+20 injectors

[WOP'R]

I have a '90 2.5L T2 with the original T1 computer. I have installed the apparent +20 injectors and set my fuel pressure to 35psi static pressure.

However, my spark plugs are white. I used the chart from thedodgegarage.com to get this setting but it seems that its still too lean.
The weird thing about it is that it says this : "42 pph injector- It flows exactly 20% more then a stock 33 pph injector ". BUT, 33pph + 20% = 39.6pph. So why does the site say that +20 injectors flow at 42pph?


Any suggestions, thanks.

[BadAssPerformance]

Thats why I call them 42pph injectors...

I'd suggest starting at stock fuel pressure and slowly turn it down monitoring A/F Ratio or EGT until its happy.

[Alberta_Daytona]

when do the 42pph injectors start to max out? what hp rating?

[mrboost]

It's best to go off a scan tool or air fuel gauge hooked up to the O2 sensor signal. Anytime you go to closed loop (which is most of the time) the computer is trying to keep you at 14.5:1 A/F making plug reading not the best method to check mixture unless you're willing to shut it down after a WOT pull, and that's just not a good idea.

42PPH - 20% = 33.6PPH. MP uses the percentage that it takes to get the larger injector back down to stock size.

I have a '90 2.5L T2 with the original T1 computer. I have installed the apparent +20 injectors and set my fuel pressure to 35psi static pressure.

However, my spark plugs are white. I used the chart from thedodgegarage.com to get this setting but it seems that its still too lean.
The weird thing about it is that it says this : "42 pph injector- It flows exactly 20% more then a stock 33 pph injector ". BUT, 33pph + 20% = 39.6pph. So why does the site say that +20 injectors flow at 42pph?


Any suggestions, thanks.

[WOP'R]

hmmm. at a WOT run the a/f gauge lights up the last three lights (rich)!! I know my a/f gaige isnt screwed and my O2 sensor is brand new!

my insurance expired on the car and ill re-new it once everything else is finished. So what do you all think the fuel pressure should be set at to be = to stock injectors??

[GLHSKEN]

42-44psi

[WOP'R]

42-44psi

[Wink]

Yea, the +40% injectors you could get away with that low pressure. I third that you will need about 42-46 psi of fuel pressure with those +20% units.

I ran mine with a Volvo/BMW 3 bar regulator (44.5 psi)

Just a tad rich. rich enough to raise the boost two psi or so.


Wink

[GLHNSLHT2]

Leave it at 55psi, the computer should be able to pull out enough fuel to run fine. If you've got airflow mods, bigger exhaust, ported intake/exhaust, bigger turbo etc it should be even better. But 35psi is way low

[iTurbo]

I have +20s in my Omni GLH Turbo and Shelby Lancer. Both run great with 55 psi base fuel pressure and I get 21-25 MPG delivering pizza in these cars. Believe it or not, I've gotten 40 MPG in the Lancer with little to no boost cruising on the highway driving 400+ miles before stopping to refuel.

The Shelby is fairly stock with 3" exhaust and a few other minor mods. I've had the max boost set at about 19 psi for almost a year now and it's doing great. I use an adjustable zener to defeat cutout with the stock logic module.

The Omni has an '89 2.5 TI engine, 3" exhaust, and big NPR intercooler, but mostly stock other than that. I use an adjustable zener on this car as well with the stock SMEC for a turbo Caravan. Boost is at 17 psi in this car until I go back to 2.2L.