Grassroots Motorsports

Register Log in to GRM
- Community

Birthdays
Recently on the Classic Motorsports forums

Subscribe get a full year for only $23.95 Sample Free Test Drive—no strings attached

Login to post Forums » Grassroots Motorsports » What to do? RX-7 restoration? Buy a Miata? Something else???

1 2

Sept. 22, 2009 10:32 p.m. P71 SuperDork
Oh great minds of the GRMiverse, I need your advice.

The autocross season is effectively over here until March (we have one PCA one left in October). My poor, poor RX-7 has had it. It has 236,000 miles on the original 12A/trans/rear and probably suspension as well (less shocks). It was reasonably competitive but the 250+ autocross runs in the last 18 months has taken it's toll.

Here's what the car needs to race next year:
- Rear diff rebuild (bearings, r&p)
- Suspension (springs, shocks, swaybars, bushings, balljoints)
- Bodywork and paint
- Swap in the new interior I've owned since I bought the car
- Engine bay (re-wiring, coils, radiator, OMP, oil cooler)
- Tires (at least 2 Azenis to replace the 2 bald ones)
Plus some other stuff that's annoying (gauges that work intermitently, etc). Basically, I'm looking at nearly a restoration here, and that's a LOT of work and a LOT of money to poor into a 26-year-old Mazda I traded a 5.0 for.

So here's what I need help with. I have a budget of $3,000 over the course of the winter. Do I:

A: Restore the RX-7 that I already own, enjoy, and race B: Buy a Miata to race with Audra (she raced 4 autocrosses this year and had a blast in the 7, she wants a Miata though, and so do I) C: Buy something else? Maybe another cheap project and just make the RX-7 a nice DD/show car? (Paint job, stock-replacement parts)

I really like my car, but I think it's outclassed most of the time and I feel like my driving has improved to the point where 105BHP isn't adequate anymore.
Sept. 22, 2009 10:45 p.m. Junkyard_Dog Reader

A bird in the hand-stick with the problems you know instead of buying more. If you buy a Miata will it suffer the same fate in a year and then you'd have TWO restorations/projects? The RX7 will have appreciated by the time you're done. The Miata not as much (depending on what you start with).

I can't speak to the classing issues. I still think its all about fun and that buying/building to class rules (that can change overnight) is dumb.
Sept. 22, 2009 11:06 p.m. P71 SuperDork

I wasn't concerned with the actual "class" (since most of my autocrossing is with the Porsche Club in "Non-Porsche") as just generally being slow compared to everybody else. It's tough to look a 1.6 Miata in the face and know it has more power and torque.

I think the suspension rebuild and new rubber will go a long way towards making the car quicker, but I seriously get the feeling that I'm fighting an uphill battle that's constantly increasing in slope.
Sept. 22, 2009 11:57 p.m. ReverendDexter HalfDork

If you get a Miata, what's the plan for the 7?

Personally, I'm for changing out cars, but I get car-bored in about 18 months (on average).

Another thought, why restore the 7 instead of modding it? If you have to redo the diff and engine bay, why not just swap in something else at that point (maybe a 5.0 as a nod to what you traded)?
Sept. 23, 2009 6:33 a.m. aussiesmg SuperDork

You already know what I have to add....
Sept. 23, 2009 6:39 a.m. BoxheadTim Reader

IMHO - get a Miata for autocrossing and rebuild the SA into the nice DD/weekender.

There isn't much of a comparison handling-wise between a 1st gen and an early Miata - the latter will run rings around the former. But I do like RX7s
Sept. 23, 2009 7:29 a.m. dj06482 New Reader

I hate to say the obvious, but - RX7s were made for V8 swaps. I'm sure a 5.0L could be done for under $3K.
Sept. 23, 2009 7:40 a.m. jrw1621 Dork
P71 wrote:

Here's what the car needs to race next year:
- Rear diff rebuild (bearings, r&p)
- Suspension (springs, shocks, swaybars, bushings, balljoints)
- Bodywork and paint
- Swap in the new interior I've owned since I bought the car
- Engine bay (re-wiring, coils, radiator, OMP, oil cooler)
- Tires (at least 2 Azenis to replace the 2 bald ones)
I have a budget of $3,000 over the course of the winter.
For your $3,000 budget I have assumed a $1,500 Miata purchase price and $1,500 for Miata upgrades vs upgrading/updating the RX7.

Rear diff: what does this cost?

Suspension: If you buy a Miata you will want at least half of these items new as well. I see at best a "half price" savings in this department by buying a $1,500 Miata.
More than likely, no savings at all. No Advantage to either car.

Swap Interior: you already have the interior so I guess this is a no cost item. My guess is that this will leave you with a nicer interior than you could wish to get from a $1,500 Miata. Advantage RX7

Engine bay: Also sounds like more time than money.

Tires: expect that a $1,500 Miata needs tires as well. No advantage to either car.

