I'd pull the dash immediately, you seem to have really major rust issues here.
You mentioned months ago that you put your hand through the firewall and then more recently, that the fusebox had gotten wet...neither of which are normal.
If the same level of rot that you can see has permeated the firewall, you have a parts car, not a runner.
In fact, looking at your pics, I'd strip the whole interior to see what's going on.
I'd bet there's some significant damage hidden under the carpet, especially in the footwell area.

Getting the car to run well is not your primary concern right now, seeing if it's all one piece should be.

There's definitely a large hole in the wiper tray. The vertical portion of the firewall looks solid from the engine room side, though. When I give it to the shop to repair it will come in with the whole interior pulled save for the driver's seat. The dash will come out first thing. I want these holes taken care of. I'll probably have them run spot welds around the the door and hatch openings and if the rust has reached the windshield area pull it and rebuild that area.

Japanese metal slappers must work cheap.
In the States such extensive metal repair would far exceed the value of a FC, only a dedicated DIYer would bring it back.

No, not cheap. I could see it going up to 3-4K.

For just metalwork, not including paint?

Eeesh, hope they don't charge an arm and a leg to get that rust out. I patched a big hole behind my dash with fiberglass. That was fun.

that's for metalwork and paint.

Finally finished installing the intercooler kit. What a fucking PITA! I'm glad I grabbed two kits. The NITB kit I got from an old runnin buddy expected me to pull the turbo and clock the compressor housing down. Yeah, F that. The used kit was also a Greddy kit, but this one went over the top. I've never installed a kit that was so tight fitting.

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The last owner welded on a blow off valve. It was a newer Blitz which I don't like. I switched it with the early model super sound off my truck which is a hell of a lot louder. I had to reroute the idle control hose. It used to feed off the pipe between the turbo and stock intercooler, but that's gone now.

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Luckily it seems any metered air is fine because hooking it to the old stock blow off valve port in the hose between the air flow and turbo seems to work well. I had to bump the idle up to 1K for now.

The battery was dead so I dropped some coin on a big 100AH Panasonic with a charge indicator. You can see how much space there isn't. I had to slide some fuel line over the hold down bolt to keep it from vibrating against the intercooler pipe.

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The core and charge pipes bang into the bumper so I had to chop some off. A little tape to keep it from chipping up.

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EXCUSE TO BUY NEW TOOL!

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It took some recutting, but I got the clearance I needed.

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I took it out to test the system and get a quick pass through an automatic car wash. It was really dusty and covered with bat shit and cat paw prints, poor car. I'm going to have to keep the idle set a bit higher, it's settling down to about 950 RPM right now. The blow off valve is so loud, it's crazy. People a block away jump when it pops. Me being a selfish show off asshole, I dig that.

There is lag now, not bad, though and if I hadn't driven it with the stock intercooler I wouldn't have even noticed. Filling up fifteen feet of pipe and that big core takes time and it also has given me a lot of pressure drop. The turbo used to push 0.9 in the blink of an eye and occasionally spike up to 1.0, but now after the slow build up it barely pushes 0.8. I guess I'll have to dig out one of my old boost controllers and crank er up a tad.

This is really not a great thing for a togue car. I'll have to learn the way it behaves now to make sure the power is being delivered when and how I want it. I think it's a good tradeoff, though. After taking a couple of full throttle long runs and checking the core temps I am very impressed! The hot side feels like a hot cup of coffee, but the cold side feels like a can of soda fresh out of the refrigerator. It's too big, but I will never need to worry about charge temperatures.

I quite enjoy this build. It makes me want the white fc I've been eyes up for months and to move to Japan to work on subarus lol.

Very nice. I do agree with Clokker though, get that rust estimated to see what if its worth it. Otherwise, find yourself a blown up non rusted TII (I would assume they are pretty cheap over there in the motherland) and swap all the goodies over and sell the old stripped shell. FIN.

great thread

wow i thought this is a big win to get those wheels with the car, those rims are really expensive, at least out of japan, but then i saw the rust... that is going to cost a lot :( i suggest buying a welder, diy is not so hard as you think :) but takes a lot of time.

Wow, of all the rust I've seen on an RX-7, I've never seen a subframe rust out like that. That metal is like 1/8" thick, not exactly 20 gauge sheet metal. Probably easiest to just get another subframe and swap vs. repairing the existing. Not hard.