After modding my SS some, I've been seeing a little knock retard and my air fuel mix begins to rise in the upper rpms. I knew the SS came with the same injector that all 00+ trucks use (except the 8.1 and flex-fuelers), which is on the small side for my needs. I decided to log my injector pulse widths this morning to see whats going on. Well, guess what. I'm hitting 100% duty cycle (always on) at 5000 rpms. At 6000+ rpms, I'm nearing 115% injector usage.

I have a set of new 8.1 injectors just waiting to be used. Looks like I'll be swapping them out sooner than expected (this weekend). I bought a wideband a few weeks back, but I haven't used it yet. I'll log some before and after injector runs and see if the larger injectors help me out.

Stock truck fuel injector info

(These values have been extracted from LS1 Edit and include the injector offset values which will be helpful for anyone messing with their fuel system)

 

Tex - I think you should go with these. Just do the Fbody swap stuff and your set. With the HUGE power that LQ9 is putting out you might be OK with them. :p J/K

http://www.racetronix.com/Racetronix..._Sale-55h.html

 

I didn't really want to spend $400 on fuel injectors. I have brand new boxed 8.1 injectors, which flow about 30#s, but those are only 20% larger than stock. Unfortunately, I'll be needing more than they can provide.

Anyone have a set of Flex-Fuel injectors lying around? Anyone need some brand new 8.1 injectors?

Probably need to address my fuel pump before I start spraying it.

 

Tex, I'm *VERY* interested to see what you find out. I just ordered EDIT yesterday! I'm wondering now if the 8.1 injectors will be okay for the TR224 in the LS1. I'm hoping to push around 350-375 whp.

I have absolutely NO IDEA how to even start tuning the truck, so I'm going to need to count on you guys for some help and advice.

I guess my first project once the motor is in will be to switch to the LS6 intake and some 40-50 something # injectors. I'm just waiting patiently for the prices to go down once the LSx intake hits the market soon!

 

I'm also thinking about the LS6 intake.

Stock Fbod injectors can handle 350-375 with no problem. The 8.1 injector is just a bit larger then them.

I think I'm going to go ahead and use the 8.1s for now and see how my injector pulse widths change. I can always swap them again. I'll just keep the boxes in case I need to go to ebay with them.

 

I put some 02 5.3 injectors in my 99 and started out using 3.18 for the flow rate. My ltrims were + so I changed it to 3.14. That brought them down some but not enough. For the offset I used the 00 table(not sure why I did that) but im thinking I need to change that to the 02 table and see if that effects the ltrims any.

 

twobit- give it a try. I did the same thing on my 99 truck and I didn't really have any issues. I don't think my LTRIMS were dead on 0, but they were within 1 or 2, which was just fine. I think I ended up using the 02 offset table and flow rate.

 

TeX.Did you do any racing last friday?What kind of ETs are you seeing with your Gtech?

 

Cold front didn't come through last Friday, and temps were in the 90s. I stayed home.

You really want to know?

You gonna call BS or say the Gtech is way off?

 

lets here it!It sounds real good when you start out by saying someone may call BS.