Next Mods?

I have a 2000 GT 4.6L 5spd with the following, BBK cold air, BBK 75mm TB, X-pipe & catback, 390 gears. I plan on adding a intercooled Procharger down the road which will come with a chip etc but it doesn't come with injectors or MAF. What would happen if I added the required 42 pound injectors and the MAF before the supercharger. My guess is it would run bad but I don't know.

It'll run fine with the injectors and the MAF. Remember the MAF measures the volume of air going into the motor, and tells the computer how much fuel to add for that much air. Keep in mind that when you're blown 90% of the time you're going to be driving around totally off boost, and it's still going to be powered by the 42 pounders.

I highly disagree. I ran 42#ers on my car temporarily and it ran so rich after a couple starts the plugs were saturated with gas.

Was the MAF properly calibrated? Was it big enough, or just stock? Did you have the 80mm then?

i'd think that advancing the timing a bit would help with running way rich at idle. but morelikely it's a miscalibrated MAF sensor. i know a few guys who run both a MAP and a MAF sensor. they get great fuel efficiency and stuff.

I highly disagree. I ran 42#ers on my car temporarily and it ran so rich after a couple starts the plugs were saturated with gas.


That isn't the injectors fault, that's your MAF's fault. I've ran 72 pound injectors with a resistor pack on a MAF car before and it was drove over 500 miles without problem. Think about it man, if you're driving a blower car with 42 pound injectors part throttle your motor is still in vacuum, the BOV is open and your motor is not seeing any more airflow than it would when naturally aspirated. If your case was true for every application then every single vortech and procharger car out there with 42's and a lightning MAF would be running rich as hell unless they're boosting.

There is a formula for figuring out the biggest possible injectors you can run without having to bump up the idle to compensate. At some point the injectors can't possibly be open for short enough of a time to prevent a rich condition.. but thats way up there. I'm going to be running 48lb/hrs on increased fuel pressure(probably around 50-55psi, I think they're rated at 43.5psi or something) for my turbo'd 351c, and I'm in no danger of running 'too big' injectors at 600rpm idle. I'll dig up the formula and post it.

I found it, but I think it only applies to the tuning abilities of the FI controller I'm using(megasquirt).. If you're interested, you can find it here: http://www.megasquirt.info/manual/minj.htm
Its about a 1/5th of the way down the page.

If I remember correctly #42 injectors are the on of the biggest injector before you start having to use low-impedance injectors. And #42 injectors have be know to cause a lot of problems with starting and idle of a car. Anderson Ford's PMS even has a special setting for #42 injectors cause of this. Also #42 injectors seem big for a 2000 GT ATI Procharged unless your going to run large boost levels.

Was the MAF properly calibrated? Was it big enough, or just stock? Did you have the 80mm then?

C&L 80mm with 42# sample tube

C&L 80mm with 42# sample tube

But was it calibrated?

Also #42 injectors seem big for a 2000 GT ATI Procharged unless your going to run large boost levels.

Exactly what I was going to say. How much boost do you plan to run? Does ATI suggest 42# injectors?

8-10 lbs of boost. I was told 42 lb injectors.

But was it calibrated?

How so???

That's what the guy at a reputable performance shop in Phoenix says. Do you think 42 lbs is too much? What do you recommend?

That's what the guy at a reputable performance shop in Phoenix says. Do you think 42 lbs is too much? What do you recommend?

I have almost a dozen friends with mod motor cars running 42's with centrifugals on the street. If you get a good MAF the car is going to run perfectly fine.