I have an '87 FC (stock N/A with 2.5" dual exhaust) and I am wondering what the best upgrades for your money are. I was thinking about a new ECU (mainly because someone went tweaker on my current one) and maybe a new intake. What would those two alone do for me and can I get some recommendations? Ideally I'd like around 250hp, and as some people have suggested, a 100hp shot of NO2 is not what I had in mind.

Thank you,
~Doc

 

You won't make 250 hp on an n/a without some serious porting (or nitrous).

First thing to do is a complete tune-up on the car (new filters, plugs/wires, change fluids, etc).

Another important thing for n/a FCs is to make sure your auxiliary ports are working correctly (do a search for the proper procedure for this). They operate off of exhaust pressure, so the exhaust you have may not be allowing them to work. No matter what anyone says, removing the aux port sleeves won't gain any power and will just mess up your low end if they're not working.

The stock intake isn't even a restriction until power levels higher than a stock port n/a will ever make, so I'd get a K&N drop-in filter and call it done.

For an n/a, I'd forget about making a ton of power, focus on getting the suspension and chassis dialed in so the car is fun to drive on twisty roads. It'll never be a pants shittingly fast straight line car.

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/frequently-asked-questions-2nd-generation-rx-7-faq-fc-494667/

 

^ wow thanks man. first thing i start reading is post #3... lol i now know why my power antenna doesnt go up lol

sorry not related to thread

 

The car has had some work done to the suspension already by the previous owner. It handles just fine and I do live in a mountain town with twisty roads. In fact I just lost my Cali good driver status for going 91 in a 55 but it was written as 65 (Bad day). My motor is high mileage so if I can't go where I want on an N/A, how much is a TII swap?
Oh and can I even do that anymore thanks to Schwarzenegger's **** smog laws that say you can't install any motor that wasn't a factory optioned. Was the SE ever a Turbo for my year?

 

You are better off just buying a TII.

 

this...


considering where you live...

 

Best bang for your buck is illegal in Cali, cat delete and replace with 2.5" straightpipe or RB resonator. Failing that, a performance (high flow) 3" cat replacement would likely be similar. You will not see north of 200 whp on a S4 NA without some serious work, including some serious porting. There is a thread on here with a 232hp na, but that's by a rotary pro with a lot of work and experience into it. If you truly seek over 200hp, go TII, exhaust and a few simple mods and you're done and you can stay Cali emissions legal. Or, sacrilege to many, drop in a Chevy LSx and make double the power and double the fuel economy. Won't cost more than a decent TII setup or trying to make 250hp from a NA.

Beyond that, go thru the FAQs and maintenance.

 

the best bang for buck is a programmable ecu, header and catback combo.

after that... you can focus on steering and suspension. this is a good upgrade rout for people with no turbos. dont expect to see above 190 wheel hp without cracking open the keg and doing port work or tuning the exhaust. but a new ecu/header/ catback with stock cat in place will net you 20 to 50 more hp depending on tune and condition of the engine.

 

could also check out the N/a performance section of the forum... lots of good info there

 

Suspension
Because speed kills.

Have fun with the car. Spice up its looks if yours is old and ratty. Make it a fun date car.

 

The suspension's great, it needs a body work and paint but the reason I bought it was because there was a good amount of work done already. Besides the right rear fender and a dimple in the front, the body is straight. The whole front suspension's brand new, AC converted to R134a, exhaust, etc. I only paid $1100 after telling him $3000 was a total wet dream. My RX is actually the best car I've owned and I'd like it to look clean.

What I really need is to do electrical work on it, someone spliced a new Molex connector on the wiring harness for the ECU and left the old connector just hanging there.

Thanks for the input. The last question I have is what a TII 13b motor and aftermarket ECU would cost. My motor 248K miles on it and I assume I am going to need to replace it in the next few years so I would like to do it with a turbo. I've thought of just buying another RX and I'm looking at like 3-4K for a clean one where I live.

 

usually $1500~$1750 for the complete swap... that before possibly having it rebuilt and installed (unless you do all the work yourself).

you can PM Japan2LA for more info.

 

I would get a set of decent tires. (like some Kumho XSs or something similar)

It's probably the best mod you can do. or maybe put some sway bars on it.

or better yet... save your money and enroll in an autocross. becoming a better driver will make your car way faster than any mod.

 

Always start with exhaust on a rotary but don't expect to make any serious power with an s4 N/A. Next time you replace the clutch, go with a lightweight flywheel even though you won't see any horsepower gain from it.

Whatever you do, keep your stock cold air intake. Do not put a "short ram" or any other aftermarket cone intake unless you properly duct it.

 

FIXED

But don't get a lightweight flywheel. Not worth it.

 

I disagree, even my lightweight steel flywheel was a world of difference although in retrospect I should have gone straight to an aluminum.

I do agree with your ducting and sealing of an aftermarket intake.

 

Yeah a friend of mine said that he didn't like the lightweight flywheels basically because the decrease in mass means less energy transfer when shifting gears. Does anyone know if there will be an issue with the recent Cali smog laws. Basically the law says that you can't put a motor in your car that was "Not a factory option" so no small block Z's anymore. Was the SE ever manufactured with a turbo? I know Mazda made the N/A specifically for exporting, it made a huge difference with insurance. I heard there were no N/A's sold in Japan.

 

the engine has less inertia so you can shift gears faster... that's a good thing. I like my 9 lbs flywheel... but I wouldn't change it unless I was replacing the clutch.

the '87 RX-7 had a factory turbo option, so you should be fine if you want to go that route.

 

In CA it is completely legal to swap any engine into a car as long as the model year of the engine is newer than the chassis of the car. To be 100% legal, after the swap is performed it must be signed off by a state smog referee.

The SE model of the FC never came turbo, only the "turbo" model did.

Less energy transfer between shifting gears? A lighter flywheel will decrease the inertia of the drivetrain, yes, but I do believe most people consider that a good thing unless you commute into San Francisco.

 

Actually I do go to SF lol. But when I heard that I was not so sure about it because you can also argue that a lighter rotating mass requires less energy to move.

Basically as long as I use a '88 or newer motor I'm good, although I have an open diff and I'm wondering if I should look into a LSD swap. What do you think?

 

You aren't going to make much TQ. You want momentum. Well i do

 

Well from everything said here I'll probably just fix the cosmetics. For what I'd have to spend to get the power I want I may as well just shoot for the moon, save my pennies and do a 20b TT swap sometime in the future.
http://www.jdmtigerjapanese.com/details.php?id=3281

Thanks s lot for all the responses

 

Best advice I have read so far. The stock intake is a cold air intake. You will lose power if you add a cone filter; this also applies to the so-called electric fan set up vs. the stock fan.

 

That is going to be a lot more then what I think it is your thinking about, it is not a drop and play “swap”. Anything over 400hp you have to be over protective in the since a small vacuum leak is not longer a small leak and that little leak can cost you your whole build.

1) You need to run a standalone
2) You then have to tune your standalone
3) The custom work that will have to be done will not be easy
4) Electrical harness extensions
5) Full fuel system make over

Most 20B swaps run around $10k from what I have read. I would ask around before even taking into account of doing that stated swap

If you are thinking of going Cosmo I would recommend the REW two rotor Cosmo, but even so that will be just as much work, however; finding parts and people who are also going through the same swap will be more abundant.

That is my 2 cents I’m sure someone will enlighten you more. I just want to point that out because once you know fully what your dealing with, the easer the decision is to make.