30lb. injectors on a C5

[TODD L GRIFFITH]

I have just returned from a long test drive running new Accel 30lb. fuel injectors. Talk about effortless power. The 30lb. injectors are oversized, but I plan on adding a cam, ported heads and LT headers this year. In my 99 C5, fuel pressure was measured @ 60 psi. The injectors were factory tested @ 43.5 psi., and flowed at 30lb. The resulting injector rate is more like 35lb. @ 60 psi. with my C5. Using the mass air flow translator, I have leaned the injectors out 20%, resulting in a target 28lb. flow rate. First gear the car will kick out sideways at any speed, hit second and more of the same. I was on the on ramp to the highway and hit the century mark with no effort involved. On the highway, fourth pulled extremely hard, well into redline, faster than ever. Fifth has gobs of pep anywhere from 60 mph on and will probably take most domestic cars in a drag race from that speed....lol. Sixth is just great for fuel economy. The car is going to be dynoed next week for a first dial in with the new injectors. I will post the results then. Has anyone else had any experience changing injectors, and had positive results?

 

[TODD L GRIFFITH]

Sorry about the post

I guess I just got carried away, in all my own excitement about the injectors. I read through it later on and didn't want to reply either.

 

[DkBG]

On the contrary ! I found it very interesting . I guess you have a reader/reprogramer . I'll be waiting to hear your dyno results . Cliff

 

[Don&Kelly]

I also added the larger injectors - I'm running real rich - usong LS1Edit to lean it out a little at a time ..

 

[TODD L GRIFFITH]

Reader Reprogrammer

No, I don't have one of those, but I'm running a programmable chip. I have some heavy intake mods. I installed a 6" K&N conicle truck filter, 1000 cfm MAF ends, Vortex Power Duct, 80mm BBK Throttlebody and Z06 intake manifold. I cut my radiator shroud about 75%, and removed the front facia fog lamp plastic inserts. Air comes in from the nose and from underneath. I had to buy the Mass Air Flow Translator to off-set a fuel lean condition, with all that air. The 30lb. injectors are oversized, but I used the translator to dial in a fake rich condition to the PCM. The PCM is compensating for the fake rich condition, and retarding the spark, thus reducing the flow to the fuel injectors to where they can operate, and not make the car run rich. It's not perfect, but it works. My fuel/air mixture is still probably alittle rich, because there is no modulation in the adjustment, I'm stuck with settings in 5% increments basically. When I visit the dyno a few times, I can adjust the fuel delivery to get as close to 14.7 : 1 as possible. It will never be perfect, but I'm looking for the horsepower, and may have some trade-offs. I just purchased a new set of 10.4mm wires, and I'm trying to find more powerful ignition coils to give me that powerful spark. My exhaust system is a Borla T-304 XR-1 competition catback system to get rid of it all. Cam, heads and headers will be the final modifications where I would dial in a lean condition to compensate for those mods. without having to change the injectors. Thanks for responding, and sorry for being long winded. Yes, LS1 edit is another way of doing it Don. It looks like you do some racing.

 

[Don&Kelly]

Todd, yes we "Open Road Race" - AutoX and some drag racing .. all lots of fun ...