Unless you can truly find a race-ready car for $3,000 it looks like the RX7 may be the economical choice. Now, aside from economics, if you just want something new, then spend away. Cars are really never logical choices anyway. Drive what you like.
Sept. 23, 2009 8:20 a.m. GlennS HalfDork

you have what? 5 months? PLENTY of time to build a car from scratch. LOCOST GO!
Sept. 23, 2009 8:36 a.m. belteshazzar SuperDork

jrw1621 wrote:

For your $3,000 budget I have assumed a $1,500 Miata purchase price and $1,500 for Miata upgrades vs upgrading/updating the RX7.

Rear diff: what does this cost?

Suspension: If you buy a Miata you will want at least half of these items new as well. I see at best a "half price" savings in this department by buying a $1,500 Miata.
More than likely, no savings at all. No Advantage to either car.

Swap Interior: you already have the interior so I guess this is a no cost item. My guess is that this will leave you with a nicer interior than you could wish to get from a $1,500 Miata. Advantage RX7

Engine bay: Also sounds like more time than money.

Tires: expect that a $1,500 Miata needs tires as well. No advantage to either car.

Unless you can truly find a race-ready car for $3,000 it looks like the RX7 may be the economical choice. Now, aside from economics, if you just want something new, then spend away. Cars are really never logical choices anyway. Drive what you like.

what this guy said. all of it.
Sept. 23, 2009 8:46 a.m. P71 SuperDork

I'd love to scratchbuild a car, but I have no welder and Audra's car lives in the garage. Most of my work will have to be done outside or on weekends where the car can roll back out.

The RX-7's rear diff is the really expensive thing here. It's over $500 just in parts (bearings, seals, new ring & pinion) and I don't know how to set one up, so it has to go to a shop. I could try to find a used one, but I think it will have the same eventual problems as mine.

I don't want to V8 swap because the engine is the best part of my car. The 12A always fires first try and is a little screaming demon. I also have a Racing Beat header on it, RB intake/filter, dual alternator pulley, Magnecor wires, fresh NGK's last year, and a full 2.5" exhaust. It never gets hot and it doesn't leak (except the OMP). The trans is in relatively good shape as well. I have a new Mazda clutch in there with some RP gear oil and the only problem it has is the 2nd gear synchro makes noise.

I see at a bare minimum that I have to fix the rear diff (again, I can swap one if I can find it, it's an open), swap on the new door, do the bodywork, paint it, swap in the interior, buy 2 tires, and fix the OMP just to make it drivable/livable next year.
Sept. 23, 2009 8:55 a.m. JFX001 Dork

I dunno...I've gotten used to you extolling the virtues of the RX7...I would feel empty inside if you were to get rid of it.
Sept. 23, 2009 8:59 a.m. Keith PowerDork

The real question is - when all this is done, which would you rather drive?
Sept. 23, 2009 9:18 a.m. belteshazzar SuperDork

maybe a used LSD rear end would cheer you up.
Sept. 23, 2009 9:23 a.m. P71 SuperDork

I'd rather drive an LS7 but that's not going to happen on my budget.

Audra wants a Miata sooner or later anyways, though whether or not she'll share it with me is another story.

I also have an AMC 401 and a 5-Speed in the garage that I've owned for 5 years. I really want to build it soon and I found a Hornet Coupe, bu that would be a drag car.

I guess I just really like my car, but I see the really nice RX-7's going for cheaper than the amount of mods/repairs mine needs. I don't think it would be smart to scrap my shell and start over though (the problems you know thing). Mine is rust free and doesn't leak.

Here's some of the ads clouding my judgment:

http://portland.craigslist.org/yam/cto/1387911407.html

http://portland.craigslist.org/clc/cto/1384326081.html

And especially this one:

http://portland.craigslist.org/clk/cto/1381700957.html
Sept. 23, 2009 10:08 a.m. Greg Voth Reader

The problem that I see is that for $3000 you will have a pretty nice Miata or a ratty miata and some money left to update it. It will still barely have any more power and will likely have some of the same needs as your RX-7. The chassis is a better starting point and your SO will like it however everyone and their mom has one. I like to be a little different.

For $3000 you should be able to do a whole lot to the RX-7. Hell for that money you could throw in a turbo setup.

I have had good luck finding used LSD rear ends for $75 to $300. I bought an entire GSL-SE setup for $350 from a guy a hour and a half away. Of course it needed the consumables replaced but otherwise it seems fine.

