Fuel help you guys

[kenneth kimble]

Thanks in advance! This is going to be long. Please bear with me. I am using a 14# procharger system on my GT. the fuel system consist of factory intank pump, a 190 pump supplied with the kit. Accel fuel pressure regulator set at 45 psig at idle no vac - ford blue 24lb injector and the adjustible FMU supplied with kit. 73c&l air meter. I know the injectors are to small for this application and the fuel system will see very high fuel pressure (+80psig) trying to make up for their size. I played with the analyzer on this site, using 450 to 500hp as a bench mark and came up with 38 to 42lb injector as the size to use. I want to run a fuel system without the FMU and High fuel pressure spikes. I've been told by another mustang guy, not to use the 38lb injectors, because I will suffer driving problems with the 38lbs. Its not a daily driver but the car may have to be so it must have good street abilty. Has anyone used the 38's and ran into problems with street ability. For the rest of my combonation 306 TFW track heat heads X303 cam and tunnel ram intake 3.55 rear.

[91GTturbo]

Originally posted by kenneth kimble
Thanks in advance! This is going to be long. Please bear with me. I am using a 14# procharger system on my GT. the fuel system consist of factory intank pump, a 190 pump supplied with the kit. Accel fuel pressure regulator set at 45 psig at idle no vac - ford blue 24lb injector and the adjustible FMU supplied with kit. 73c&l air meter. I know the injectors are to small for this application and the fuel system will see very high fuel pressure (+80psig) trying to make up for their size. I played with the analyzer on this site, using 450 to 500hp as a bench mark and came up with 38 to 42lb injector as the size to use. I want to run a fuel system without the FMU and High fuel pressure spikes. I've been told by another mustang guy, not to use the 38lb injectors, because I will suffer driving problems with the 38lbs. Its not a daily driver but the car may have to be so it must have good street abilty. Has anyone used the 38's and ran into problems with street ability. For the rest of my combonation 306 TFW track heat heads X303 cam and tunnel ram intake 3.55 rear.

I haven't heard of any specifics about driveability problems with 38's, it usually the 42's people have problems with. Once the car is up to operating temperature, if you cut the car off, the 42's flood the car and make it hard to crank. Usually holding the gas pedal to the floor while trying to crank it will work for getting it recranked, I guess 38's could have the same problem. I run 30's with my setup and no fmu. As long as you have a regulator that will increase fuel pressure as you build boost, you'll be fine (assuming the injectors and fuel pump are big enough to supply enough fuel). My 30's are leaning me out and I'm only running 6-8 lbs of boost right now. I only have an inline bosch fuel pump to go along with the injectors. I've just been to lazy to pull them off and switch fuel pumps. I'm going with 36's and no fmu when I get motivated enough. Plus I would look into changing from a C&L meter to a Pro M meter. They seem to work much better on forced induction cars. Whatever injector size you go with, a custom burnt chip for your application will solve any problems you may have with the injectors.

[kenneth kimble]

THANKS FOR THE REPLY IT SEEMS THE SUPERCHARGER GUYS COULD LEARN ALOT FROM YOU TURBO GUYS. WHAT FUEL PRESSURE REGULATOR ARE YOU USING WITH YOUR COMBINATION

[andy669]

Originally posted by 91GTturbo
I Whatever injector size you go with, a custom burnt chip for your application will solve any problems you may have with the injectors.

Exactly!

Also I would add an inline pump such as a T-Rex.

Andy

[91GTturbo]

Originally posted by kenneth kimble
THANKS FOR THE REPLY IT SEEMS THE SUPERCHARGER GUYS COULD LEARN ALOT FROM YOU TURBO GUYS. WHAT FUEL PRESSURE REGULATOR ARE YOU USING WITH YOUR COMBINATION

I run a Kirban, but Aeromotive also has a very good regulator.

[bigblockcoupe]

i'm running 42# injectors on my '93 cobra and have never had any trouble with them at all i drive it on the street all the time oh well i did have a minor problem when i went full boost on my s-trim they would suck the fuel rails completely dry because of the enourmous fuel flow and blow head gaskets but a custom made fuel log with -8 fittings solved that little problem but as far as streetability they are just as reliable as stock injectors.

[USMC302]

please excuse my ignorance in this for I am new to the supercharged world. We have a 95 that has the vortech supercharger, with the trex 190lph inline fuel pump, the stock vortech FMU, and the ignition that was installed a year ago doesn't work but anyway, we are running the stock 19lb injectors, when we go up to 24lbs squirters should we go bigger and drop the fmu? What does that do for you, I though the FMU was needed for the fuel to keep up?! It is only 5lbs of boost for now. Everything else is in the sig. thanks guys

[USMC302]

oops, I meant 155lph.

[Forcedpower]

kenneth kimble

Is your car the color shift 86?

[kenneth kimble]

I have a 88 turbocoupe and a 87 gt with a blower, to compare the two fuel system component for component. My GT has more components (excluding 4 more injector) A FMU and a extra fuel pump. I know the fuel system on the t-brid is stock but---- but it was designed to handle boost 12lb with out a fmu and it has the right size injector and fuel pump. SO why run a system with small injector,,, spike high fuel pressure under boost from the fmu(because the injector are to small)? And poor drive ability. Forcedpower its a black GT (needs pant real bad )

[Forcedpower]

One thing to remember is the computer for the turbocoupe is programmed for a blower as well. Your mustang will need bigger injectors b/c it will make more power. One thing a lot of people do is run 42# injectors, no fmu and have a chip burned. This will work for you. On my car I ran 42's and a 4:1 fmu with bleeder screw. The bleeder made my fmu close slowly and only let my fuel pressure get to 75psi. The big problem with the fmu is it slams shut so it gives your motor to much fuel in low rpms. Thats why I went with the bleeder you can tune that out of it. I gained 40rwhp at 4300rpm with the bleeder screw.

[91GTturbo]

Originally posted by USMC302
please excuse my ignorance in this for I am new to the supercharged world. We have a 95 that has the vortech supercharger, with the trex 190lph inline fuel pump, the stock vortech FMU, and the ignition that was installed a year ago doesn't work but anyway, we are running the stock 19lb injectors, when we go up to 24lbs squirters should we go bigger and drop the fmu? What does that do for you, I though the FMU was needed for the fuel to keep up?! It is only 5lbs of boost for now. Everything else is in the sig. thanks guys

The fmu spikes your fuel pressure, which essentially makes a smaller flowing injector seem like a larger flowing injector. I would go with 30's as the minimum, plus their the same price as 24's anyway. With only 5 lbs of boost and your current setup, the 30's alone will be enough. Does your fuel regulator increase fuel pressure with boost? The reason I ask is because your fmu is doing it for you now, if you bypass it and don't have a regulator that increases fuel pressure for you, your going to have to get one.

[USMC302]

Awesome, thanks, I'll get the 30's and an adjustable FPR as soon as I can afford it!

[kenneth kimble]

a tech at a local mustang shop told me the lucas 38lb injector are the injectors with the drive ability problem, are thay compatible with the ford ECM?????