Is there much of a difference in performance with the 24.7lb injectors over the '99s????

 

If you plan on other mods (cam, etc.), it would be beneficial to have the better injectors so fuel starvation at higher RPM's won't be an issue. Plus, the 01 and up PCM is factory tuned for the higher flow injectors. If you plan to keep you're 99 injectors, you will want to mention that to the tuner who's doing your tune so he can make the necessary adjustments.

That's good info...what did they update to in 00?

 

I picked some up in the classifieds for $30 shipped.

 

I think you were correct on the 00 part, I thought mine were bigger to, Nelson told me they were 19#. I'll have to ask what they 00 were. Anywho, if you are upgrading, go with the largest ones to give some wiggle room.

Chris

 

Will you see that large a benefit from going to the newer model injectors.
I have a 99 with 02 pcm.. I only check a few sites so if you know of some currently for sale please let me know.

My currect setup- 1999 ECSB- 5.3l ,Z-71 ..
Only mods- Ultimate PD air intake, Nelson Tune-02 PCM, PV Cat-Back Exhaust and Transgo Shift Kit.

Thanks,

Brian

 

I would think that the a/f ratio would be better corrected with the proper injectors. The 02 PCM's tables are calculated for 24lb injectors, so their base logic is set up to duty cycle less than the 99 PCM. It could possibly run a tad lean...although, theoretically the PCM should pick up on the a/f ratio via the O2 sensor's input, and adjust accordingly. Best way to tell would be to hook up a scan tool or scanning software and do some data logging. You could also give Nelson a call and ask his opinion since he tuned the PCM.

 

Nelson told me I didnt need the larger injectors, however I am showing over 100% duty cycle, I think I will get mine changed, but overshoot and go with around 30#ers if i can get em cheap.

 

Check ebay...I just got a set of 8.1 31# injectors for $95 shipped, I plan to use them when I put the 6.0 together

 

I hate to high jack the thread but what injectors fit the 99 Trucks. Are all the trucks the same? Does the Camaro / Corvette injectors fit too?

 

no the fbody injectors are a diff size, cant remember if they were longer or shorter, but wont work.

If the 02 pcm tables were calculated for a diff size, wouldnt retuning these tables take care of that? After all, thats what tuning software is for.

Chris