Decisions.....S4 vs. S5

[jt94130]

Hello all, new here and after going thru the entire forum I ask for your advice.

I'm looking to pick up an FC strictly for track use. No racing, yet, but for DE's. Wanted to get opinions from you more experienced racers.

I've been looking at some cars, and am kinda favoring 2.

1) '88 SE w/roof, 4 lugs, just under 200K, all stock, comp ~110 on both rotors, bad clutch. $1200

2) '90 GTU w/everything from a GTUs....tranny, rear end, brakes, aluminum hood, & has manual rack. 140K chassis and 60K motor....but comp was ~70 on the front rotor and ~85 on the rear. $3000

My question is which would be a better starting point?
Which, for a wannabe backyard mechanic, would be easier to track prep?
Would the cost/time/ease to convert the 88 suspension/brakes/rear end be smarter then the probably rebuild on the 90?
Is the difference in price enough to make up for the differences in setup?

Any advice would be greatly appreciated. Thanks in advance.

[xr4racer]

Were the compression tests done on a Mazda type compression tester or a piston motor tester? As for which one is better, it depends on your future plans. The S5 would be better if you plan on racing ITS in the near future. I say this because if it actually has the GTUS trans and still has the S5 engine you would have the better rotors and injection needed for the ITS engine. The aluminum hood is a nice piece to have but is not necessary to get to ITS weight. I would definitely be afraid of the higher mileage engine regardless of the compression, as soon as it hits the track is when it will break. The 5 bolt brakes are fairly easy to come by. Take a good look for rust, I do not know where you are but the rust on Rx-7's is not always in the open. Make sure the cooling system both oil and water are in good shape or you will need an engine anyway.

Matt

ITS #7

[jt94130]

I believe they were both done on the Mazda tester. I got 3 #'s for each rotor. The #'s I put up were just the average. I don't really see myself actually racing soon, I have pipe dreams about it....but don't think I'm near ready yet. I don't remember seeing any rust, I'll have to take a closer look if I get the chance.

[xr4racer]

Where are you located?

[jt94130]

San Francisco, CA