Tylerx7fb

I saw an amazing ad on Craigslist a couple minutes ago. It's $2000 for the complete power train from intercooler to muffler off a 95 fd. Which blew me away and has me considering getting a loan to buy it (high school paychecks lol) I was wondering if that swap would be practical for someone who has little experience and not much time or another dd. I am definitely willing to experiment and take on a big project, but I don't want to waste money or time.

Jeff20B

iTrader: (13)

You might consider reworking/rethinking the complete FD setup to ditch the clunky (heavy) stock twin turbos and go with a better more efficient aftermarket single turbo like a lot of the FD guys do. Another reason is the stock twins don't fit with a stock 1st gen radiator as the lower hose is totally in the way of the front turbo and the two wastegate spring housings. Been there, done that.

Your front cover should also be changed to a 1st gen version because otherwise you'll need to fab up some new motor mounts to mount under the rear iron. But why reinvent the wheel? Been there, done that.

I think you can substitue an FC CAS in a 1st gen front cover and have it work with the stock FD ECU instead of the front cover mounted FD CAS modules. j9fd3s mentioned something about this recently. But of course I wouldn't want to stick with the stock FD ECU anyway.

You also need a GSL-SE oil pan. No other pan will fit with the stock main crossmember. And any other option requires some re-engineering.

I guess I'm wondering how dedicated you really are.

Tylerx7fb

I plan on 100% swapping in the near future and I figured this is a perfect deal and I just wanted to know if it's been done. I wouldnt start ripping things apart till I have it all planned out and everything put together on the new engine. Also, would an 84 12a tranny fit on the 13btt? I'm guessing not so would the 13b fit on my 84? I would whole heartedly go for this project even if I need to get a cheap beater as a daily. And as for the rad. Could I come up with a clever way of mounting to fix any clearance issues? I'm mostly concerned about clearance, if it will fit on the 12a subframe, if the rear axle would have to be changed out, etc. If you have any links to a build thread that would be awesome, I can't seem to find any. I'm betting I wouldn't be able to afford a single am turbo right now so keeping it stock and getting it to fit with the lowest cost would be best. Thanks

Jeff20B

iTrader: (13)

In one of my "been there done that" references, this post by PercentSevenC has info on how we did his FD install in a 1st gen and the problems we had. You'll see what I'm talking about regarding the radiator vs stock twins. https://www.rx7club.com/nw-rx-7-foru.../#post11192106

By the way he kept the 1st gen tranny. Why swap to an ill-fitting FD trans? Heck even a T2 trans will fit better than an FD trans with only a bit of work and you won't need to worry about the lame pull style clutch the FDs had. There is plenty of info about T2 trans into 1st gen swaps.

Here is a link https://www.rx7club.com/1st-gen-non-.../#post11833198 to the other "been there done that" which has to do with the stock FD motor mounts and what the previous owner did to make them "work" in a 1st gen. It is a flawed concept because it takes a lot of weight off of the trans mount, which it wasn't designed for, and the stock FD motor mounts are liquid filled and very soft as they were designed to work with the FD's power plant frame which is fairly rigid and traverses the end of the trans to the front of the diff, connecting the two and adding stiffness or helping in some way. Without the PPF, you could grab the upper manifold and easily rock the engine left to right. Terrible end result and would have driven really crapily. I'm glad he never got it up and running. Because it allowed me to get the car when he gave up on it.

Tylerx7fb

Thanks A LOT for the info. And sorry if I seem slow, but my brain has been trying to comprehend heaps of new info the past couple hours lmao. I think i understand what you mean about the mounts and changing the front cover. So the first gen trans is pretty much a bolt on to the 13b? Or would it require some modification to fit on? Keeping my tranny would mean a lot less work but not that great of performance I guess, but that could be a later project. I'm not too worried about wiring because I am decent at electrical when I'm in practice but the mechancel is where I struggle and could benefit from some experience xD

Jeff20B

iTrader: (13)

The 1st gen trans is a bolt on. All bellhousings are the same bolt pattern from '74 up.

I am awesome at wiring and mechanical but I prefer carbs over EFI. Because I don't like EFI, I went a different route on my car. It's a GSL-SE that now has a somewhat old school 4 port 13B and a 12A Nikki carb. It sounds like I went backwards but in reality I've pushed the envelope further than anyone else on the forum (as far as I know) with my setup. It's the best most well set up 1st gen I've ever done, and I've been in the rotary game for a while now. Also the most powerful.

Oh I do have an FD shortblock and I could have swapped it into my car with a carb intake manifold, and I still could, or I could do a MegaSquirted setup just like we did in PercentSevenC's car, but he has had endless problems with it and is looking to sell while mine hums along like a rotary should. He's actually moving out of the country and can't take it with him, but if he were staying, he said he'd opt for an identical setup to mine. That's coming from someone who actually does prefer EFI but can't wire to save his life. He's better engineer than I am though. Hence the easier boost prepped carb setup is what he wanted to do next, probably based on all the engineering I had to figure out to get it to work, with his help obviously. We all have our strengths and weaknesses.

