ApexHunter

Well its like the thread title says. I've had my Rx7 for awhile and I want to start making more power.

First off let me list what is done to the car.

Its an 86 chassis with an 88jdm motor with 45k total mileage, 5k on rebuild.
Apexi N1 exhaust, no cats.
S5 Upper intake
Denso MKIV twin turbo fuel pump
R/C Engineering injectors (is there any way to check what size they are without having to remove them? they were installed before I got the car and idk what size they are)


Now what I basically want to do is be able to tune the car for more power. I have a rough idea of what I need but am not entirely sure. I don't plan on making mad power, just more power than I have right now.

For instance what to do about fuel. I think my fuel pump should be sufficient, but assuming that my injectors are larger, do I need an aftermarket Fuel pressure regulator (my gut tells me yes).

And for the actual tuning itself. What would be the most cost-friendly solution to tune the car. I don't want to be cheap, but I am looking for an affordable solution.

Like should I look into SAFC, powerFc with harness adaptor, rtek? And would I need a wideband a/f gauge?

Essentially what would be the most cost effective way to get a tune for my 7 and make some more power.

Thanks.

BenRX

I assume you have a Turbo charged 7?

I would suggest a aftermarket chipped ecu, like a blitz, RE-A redom, knightsports etc. This will support a free flowing exhaust (which you have) airfilter, bigger intercooler and more boost. This is a good start to more power. I admit however that i am not very knowledgable on all this stuff, but this is what is reccomended to me

ApexHunter

Hmm I was thinking chipped ecu, but I think I want to be able to mess with fuel stuff. but I don't know for sure.

And yes its turboed.

gameover2145

iTrader: (1)

If you want the ease and price of a chipped ECU but want to be able to have some control over fuel and timing, look into the Rtek 2.1. It is relatively cheap compared to a full standalone, but does offer the ability to change the fuel and timing maps yourself. However, if you do not have much experience with tuning, I would not recommend you start messing with it on a modified, turbocharged 13B. Sounds like a recipe for a blown motor. If you are experienced with tuning though, it is a great option

You'll also need some sort instrumentation to monitor things such as AFR (wideband) if you're going to do any tuning. There is a lot that goes into a proper tuning setup.

In order to really help, we will need a better idea of your goals and what it is you wish to accomplish.

Regardless, whatever you do, do not cut corners. This is the best way to send your apex seals out your tailpipe (right after they have a good ole' time with your rotors, housings, and turbine wheel).

ApexHunter

My goals are probably around 250whp. Nothing to crazy, but I guess I'd like the ability to possibly make 300whp down the road without having to change too much on the tuning side of things.

gameover2145

iTrader: (1)

According to my calculations, four 720cc injectors at 85% duty cycle should support ~309 whp. So, if that's all your goal is, I would just get four 720cc injectors and an Rtek 1.8 and be done with it.

Bamato

iTrader: (6)

250 WHP is fairly reasonable with what you have already (aside from fuel control). If you verify your injector size (hopefully 720 secondaries at least) an Rtek 2.1 would be a great option. Assuming you have an S4 turbo, I'd also recommend you make sure the wastegate was ported to some degree.

A wide-band O2 system is a *must have* whenever ANY fuel control mods are done to a vehicle in my opinion. Especially with motors that are very sensitive to detonation.

If you want to make the 300whp mark, a BNR turbo upgrade would probably get you there with a few more minor fuel mods.

K-Tune

iTrader: (26)

250whp is attainable with the stock turbocharger and enough fuel.

A nice setup would be: Rtek 1.8, SAFC, wideband, 4x 720cc, MBC at 12psi, FMIC, Intake/Exhaust.

You'll need an upgraded clutch for this power level, and some decent tires.

arghx

iTrader: (3)

For a stock or bolt-on turbo the Rtek 2.1 is a good choice. There is a significant amount of information on tuning fuel and timing in the Rtek section. One advantage of the Rtek is that it doesn't require a ton of driveability tuning compared to a standalone computer. The problem with Rtek 1.8 + SAFC is that you don't have timing control, injector staging control, or cranking fuel control. Cranking fuel control helps prevent flooding.

The fuel pump is good but if it hasn't been rewired it may not produce enough flow

The FPR is IMO optional for your setup. With the stock FPR and a rewired Supra pump you will have high fuel pressure at idle which will make the engine run richer than it needs to.

ApexHunter

So at this point I'm leaning to an Rtek 2.1 with a wideband sensor. Assuming my secondaries are 720cc what else would I need to reach 250?

and Thanks.

gameover2145

iTrader: (1)

-RTEK 2.1
-720cc primary and secondary injectors
-Rewired fuel pump (if you haven't done so already)
-Wideband O2
-3" straight through exhaust
-FMIC (not necessarily needed)
-Some form of boost controller
-Wastegate port
-Stock turbo should be able to make 250whp, I made 240whp on one a few years ago
-A stronger clutch would also be a good idea

ApexHunter

How do I go about rewiring the fuel pump?

SirCygnus

iTrader: (1)

there is a how to in the FAQ.