RX7withNitrous

It's on the RX7store.net website just wondering if it's really capable of holding alot of power. I dyno'd recently and the guy said i could use bigger fuel pump cause i was going lean at higher rpm's. I still have stock injectors i was thinking the injectors would need to be upgraded instead of the walboro 255lph i have in there now. But what do i know i guess. What do you guys think dyno'd at 252rwhp @ 6,000 rpms at 10 psi running pretty lean.

RX7withNitrous

Oh also the Nippondenso 850cc injectors on rx7store.net it says they are stock replacement for third gen. What would it take to put them into a second gen or is there someone else that makes a stock replacement 850cc besides rc engineering cause i dont' really want to pull mine and let them bore mine out.

DyNaMiTe KiD

You need top-feed injectors.You can put in greddy 720cc injectors which would be perfect, or blitz 1000cc injectors but blitz are expensive and i doubt you can control 1000cc injectors with a safc. border racing sells a adaptor kit to mount the 850cc injectors from a fd to a fc but something i would not recommend doing,eventually if your planning to get more power,u'll most likely go with 1600 secondaries meaning boring out your stock fuel rail or getting a new one from k2rd for 1600cc. your choice,lettin u know whats out there.

Goodluck

RX7withNitrous

I guess i could just go with the 1000cc's and just lean them out some.

DyNaMiTe KiD

Thats the problem, safc may not be able to lean them out that much,and you'll be running rich. do a few searches,theres been a few posts.

RX7withNitrous

Any other sites or company's that make injectors im missing.

$150FC

www.injector.com marren injectors are very inexpensive. you can find the correct size there, for certain.

DyNaMiTe KiD

I wouldn't go higher then 720 with the safc.

RX7withNitrous

why you don't think it is reliable to tune it with the s-afc with more fuel than the 720cc?

DyNaMiTe KiD

because you can only lean safc for about 50%.

RX7withNitrous

so i could use some 850's with the Nippondenso fuel pump or maybe some 1000cc's i just want some that are drop in replacements.

DyNaMiTe KiD

Get 4 720cc injectors and you'll be fine with the mods you have.heres a calculator for fuel fuel calculator just dont ever go over 80% duty cycle, 85 is absolute max for duty cycle you want to goto.you'll be able to control them with the safc, and they are drop in, 720cc are low impedence most of the time, do a search if you have to do anything to change impedence,all it will mean is u may have to put in a resistor inline with the injector,but do a search on that part i have a 1990 rx7,not too familar on the s4 regarding impedence.

goodluck

RX7withNitrous

Actually that's not enough fuel that says like 240hp suggested with 4 720's

RX7withNitrous

I don't know how accurate that thing is cause it's saying that 720cc's and 1300's are only for like 337 that just seems off to me that's a **** load of fuel man.

DyNaMiTe KiD

change the duty cycle to 80%,dont go over 85% it even says in the fuel calculator if you change dutcy cycle to 90%

dr0x

First of all, if you have a walbro 255lph pump you dont need a nippon. Order a microtech already or install your safc.

RX7withNitrous

S-afc is on. It leans out around 5,800 so the guy that was tuning it said it was prolly the fuel pump. But he isn't really an rx-7 guy so i as trying to decide what kind of injectors i should go with cause im going to need some eventually. But should i get a bigger pump? How much hp can the walboro support?

RX7withNitrous

S-afc is on. It leans out around 5,800 so the guy that was tuning it said it was prolly the fuel pump. But he isn't really an rx-7 guy so i as trying to decide what kind of injectors i should go with cause im going to need some eventually. But should i get a bigger pump? How much hp can the walboro support?

RX7withNitrous

Anybody??

dr0x

Whats the setting on the safc around 5800rpm? Is it maxed at +50%? I think 1fastt2 runs a walbro, and he runs 11.9 or so in the 1/4.

RX7withNitrous

He said it's just leaning out at 5,800 and you can see it on my a/f ratio print out. Im hoping for 12's with about 15psi the injectors and maybe the pump if i need it but it sounds like i don't. Would it be better to run 4 720's or 2 850's?

Scott 89t2

fuel pump is fine. the walbro might even be bigger then the nippon.

the guy doens't know what he's talking about. unless you have a fuel pressure guage hooked up you can't tell if the fuel pump is too small.

you need injectors. 1000cc secondarys would be fine.

4x720 would probably be better.

stay off boost till you do

4x720 or stock with 1000 is both good for over 400

Scott 89t2

by running lean at 250RWHP tells me you are probably still on all 4 stock injectors. turning up the S-afc will not help at all.

gsracer

:sigh: Have you listened to anything the board has said since you got that car? It still amazes me it's running, can you post the dyno? That being said I'd hate to see another t2 grenade it's engine.

You have two options: Keep the safc or go with a standalone (microtech lt8 would be my pick since it's a begginers ems and seems a lot more user friendly than a haltech e6k or ell)

Provided you keep the safc, go with 4 720's. Two 850's might be decent amount of fuel, but 4 720's would flow more, and once you try and turn up the boost you will start running lean before the secondary injectors come online.

The walbro is just fine, it can flow enough fuel for a LOT of hp, provided you have big injectors for the fuel to actually flow through.

If you go with the microtech you could easily runn big 1200cc secondaries and stock primaries, or any number of combinations.

Don't skimp out now, from your sig it looks like your car has the potential to make a lot of power. I'd personally go with the standalone. In the end you could probably get away with the safc on the stock ecu, but for how long and at the cost of how much power and fuel economy? Spend a little more now, and it will be cheaper than rebuilding your engine when it runs lean and shatters the seals.

RX7withNitrous

So im prolly going to go ahead and order 4 greddy 720cc injectors That seems to be what you guys are saying is the best. As for the microtech. I'm actually looking into that. But until then i need some injectors and i figure the s-afc will do till i have the cash for the microtech then i can sell the afc.