do they squirt more fuel and do they fit?..pro's and cons please!...thanks.

I have a set of 3.1 injecters in
mine,out of an 91 corsica an they work
fine....

even if they are capable of greater flow than the originals, the ECM would simply drop the pulse timing to keep the mix from going rich. I don't think they will matter under most conditions.

where they may help, if they flow better, is at higher RPM.

I thought they were the same size 16 or 18 lb. At cruise, no change. At wot, more fuel which may actually slow the car down. The acceleration enrichment will give you an initial seat-of-the-pants feeling of more power, but when power enrichment takes over, it will likely be the same or slower. GM actually runs the engines a bit rich to cool the cylinders. Leaning them out usually gives more power, but you risk burning the pistons or valves. That's why the 800mV rule rules.

I'm planning to use a 100-125 HP nitrous on my 2.8. (The engine is being built to handle this extra) I have been told the only problem that I may have is at boost the engine my run lean. One thing I have done to help some of this is upgraded the fuel pump to a Holley high volume fuel pump. My question is, if I run the other injectors that you are taking about (from the 3.1)with the nitrous on would the biger injectors help keep if from leaning out at WOT?

Find a (preferably) analog voltmeter with a 1V range. Connect it to the O2 sensor. Do some WOT runs. If the O2 drops below .8V, you need to enrichen the fuel.

For safety's sake, do this to three O2's and use the one that reads the lowest.

terryk- you really made a good point about reading the O2 with a voltmeter. Before I added the fuel injection to my Suburban, I used an O2 sensor and volt meter to check for proper jetting in the carb. It really came in handy because out of the box, my Holly was WAY too rich for max power and economy. Using the sensor is a great tuning tool- I used one on my kart engines to set the jetting. It is a whole lot cheaper than the EGT gauge and did the same thing.

I use the O2 religiously, but keep in mind that it is a "bang-bang" sensor meaning it will be above .456V when rich and below .456V when lean, but how rich or how lean, it doesn't know and the output can vary wildly between sensors for any given AFR. The only thing you can count on is:

1. It will read right at .456V at stoich (14.7:1).

2. In the 800-1000mV range, it's pretty close to 13.8-12.5:1. That's why the 800mV rule rules. Without an EGT, further AFR tuning is impossible.

I will tell you that the 2.8L engine really likes about 12.8:1. Any leaner and the cylinder temps get pretty high.