Don't get me wrong; I'm not trying to convince you away from the FD swap, but there are other options out there. Check my recent build thread out for some more info to add under your belt. https://www.rx7club.com/build-thread...build-1078987/

Tylerx7fb

I get where the problems can come from when running EFI. But say I get the engine and ecu. Would it be possible to just slap it in with the modifications needed, wire it up, and then have it ready to drive? Keeping it stock with the stock ecu wouldn't require tuning right? I'm looking for a fun daily driver, not really a high power beast, well at least not right now.

Jeff20B

iTrader: (13)

I'm probably not the right person to answer that because I don't know how much more complicated a stock FD install could be compared with a stand alone ECU. You have the electronic MOP to deal with, for one thing.

I've done one stock S4 NA install in a 1st gen and it was a big job, and the end result wasn't really worth all the effort in my opinion for the amount of power you get (because I got more power with my hogged out Nikki while it was NA which was far simpler). I'm still glad I went through the process because now I can say what I just said with confidence. I probably wouldn't do an EFI install again, unless someone paid me well for it. I'd gladly do another boosted Nikki though. That's where the real fun is.

You'll need a practical parts list. I'll get you started:
•GSL-SE oil pan

Now you add something.

Tylerx7fb

Haha I can't really add anything to that list right now from my lack of experience, that'd be something for the mock up stage. The more I think about it, the more difficult it seems. But the ecu should in theory take care of all the electrical stuff that has to do with the engine including the mop? Then there is the fuel system. The gas tank from my 12a gs would have to be replaced with a gsl-se or modified to fit an EFI application I presume. I plan on going the EFI route mostly because I don't have the resources to engineer my own parts right now.

So this is me thinking out loud:
Front cover from a gslse to fit stock motor mounts?
Gslse oil pan
My trans can bolt onto the 13b, maybe need a clutch upgrade
I've heard the first gen diff can only really withstand about 200 hp?
Gas tank modifications or replacement
Possibly a standalone ecu which would require a single turbo? if I can't get things to work

It seems like a big project, but that's what I had planned for this car from the beginning. Power upgrades can come later once I get everything working smoothly and after I'm through school with a lot more mechanical experience. If I can't get this setup in the end, I will go with a t2. But I'm hoping I can get this because it seems different and has more potential for power if it's done right.

Jeff20B

iTrader: (13)

The FD MOP is going to be a problem for you because it won't fit any 1st gen front cover.

You can use a 12A or GSL-SE front cover but neither is really right for an FD engine if you want to hook up the MOP. For example you CAN NOT hook up a 12A MOP to the two oil injectors on the rotor housings. If you do, it will blow out the seals in the 12A MOP. There is a chance you could get away with a 13B MOP, which has banjo bolts and was designed for rotor housing oil injector use. However, the FD was designed to put all of its MOP oil into the rotor housings as its MOP only has two outputs. The GSL-SE MOP has four outputs where two go to the housings and the other two go to the intake manifold.

We solved this problem on the S4 NA install by drilling out the tiny hole in the intake manifold injectors to the same ID as the MOP nipples on a Nikki. This allowed the 12A front cover and MOP we used on his 6 port to work ok and not blow out the seals. It actually worked.

Unfortunately you won't have such luck drilling out the tiny holes in the little brass inserts in your FD housings, and I wouldn't recommend it. Why? Because the engine compresses the incoming AF mixture there. In my opinion, you're partially out of luck. Now maybe you can find a GSL-SE front cover and use its 4 output MOP, and Tee 4 lines into 2 to go directly the rotor housings, but that's some plumbing. I'll leave you to it. Oh and don't bother using aftermarket tubing with a large ID because the MOP lines are designed with capilary action in mind, so the oil doesn't drain back down into the MOP after shut down. Way too many rotorheads here on this forum have redone their MOP lines with whatever large ID (but same OD as stock) they could find only to have dry starts every time until the oil has had a chance to work its way back up the lines and into/out of the injectors into the engine. That is horrible for engine life. But everyone who doesn't understand this, does it.

Yes that's a lot to consider this late at night but it needed to be said.

And then you ask about stock motor mounts. For one thing I don't like stock motor mounts because they are too soft. I use hockey pucks or competition motor mounts, but that is another topic.

As for whether a 13B will fit a 12A car? Not unless you get an RB front mount bar. I wouldn't bother modding a 12A bar to fit the 20mm extra length of a 13B. Others have but I wouldn't, not with a very nice looking new fabbed SS bar from RB for about a hundred bucks.

GSL-SE oil pan, yes. You may also consider some old school load spreaders to cover the large rear motor mount bolt holes in the rear iron. Otherwise oil leaks could happen. I did that on Percent's FD engine with ok results (some bolt heads were a bit moist with oil but not enough to drip).

