OK so ive had my 7 for a lil over a month now and absolutely love the car. It still needs a bit of work before its back to what it once was, but im not sure i want factory HP. I had been contemplating doing the SBC swap, thats actually why i was so interested in this car. After reading everyones issues with turbo swaps, and the BS about how hard it is to turbo the 6 port, it seems like going SBC would be the obvious solution. However, i dont want to change the way the car drives, i just want to make it drive faster

So can someone explain to me, in truth and reality, why you should sell your NA and just buy a T2? What the hell is so hard about putting an s4 or s5 engine, ecu, and harness into an 87 na? You can put a SBC in there, but its to hard to put a T2 engine? Somethings not adding up here.

Ive seen the mount kits for the 3rd gen swap into an FC, but thats way hard too, right?

Ive read thru threads, ive searched the internet and other sites. I liked Arons site, and i think they make an FC turbo mani now, but im not sure. Ive also read rotary resurection deal about the hassels of swaping series and all.

Why is it that you just cant swap the intake mani to solve the turbo mani issue? Why can you take a complete running engine out of a 90 and put it into an 87? Its the same body style. Arent the mounts the same? Shouldnt you be able to just run the wirring harness from the donor to all the motor and be good to go? I jjust dont understand all the hassle. I went to the scrap yard to try and figure this mess out, but i cant even find an rx7 of any year...

I would love to rebuild the rotary, or do a turbo swap, but all the talk on swaps an such lead me to believe id be better off going v8. Someone please gimme some insight

 

Depends on where you want to end up.

-Rebuild the NA- leaving it basically stock- and figure you'll get 150k miles out of it (assuming regular maintenance). Gas consumption @15-17mpg/city, 24-27mpg/highway. Maybe 150-160HP...no bottom end.
Learn to drive it for what it is.

-Swap to turbo. No sense putting in a worn engine, so plan on a rebuild.
Assume you'll get 50-60k before next rebuild. Mileage slightly worse depending on how conservatively you drive it. 200-220 HP...still no bottom end.
Definitely more fun to drive but much like a two-stroke, figure you'll be revving it to get to the sweet spot.

-Swap in a V-8.
Your lack of bottom end torque has gone away. So has the free-revving rush to 8k RPM. Gas mileage similar, if not better, depending on gearing. Weight distribution/handling are essentially unchanged. Depending on engine, figure 275-300 HP to start...mods are endless.

Rebuilding either the NA or Turbo Wankel...figure a minimum of $1500 (not including labor if you have it done) and go up depending on mods/additions.

Basic refresh of the V-8...about half ($750, again, no labor) and then the sky's the limit depending on mods.

See if you can find a turbo and a V-8 swap locally and try to cadge a ride/drive.
Make up your own mind.

 

I never would've imagined that a v8 would get better MPG than a 1.3l until i met a guy with a 2nd gen supra. He stuffed a toyota truck v8 in the car and gets 30 MPG if he drives nicely. It blew me away! Couldnt catch a ride tho, he gutted it out for drifting, and i was unable to convince him that i was ok sitting on the floor pan.

 

It isn't hard if you swap in an 87-88 engine, but you still have the n/a drivetrain which is weaker than the turbo. The lifespan of the n/a drivetrain with a turbo motor is debateable and depends how you drive it. If you have a 4 lug nonturbo than you have a bigger uphill climb because you have crappier brakes and probably an open diff.

You can. But there are 6 holes on the side of the n/a engine and 4 holes on the turbo lower manifold. There is a guy on here (Japan2LA) who can modify the turbo manifold to fit. The throttlebodies are different as well. The n/a cars also have restrictive exhaust port sleeves that the turbo cars don't have.

The differences lie in the wiring and engine controls. It's just more wiring trouble than its worth, unless you used an s5 shortblock and swapped in s4 front cover etc. then you would basically have an s4 turbo setup. Or you could just buy an s4 turbo engine and save yourself the hassle of hunting down parts.

The closer the donor engine is to your car, the easier the swap. There are differences between turbo and non turbo fuel injection wiring harnesses ("Emissions" harness) and differences between series 4 and 5. When you go from s4 n/a to s5 turbo the usual result is a basketcase car. It is easiest to retain your nonturbo engine harness when during a turbo swap, because of differences in the alternator wiring.


Your best bet is to find a JDM s4 longblock from a trustworthy person, rebuild it, or swap it in as-is and cross your fingers. There are maybe two wires to modify then. Then you can keep your n/a tranny and drivetrain until it blows.

 

In all honesty, it looks like you're missing the finer points regarding the swaps you mentioned.

