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2nd Generation Autocrossing

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Old 01-22-03, 10:35 AM
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2nd Generation Autocrossing

Okay here is my situation. I am looking to get a second car to drive on the street and autocross. I have always liked the look of the 89-91 Rx7. I want the car to be non-turbo. I know my ideal choice is the GTUs, but I have never seen one for sale in my area, so I doubt I will find one in the next couple of months. That leaves the GTU or GXL. One has better brakes, one is lighter, both don’t have LSD.

Is it worthwhile to autocross a 89-91 that doesn’t have LSD? I am only planning on autocrossing at the local level for now, probably in Street Prepared. Basically, I would really like to have a 89-91 because of the looks, and better engine. I plan on getting good tires, springs, shocks, and exhaust for now.

I would like to hear from some people that have experience autocrossing with second generation Rx7’s to see how you did against other cars.

I really want to buy an Rx7, but don’t want to end up wasting money on a car that is holding me back from being decently competitive.

Any insight on which car to look for would be appreciated.
Old 01-22-03, 08:15 PM
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that's strange, i have a second gen GXL with a LSD. it has the full oem sport package, including a limited slip diff and adjustable suspension....
Old 01-22-03, 08:54 PM
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What year is your GXL?

The 86-88 GXLs had LSD, the 89-91 years did not. To my knowledge the only 89-91 non-turbo Rx7 that you could get a LSD with was the GTUs (and possibly the 1991 model as a rare option that has been discussed on previous posts).
Old 01-22-03, 10:38 PM
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you can put a 94-up miata lsd in the pumpkin
Old 01-23-03, 10:09 AM
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I thought all the GXLs had the LSD...
Couple thoughts here:
The car you get isn't the bigest factor when you begin autocrossing (I get my *** handed to me all day long by a guy in a bone stock 80s civic hatchback that's got low compression and about 90bhp...). It's about the driving. You'll be learning for a couple years how to go fast.
You want the LSD so keep looking for a car that has one. You also want the 5-lug suspension and the bigger brakes. If it's a competition car and not a daily driver, try to find a car without a sunroof (if you'll fit in it with a helmet on...) and no power accessories.
When you get a set of wheels for competition, look for light at the expense of pretty.
uh, that's it for now...
Old 01-23-03, 04:32 PM
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snarf

Unfortunately, the FC isn't too competitive in C Street Prepared. It runs against CRXs and Miatas, which are usually faster by virtue of being so much lighter/smaller.

A FB GS with a 13b transplant would probably be a better CSP candidate than any other RX-7, though still isn't a guaranteed winner.

Which isn't to say you can't have fun locally with any RX-7, just expect a steep uphill battle to do well Nationally if you ever want to try.

You'll want the LSD and 5-lug. Both can be bolted on without too much trouble. The LSD can come from a Miata and possibly some of the other RX-7s (there are charts floating around that have parts swap-a-bility). the brakes and 5-lug might be harder to source, since it's popular upgrade.

The later cars are a bit more powerful b/c of higher compression ratio (I think 89 and up).
Old 01-29-03, 12:03 PM
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Thanks for the replies so far.

I am thinking about looking at a 1987 Base Model. I think I can get it at a good price, and it would be the lightest possible 2nd generation Rx7.

I saw that Rx7.com has a performance brake upgrade kit for $750, and they also have a suspension upgrade kit for around $600. Then, I would buy some new wheels ( I can't stand the dial wheels), and get some Falken Azenis Sports for it. I know it still wouldn't have the 4 piston brakes, but they can't make that much difference in autocrossing, can they?

Eventually I would probaly make it look more like a S5, and I would have to add a LSD too.

Then, I would probably have a pretty fast n/a Rx7, after the exhaust and intake upgrades.

I will have to see what kind of condition the car is in. I may change my mind before then anyway
Old 01-30-03, 04:37 AM
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GXL,GTU,GTUs, and Turbo II all have stock LSD's. If it was before '89, it has a 2-way mechanical LSD. If it is '89 and above it has a 2-way viscous LSD. I did some looking around and that's what I found. I think the only difference between teh GTUs and GXL LSD is the final gear. I think the GTUs is 4.30 and the GXL is 4.10? Not sure.

The 2nd generation RX-7 came with various differentials depending on model and year. The only models equipped with Limited Slip Differentials (L.S.D.) were the Turbo II, GXL, GTU, and GTUs models. A L.S.D. will help distribute the power to the drive wheel(s) that have traction. This improves cornering and stability by reducing oversteer and allowing you to put down more power as you exit a corner. In the '86-88 L.S.D. equipped models, Mazda used a standard 2-way mechanical L.S.D. and then switched to a viscous-style differential for the '89-91 L.S.D. equipped models. Viscous utilizes wheel speed input more than torque to sense loss in traction and is slightly slower to react which makes it more predictable for your average driver. It also doesn't require any special additives in the gear oil which made maintenance issues easier as well.
Anyways, I went to my first auto-x in my Rx-7 Base model. (hey bought it for 900 bones) I didn't know what class I was. The official thought that I was C stock. So I competed in C stock and got my but kicked! I was atleast 5 seconds behind everyone. It was also my first auto-x in this car... so that might contribute. Anyways, I did some looking around and found out that I am supposed to be in E stock with the rest of the n/a Rx-7's. Maybe next time I will be more competitive. Hopefully I can go to the next auto-x in two weeks but I need my membership before then. As far as tires I just have Dunlop Sport A2's (loss of traction is fairly progressive in my opinion)

I say you should get atleast a GXL. Don't get a base or conv. Put some sticky tires on and play around with your suspension.(considering you wanna auto-x) Considering you will be buying an used rex you might wanna change the suspension bushings(prob'ly old and sagging by now) and then mess with the rest of the suspension. Just my opinion but do as you like. Just realize the rx-7 second gens are getting old. It wont be completely reliable and you will need to put some money in her on a regular basis, especially if you wanna drive her hard. Good luck.
Old 01-30-03, 12:53 PM
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in the s5's, ONLY the gtus and tII had lsd. there are a few exceptions, probably addons at buyers request.
Old 02-11-03, 06:50 PM
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Yep...I have a 1989 RX-7 brocure...only the GTUs and T2 have the LSD
Old 02-11-03, 10:50 PM
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well, remember that unless/until you put the legal mods (shocks, front swaybar, brake pads, and R compound tires), generally you're not going to be competitive, no matter what class you choose.

If it were me, I'd get the GTU, light weight, and the bigger brakes aren't that big of a factor, just run decent pads. The 2002 ITS champion in the SFR region runs single piston front brakes, so don't get too starry eyed about the big brakes. They're nice, but not an absolute requirement.

PaulC




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