SpAm@FC

iTrader: (4)

hello guys...

i know, this thread and this question sucks... it comes along every other day... but please, help an austrian redneck ^^

my setup:

24x12x3" FMIC
Turbonetic T60-1 turbo
HKS racing wastegate
Greddy manifold
sard 280lph fuelpump
sard FPR
open intake
3" exhaust turboback
Apexi PowerFC
etc.

my goals... about 350rwhp... i was thinking about tuning the boost at 0.8bar to reach my goals... but i would like to buy some injectors to have some room to play in the future (new engine, extended streetport, turning up the boost...)

is it ok to use 4x1000ccm Sard Injectors or should i go 1000/1600ccm?

how much rwhp will woul 4x1000ccm injectors feed with turned up fuel pressure?

thx for your time and help guys

Patrick

Nick_d_TII

iTrader: (6)

Try this...

http://rx7.com/cgi-local/2ndgencalc.cgi

toplessFC3Sman

iTrader: (1)

also when choosing injector sizes, keep in mind the balance between primaries and secondaries. smaller primaries allow for more precise low-load and low speed tuning, as well as more adjustability at and around idle, but more closely matched injector sizes can reduce stumbling at the staging point, making this smoother.

SpAm@FC

iTrader: (4)

@nick

the rx7.com calculatur is based on stock fuel pressure as far as i know...

@topless

i have a good PowerFC tuner at the hand, some guys on the forum said that it should be no problem with a good tune to run a nice stable IDLE with 1000ccm primaries..
but thx for the input
the sard 1000ccm injectors have a lag time of 0.85msec...

nik

Cheapest solution is to use 550/1600. You can then upgrade the primaries later if you find you need it (you probably won't with that turbo). The beauty of the PFC you can then just punch in the changed primary size and reuse the same map.

RETed

Are these high or low impedence?

Last time I checked, the P-FC doesn't handle low-impedence fuel injectors, and you need inline resistors for them.

There's an interesting article on high versus low impedence fuel injectors in the Single Turbo(?) section.
You lose like 10% - 15% pulsewidth messing with the high impedence stuff.
Adding resistors basically throws away the advantage of the low impedence fuel injectors.


-Ted

SpAm@FC

iTrader: (4)

the sard injectors are low imp... :/

****, i really dont know which injectors i should buy

Spectator

iTrader: (1)

Unless I'm retarded, Ted said that low impedance was better...

SpAm@FC

iTrader: (4)

nik

Simple solution(if you have an s5 car), keep your 550 primaries which are high impedance. Buy 1680 which are low impedance. Use either inline resistors, or low impedance driver box for the 1680.

cptpain

iTrader: (1)

there is an actual formula to tell you which injectors you'll need for your power output. i just cant find it anywhere in my books

SpAm@FC

iTrader: (4)

@nik

its an s4 turbo...
doesnt have the 550/1680 combination a noticeable lag when they come only?
i also dont really want to keep the 20years old stock injectors...
as i have an s4, i have the choise... 4xlowimp + leaving the resistor box or 4x highimp and throw the resistorbox out of the car and make some bridges at the resistorbox connector

toplessFC3Sman

iTrader: (1)

you may have a little bit of trouble finding high-imp injectors at the sizes you're looking, since the greater the injector flows, the more force it needs to open, thus the greater current required. High resistance (or an inline resistor) will drop the voltage differential across the injector coil, reducing the current it can draw, and possibly making it slower to open or more inconsistant. The proper way to do it would be to get low-imp injector drivers for both the primaries and secondaries... but mazda used a resistor pack on low-imp injectors stock, so that setup can work as well.

However, for a given PW, an injector running off of an injector driver (peak and hold mode, just some vocab) will flow more than an injector with an inline resistor at that same PW because the former takes less time and is driven more efficiently than the second.

SpAm@FC

iTrader: (4)

ok, so i will get low impendance injectors and let the stock resistor box untouched is that ok?

so, now its only about size... size matters everytime lol

RETed

Boy, no one reads my replies? :P


-Ted

toplessFC3Sman

iTrader: (1)

that will work, but you wont be getting the full advantage of the low imp injectors, and will be flowing less fuel overall than otherwise. You should be able to leave the stock resistor pack alone, but id check the resistance across the stock and the new injectors anyway, just to make sure that they're close (should be ~3-4 ohms IIRC)

SpAm@FC

iTrader: (4)

any other input which size i should take?

Donn Hecht

I think 1000ccm injectors are overkill in the primaries for at least the setup you’re running as far as the turbo you’re using is concerned. Like Nik said previously I would do the same. You can go with 550's in the primaries or better yet 720's and for the secondary go with 1000ccm or better yet 1600's in the secondary you will be fine. With the Apexi Power FC you can then tune accordingly. Also with your 60-1 you can do high 11's in the quarter mile. A friend of mine was running a 60-1 and ran high 11's at the track consistently. Good luck and let us know how everything went.