Garsard

Hey everyone,
I'm new to this site and rotaries in general. I have been gifted the opportunity of a free car, a 1983 RX7 GSL. It ran but not very well so I've taken the motor out and decided to do a rebuild. I've decided I wouldn't be satisfied with the stock 100HP out of the 12A so I've decided to turbocharge the motor. I've done some reading and think I've found a starting place for some of the major parts and decisions. I am looking to make around 200 HP so nothing crazy from what I've read. I would like it to have some resemblance to a reliable car.

I'm going to follow the first 6 points in this thread. Because of my power goals I believe the new rear plate is unnecessary(If you think differently please speak up)
https://www.rx7club.com/1st-gen-arch...-motor-380353/

Turbo Exhaust Manifold from Rotary Work.
https://www.rotary-works.com/header-...W-MF-FA-12A-WT

Blow through carb tuning can be a hassle, I am going to go with a Holley Sniper EFI System.
https://www.holley.com/products/fuel.../parts/550-511

New Intake Manifold for the Holley.
Holley Intake Manifold for 79-85 RX-7 12A - Racing Beat

Some big starting Questions I have are going to be about the Fuel pump situation. How does this car do fuel and do I need to do any upgrades?
In addition I know that turbo sizing for rotaries is very different. Any suggestions at all on what turbo would work well for my use (relatively low boost)

Obviously there is way more to do but im just starting out and need any advice I can get.

Thanks in advance guys!!!

JOE68

that archive threat is ok ....never showed the finished product ..so whatever that exhaust manifold looks ok .....but will the RB intake be in the way of the turbo? holley 390 4150 are perfect in my opinion .. the right amount of cfm's... that self tuning ecu was meant for piston engines rotaries breathe different....but u can guinea pig your engine maybe it will work that throttlebody looks pretty big

JOE68

my advice to u is to search a lil bit more... all the information is here just got to
dig ....... or you'll end up with parts trying to resell.....

chuyler1

iTrader: (1)

There is not a lot of support here for the self tuning EFI throttle bodies. Many claim to start a build, then don't come back to report whether it worked. Consensus is that they should work as long as you open up the plenum so the carburetor sees an even MAP signal from both rotors. If you watch "Engine Masters" on the Motortrend channel (used to be on YouTube but they may have taken it down) they ran into the same problem when using a dual plane intake on a V8. That was a few years ago so before you cut up your Holley intake manifold, I would contact Holley and see if they have resolved the issue. Otherwise, going with a dumb EFI throttle body that has all the components you need (minus the computer) and connecting it to an aftermarket ECU might work out better in the long run.

Your best bet, if you are sticking with the Holley Sniper, is to buy one of the kits that comes with everything including new filters, pump, and hoses. I'm working all this out on my own build and it sounds like I'll have to modify the tank inlet/return because they are only 5/16" and 1/4" and Holley (and everyone else) recommends 3/8".

Don't forget about oil cooling. I didn't see it mentioned in the thread you posted but your 12a has "the beehive" cooler and that isn't going to be sufficient for a turbo. Plan on getting a front mount oil cooler and deleting the beehive.

GSLSEforme

The dual plane intake issue can be resolved(on a piston engine) by using a 1/2" to 3/4" 4 hole spacer between intake manifold and throttle body,also resolves a whistling sound some engines with dual plane intakes get at 50%+ throttle openings. I have had some success prior to using previously recommended spacers by machining a 1/2" gap front to back in separator plate in dual plane manifold and suspect doing the same to a 4v manifold for a rotary would help with this(along with some software manipulation).

chuyler1

iTrader: (1)

Yes, that works...but it results in very short intake runner lengths. Torque is better if you keep the runners separated, but I suppose adding a turbo will make that a non-issue to some extent.

Garsard

If you recommend a separate ECU do you have any suggestions? I'm not set on the Holley it just looked like a relatively easy way to implement throttle body injection with boost.

Garsard

Yeah I forgot to mention that. I am already aware of that problem and probably going to try to get a front mount from a later model year.

chuyler1

iTrader: (1)

Check the Engine Management section of the forum to see what others are using. Then check your local shops to see what systems they are familiar with. You can probably get by with a road tune to start, but it will eventually need some dyno tuning to get things dialed in.

Qingdao

iTrader: (3)

Ignition? You're going to need some type of direct fire.

Why not use a stock S4 or S5 turbo. With some porting (you're going to need to port it to make the turbo work right) you'll have more power you can shake a stick at.

You're going to have to get creative with the tank. When you start drawing lots of fluid with a pump rubber lines can collapse. I burnt through several bushings with my COMP140 pump before I realized this. I think with fuel injection you're just going to have to get an in tank solution, but I don't know too much about fuel injection.

WANKfactor

iTrader: (1)

Was going to pipe in and say s4 or s5 turbo but quingdao beat me to it. They are a very underrated turbo, very responsive, and will be understressed at 200hp.
while you are at it you may as well go fc fuel injection, ignition and ecu. There should be adapters to use the fc intake manifold.
as to fuel pumps easiest bet would be external lift pump, swirl pot and efi pumps.
EDIT, or 13b GSLSE? fuel injection fuel tank? Im in aus so i forgot you have those. I imagine it wouldnt be too hard to upgrade the pump in one of those.

Garsard

I am going to be porting it. With a S4 or S5 turbo does anyone make an adapter for a 13B exhaust manifold onto a 12A? I'm not familiar with the turbos at all what flange are those are they a normal t3 or t4 flange, or something Mazda specific?

After some additional reading with people being hesitant about the Holley EFI I'm thinking the best option might be to go with a Megasquirt with some other "dumb" TBI unit for the fuel injection instead. Its gonna be more work but a lot of people have made that work so I can too.

As far as the ignition goes I was planning to continue using the stock ignition at first. I would fix the timing so it doesn't advance under boost and keep the dizzy for now. However if i go with a megasquirt that does give me the option of shoving a 2nd gen CAS in it and using it for ignition as well.