what size injectors is everyone running?

i have my blower setup for 8psi and have 42lb injectors in the car and Ion has tuned for the injectors twice and they are still fouling my plugs... i have a stock cam by the way,stock FPR. now should i ditch the 42lbers and get 38lb injectors instead? i would guess i would have high 400ish hp at the flywheel.

what should i try??

Buy LT1 Edit and test and tune your own programs. 42 lb injectors should not be difficult to program so they don't foul plugs. Make sure your plug wires and gap settings are all good.

I'm running 42 lb'ers at 12 psi right now, but they ran fine with 6 psi also. The PCM will take care of partial throttle cruising fueling, but you'd just have to adjust the power enrichment tables downward some to lean it out a little.

you have a more powerful motor then i do though even when you had 6psi.. i have downloaded tunercat and winflash onto my computer. i don't have a laptop nor would i have a clue how to adjust the tables??

you have a more powerful motor then i do though even when you had 6psi.. i have downloaded tunercat and winflash onto my computer. i don't have a laptop nor would i have a clue how to adjust the tables??

Everyone's gotta start somewhere. ;)

I didn't have a clue either when I first started, but I've learned through experience and reading the LT1 Edit mailing list.

Trust me, you're much better off knowing how to tune your own PCM because it will make you much more aware of what is going on with your engine and why certain things happen and what you can do to correct them. Also, if gives you the ability to reprogram your PCM to accommodate new mods or upgrades without having to rely on someone else to do it for you.

haha - yeah i suck at computers. there is a place a hr away that will dyno run and tune my car on the dyno for $300.00. which is a steal. i have to rent a trailer which is $50.00 a day. i don't feel llike shelling out the cash on a laptop and the cable itself is like $100.00 for obd1. i want the car running asap also. with me messing with it will take more time then i want to wait. only drove the car one time this summer :cry:

heres an idea for ya, install stock injectors, stay out of the throttle and drive to the dyno, swap injectors in the parking lot when you get there.

LT1 edit is the shizz.

I got 65s for mine sence I would be pushing my limit with 48s I had to go out and get a DFI system so I can run them.

i have my blower setup for 8psi and have 42lb injectors in the car and Ion has tuned for the injectors twice and they are still fouling my plugs... i have a stock cam by the way,stock FPR. now should i ditch the 42lbers and get 38lb injectors instead? i would guess i would have high 400ish hp at the flywheel.

what should i try??

I would call Bryan @ www.pcmforless.com he will get you fixed up!!

I've got 72's with no problems. I believe you have something wrong (tuning or mechaical)... you shouldn't be fouling plugs with 42's if its programmed for them.

I use 30lb SVO injectors with an FMU set to 2.5 turns. Plenty of fuel and nice throttle response. 55 psi on the fuel pressure at full boost.

I use 30lb SVO injectors with an FMU set to 2.5 turns. Plenty of fuel and nice throttle response. 55 psi on the fuel pressure at full boost.

is 30lb enough for your setup? Your injectors' duty cycle should be over %100
What is your car's hp at flywheel??

Back in the day when I had my stock motor and my old trusty P600B running 8#'s I was using 42# injectors and making 405 RWHP no problem.

You're not still using the FMU are you?

What plugs are you running and what gap?

my plan is to get my car to the dyno tomorrow or saturday...

is 30lb enough for your setup? Your injectors' duty cycle should be over %100
What is your car's hp at flywheel??


The fuel pressure is raised by the fmu and it helps compensate for the 1 bar stock MAP. My O2 readings at 6200 rpm and wot are .93. I can go to 100 psi if I need to.

I know everyone is gonna disagree but i think 42 pd injectors run poorly at idle and low rpm because of the impedance.

The fuel pressure is raised by the fmu and it helps compensate for the 1 bar stock MAP. My O2 readings at 6200 rpm and wot are .93. I can go to 100 psi if I need to.

I know everyone is gonna disagree but i think 42 pd injectors run poorly at idle and low rpm because of the impedance.

100psi fuel pressure?? No way ! You can't raise the pressure that much to reach fuel requirement. You should buy bigger injetors if you need much more fuel and more than 60psi pressure hurts injectors.. Yeah its going harder to tune bigger injectors,but trust me 100psi pressure is oveeeeeer the line..

"O2's at 6200 rpm are .93" Stock O2 sensors are very inaccurate at anything other that 14.7 AFR, I suggest you check your setup on a dyno with a wideband O2 sensor.

I'm running 10# of intercooled boost and stepped up to 75# injectors and an Acceleronics converter box. Wideband O2 on the dyno showed a nice flat graph accross the rpm range with a 12.0 AFR. Previously I tried the 36# injector route with the fuel pressure up at 60 psi, my tuner was able to provide enough fuel at WOT but part throttle driving was compromised and fuel mileage suffered.

100psi fuel pressure?? No way ! You can't raise the pressure that much to reach fuel requirement. You should buy bigger injetors if you need much more fuel and more than 60psi pressure hurts injectors.. Yeah its going harder to tune bigger injectors,but trust me 100psi pressure is oveeeeeer the line..

100 psi is the max for stock injectors. After that they will lock up. It is also the max procharger recommends. I've have never heard 60psi in any of the forums or searches I've done.

Plus using an FMU makes the car alot easier to tune. With a one bar map I think an fmu is really smart insurance. What happen's when it gets cold and high pressure outside? Now your making more boost on a car thats tuned for the boost you made when it was hot and low pressure. After the MAP reaches its 1 bar limit it can no longer compensate. Raising the fuel pressure under boost makes sense.

Using big injectors and stock fuel pressure works well. But you have to admit your going to have a hard time tuning at idle and low rpm. How many guys on here do you see with big injectors that cant pass an emissions test? :D

97WS6Pilot, I agree you'll have drivability issues with large high impedance injectors, I'm running low impedance injectors through an Acceleronics Versafueler.

Here's a link to a good write-up : http://www.acceleronics.com/faq.htm#4

97WS6Pilot, I agree you'll have drivability issues with large high impedance injectors, I'm running low impedance injectors through an Acceleronics Versafueler.

Here's a link to a good write-up : http://www.acceleronics.com/faq.htm#4

That is an interesting article. Can you vouch for the versafueler first hand. Did your versafueler make a noticable difference in low rpm, idle, and driveability. I hesitate to believe in some of the propaganda some companies put out. I just wish I could afford a FAST system. I guess a better way to put it is I wish I could talk my wife into it. :cool:

I'm running the Versafueler with 75# Delphi low impedance injectors for the last 3 weeks and driveability around town seems great. I don't smog until next year so I guess the jury is still out on that.

60# Seimans Deka
Pro-M Universal MAF
-8 AN supply line
-6 AN return line
Sumped tank, Bosch 390 pump.

72# Seimans (almost 100% DC :()
Weldon A2035 pump (-12in/-10out)
Weldon regulator & dial-a-flow
split fuel rails w/ -8AN feed/exit
sumped tank (by me!!)

Gonna upgrade to 96 or maybe 160s next year.

Running Simens 72# with an acceleronics fueler. LT1 edit is fairly easy. Although I have fouled my plugs by not having a wide band, and, PE curve to high @ WOT. I had previously run with the FMU, but it was difficult to adjust. I prefer the peak and hold type injector.