OT: RX-7 twin-turbo Gen. III ? - PeachParts Mercedes-Benz Forum

ke6dcj · #1 10-16-2004, 10:10 PM

Hey guys, I'm thinking about a 1993 Mazda RX-7 Gen.III (twin turbo) for autocross and the track, since there's a local one for sale in good condition for $9K with a spare factory new motor.

These cars run a skid-pad of about 0.97g out the box, and with very little suspension work (install the factory R1 suspension) will pull over 1.0g on the skid-pad.

Moreover, with less than $2K in mods, over 450HP.

Any caveats or experiences ?

Thanks,
:-) neil
1988 E36T AMG
1993 500E

ned2683 · #2 10-17-2004, 12:56 AM

As far as i know they are awesome cars. 1.3 liter wankel with an almost perfect 50/50 weight distribution. such a sexy car. but the general idea behind them are they aren't that reliable. i know that the apex seals crap out on them all the time and they are prone to overheating. i know some people in california actually run 2 radiators to try to cool the thing down.

so in general: great sports car, not so reliable.

mr.thi03 · #3 10-17-2004, 04:04 PM

I had one for years. Had 550hp at the rear wheel. great cars if you do it right. One of the best and most fun cars on the track you can get. The extra motor doesn't mean much since it has stock apex seals. I think they are very reliable cars especially on the track if done right. BTW, is it a touring or the R model? sounds like a good deal for $9k.

ke6dcj · #4 10-17-2004, 05:26 PM

Touring model.

Any suggestions on some first upgrades ? Should I do a "R" suspension, or skip it and do something else ?

I'm looking for a combo autocross and track-day car.

:-) neil

mr.thi03 · #5 10-17-2004, 06:15 PM

The first upgrade is IC (when I was in it, on the rx7 post there was a guy making ICs that was a really thick core that mounted after the radiator, worked great, I used the GREDDY one and was never a problem, even at Willow or Vegas raceways running full BAR of boost)...a must...then if you have a touring model, get springs (H&R), Strut brace front, Cat back exhaust and high flow 3" CAT. With the second motor I would send it out to get bored/ported w/ 3" ceramic apex seals. After all that I would then get a computer or a boost controller and bring the boost up to one bar. HKS makes a F-Con V that worked great for me. But that was a few years ago and they might have better stuff out there. Peter Farrel in florida has some good stuff. But I would look for the rx7 posting and just find out what is the latested and greatest...I'm considering getting one again for track..Try to find a 95 if all possible and the R1 models...I really didn't have any probs w/ over heating..just run the redline cooler stuff..worked for me..the only prob is the plastic casing might expand too much and leak..but any race radiator would work.

Jim's500E · #6 10-18-2004, 08:20 AM

Hey Neil

You'll love that car !! I drove one once at an auto-x...was stock except for slicks and lite weight rims; was ALOT of fun, very predictable and easy to control at its limits. Not sure what year but it was the new generation.

I'm not a big fan of Jap cars but for what you want it for and that price; it probably won't do you wrong. Supposedly they are pretty durable too.

Quite a departure from the C36 wagon I'd imagine !!

ke6dcj · #7 08-12-2007, 11:25 PM

Well, I've had the RX7 for about 3-years, and am having a great time!

I am now a Porsche, BMW, Z, and Alfa club instructor.

In my first time trial, I took fastest time in a non-prepped track car, and am 2-seconds off the fastest NASA time for Roebling Road in my class.

Check it out here:

http://www.youtube.com/watch?v=FXpRYLzsMxE

http://www.youtube.com/watch?v=bhYz2obY-bg

:-) neil

BTW: I did pop the the engine within the first 2-months of ownership, but put in the spare factory engine and has been well so far!

jhodg5ck · #8 08-13-2007, 01:40 AM

Nice driving!! Ever make it out to Road Atlanta??

Jonathan

Ara T. · #9 08-15-2007, 05:07 AM

I bet a lot of the problems with the Apex seals are because of folks who dump a chip in there and increase the boost.

If it were me I'd leave it at intake/exhaust, that sort of thing.

Hit Man X · #10 08-16-2007, 07:52 AM

Problems with the sequential system is common, they're verysmall (I'm only 6'1" and I feel like a bear in a cart), WAY too many vac lines, apex seals as stated, etc.

A '99-00 FRC C5 is a better deal, Heads/Cam/Headers and you're nearly at the same powerlevel (380-420rw, not crank, big diff) and will still knock back 28-32mpg freeway.