For example, wiring between the S4 and S5's are different. The Engine and Chassis harnesses tie in to each other, so it's not a plug and play operation. The ECU does not only plug into the engine, so it matters what chassis you have. The TII isn't just an NA with a turbo added on, as you may know, so things like fuel mixture need to be dealt with. Mixing an S4 engine with an S5 intake setup has been done too, but you need to swap the components from the s5 chassis that control the 6PI and VDI systems. A V8 swap has its needs too.

It's all been done. Each swap has its merits and issues. Personally, when I advise someone to just buy a TII, I'm trying to help them avoid wasting time and money on swapping engines, finding parts, doing some wiring, etc. You'll see some on this forum take this route. Others may like to tinker a bit more and figure **** out. I think series swaps are a waste in terms of time/parts vs. power differences. Staying within series simplifies things, so going TII within your series is not too bad. Sometimes, if you have a base or SE (GX in Canada) you also want to go to 5-bolt hubs and 4-piston brakes (calipers, rotors) and vented rear disks (with its different capliper) in the back. Once you're done with all the crap, you would have been better off buying a TII. Before considering a V8 swap, consider all the costs and as said ^, different characteristics, which for some people really change the RX-7's soul.

I really started rambling here.

 

Rambling is good. i can follow along with that, as i do tend to do it to. i know they make a carb conversion for my car. Would a carbd series swap be easier since you wouldnt have to deal with all the wirring? I realize that there are many "new" things to learn and play with when changing from FI to carb, but for the sake of the conversation, would it be less of a hassle?

What about a series swap with a standalone? Would that solve the wirring issues? Again a new set of issues arrises from that, but in search of more power, an aftermarket ecu would be needed anyways right?

The hardest part of the v8 swap i can think of (having not done one previously) is finding headers that fit without notching the frame, getting the right gearing, and learning how to keeo the tires on the ground. I realize that there are drive train issues with this swap, but they dont sound to be any more expensive/complicated to me than rebuilding a 6 port as a 6port turbo, or swaping in a diff 13b?


The reason im bent on a series swap?

Well first they make more power from the factory

2nd: The issue that im having is finding S4 turbos locally. I undesrtand that i would have to rebuild any engine prior to a transplant, but i cant find an S4 T2 around here. I can find S5 T's all day long, but no S4's. I can walk into any you pull it yard and walk out with a v8 and trans for a few hundred bucks. Cant find an rx7 in anyone ive been in for a while. In order to grab up an engine from a shipper id have to deal with all the fees.... that makes the build even more unreasonable. I have not talked to fromjapan2la yet, so dont kill me if im wrong about pricing, this is just what i encountered when i had a 240 a few years back.

 

Headers are not a problem...there are a variety of options, none of which require any frame modification. Both of the big install kit makers (Hinson and Grannies) offer driveshafts to mate the common trannies (typically a T-56) to the Turbo diff.
A Turbo diff will handle the power (depending on how insane you get) and there are install kits (bolt-in, YAY!) that will swap in a Viper diff, which will handle all the power you can throw at it but is clearly not cheap. That also provides for pretty much any gearing you want as well.

Getting the V-8/tranny in place is actually the easy part.

Assuming your chassis is already in good shape (suspension & brakes, mostly) and your engine/tranny doesn't need anything, figure about $2k minimum! for all the little odds and ends to actually complete it.
Naturally, that figure can escalate quickly once you start adding high zoot intakes, etc.

Oh...you'll be roasting tires fairly regularly, so budget for that as well.

 

Where exactly do you live? There are something like 700-800 S5 T2's (real ones) still registered in the united states. Somebody did a bunch of research at the DMV a while back and posted registration numbers. They are far more rare than FD's. I have only seen 2 in person. One guy locally has one and I think I've seen one at deal's gap.

If you read up a little more you would realize that the S5 turbo mostly made more power mostly because they ran at higher boost with a different turbo hotside/manifold design. They do have higher compression rotors and stronger side housings, but that isn't a big deal for the power level you would be making. Certain parts are pretty hard to find for those engines but internally they aren't much different from the S4's in terms of the basic engineering.

 

I stay in the tampa area, and i was referring to the S5 T2 engines. Not the cars. If i could have stumbled across a T2 i wouldve bought it over what i have now, but i didnt so this is what i have to work with. Im pretty familar with the v8 conversions, the 240z, 280z, rx7, 240sx, s10, rangers, volvos, fiero's, its been the cool thing to do for years.

I will admit that i have much to learn with the rotary scene. I just dont see learning hands on as an option due to the financial costs and the availability of the parts. It would be nice tho!