A clutch upgrade to at least a 225mm disc and street strip pressure plate. By the way, the FD flywheel won't fit so you can use an S5 NA flywheel, which is 225mm and is correct for the FD rotating assembly. I've got a freshly resurfaced one sitting here waiting to go on my FD shortblock. Or you could do an aftermarket flywheel like RB's light steel. I would avoid aluminum flywheels on a turbo engine because they hurt spool due to less load during acceleration, apparently. All I know is I've got an RB light steel and I love it! They are the perfect weight for a 1st gen.

I've heard the 1st gen diff can handle 400HP. Who do you suppose is right? Heck my setup makes close to 200HP now. Well, probably somewhere close to what a stock S4 makes which is like 180HP flywheel, so subtract 15% for the rear wheels, but I'm only 90% tuned at stock wastegate pressure and no intercooler. Well, it creeps to 7psi due to my full 3" exhaust, but the point is I've not started adding power yet. When I do I'll crank it up to 10 or 12psi which I'm sure will get me to 200 rear wheel HP. Thoughts?

Gas tank mods? Hmm, I've got a GSL-SE tank so that part was easy. You could drop your tank and have a hole cut in the top to add a sump cup. Maybe even an in-tank style pump added. I'm personally very glad that my pump is external because I can more easily access it. I just did some fuel system work the other day and was very grateful the pump was easy to get to. Something to consider. Even the stock GSL-SE had an external pump. There are also swirl pots and surge tanks some 1st gen guys add. That's something else to consider.

You can't get the stock twins to work in a 1st gen wiothout some serious mods to the engine bay layout. Percent and I weren't interested so the S5 turbo which was previously in there, went back in. I was disappointed because I got that turbo from him in trade. But we did what we had to do. I eventually got it back when it smoked so bad, due to the super high stock oil pressure of the FD, that he couldn't drive it anymore.

As for a standalone, I'd do that either way. Dealing with the stock ECU of an S4 NA was bad enough. I can't imagine dealing with the horrible US-spec FD ECU. Even j9fd3s says the J-spec one is better and that we got the weird one.

Yeah, the FD can make more power if done right, but I'm not power hungry. I'm sticking with my sub 200HP setup for now because it's just too darn good. Then when I'm ready I'll up the power until it won't go any higher on the current parts. Then I'll consider the FD swap.

Tylerx7fb

Damn this is a hard decision. I'll probably end up swapping an fd engine eventually. So I could buy it now which probably wouldn't be the best idea and have it sit while I gather parts and come up with a plan. Or I could wait to buy one. They are already hard to find and it'd be much more expensive.

It sounds like a ton of time would be need to be invested to have a good outcome, but it seems worth it to me. I haven't driven any other rotaries, but 280 some hp sounds perfect for drifting or autox. Thinking about it, is there any easy swaps for a 12a car?

By the way thanks a ton for all the help.

jayjak

Why not just upgrade the 12a?

craaaazzy

iTrader: (9)

i'm going through this process right now so take a look at my build thread to find more info. i am using the stock twins but needed to go non-sequential due to mounting issues (not going single due to budget). other than that, it does fit well with the GSL-SE oilpan and 12a front cover. even downpipe fits without issue. I am not using the OMP so will have to run pre-mix. in terms of electronics, i'll be using PowerFC as i did not want to deal with the headaches of trying to figure everything the stock ECU required (but have yet to tackle wiring myself).

Tylerx7fb

I don't want to upgrade the 12a because it is rather expensive for not a lot of power gains, plus I have no idea how old this engine is, runs decent but super slow. So I'm not sure if that's how the 12as are or if there's issues.

I'll definitely be sure to check out your build, craaaazzy.

j9fd3s

iTrader: (3)

i have an FD engine in an FC (don't do it! nothing fits), and one of the nice things is that you can "slap" it in and use the stock ecu, or one better, i found a chipped ecu for $50, and it runs like a proverbial...

like the guys say, "slapping" the engine in the car is the hard part. there are a couple ways to do it too.

i have seen a JDM SA swap kit for sale, and it was a GSL-SE oil pan, and an FD front cover that had 2 little blocks welded to it, so you could use the 1st gen engine mount.

the other way is to use the GSL-SE/12A front cover and FC CAS.

the wiring is a big project, although it is conceptually pretty straightforward. you need to make a small harness, as things like the MAP sensor, and ignitor are on the FD body harness, not to mention the relays (air pump, fuel pumps, fans), and the powers and grounds. like i say, wiring a relay is simple, wiring 8-10 of them is a bit of work.

i've been looking at a bunch of JDM REW-FC's and i am finding that they usually aren't swapping the whole engine. most of them, like this one are using the FC engine, with FD stuff on top of it. so its running the FD intake, front cover/CAS, etc.

the other piece of hardware that the JDM people have is the F-Con V, which plugs into the stock harness, and then can run whatever sensor you want, so it isn't the big wiring adventure that we do in the US. they just plug it in, and add/remove whatever they want.