kevinapex

iTrader: (22)

So am I correct to say, you should size your injectors based upon your hp goals? Shooting for around 550 rwh, 550cc injectors. Shooting for around 750rwh 750cc injectors?
I know the larger you go it can mess with idle, and city stop and go. Why do some guys go to 1000cc injs.?
Seams to me the 750cc are a good choice, I think I can hit between 600 and 650 hp. (I hope) Would 750s be my best choice?
Thanks for the help,
Kevin

breed

iTrader: (3)

you can always tune them down.

meatbag

iTrader: (9)

Sounds like 750cc would be your best choice if you have the supporting lines and pumps to go with it. People have be able to idle fine with 1000cc injectors too but that would probly be overkill for you at this point.

roncfpz

iTrader: (15)

Sharif used 1000cc low impedance injectors on mine and they seem to be fine. We used them in case we go for more power later and the add'l cost is minimal.

SpoilsofWar

iTrader: (39)

As long as your tuning solution can scale the injectors you can use 1000cc injectors now to support more power later.

kevinapex

iTrader: (22)

I have a Utec, so I could scale them down but, the Utec will not run low impedance injectors.

atlsupdawg#2

That's how I always thought it to be in terms of HP to injector size. 750cc good for 750rwhp, 880cc good for 880rwhp, etc. etc. etc.

Anyway, as far as idle is concerned with larger injectors low impedance (peak hold) are best because of shorter triggering times. You'll have to run an AEM peak hold injector driver or splice in resistors.

kevinapex

iTrader: (22)

Everyone with injectors lagrer than 750cc and run a Utec are using a using a peak hold injector driver, or resistors?

Sharif@Forged

iTrader: (92)

Kevin, 750cc's will be the limit with the UTEC. Drop down resistors defeat the purpose of low impedence injectors, and the UTEC wont be able to control a 1000cc injector very well on the VQ35.

If 550whp is your goal, then 650cc is more than adequate, and 750cc would be the max.

kevinapex

iTrader: (22)

If I think I will ever go over 750cc with Utec, I will need to use a system like the AEM peak and hold injector driver module.
Could I get 750 rwh out of 750cc inj. I'm sure the duty cycle would be maxed out?

Sharif@Forged

iTrader: (92)

750cc injectors at 750whp would definately be running at or near 100% duty cycle, depending on your fuel pressure used.

With 1000cc low impedence injectors, driven by the FCON at 50psi of static fuel pressure, we are at about 70-75% duty cycle at 750whp.

hr2burn

iTrader: (1)

Hmmmmmm, do it right the first time? You know your shooting for more than 600~650 rwhp!
J-man

kevinapex

iTrader: (22)

If I go to 1000cc, I would have to do an AEM peak hold box, or change my Utec to something that can run the low resistance injectors, I don't want to do that, I like my tuner. Unless Sharif comes to Denver to tune a fcon... hint.... hint....wink....wink!!
Kevin

Sharif@Forged

iTrader: (92)

If you are shooting for 700-750whp, the FCON is a must, IMHO. I could use a little ski trip.

DXJP

The rule of thumb on this engine is 100cc per HP minimum. So if your looking for 500 then 500cc to 550cc would be your choice.

DeatschWerks

iTrader: (1)

For a 6 cylinder motor 1hp per 1cc is a good rule of thumb for what type of power one can get out of an injector. Of course, the tune has everything to do with it.

Running larger than needed injectors at lower duty cyles is not a bad thing. But on many of the balance and blue printing we do, there is a definate advantage to knowing how well the injectors are balanced at different duty cycles. There is definately a "sweet spot" most injectors have and we usually find that to be around 70%-80% duty cycle. Of course I am speaking in general terms and to know for sure on a specific set of injectors they would need to be tested.

Cannysage

iTrader: (29)

hey can you really use a 1000cc for, let's say 450 whp? Wouldn't it be wiser to upgrade later?

GTM

iTrader: (12)

On my 91 octane tune I am running ~440whp with HKS 1000cc injectors, Idles like stock and feels great, Of course I am using the HKS FCon VPro for EMS

-George
GT Motorsports