Also a Z32 300ZX TT will make quite a bit more than 400rw with some minor mods to uncork it. Big down fall are the four cats and lil turbos. Fantastic vehicle for the money today.

mramay · #11 08-16-2007, 09:03 AM

A friend of mine in San Fran has a '94 RX7 and took out the GM LS6 V8 he put in it because 480HP wasn't enough. He's installed a nicely built LS7 and it should be running by now. He's expecting 600-625HP out of that 427 cubic inch normally aspirated motor. It is being built as a track car.

FYI, the LSx engines are about 390 pounds and supposed to be 434 pounds with all accessories. I have the "underpowered" LS6 - it's the engine going into my '87 560SEC.

Yep, a Gen III RX7 can be fun!!

Hit Man X · #12 08-16-2007, 09:11 AM

Quote:

Originally Posted by mramay

A friend of mine in San Fran has a '94 RX7 and took out the GM LS6 V8 he put in it because 480HP wasn't enough. He's installed a nicely built LS7 and it should be running by now. He's expecting 600-625HP out of that 427 cubic inch normally aspirated motor. It is being built as a track car.

FYI, the LSx engines are about 390 pounds and supposed to be 434 pounds with all accessories. I have the "underpowered" LS6 - it's the engine going into my '87 560SEC.

Yep, a Gen III RX7 can be fun!!

Can't beat the Gen III/IV motors they have out. INSANE power can be made for way less cash outlay than most think. The 15° degree head design was about 15 years too late, now you have 12° on the LS7 and the 6.2L motors.

The aluminum ones are nice and light. The iron truck motors are in the 560lbs area I recall. Hell, the M70 V12 in my 750iL is only 529lbs fully dressed!

If you haven't completed your swap yet, I'd skip that 60E. They're just not that great of a trans (unless you get billet shafts, vac mod for shifts, and a modified input drum) and the HUGE drop on the 1-2 shift is awful, I run a triple clutch, 4k stall converter in my Z71 for that reason (no, it's not anything near stock). I'd look at a 200-4R for the lower power loss over the 80E and better gearing.

Probably will want a 3.54:1 diff from a 300SE/L also to help with the shorter first over the 722.3

mramay · #13 08-16-2007, 10:29 AM

I've even seen a posting of a Lotus Super 7 clone with an LS1 in it (www.ls1tech.com) - can you imagine!!?

My 4L60E is a custom built piece with heavy duty sun shell, 5-gear planetary vs. the stock 4-gear one, kevlar bands, etc. etc. The nice thing about 480hp/450ft.lbs is that I'm not worried about the big 1-2 shift. 6500 rpm in first is about 53 mph and that equates to around 3500 rpm in second. This isn't a drag racer, it's a driver with a minor capability for a track car. I have a 3.07 limited slip differential. My goal is the Silver State Classic (www.sscc.us).

Hit Man X · #14 08-16-2007, 10:03 PM

I make considerably more torque than you do and the 1-2 shift is still crap. I wish the 1st gear was around a 2.70:1 and 2nd still 1.57:1 I've been trying to have the converter lock at the top of first gear @ 6200rpm at WOT, to have somewhat of a 1st-prime gear, then shift to second for less RPM drop.

The sun gear reaction shell should be used in every 700/60E rebuild, I'm surprised it wasn't updated when the 700 went electronic and turned into the 60E. I hope you modified the oil circuit within the valve body and case as they five pinions begin to starve for oil past 6500rpm.

Anyway, I do love the idea of the LS6 in the SEC.

If you're going to be doing that crazy high speed stuff, be weary of any full throttle 3-4 shifts. It puts that transmission at a HUGE mechanical disadvantage and nearly kills it. If you get real silly like me, wait until the 6L90E is able to be swapped. Six forward gears and input torque in stock form is ~650ft/lbs.

Are you going to make some custom headers for it? What top end setup are you running (i.e. heads/cam/intake)? How are you going to integrate the system and still control the other functions?

ke6dcj · #15 08-16-2007, 10:33 PM

Check out this 3rd Gen. RX7 with a Buick Grand National engine.

Reliable 621 HP and 30mpg when just cruising. Too bad it's only an automatic. A Viper diff and custom half-axles complete the picture.

Weight distribution is still 50/50 and the car weighs 2780-lbs.

:-) neil