FC Chassis RX7

I'm getting my first post-college, decent pay job and I want a super-duper street legal car I can take to the road course every other week. I'm thinking second generation RX7 because they're light and therefore easy on tires/brakes/bearings and because they supposedly handle very well and because they make decent power. The plan calls for exhaust/intake, some Tien coilovers (nothing radical since I want to do hillclimbs), the biggest Falken RT615s I can find for a 16 inch wheel and slotted brake rotors. Eventually I want to flat-bottom the thing and do a v-mount intercooler. Please let me know if anything I suggest above falls into the retarded category.

I have a couple of questions before I decide on an FC, though.

1. I know the FD's are horribly unreliable. How are the FC turbos?

2. Would I be better off with a GTU?

3. Is 200 hp reasonable from a bolt-on, naturally aspirated 13b?

4. How big of a deal is it to get rid of the rear steer?

5. Do I need to worry about getting the bigger brakes if I buy a GXL?

6. What size tires can I tuck under the fenders?

well, the answer is mazda(so they say) but i think they mean the miata, not the spinning triangle powered 944 lookalike(kinda) 1. i see these dead all the time, so i would assume no. 2.nope, you need the m. m for miata. 3. the turbo motor makes that much stock. besides, you need all the torque you can get out of a rotary. 4. buy one with out it. 5. save the money for tires, those will decrease your stopping distance a lot more then new brakes. 6.how large are you willing to roll them? ok, so i might have been a little pessimistic. but an rx7 is a good platform thats well documented. however, your v mount intercooler won't be doing anything if you want a naturally aspirated 13b. besides, if you want light, the lightest 7s made were the sa/fb's. put a 13b in that and you will have a hot car. or just get a miata i guess. but i think that a 1st gen rx7 would be better suited to your goals. EDIT: here you go. http://grassrootsmotorsports.com/forum/2008-classifieds/1991-miata-track-rat-for-sale-2000/3845/page1/

1st Gen RX-7's (79-80 SA and 81-85 FB) are the lightest but also the least powerful stock.

2nd Gen (FC) will do great. Very few actually had the rear steer so just look for ones without it. The GTUs is the hot N/A setup as it's the lightest. Turbo II's are all pretty much the same. GXL isn't a bad choice either. 255 front and 275 rears fit on 17's with a little fender rolling so 245 16's should drop in stock.

3rd Gen (FD) are reliable if you take care of them. Everything costs ten times as much though.

The guys at www.rotarycarclub.com can answer specific model/year/trim questions and track day setup stuff. I just autocross an FB.

My roommate has an FC. I was surprised how easy it is to get the power up. I'm more about DIY mods... but I think he's done pretty good.

He's got dual stainless 3" exhaust, BOV, huge FMIC, and the electronic boost controller should be arriving tomorrow... should put out 350+ real quick and those mods were like $1300..

TheBen wrote: I have a couple of questions before I decide on an FC, though. 1. I know the FD's are horribly unreliable. How are the FC turbos? Not much better than the FDs. All rotaries suffer from heat issues and any overheating leads to quick engine failure. 2. Would I be better off with a GTU? Probably, but good luck finding one. Only a few of the years had the big brakes and high compression motor. 3. Is 200 hp reasonable from a bolt-on, naturally aspirated 13b? No. Top SCCA ITS cars barely get 180rwhp, if they even get that. A standard bolt-on street car might get 165. 5. Do I need to worry about getting the bigger brakes if I buy a GXL? No, but it won't hurt.

Really, for something you plan to drive daily, you'll be better off with a Miata. It won't be much slower and will be WAY more reliable.

Are there any grassroots options for suspensions on FC's? Aftermarket, off-the-shelf set ups are do damn expensive. The issue seems to come down to the strut set up. I'd love an FC as a track car, but the suspension seems hard to do on a budget.

These cars can be SUPER AWESOME.......BUT!!!

