Hi All, I have 2004 LS1 in a 68 Camaro. Current set up is 228/228 .600/.600 112LSA cam, LS6 intake and injectors, still have the 78mm throttle body and I'm running 1-7/8 long tube headers. I just had the 28lb injectors serviced and they're flowing 294-295 CCs per min. With this set up I'm making 390 whp at 6,500 and I'd to see how many ponies I can add cheaply and without grenading the engine. In looking at my options I don't want to change the intake.

I'm not opposed to buying rebuilt and matched injectors (I'm cheap) someone also mentioned having the 78mm TB ported and polished. I don't know if there's merit in doing this or if it just looks nice. Here's a screen shot of a pull we did after installing the serviced injectors. What should I be looking at out there? Thanks!

 

I don't think you're at the limit with your injectors. I had the same ones in my LS1 with a very similar cam, had ported heads, a FAST LSX intake and a ported and polished throttle body that I ended up swapping for an 85MM one that I also ported and polished. Never had it dyno tested, but it never was fuel limited. Depending on what your goals are, a set of 36 or 42 lb./hr injectors would be enough for 450-500 at the wheels. My LS3 uses stock 42 lb. injectors and I've dynoed 471 to the wheels.

 

What's your fuel pressure when the duty cycle is over 100%? If it's dropping then your pump is not delivering. If its stays consistent, you need larger injectors.

 

I missed the 100% duty cycle... Definitely seems like a pump issue because 390 to the wheels is not enough to max out 28's.

 

Thank you for the insight, I had not thought of that. I'll have to check this out, hopefully this not the problem it as I have just 4k miles on the 60psi/255lph pump I have.
If my pump is good which Bosch injectors to you suggest I explore? Thanks Again -

 

Could be the regulator also. The Corvette filter/regulator combo can especially have problems.

 

I do have this combo...