Seems to me like you could grab that 79 with the SE setup. Swap the suspension over and sell the 79 with the bad rear end and plus "+" wheels for a couple hundred. Your LE wheels should bring a couple hundred on top of that.
Sept. 23, 2009 10:19 a.m. Junkyard_Dog Reader

Car prices are artificially low up there. For some reason whenever I find an awesome deal on a car I want its in the pacific northwest. Check closed eBay auctions for a more realistic view of what your car would go for restored. I'd bet $3500-$5000 would be a more accurate number.
Sept. 23, 2009 1:48 p.m. P71 SuperDork

Greg,

I don't have the + wheels anymore, sold them off long ago. John actually picked up a complete SE suspension/rear axle (minus a dust shield) for his 82 RX-7 (which is getting a 302/T5 swap). I'm getting his old suspension/rear and I'm hoping that in between the two I can shave some costs on the rear diff rebuild. I don't want an SE suspension as I'd like to run SCCA STR next year, that's why I'm looking into a Miata LSD or a Torsen.
Sept. 23, 2009 2:21 p.m. Capt Slow Reader

Don't knock your rx7 too much, a LSD would probably do wonders for it. I have witnessed amazing things out of a local guy's GSL-SE. I know he has done a bit to upgrade the suspension but I think his motor is relativly stock. He kills most of the miata's in our club...

Then again never underestimate the value of keeping the girl happy...
Sept. 23, 2009 2:24 p.m. P71 SuperDork

Audra has her own money, she'll probably buy a Miata anyways

Anybody know when the "official" STR rules will be posted or where I can find them?
Sept. 23, 2009 4:12 p.m. RexSeven Dork

<http://www.scca.com/newsarticle.aspx?hub=3&news=3629

http://www.scca.com/documents/Fastrack/09/08/09-fastrack-aug.pdf (read pages 21-22.)

SCCA Fasttrack (page 21) said:
Per the STAC, the following revised version of the STR proposal is published for member comment (significant changes are shown in italics):

“Street Touring Class R (STR)
Class requirements and restrictions:
- Only those cars listed below are eligible
Eligible vehicles are:
- Honda S2000
- Mazda Miata (except Mazdaspeed)
- Mazda MX5 Miata (’06-‘09)
- Toyota MR2 (non S/C, non-turbo)
- Toyota MR2 Spyder
- BMW Z3 (non-M)
- BMW Z4 (non-M, non-turbo)
- BMW M Coupe & M Roadster (1998 to 2000)
- Mazda RX7 (non-turbo)
- Porsche 924 & 944 (non-turbo)
- Porsche 911 (1984 to 1989 Carrera 3.2)
- Porsche 968
- Pontiac Solstice (non-turbo)
- Saturn Sky (non-turbo)
- Datsun 240Z & 260Z & 280Z & 280ZX (non-turbo)
- Nissan 350Z
Additional class notes include:
- Tire Allowances (add to 14.3):
AWD – 225mm
2WD – 255mm
- Wheel Allowances (add to 14.4):
AWD – 7.5”
2WD – 9”
- Catalytic Converters (add to 14.10.E):
Same as ST, STS allowance.
- Limited Slip Differentials (add to 14.10.K):
Aftermarkets units allowed per STX/STU rules.”

NOTE, per the STAC: Classing for STR will not be formula based, but will utilize a list of eligible vehicles. Cars not on this list are not eligible. However, as in all subjective classing, cars may be petitioned by the membership for inclusion and will be reviewed on a case by case basis.

Official rules will probably be finalized over the winter.
Sept. 23, 2009 4:33 p.m. RexSeven Dork

As for your RX-7, I'd say keep it. Like everyone else mentioned, unless you can find a cherry Miata for under $3000, you're going to have stuff to fix and upgrade on it anyways. Besides, you have a future (if not current) classic, it's been trustworthy for you, you have experience working on it, and you have all winter to work on it. I have a similarly long list of stuff I have to do to my FC to get it ready for STR, but if I can't get to everything before the first race of next year, I'm not going to sweat it.

Since any stock and aftermarket LSDs are allowed, get one if you can afford it. My FC's factory LSD is old, but it still bites into the pavement pretty well when I step on the gas mid-corner. I refused to remove it when I found out it wasn't eligible for ST class (before STR was announced), which confined me to E Stock. I think with the STR ruleset I could build something that might be locally competative since the FC really wakes up with ST's allowed mods.
Sept. 23, 2009 5:33 p.m. Mazdax605 Reader

Keep the RX-7!!!! I love mine,and can't stand to even think about selling it. It is killing me that I can't drive it right now because the engine is getting a set of fresh oil seals from smoking a bit. Other than that trouble which may not even be an issue if you really hate mosquitoes(who doesn't?) it runs very strong,and puts a smile on my face more than any other car I have owned. Also the RX-7 is pretty rare,or is in MA at least,maybe not so much in WA.
Sept. 23, 2009 5:54 p.m. Capt Slow Reader
P71 wrote:

Audra has her own money, she'll probably buy a Miata anyways

Anybody know when the "official" STR rules will be posted or where I can find them?
1. keep your rx7
2. Encourage to Audra hurry up and buy a miata
3. Profit ???
edit hmmm my list isn't working as expected...
Sept. 23, 2009 7:31 p.m. CLNSC3 New Reader

I would keep the RX-7 and spend your money freshening it up this winter. $3000 will get you a long ways with a 1st gen rx-7! If you do decide to sell your rx7 let me know, I have been looking for a deal on one recently(that is if I don't buy that second one you posted a link to!).

1 2

You'll need to log in to post.