If you keep it stock on the turbo version you should be ok. Once you start giving it some wick the thing will be stupid fast and fun, but it will overheat after a single autoX run bout 60 second course. If you want to track it, I would be leary of this.

Every modded rotary turbo I have seen has blown up. Literally. Even with the biggest baddest cooling system its not pretty. Maybe the answer is LS1 in it? Still fairly light and you can do it fairly cheap. Just run the car as you get it till you pop the motor then heave in a V8. Its a thought, but also depends on what you want to.

Tire sizes of around 255 will fit stock at all four corners. Everything everyone else said applies. I just want to get a warning out about the turbo versions in case you did not know.

After having lived and breathed rotaries for the past few years I can say that an FC3S RX-7 sounds like a good fit for you. Myself and a few friends DD ours when then weather is nice and none up us have ever been stranded on the side of the road. Respect the car and it will go through hell and back. Everyone that bitches about them not being reliable or blowning a seal doesn't do the basic maintenance on them. (PERIOD) A properly maintained n/a will go 250k+ miles, and turbos will last atleast 175k miles.

1) Silicone vacuum lines fix most of the problems and keeping up with the preventative maintenance takes care of the rest.

2) The S5 GTU is the base model, the 1988 GTU is the lightweight sport model. Look for an S4 GXL as it has: clutch type limited slip, turbo brakes, turbo suspension, or search the forums and swap the parts in. (Everything is interchangeable from 86-91) I would avoid the S4 n/a non-GXL models as they came with 4-lugs.

3) 200whp from an n/a isn't very realistic on a street car without porting. An S5 can hit 180whp fairly easily with boltons and a good tune.

4) A bunch of companies sell DTSS eliminator bushings for under $50. Labor is a couple hours / side. I have installed/removed them with a puller and a bench vise.

5) All GXL come with the turbo brakes. The S4 Sport and GTU also come with them.

6) Without coilovers (2.5" springs) you will be hard pressed to fit anything larger than a 225 w/o rubbing. With coilovers you can run 245-255 front. The rear will fit 255.

I've had 6 turbo rotaries over 15 years or so. 4 FC Turbo IIs. 2 FDs. I tracked all of them. One was wrecked, another stolen, others sold for one reason or another. I never blew a motor.

Why?

B/c I'm not an idiot and do my research about how to properly mod the car so it doesn't blow up. Add air flow (exhaust, intake) means you need to control boost. Increase boost means you need to add fuel. Follow that simple formula and you'll do OK.

Most kids don't research the car and motor setup and just turn up the boost and blow it very quickly resulting in the car's "reliability issues". People who can't figure that out rationalize an LS1 conversion but those can and do blow too (usually on track) due to the motor's oil system weaknesses. LS1 conversions are pretty cool but the rationale that the rotary is weak or unreliable is unwarranted. Double the HP on an LS1 w/o increasing its strength and see how long it will last you...

The most reliable track car I ever had was my 88 GTU which I had in the mid 90s. Normally aspirated w/ full exhaust and intake and suspension work. Beat on it for 4 years and 100k miles on street and track and the only mechanical failure I had was a master cylinder.

Given the age of these cars at this point, you probably won't be as lucky as that. Any car 15-20 years old is going to need some TLC. Most of the stuff you'd wind up replacing (bushings, cooling system etc) anyway as you progress your skills.

I'd heartily recommend a normally aspirated FC with some suspension work. Great car to learn on. Not as entertaining a chassis as the Miata but it is roomier and has a bit more power out of the box and is a bit safer since you don't need a roll bar. At 5' 9" tall, I'd need a roll bar and race seat in order to track a Miata and pass tech. I hated driving my Miata with a roll bar an inch away from my head on the street. The what-if scenario of busting my head against it in accident on the street led me to sell it.

The FD is unreliable unless the tuning isn't done right. That is why their are so many exploded FDs their owners have no clue how to tune them.

As a point of reference, I've been tracking my current FD for the last 3 years w/o a mechanical failure. Preventative and basic maintenance and replacing 15 year old wear items as necessary. Did about 10 track days this year.

