sfuller442

Currently have a completely stock fuel system on a 04 gto. Its a heads/cam set up that put 440-450 hp to the wheels according to the previous owner who also says the injectors are at 95%. So the question is should i go bigger and if so how big?

brian_rs/ss

what heads and cam? i'm assuming you didn't see a dyno sheet.

i have 30 lb svo's in my car and they are plenty. i made 400 ish with stock 799's, ls6 intake, and 224r. i went to 30's because my car came with 26 lb stock.

Greekey

iTrader: (3)

Running at 95% duty cycle is pretty much maxing out those injectors. Their not going to offer you any more future expectations. I don't run injectors over 80% duty cycle.

sfuller442

ls6 heads with comp 918's; didn't see a dyno sheet sadly

its a g5x3 cam which is 238/242 and .600/.610

Looking to find some ported ls6's in the near future and get closer to 500rwhp

brian_rs/ss

just take your ls6's off and have them ported and milled(slightly). and since you plan to do this then i would absolutely say to upgrade injectors. maybe even to 36 lb.

BOBS99SS

iTrader: (2)

^agree

sfuller442

so 36's will run safely at 500rwhp and also not be too big for what I have now?

brian_rs/ss

definitely not too big. as for the 500 rwhp thing...yeah you're not gonna reach that. 36 will be fine unless you intend on spraying. in which case 42's would be in order.

hitmanws6

iTrader: (20)

The only car i know that went 500 at the wheels NA through LS6 heads was the WS6 Cartek built. Their cam was a 242/242 .630/.630

NVR_SPDS

iTrader: (39)

Like was said, the 30-42# range would work for you. The 42s would leave you more room to make more power, but they arent necesary.

Also, i would look in to possibly upgrading your fuel pump, just to be on the safe side. Fuel delivery is NOT something you want to skimp on, especially if you dont have a wideband.

On my 01, with the heads/cam. and most the bolt ons that are going in, i just picked up a set of 30s to go along with the Racetronix Hotwire kit, and pump that was installed by the previous owner.

180ls1

iTrader: (4)

ya bigger injectors are a good thing for you to get. what intake you running?

sfuller442

intake is Fast 90 and Nick William 90mm TB

Adam2001WS6

iTrader: (1)

Not to hijack, but whats the problem with running injectors at close to 100%?

brian_rs/ss

you run the risk of running lean. you also have no room to grow. which idk about you but i am constantly looking for more hp. so unless you want to buy injectors 3-4 times, it's best to have room to grow and do it once.

sfuller442

exactly what I'm trying to do, find the right size for future plans... and 95% seems to close for comfort with me

01ssreda4

iTrader: (96)

You aren't supposed to run injectors at over 80%. That being said, I would call up FIC and have them send you out a set of rejetted and flow matched stockers. Im running some that were rejetted to 42 pounds. They are cheaper then new SVOs

allbaugh_04

iTrader: (6)

I believe the sponsor FIC injectors will change your discharge plate to increase flow. Cheaper than new injectors. I chose 48lb.

EDIT: I am a bit late on this but whatever

Greekey

iTrader: (3)

Happy with the outcome of everything? Sending mine out tomorrow to get rejetted.

brian_rs/ss

yeah i found a set of used 30 lb real cheap.

01ssreda4

iTrader: (96)

Funny you ask that, I was a little worried about what my tuner would say on the injector choice. He told me that FIC injectors always scale out very nice when tuning. Obviously, you must alter your tune when swapping injectors so the computer can add the correct amount of fuel. With some injectors, you can scale (size) them correctly in the tune, yet still have to go back and fine tune bc the mixture isnt exactly right. What he was saying is that with the FICs, they turn out very close by simply telling the computer what size injector it is. I have no first hand knowledge on this as I dont tune, but I trust his word. I sent him my computer and he rescaled from SVO 30s (36lb) to the new 42lbs (at our pressure) and everything is great. Havent done an in-person tune yet but I'm sure everything is really close based on his word. The car runs fine also.