Rx7 Fc Mods!!!
 

Ok guys im just trying to fogure a few things out. SO heres the "lowdown" I am in the process of aquiring an 1987 RX7 FC TII. The motor has blown apex seals so im most likely going to go and find an S5 motor. The car already has a 3" turbo back exhaust. What i want to do is run an AEM meth kit, stock turbo, MSD 6A/ wires/ plugs etc, a tiAl open dump (and OBV new mani), HKS BOV, and a 3" inlet/ outlet FMIC. Now my questions are; 1. what size wastegate should i run. 2 what size BOV, 3 what kind of plugs should i be running?>( platnum 4's or just plain copper... you guys are the experiances, what works best?), 4 what size injectors?, what kind of computer modification should i be looking at doing? I am sticking with stock CPU for now so just wondering what can be done with that? If anyone has any sugestions please feel free to throw em out there.

you will need a standalone and at least a few thousand dollars for these mods.

More than a few thousand dollars. For any of these mods you're suggesting to be honestly meaningful, you will indeed need to go to an aftermarket ECU.

For reference, for my S5 TurboVert I just put in an Haltech E8 ($1,200) which requires a professional tuner ($550) and a few other things like a Haltech Boost controller, HKS Actuator, etc (another $500 or so) to work properly.

HKS BOV - Maybe $150 if you shop around.

For more information, you will find the search button will prove extreamly valuable.

Would i still need to change the ECU if i kept the stock turbo, meth, exhaust, FMIC and Boost controller???

Thats the first thing I thought

Meth, yes. I don't see why you would go buy a s5 turbo if you're going to do all this other stuff. And either way you will need a piggy back(fcon/SAFC), a chip(rTek), or a standalone to control the fuel upgrades for all the boost.

good luck tho:icon_tup:

Is this your first TII?

Ok thanks!!

All that, but with the stock turbo? Why?

OK so if i kept to the S4 motor, with an exhaust, meth, FMIC, and a Boost controller, i could run an rtech ecu. Are those easy to tune, my friend knows megasquirt fairly well. I just need sugestions on what would be the best and easyest ECU to use and where to aquire such things.

Why would you want to use meth on a near-stock TII with the stock turbo?

a friend of mine did it told me it helped. I will eventually probably put on a arret GT28 turbo but for now it will stay relatively stock

well.. like you said, "it will stay relatively stock" then whats the purpose for meth injection??? you can easily max out what the stock turbo can put out without a standalone/meth so why waste all that money for a stock turbo? i dont understand..

Maybe you guys missed this but he's wanting to put a S5 engine in an S4 frame.

You sure you wanna do that kind of swap emdog16? If so then that means I now have to write up how to swap an s5 engine in a S4 body to eliminate the questions. You're probably wondering why. Reason is, is the S5's are not just plug and play with S4. you have a few options but nothing short of modifiying a few things electrically seeing that you'd probably use the S4 ECU with the S5 engine like I have sucessfully done many times.

Truth is the stock S5 turbo has effective boost up to around 12ish psi I believe and if you really do put a FMIC setup on it the meth injection might gain you a few poneys but nothing amazing. I'm failing to see why your friend told you it really helps when you'd be running that much boost.

Undoubtably the Rtek 2.1s are the cheapest, simplest, and most effective standalone ECU upgrades I believe you can do. I have no problems hitting over 400hp with the fuel maps I create with the Rtek in one of my 7's.
The Stock wastegate on an S5 turbo is about 8.5 psi and any higher with the stock ECU will have you hitting the fuel cut and that does more damage on these engines than safety. With more boost means more fuel so you'd wanna look into larger injectors too along with the upgraded ECU.

If you kept the stock turbo and boost with with an exhaust, meth, FMIC, and a Boost controller then you could use stock ECU - meth cause there's really no need IMO.
Have fun and good luck

AEM meth kit - Don't bother until you upgrade the turbo.
MSD 6A - Don't bother until you upgrade the turbo.
Wires - Stock wires are fine.
TiAl wastegate and new manifold - Don't bother until you upgrade the turbo.
HKS BOV - Good brand.
3" inlet/outlet FMIC - 2.0" or 2.5" pipe would work better.

