! Also gives me a chance to work on my driving skills. And stay a bit cheaper for now...

How easy would it be to repack the wheel bearings?

 

Yes, that makes sense! The car was pushing like crazy and wouldn't steer out of the corners. A gentleman I spoke with today was running a '90 N/A coupe and claimed that 10 psi more in the front cures his understeer on street tires. Today he beat the Porsche 944 quite easily, for the record. AND with a bad exhaust leak in the Y-pipe!

Thanks for the advice! I just have to bite the bullet now and tell the wife I raced the pretty convertible. Will she ever understand?!

 

will she ever understand? NO! hehe but you will do it anyway cos your a guy. good luck on your races. i own a vert also and like hearign things about the verts here and there doing different things.

Fred

 

She will if you bring her to the next event and have her co-drive the car.

Tire pressures will help control the pushing a little, as will the correct alignment (1/16 toe out front, 0 toe rear).
BUT, the best thing to prevent the car from pushing is to avoid overdriving. This is usually a hard concept to believe at first, but going slower to the point where the car won't push will be much faster than driving at the same speed and trying to make adjustments for the pushing.

As for brakes, you don't need to spend a lot of money since autocrossing is no more stressful than heavy street driving. I ran a set of Pronto (aka no-name) semi-metallic pads on my car. They cost $26 per axle and lasted thru 5 years of autocrossing before needing replacement. They never faded on the street or in an autocross. Spending more money on some things doens't always mean you're going to go faster. It just means you spent more money.

The 'vert has got to be the least competative car you could possibly run in E-stock, so when you beat anyone, smile because that means the best mod in the car is sitting in the driver seat.

I autocrossed my 'vert for 5 years on Stock and Street Prepared. If you have any questions, about what to do next shoot me a PM or just post here. There is a pretty decent population of autocrossers in the 2nd gen section.

Your next mods for the car, in this order are: Seat time, Seat time, Seat time, Lessons, Seat time, Tires, Seat time, Seat time, Suspension.

 

Nobody has really answered your original question, so here goes. You'll obviously use up your tires faster and also your struts. Especially the fronts. If you have any bushings or bearings that are on the edge, you'll push them over. That said, this is what these cars are made for. You won't hurt the car. Especially on street tires.

I have an 88 GTU running CSP. In our club we combine some classes so yesterday I ran against a 93 911 RS America in ASP. Thanks to his cone, I beat him and won my class. What fun!

Here are the combined PAX results from this weekend at the SCCA's Atwater National Tour.
1 Steve O'Blenes 87 Mazda RX7 Turbo Yellow 68.425
2 Tom Berry 96 Chevrolet Camaro SSR W 68.715
3 Tom Ellam 72 Mazda RX-3 White/Blue 69.184
4 Glen Hernandez 01 Fordahl Mustang Green 69.565
5 Scott McHugh 89 Chevrolet Corvette Whi 69.724
6 George Doganis 94 Mazda Miata Red 69.743
7 Ken Motonishi 99 Mazda Miata Silver 69.808
8 Chris Kannan 84 Honda CRX White/Bl 69.808
9 Steve Eguina 96 Chevrolet Camaro SS-R 69.956 10 Jason Uyeda 87 Maxda RX7 Turbo Yellow 70.217

Looks like it paid to be driving a Mazda to me.

 

get a set of kuhmo autox tires, it will take seconds off of your time.

 

Thanks for all the advice guys!

I'm a newbie when it comes to autocrossing. But, every experienced driver I've talked to during these events tell me the same thing: seat time! And the old mantra of going slower to go faster, which does make good sense.

I will overhaul the brakes and the suspension components this coming week, to make sure there are no potentially dangerous, weak points before pushing the car again. I know the rear shocks are shot since one is visibly leaking, and the brake lines seem a bit tired and fragile.

My buddy races on Kumhos, and swears they do wonders for his times. But race rubber would also stress the suspension even further, correct?

I actually have another autocross-specific question here:
What is the best way to keep the RPM's up in the powerband (thinking mostly of 2nd gear) during runs on tight and twisty courses? I'm hesitant to shift into 1st while moving since the transmission seems not to like it, even with double clutching and so forth. Is this normal for this transmission, or are the synchros going south on me?

I love the idea of my convertible on the track! Lots of Miatas out there racing of course, but I think the vert would be somewhat unique in my area. Makes it fun to be different!

Thanks again for the input! I no doubt will have more questions as my seat time increases. This forum is indeed knowledgable and very helpful!

 

As for repacking your wheel bearings.... piece of cake! Take off the wheel, and you'll see a little aluminium cap in the center. Pry that off with a screwdriver, and there's the wheel bearings locked in with a nut.. There's a good chance the nut is loose, so this is a great time to check/tighten it up.

Actually, i'll just post the link, instead of re-typing it all..

http://www.fc3s.org/wheelbearing.html to check/repack your bearings

(edit) actually....that's the reGREASE procedure... not sure if that's what you were after or not...

 

Put you some KYB AGX adjustable struts and make sure the brakes are working properly. Get you some r-compound tires as soon as you can and run in a stock class all year long. If your serious about and want to modify your car more buy another 2nd gen and spend your money on it. The convertible will always be overweight for any class and IMO you would be happier in a coupe especially if your serious. If you stick with the vert, keep it in a stock class and just put some adjustable struts and get some dedicated race tires for it. Brake pads are next and then have some fun. Don't forget that seat time is the best way to make your car quicker.

 

Yes, the race rubber will induce more stress. Your lateral G forces are increased as well as braking force. I would suggest that you run on street tires for several events. It's very easy to rely on the tires and learn some bad habits.