There's a guy in the NoVA area who I see at the track frequently with a nicely set-up FC. He said he will be selling the car soon. I can get his info if you're interested.

And FD's can be reliable if maintained and modified correctly ;) They are a lot more expensive to own though.

And here I was, trying to avoid another one of these "learn me 'bout" threads:

http://grassrootsmotorsports.com/forum/grm/fc-rx-7-buyers-guide/3848/page1/

The buyer's guides VG gave me in this thread are really useful.

I have a line on an '87 GXL with a 10K-mile motor in it. The swap was done by a Mazda dealership. I know not all Madza dealerships have rotary experience, but I feel a little better about them doing it than a shade-tree operation. I'm not sure about having an RX-7 as an only car, but I plan on keeping my Subaru as a DD and the RX-7 as a toy/occasional DD. It has some minor theft damage to the interior (some shiny happy person made off with the shift knob, shift boot, radio, and heater core) and a stuck TPS sensor that makes the motor idle at 1500rpm. About how hard is it to replace a TPS on a rotary?

To replace a TPS. 2 bolts and 5 minutes.

However most of the time they are not stuck they are out of calibration. There are write ups on how to fix it. In fact in my first gen I leave mine disconnected as it was causing part throttle bucking.

My car (if it ran right now) would idle about 1200. It seems high but it is not so noticeable in a rotary. They really do run smoother.

It's not so much that the TPS hard to replace but the freakin' thing can be pricey, like $350.00 for the 'double step' version. Usually they can be adjusted.

Rotaries die mostly due to stupidity. It's amazing how many people do not realize these engines are SUPPOSED to use oil meaning they don't check it. If it uses a quart in 750 miles (about average for anything pre- Renesis with some miles on it) it will suck the crankcase dry in 3750 miles, meaning if they don't check and add regularly then by the time the Jiffy Lube sticker says it's time to go back there's maybe a quart left in the pan. Of course, that red 'check oil level' light is merel;y an irritant.

As mentioned earlier many people cover the engine with ZOMG 1!1!1! bolt on crap and pay no attention to how things must work together. Then they wonder why the motor scatters itself across the landscape.

As far as the earlier 4 lug cars (86-87), they are generally pretty inexpensive and it's easy to convert to 5 lug. In fact, I'll have a complete 5 lug conversion available soon as I part out the 1990 'vert that's my engine donor for the J-H racecar project.

Thanks for the info. If I go with a turbo I plan to leave the boost completely stock and throw in a FD fuel pump anyway. I've read that's all you need up to about 10 psi and I think (hope) just an exhaust won't push me past the 8 psi boost cut.

When I said 200 hp, I meant at the flywheel. So 165 whp will probably be in that neighborhood.

I also heard about the cooling issues. My plan on this front was to eventually go with an Lancer-Evo style hood vent at some point and then build an aluminum box to route incoming air through the radiator and (if I get a turbo) v-mount intercooler and out through the hood. Sorta like this, but with more ducting and less splitter. http://www.sportcompactcarweb.com/projectcars/0707_sccp_time_attack_mazda_miata/specs.html

If I ever do a built motor I'm torn between an LS1 and a mild street port on a turbo rotary running a 2.0L VW DSI turbo. That's a way off in either case though.

Thanks for the info on the rear steer. I thought they all had it.

One more thing occured to me. Is there anything different between the FC's I see with a 7000 rpm redline and the ones I see with an 8000 rpm redline?

One of the things that drew me to the fc was the notion that rotaries handle getting the piss revved out of them better than most piston engines, is this true?

I might be wrong, having never owned one, but one of the things I read said the FC is supposed to idle at 1500 rpm for the first 10 minutes or so.

TheBen wrote: ... and I think (hope) just an exhaust won't push me past the 8 psi boost cut.

