Fuel Pressure?


Nov 23, 2003
How much boost can 42psi injectors handle and what kind of fuel pressure should I run with them at around 18 to 20 psi of boost? Also I need different opinions on a chip for this set up so I can decide where to buy the chip and which chip is most commonly considered the best. Also I need advise on mufflers;)

moose do you have a scan tool and what octane fuel are we talking about? 18 psi is alot for streetdriving on pump gas.

From what I understand you can increase boost (depending on octane....of course) and fuel pressure in small increments separately for best results. if you start showing knock of more than 3 degrees on pump gas, let off and turn down the boost.

The car will make the most power at a given boost level with the SAFEST leaner mixture of air and fuel (750-800 mV) and the least amount of knock retard.

I just put 50# injectors in mine last week and had a chip burned by Eric@turbotweak.com.....have not had tons of time to fiddle with boost levels, fpr etc yet.

I have rarely had any knock problems with race gas and 18-20 psi but be careful with 91-93 octane. I usually run 15 psi or less on the street as it keeps me relatively worry free about kabooming the motor.

As for mufflers, I have a crossflow flowmaster which I would prefer to switch to a hooker true dual system, check out what others have to say on this there are so many choices out there....

;) chris
Thank's, I am currantly running 15psi on stock injectors with no detonation on 93, I only have an air fuel guage in my car. So far I have taken it up a little at a time and figured out I can run 15psi on pump gas and I can turn it up to 16psi and I have to put about 10 gal of 110 in my tank for no detonation. The only problem I have is I don't know what the chip is supposed to do, It has stage I on the back of it and I have no info at all on It. I found it in the glove box, stuck it in and noticed a big increase towards the rich side on my A/F guage. I started turning up the boost after I put it in and I'm still on the rich side at WOT with the boost at 16 creeping to 17psi, But I'm afraid to go any higher because I have no idea If the chip is doing the right thing with the timing:confused: I don't know how high I can turn It up with this chip. This is why I was looking at chips also. I don't have my wastegate actuator hooked up through the solenoid, I just have a hose coming off the housing straight to the actuator, Should I hook it back up to the sensor or solenoid?(whatever it's called)

Thank's for the help;)
I'm still learning;)
15 psi w/o detonation is good but if no scan tool you are talking about audible knock right? There may be knock you cant hear (not to get you paranoid....)

If you want to run as much boost as you can safely spend the 250 on a scanmaster from ramchargers.com......it's really much safer to know exactly what's going on. A little rich is safer than alot lean regardless....

The wastgate solenoid I would connect because it protects from accidental overboost. If it is as old as the car I would replace it. They are like 35 bucks i think....also the three little black hoses and the Y. When I did mine the Y had a metal restriction which had to be drilled out per recommendation of the place I bought it forom(poston).

Your chip I am not sure, was it burned for those injectors or were both there when you got the car?Eric will get the timing right for you......chip burning has come a long way recently//

The chip was there in the glove box when I bought the car, The injectors I just bought to upgrade a little. I haven't put them in yet.