Just got a good deal on some 22# injectors and was wondering if any one has used them on a 1991 305 sd system? Will it work and will I need to get the prom burned? I have the normal bolt ons and all the free mods aka 3in flowmaster catback, cold air, ported plenum, slp runners, ported intake, timing at 8* and so on..... Should I stick w/ the 19's or will there be any benefit with the 22's. Also is there any difference between the 305 fuel regulator and the 350 reg? I have the whole fuel rail off the other engine----came from a hardly used gm test motor. I'm in the process of building a holley stealth ram 327 but for now i'm toying with the 305. Don't want to waste money on a prom yet until I put the other motor in. Any advice appreiciatted

 

The 305 will run best with the 19s. The Eprom chip is programmed for 19s.

 

would a 350 chip make a difference? Or maybe if I lowered the fuel pressure. Going from 19 to 22---would the computer still be able to map the fuel and adjust accordingly with the 02????

 

You will run rich and lose performance regardless if you swap computers or not...just stick with the 19lbers. Unless you have a 350whp Lb9

 

Injector spray pattern is affected by pressure, more is better, but may damage injectors over time. Less pressure will definitely hurt the spray pattern (atomization of fuel.)
Lowering the 22#er's fuel pressure will meet the 19#er's flow rate, but not the 19#er's spray pattern requirements.
Injectors should be sized for motor hp and the ECM programmed accordingly.

 

I actually have a set of 24lb-LT1's on my '91 LB9.

It runs rich but never lost a bit of performance, just fuel mileage.

The reason why I went that way was I thought I was maxxing out my 19lb's with the nitrous and had these injectors sitting around anyway.

I have not changed the prom yet, but it will be interesting to see if that does anything!

 

I'm running the SLP 25lb injectors in my 305 and the engine runs fine. I changed the flow rate in the eprom to match.

 

WIll I Be Runnin Rich If I Install 24LB In Injectors On My 88' 350? I Also Use A Cold Start Injector

 

Ran my best time with the 22# injectors with the same mods.Got 2 chips that are the same except one is for the 19# injectors while the other is for the 22's.

 

what do you change in the chip to fix the 22# injector problem on a 305?

 

In Tunerpro there's a category that reads "Injector Flow Rate(lbs/hr)" and slide the scale to 22 lbs or whatever size your injector is. You'll find more info if you search in the DIY PROM section.

 

thats it?? You dont have to mess with fuel tables and other crap?

 

maybe if you run around stock pressure with upgraded intake/runners and 1.6 rockers. it might run ok...and a 350 chip might work... but its best to use a custom tuned chip for the combo.

 

You can mess with the tables for fine tuning but I'm running it with the stock fuel curve and it runs a little rich which is what I want with the nitrous.

 

i have a 91 gta with the lb9.

stock
ran 15.9

march underdrive pulley set
slp cold air intake
15.4

march underdrive pulley set
slp cold air intake
22lb injectors
bbk fuel pressure regulator
15.03 and better gas milage

 

With a custom chip will it still run rich without any of those mods??
I have blank chips and the equiptment to make a chip.

 

ok I really have not talked at all about what I have done to my motor. I have 22 lb injectors. You have to make your car breath better. this means head work, gasket matching and porting. you have to open your plenuem. and most importantly you have to have the spark to burn all that gas. do not skinp on the ignition components.

Have a custom chip burnt by someone who knows what they are doing. or learn to burn your own but it is a good idea to have the first one done by someone who knows.

I am running a 305 or so with 2.77 gears and at 20 mph if I hit the gas the car acts like it is on a patch of ice. spinning your tires of the line is for bust outs. that is the worst thing you can do for your drivetrain.

 

I'm going to try the 22# injectors--worst come to worst I'll put the old 19's back on. I'm In the middle of porting another plenum to help out my slp runners. Hopefully everything will work out--some say yah some say nah but I'll post up my results. My LB9 ran a 15.8 in 95* weather going back out next week to see how the cold weather helps, Also put some march pulley on---big difference in throttle response and it's not such a dog off the line anymore.

 

how do you think the new mustang is keeping up with vette with a 4.6. fuel and spark. dont forget the spark and the custom chip to change the curves.

 

mcwpns
did you ever put the 22 injectos on and how did it run with the stock chip? thinking about doing the same, let us know

 

Yes I did try the 22's on the stock chip. In the warm weather it ran great but a little rich. Gained a bunch of higher rpm power. But when it got cooler in the 30's it ran way rich and puffed fuel out the exaust. I went ahead and put the 19's back on for now. I want to try a 350 chip with the 22's and see if it helps. Don't want to spend too much on programing for the 305 since I'm building a 327 stealth ram setup for it. If you were running nos i'd say the 22's would be great. It figures---- I get a rich code with the 22's and a lean code with the 19's. I could probably adjust the fuel pressure to help things out just ran out of time.

 

thanks man for geting back, i think im going to install 22 on the stock 305 ( i live in maine) so its a summer car, im planing to turbo so a little rich is good, thanks again