Im planning on doing a vortech supercharger this month. I plan on upgrading to 8.1 injectors. Will there be any differences in the FMU operation ( do I even need to install it)?? Im having it custom tuned for the injectors. Does the FMU do more than just increase the fuel pressure through the stock injectors??? Would it hurt to install it anyways??? Im having a friend with a great deal of knowledge help, but Id like to have a better idea beforehand. He's more interested in nitrous apps so Im not sure he would know the answer to this. I also plan on doing an alk injection kit a few months later.

 

Are you talking about the 8.1 marine 43lb injectors? Or just the regular 8.1 injectors?

 

Regular 8.1. I'll probably be sticking to 6-7#s until I do the ALK injection. Lyndon said they would be all I needed.

 

How much do the regular 8.1 injectors cost? What lb/hr are they?

 

My pops is the local fleet manager for GM. So he's getting them for me as part of my birthday present ( the other is the ALK inj kit, I think). I believe they are 32 or 36 lb/hr. From what I understand they can support up to 10#s on the 5.3's. I could be wrong though.

 

I've heard they're 32#. If thats the case, then they should support 6 or 7 pounds of boost. They might not support 10 lbs though.

If you get it tuned for those injectors, then the fmu will just make it way rich.

 

I had a friend with a sc on his truck and he ran around 7 psi with 32# in his truck. With edit on it he was running like 120% duty on them though. He went with 42# after he got a little more money.

 

So I dont need the FMU. What about the inline fuel pump????

 

No, don't need the FMU, if your getting tuned for the injectors. Yes, you'll still want to install the inline fuel pump.

You really should think about getting a datalogging program like efilive to keep an eye on Knock, injector pulsewidth, and 02 sensors.

 

Where would I get something like that??? What does it cost???
Let me get this straight. Dont need the FMU, but I do need to install the inline fuel pump. I should go about installing it as per the instructions or will it need to be set up differently???