Should I get bigger injectors?
Thread Starter
Teching In
Joined: May 2009
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Should I get bigger injectors? 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?
TECH Addict
Joined: Mar 2009
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From: Texas/Afghanistan
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.
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.
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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.
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.
TECH Addict
Joined: Mar 2009
Posts: 2,099
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From: Texas/Afghanistan
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.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
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 
Happy with the outcome of everything? Sending mine out tomorrow to get rejetted.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
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.