I have a 2002 Silverado with the 6.0l motor. I also have an STS turbo system on it. I am going to install the Multec 2 42 lb injectors but I have one question. I have read a lot of previous threads and on-line info about how to pick injectors. The multec 2 42 lb injectors are rated at 42 lbs @ 58 PSI fuel pressure. This puts them at about 37 lb injectors at 43.5 PSI which I was told is a standard for fuel injector rating. Do I have Nelson performance set my PCM for 37 lb injectors or for 42 lb injectors?? I was also told that the fuel pressure will rise as the boost rises. So with 6 PSI boost I will have 64 lb fuel pressure.

What is the best info I need to give Nelson to be in the ballpark so it will run to get it scanned.

 

Have nelson set it for 42 lb'ers. Fuel pressure only rises until 0 vacuum. It goes from 52 at idle to 58 at 0 vac.

Just tell nelson you have an STS with 42 lb'ers, and whether or not you're running an intercooler or alky injection.

 

OK thanks for the help!!

 

I just bought these from Arizona Speed and Marine, they are refered to as 43lb injectors on the site, I called them and asked and they said they are the stock 8.1L GM injectors. I have heard them refered to as 42lb injectors on many occasions here. So what are they? I am getting my PCM flashed next week, is the difference in 1lb gonna matter when they do the tune? Sorry don't mean to hijack your thread.

 

you shouldn't need the FMU with the larger injectors.

 

Me again. I spoke to Nelson and they told me that I can go ahead and install the new 43lb injectors with the tune that they sent me. The tune was for 36lb injectors @ 43.5 PSI. They said it should run good enough to get a scan and then he'll fine tune it for me.

Any thoughts? I just dont want to install the injectors and then it will not run correctly.

Thanks for the input.

 

HEY wait a minuet, thought stock 8.1s had like 30lbs while the 8.1 marine injecters for 42 lbs....or did i smoke crack somewhere.

 

You are correct....

Under boost my fuel pressure will rise to just over 60psi but I am already running out of injector with the 43lb units so just a heads up if any of you turbo/blower guys plan on running 12psi+.

 

Yes they are they are the marine injectors.