If you change it from the downpipe back, it will. The wastegate hole is ridiculously undersized. If you can get an S5 TII (good luck with that), they have a better tubine housing with a slightly larger wastegate hole. Either way, I'd port it to keep it from creeping.

My last one (an 88 TII) had an 89 turbine housing, and I still had to go back and port it to keep the boost where I wanted it.

CrackMonkey wrote: 2. Would I be better off with a GTU? Probably, but good luck finding one. Only a few of the years had the big brakes and high compression motor. 5. Do I need to worry about getting the bigger brakes if I buy a GXL? No, but it won't hurt.

The GTU wasn't special enough to be anything special, it was the "sporty" model in 88, but the base model in 89 and 90. The GTUs is, though it's basically a TurboII without the turbo, and a HIGHLY desirable 4.3 LSD rear-end.

There was no "high compression motor" in that sense. NA wise, you had 2 flavors: S4 (86-88) and the S5 (89-91). The S5's had higher compression (9.7:1, I think).

There are no "big brakes", really. You've got a few options: 86-88 4 lugs: Single piston front brakes, unvented rears 86-88 5 lug: 4 piston fronts, vented rears 89-91 N/A: Single Piston fronts, unvented rears (For 99% of them. The GTUs had all the turbo goodies without the turbo, and there's a rumor that some 91 Coupes [the only option for 91] came with the 4 pistons).

All the 5-lug front's discs are the same, and the calipers interchange freely.

The ideal car would be a Base 86 with a 5-lug swap, GTUs rearend ($$$), an S5 engine, an S5 bumper, and the S5 tailights ($$$)

Lots of rotary love here

All FC RX-7s have passive "rear steering" built into the rear suspension geometry. As was mentioned you can get "rear steer" eliminator bushings (I know Mazdatrix sells them) to eliminate the toe change in the rear suspension geomertry that is the passive "rear steering" effect.

The GTUs were rated at 160 hp vs 145 hp for the other Naturally Aspirated models. Plus, I believe that all GTUs have the groovy double round tailights under the smoked lenses.

I recently purchased a base 4-lug '86 and am learning the hard way that there are a bunch of items that need to be checked and possibly replaced on FC RX-7s...including:

Plastic coolant fill boss on thermostat housing pipe, thermostat, Fuel Pulsation Damper, TPS sensor, Oil Meetering Pump lines, oil cooler banjo bolt washers and lines, bosses on the oil cooler for the banjo bolts, all vacumm lines, oil tower o-rings, brake calipers, etc...

And the normal...all fluids, filters, plugs, wires, and belts.

So far the car is a lot of fun to drive and to work on. I am learning a lot and increasing my wrenching skill. Good luck with your search and purchase.

-Ray

Actually, the 145hp/160hp difference is between the S4 and S5 cars. (Higher CR and a different intake manifold) The GTUs has nothing extra enginewise. Same thing with the taillights.

Pretty much anything from 89-91 is better looking. Taillights, bumpers, spoiler, interior bits, etc.

Osterkraut wrote: There are no "big brakes", really. You've got a few options: 86-88 4 lugs: Single piston front brakes, unvented rears 86-88 5 lug: 4 piston fronts, vented rears 89-91 N/A: Single Piston fronts, unvented rears (For 99% of them. The GTUs had all the turbo goodies without the turbo, and there's a rumor that some 91 Coupes [the only option for 91] came with the 4 pistons).

I did some research on the FC a while back. I believe there is a big brake kit out that swaps in the EVO 8 brakes. I will see if I can find the thread...

Curious to see how this thread develops. I always wanted to know how a V8 FC setup would compare to a turbo Miata for a track car for HPDE's and all around fun car.

Still no comments for my suspension question? I can't find any good (and cheap) options.

dyintorace wrote: Still no comments for my suspension question? I can't find any good (and cheap) options.

I don't really think these are budget, but these are the ones I want to get.

https://www.upscaleautomotive.com/p-18161-megan-racing-track-series-coilovers-for-86-92-mazda-rx-7-fc3s.aspx