The rev thing can be tough. It really depends on the course design. Some courses (SCCA) tend to be faster and less of a problem than "local" clubs. It depends on the lot too. The course designer really has to work with what they've got. Sometimes you just have to live with the low-rev blues because it may be faster than up/down shifting all the time.

 

Thanks again for your helpful advice and info to make up my mind on what to do here!
Based on this, I've decided to start off slow, get the car into good shape and get the feel for the car as stock, pretty much (seat time!). If the racing bug really hits and the wallet allows, I'll certainly look into racing rubber and an adjustable suspension for my convertible.
As for getting a dedicated racing coupe, maybe in the future when the convertible feels too slow, or the driving skills sharper. But then it would have to be a TII! Or perhaps a turbo conversion for the convertible... That certainly would throw many people off on the track!

Cheers!

 

How did you guys learn to autox? I want to give it a try but I don't want to look like an idiot the first time I go out there. Can I maybe go to a big parking lot or something and maybe try? What did you guys do to start???

 

the best thing to to when you want to learn is go to the next race and start racing. no one cares if youll look like an idiot because everyone out there was a beginer at one point or another. just go out and have fun.

 

I say about 7-8 yrs ago. I autox'd my T2. All I had was a set of "blue" Tokikos, RB springs, RB sways w/adj. links, RB lower front mnt, Greddy strut bar, Dunlop M2's (205/55-225/50) and mild bolt ons.

A friend of mine autox'd in the OSP group. He convinced me to go...so I did. This was a Candlestick. I ran the first day w/ very little knowledge and quick walk though on the track ( I was NOT prepared). He told me to lower the tire pressure in the rear, slightly. So I did. The first run was a whirl. Killed cones and ran off once (you have to go back to where you had left). I did learn two things, steer w/your rear wheels and do not plow into the turns. The second run, I was focused. I ran w/ no mistakes....so concentrated that I had missed the end of the track, almost kept going (almost killed someone)...opps. Third run, same as the second.

Few weeks after, I recvd the ranking results...9th out of 22? I was suprised.

I will say it to....just need the track time.

Last example. I take my Gix to track days at Thunder Hill @ Willows. My first two track days was on the stock suspension settings (factory), stock 207's. Before the third, I had it tuned by G-Force in Sunnyvale. The third track day, I ran a 1'42, stock suspenion - tuned, same 207's. I had shaved off almost 15 seconds. 4th track day, I slapped on 208GP take offs.....ran a 1'28. Progression......

Stock is good...just get used to it. Once you know the cars' characteristics...then you can improve the points you believe is nessesary for improvement, need that base line.

Bored you????

 

roll cage anyone??

 

You need to get your wife involved. My wife brought out our convertible to the autocross in Lexington this weekend, and I continued to run my 80 in CSP. One of our friends had offered up his Kumho Victoracer mounted on his wheels for the weekend since he didn't have an IT race. So they went on the converible, and I had my BFG Comp T/A R-1's. To make a long story short, she beat me. It was a course where you really needed an LSD and the 80 doesn't have one. In fact, it is amazing how well the vert did with the simple addition of race tires. It has somewhere near 200,000 miles and still has the stock springs. Out of a field of 76 drivers, she paxed out at 13th position. I had never really considered the vert a viable autocross car before this weekend, but that view may now be changed

 

You guys with the Pax stuff are killing me!
The Pax is NOT about the car. It's about the driver. The Pax system is designed to take the car out of the equation to compare driver skills.

See http://www.azsolo2.com/reference/usingpax.htm for a more detailed explanation.

As I said before if you place anywhere well in a convertible RX-7 (raw or Pax), pat yourself on the back for a job well done.

 

I hear what you are saying about the pax, but the car is still very much a factor. The PAX index is is set by taking the most prepared cars with the best drivers and benchmarking them. When I put the RB system on my 80, it put me into CSP. For comparison's sake, Cindy ran a 40.0xx in ESL and paxed out in 13th position. I ran a 40.8xx in CSP and paxed out in 50th. The reason her placing so well impressed me is because of the state of the car. NO performance mods. NO handling mods. Bone STOCK car with 200,000+ miles and race tires. Here is the list of all the stock cars that beat her real time:

24BS 2001 S2000 38.572
21FS 1994 3000GT VR-4 38.592
71CS 1999 Miata 38.668
16CS 1996 Miata 39.164
047BS 2000 Z3 39.317
39SS 2001 Corvette 39.408
5BS 1991 MR2 Turbo 39.422
9ES 1992 Miata 39.503
50CSL 2001 MR2 Spyder 39.905
28BS 1999 Z3 39.953
42ESL 1988 RX-7 Vert 40.049 <--My wife's time.

As far as the pax is concerned, just remember that it is set with a "stock" vehicle with every allowable mod. (Catback exhaust, improved shocks and struts, etc.) Follow this link to get the Pax Index Results for the event.

 

I thought convertibles were required to have rollbars for autocrossing...

I was at an autox last summer and a friend of mine was going to run his '93 Miata, but they wouldn't let him, even with the top up, because he didn't have a rollbar.

Does this vary from club to club, or what?

 

It wasn't an SCCA event if they wouldn't let a Miata autocross. A roll bar is not required but is recommended in stock classes. I can't imagine an autocross without a Miata running.

 

too bad I didn't go...

 

Yes, the Pax is based on ~equal drivers in the fastest cars for that class prepared to the limits of the rules. Needless to say, the ol' vert is no where near resembling a competative car for the class. The MR2, Miata, Alfa, and RX-7 coupes all are WAY faster.

Therefore, for that car to Pax well, it had to be driven like a bat out of hell. Therefore, mad props to your wife and her ability to sling that big heavy car around the cones.

After tires, the best mod you can have for a 'vert is the person sitting in the driver's seat.