I've got an 87 FC NA. If I'm gonna be na with pretty low hp I'd like the engine bay to look very clean. I'd like to go carb with horns or ideally ITB. I understand chevy v8s and my 2jz but what is possible with each year rotory confuses me a bit so far so..
1. If I just go carb on the stock 87 block what will it take to ditch the entire computer? I'm also pretty into the distributer cap and rotor look, is there a spot for this engine to accept a distributer? Lastly how tough is it to move the dang alternator from top dead center to the side. Just fab a bracket at the right belt length?
2. Do I NEED a stand alone ecu to run hyabusa ITBs or similar? can they be run like a carb setup full manual or would I need webers?
3. Im already down to a miniscule 150 hp how much power would I lose going distributer/carb setup? Honestly I wont notice if it goes down to 125. Im going for a simple old school look. Plus my daily does 300 hp and my 2jz is going way over 600. I'd love a 500 hp rew in the future but this is going low and slow, and sometimes sideways
below are what im going for. Whats easiest?

 

In non US markets this engine was offered with a distributor that goes where the current crank angle sensor is located. The injection system was a bit cheaper/dumber, similar to the 84-85 fuel injected 1st generation Rx-7 13B engine. I'm hardly knowledgeable in this area, it may be better to post in the 1st gen section as there is more cab knowledge there. You can make a thread like "carb on a FC 13B n/a engine" , or search there as I'm sure it's been done on a 1st gen car. I will say that the fuel injected engines had longer manifolds and variable intake port system (like an early VTEC system on a Honda in some ways) to improve the torque curve.

You can get a high output carb'd engine but the overall torque curve will be a lot worse with poor low and mid range. The 89-91 engines had a variable intake port and variable intake runner system for better top end power and a good torque curve.

If you go carb you will have to deal with all the carb crap like getting the thing to start consistently in the winter, weather impacting performance, that kind of thing. Also the spark control is very limited on a traditional distributor with vacuum and centrifugal advance. The idle is controlled by the ECU as well, so you'll generally have to have a high idle to keep it running consistently. As I said you'll find little help here in the 2nd gen section. It's kind of a generational thing.

The EASIEST thing to do is to just fix the systems that are on there. You can delete the air injection pump if you want, just keep the auxiliary port system working and keep the idle control systems (BAC valve, fast idle/thermowax).

 

Well it looks like I'm going carb, probably weber ida 48. 12a distributor and deleting the ECU. Then just rewiring everything to some toggles. Fan needs toggle, maybe push buttle ignition, I dont know what to do with the tail lights etc.

 

ITB would be better. as much as i dislike the OEM ECU, i still think it's better than reverting to carbs. i have nothing against carbs (i identify as a Gen 1 guy all day long and i don't mind messing with carbs all day long), but removing EFI for carbs on any car is insane to me.

the cost will be more going ITBs, but i think it will ultimately make a better car for you. you can also do it in stages - run your stock system aftermarket first, then get the ITBs down the line.

if you do choose to go with carbs, then it's just a matter of wiring up an FB distributor. it will install in your front cover as is, just like your CAS.

 

+1 for ITB. But is it worth doing unless you have some kind of larger porting and increased rev limit to take advantage of the increased air flow? Might even be slower with a stock motor.

 

the ECU has nothing to do with the lights or the starter

 

really? Its on its own switches to the fuse box?
So if I go weber 48 ida carb, I can pull the engine wiring harness? Or just the ecu? connect the fuel pump to its own switch, install the distributer and ready to rock?
. Simple to me is better if it doesn't benefit to be complex.

 

you should do some searching, people have been doing this since 1987...

 

Why run the fans off a toggle switch when you can use a temperature controlled thermoswitch? There are OEM ones you can get that will switch on a fan for you.

 

That's cool to know about the fans. Im not a wiring guy, I'm actually a fabricator and body guy. So I'd like to be able to fix this car on my own, making it simpler is the goal. I will be rebuilding it myself asap.

 

I wasn't going to post in this thread but I've changed my mind. Unless I missed it your car doesn't have issues. It's running fine and making 150hp. If so I think the below advice sums it up.
To me and this is just my opinion. In this day and age removing fuel injection and going to a carb makes no sense to me. If this if for cosmetic reasons you can go ITB's like some of your pictures, keep fuel injection and have a better performing car in the end. If you want simplicity look at this guys setup. https://www.rx7club.com/time-slips-d...-dyno-1094787/ I think he made like 170whp on stock ports, though that Star Mazda manifold may have made some of the difference. Also you mentioned an REW. If that's a serious consideration I think you want to go the standalone/ITB route now. It'll make controlling the REW side easier (If it's staying fuel injected and turbocharged) than having to undo all the carb stuff to reinstall F.I. to run the REW.

 

also keep in mind the "hidden" costs.

the Carb might be $500, but you need to add the costs of jetting the thing, very easy to double the cost by the time its set right. plus you need a fuel pump that is carb pressures (the stock one might do it?), and the intake/air filter etc.
EFI has gone up too, so maybe the carb still pencils out, but as far as costs go its pretty close.

and of course the stock EFI stuff is nearly free, so its by far the least expensive way to go

 

"the cost will be more going ITBs, but i think it will ultimately make a better car for you. you can also do it in stages - run your stock system aftermarket first, then get the ITBs down the line. "

I dont understand this part about "the stock system aftermarket first"

However I do understand that I can just get a ida 48 carb, carb manifold, fb distributer, and a fuel pressure regulator and that is pretty much it.
. Im sure that I dont ever want to spend 1k on a megasquirt then more on a custom tune/map for itbs for 20 more hp. This car won't hit 200 hp. So the difference in hp will never matter. I just want it to look clean and have very few simple parts.

 

I think what he is trying to say is you can get the aftermarket/ standalone ECU first. Set your car up to run on it using the stock intake manifolds. That would be the first stage. Then stage two would be switching to the ITB setup. After that the door is wide open. If you rebuild your engine and do any porting you can tune for it. Of course you can tune the carb too I get that. The big advantage is if sometime down the road you want more and go turbo. The main thing you need to run it was done way back in stage 1.

 

Ah I see. If I were to go turbo I would start with a shell of something (planning a miata next) with an REW and standalone. I've thought about it. This is going the opposite route with a quick cheap carb.

 

Dak - thanks. that's precisely what i was saying. it was supposed to say "stock system with aftermarket EMS first," and the thought behind is was exactly what you expanded upon.

WildBill138 - the point was that (as Dak said) it opens the door to whatever you want to do down the line - ITBs, turbo, whatever - you'll have a foundation that you should be able to build anything on, if you desire. i think the costs tilt a little more with the tunable EFI, and i mainly feel that way because you will usually have to involve a third party for some aspects of it (install, tuning - that sort of thing), but what J9fd3s said about the costs of tuning a carb is very true. you're mistaken if you think they are cheap. little things add up.

that said, it sounds like your decision is made, and that's cool, too. you don't really have to involve the car itself much, if at all, when going carb.

 

I have a RB Holley kit on my na fc, it took me an afternoon to install, was not too bad. Uses the stock ecu, and you just have to mount the tps near the throttle arm so it has the same engagement it did on the stock intake assembly. Just make sure you get a fuel pump that will deliver proper pressure for whatever system you go with. I have a $33 in-tank us motor works fuel pump that worked with the stock assembly that I ordered from Summit Racing. The only thing now is its running a bit rich so I have to nail the timing, and mixture, but so far im pretty happy with it!

 

Cool. Lucky...