Fuel injector size

Must85GT · 11-04-2009, 03:49 PM

Is it possible to throw too big of a fuel injector at a 99-04 GT 2V and over fuel it or no?

I have heard that you don't want to over inject bc you"ll have to turn the fuel pressure too far down to get the right tune, and fuel injectors can't really atomize fuel when the pressure drops too low.

Must85GT · 11-04-2009, 03:58 PM

A friend of mine is thinking about throwing some 39 lb. injectors at a stock 01 2V GT. I keep telling him he's nuts and doesn't need injectors that big on a stock engine.

Allegedly his plans are mild cams, mass air, 100 shot, and pullies. The car has a full o/r exhaust with 3.73's in the rear and runs damn good on the street.

johnr2001gt · 11-04-2009, 08:55 PM

he is wasting his time by installing them. even with cams and a nitrous wet kit stock injectors are fine.

SN95FOXGT · 11-04-2009, 09:06 PM

I'm only using 30 pounds on my N/A setup but i got trickflowheads cams vic jr intake and a 90mm TB and a 150 shot

AirBrontosaurus · 11-04-2009, 09:36 PM

Quote:

Originally Posted by Must85GT

Is it possible to throw too big of a fuel injector at a 99-04 GT 2V and over fuel it or no?

I have heard that you don't want to over inject bc you"ll have to turn the fuel pressure too far down to get the right tune, and fuel injectors can't really atomize fuel when the pressure drops too low.

Nope, your fuel pressure doesn't change. Only the injector pulse-width (the length of time the injector is open) is modulated to control fuel flow. It doesn't matter if you have 18lbs or 42lbs, you'll be running at about 40PSI for fuel the whole time.

As long as your tuner program can handle the new injectors, there is no reason not to run larger injectors.

oxstang · 11-05-2009, 03:20 AM

The problem with running to big of injectors is the pulse width will be very short and makes it hard for the computer to control at higher rpms and will make the a/f ratio jump around.

AirBrontosaurus · 11-05-2009, 03:15 PM

Quote:

Originally Posted by oxstang

The problem with running to big of injectors is the pulse width will be very short and makes it hard for the computer to control at higher rpms and will make the a/f ratio jump around.

Good point! If you really overdo it you're starting to give your computer less room for error.

So running 160lbers on a stock engine is probably not the best idea. However, an upgrade from stock to say 30-42lb injectors is fine.

RedGTvert · 11-05-2009, 04:19 PM

Quote:

Originally Posted by AirBrontosaurus

Good point! If you really overdo it you're starting to give your computer less room for error.

So running 160lbers on a stock engine is probably not the best idea. However, an upgrade from stock to say 30-42lb injectors is fine.

And exactly what would you get from a stock engine, absolutely nothing except a waste of time and money.

Once mods the mods are done, then go ahead and do it. Why do two tunes when only one is needed.

AirBrontosaurus · 11-06-2009, 02:51 AM

Quote:

Originally Posted by RedGTvert

And exactly what would you get from a stock engine, absolutely nothing except a waste of time and money.

Once mods the mods are done, then go ahead and do it. Why do two tunes when only one is needed.

Sorry... I know. The OP was asking if he could use a larger injector than necessary and not have problems. I was simply saying he could.

Someone already told him there is no reason to do it. I 100% agree that it would be a waste of time and money, but that isn't what he asked.