1. what size wastegate should i run. - The stock turbo has an internal wastegate which you can port if you start getting boost creep.
2 what size BOV? - Any of the aftermarket sizes will work. Install it as close as possible to the throttle body or intercooler. If you get a TiAl BOV, make sure you order the spring for rotary engines.
3 what kind of plugs should i be running? - Just use the stock NGK plugs for now. The fancy plug brands are usually worse than NGK (which are aircraft type high-performance surface gap plugs), and some of the other brands have electrodes that stick out too far and bash the engine rotor apex seals.
4 what size injectors? - Stock 550s for now. Rewire or upgrade your fuel pump first, and a high-flow fuel filter and aftermarket fuel pressure regulator are also a good idea (I like the SX / Aeromotive brand, and the EFI rule of thumb for fuel lines is 1/4" OD or AN -4 for 165bhp, 5/16" OD for 300bhp, 3/8" OD or AN -6 for 500bhp). The stock computer can't run any other fuel injectors, so your future piggyback fuel computer, ECU upgrade, or standalone EMS will determine which sizes of injectors will work well with the given aftermarket controller. If your friend is good with a Megasquirt, he should be able to handle any of the aftermarket fuel computers or budget standalone EMS computers.

Have you seen the BNR turbo upgrades?
http://www.bnrturbos.com/2ndGen.htm

See here for general upgrade information:
http://fc3spro.com/TECH/FM2W/power.htm

OK now remember that the motor in this car has blown apex seals. So i need to get a new one anywayse, hence i wanted the S5 for some more pony's. Would this be a wise choice or is it just asking for technical difficulties with wiring etc.?

just use the s5 block, uim/lim...keep the rest s4 and use the s4 electronics.

doesn't the s5 have higher compression rotors or something?

Ok talked to my friend, the reason he ran meth was because be disconnected his MAF so he wouldnt hit fuel cut. he ran 18 PSI and ran like high 12's

Just because you have blown apex seals doesn't mean you need a new motor...

If you can find an S4 shortblock that was recently rebuilt, I would do that.

If you read the links Evil Aviator posted, you would see how much of a pain running an S5 motor with stock ecu in an S4 body is.

Correct me if I'm wrong, but doesn't fuel cut hit due to a signal from the pressure sensor, not the air flow meter? FCDs go in line with the wiring to the pressure sensor...

When I disconnect my AFM the car will turn but not start.

I would say that your friend must have been running a standalone, but you mention fuel cut. Now I'm all confused.

High 12s on a stock turbo FC is very difficult to do. There is probably less than a handful of guys on here...

Not to mention 18psi is way out of it's efficiency. General consensus is that 12-13psi is the best power you're going to get out of the stock Hitachi. Anything past that isn't making more power.

Something doesn't add up with your friend's setup. Did you personally see this car run 12s? Does he have videos? Pic of the engine bay?




A BNR turbo upgrade, FMIC, 3" Exhaust, 2 720s and 2 1000s (I'm running 4 750s), an Rtek (I run an SAFC), a freshly rebuilt S4 motor, a boost controller, and a good tune will get you into the 12s. Don't worry about all that other crap.

That's impossible.

He may have disconnected his pressure sensor, but that's just plain stupid.

it sounds like your friend has a 240sx if he's recommending a GT28 turbo to you

Good call! I didn't even notice the post below...

As you are probably aware of now, the GT28 is way too small for 13B. Two of them is OK, but they still run out of flow around 6000 RPM. Most turbo upgrades for the 13B are full frame T4s. There are some T3 based turbos used as well.

Don't both with trying to get a new motor, just rebuild the one you have, it's a lot better than just finding a random s5 motor...

Ha, I realize now this is a very old post and probably doesn't matter by now anyway...