2001 5.3 truck Norris cam

[Parkemr]

Looking for a good tune to start from stock 5.3 with a btr truck Norris cam shorty headers and a Velocity intake with 92 mm total body stock truck injectors using stock ecm

[5FDP]

Get bigger injectors, you're going to need them.

Can't help you with a tune.

[Parkemr]

What size injectors would I need

[HATEHPTUNERS]

Parkemr a lot of people are using the "flex" fuel injectors from the 5.3-myself included. If you don't plan on any other major upgrades, 36 lb./hr should serve you well. I'm running those on my .030" over 6.0L with Sloppy Stage 2 cam and many other bolt ons, ported heads, TBSS intake, etc; and under full throttle i'm reaching about 85-90% duty cycle in the top of 3rd gear at 150+MPH at 6500 RPM.. The thing you want to be cautious of is you need to use the smallest injector you can get away with. Larger injectors are needed for turbo and supercharged applications but naturally aspirated can get away with significantly smaller injectors. I've heard that the smaller the injector the better it can atomize the fuel... Better atomized fuel makes for better fuel air mixing and a more efficient engine. Some people believe that HUGE injectors will magically bring HUGE power and that is not correct. Your engine is going to only use the amount of fuel it can burn and just because you put a huge injector on there DOES NOT INCREASE your engines cubic inch size, or ability to ingest and properly burn the increased amount of fuel a larger injector can provide. Essentially you are supposed match the injector size to the horsepower that your engine can produce. For simplicity stay with the flex fuel injectors for the 5.3's and you should be fine.

[Parkemr]

Thanks I'll look into a set of the flex fuel injectors this is the first time doing a ls for anything other then stock swap

[SiriusC1024]

Parkemr a lot of people are using the "flex" fuel injectors from the 5.3-myself included. If you don't plan on any other major upgrades, 36 lb./hr should serve you well. I'm running those on my .030" over 6.0L with Sloppy Stage 2 cam and many other bolt ons, ported heads, TBSS intake, etc; and under full throttle i'm reaching about 85-90% duty cycle in the top of 3rd gear at 150+MPH at 6500 RPM.. The thing you want to be cautious of is you need to use the smallest injector you can get away with. Larger injectors are needed for turbo and supercharged applications but naturally aspirated can get away with significantly smaller injectors. I've heard that the smaller the injector the better it can atomize the fuel... Better atomized fuel makes for better fuel air mixing and a more efficient engine. Some people believe that HUGE injectors will magically bring HUGE power and that is not correct. Your engine is going to only use the amount of fuel it can burn and just because you put a huge injector on there DOES NOT INCREASE your engines cubic inch size, or ability to ingest and properly burn the increased amount of fuel a larger injector can provide. Essentially you are supposed match the injector size to the horsepower that your engine can produce. For simplicity stay with the flex fuel injectors for the 5.3's and you should be fine.

Speaking of that. Make sure the injectors are clocked right. Not a problem with a conical spray pattern, but it is with V-shaped ones.

[eXo3901]

If you are not going to buy ID or FIC injectors(which come with data) then stick to real verifiable OEM GM injectors purchased from a known trustworthy source.