Mercier

iTrader: (15)

I have seen some evidence that the Flex Fuel injectors may flow more(~36lb/hr?) than typical stock truck injectors. I've got a 2000-ish 5.3 (regulator on rail) and am having 862 heads ported and milled and going with a decent cam. Likely 400HP. I am thinking that I will need injectors and was hoping to be able to use the flex injectors as a cheap way to move up in size.

Can you guys please provide me some guidance on this?

Thank you for your time.

murphinator

iTrader: (2)

I don't have any knowledge of the flex fuel injectors sizing/compatibility but I part out some L67's (3800 supercharged) which use 36's and are identical to Fast 36's down to the PN on the injector body and you can get all the data to properly characterize them from any L67 tune , gtp ,ssei , regal gs etc...on hp tuners forum

8 used injectors for $130 shipped if you have any interest and I will make sure none have hairline cracks in the ring at the tip (common)

Mercier

iTrader: (15)

Sorry I just saw this response; please ignore my hijack of your other thread.. What is max realistic flywheel HP with a set of those injectors?

Thanks!

murphinator

iTrader: (2)

well I am not up to speed on what injectors are in a 5.3 but just did a quick search and here is a copy/paste that may or may not be totally accurate so take it with a grain of salt...

Here are the exact numbers(some will be slightly different since they're rated at either 43.5 or 58 psi).

99-00 injectors-21.767 pounds per hour

01-06 normal 4.8/5.3/6.0 engines-some I've seen have 25.2360 pph. Others are different for instance a 2006 stock 4.8L file I have has a scaled flow rate from 24.5-27.1 based on the amount of engine vacuum.

8.1L truck injectors- I show 29.9483 pph

8.1L marine injectors-41.6673 pph


so if you have 22 pound injectors and add 33#GM ones (sold by Fast as 36's) 22 X 1.5=33 so your adding 50% to your fuel delivery potential , I also saw other threads on truck forums saying going up to 28 pound injectors would support 450whp so using the interweb schwag it calculator lol they should support 500 or so

Real world info 6 of them will support 300whp on a SC'ed 3800 which needs to run around 11 to 1 at wot due to the roots sc being a heat pump , where a NA ls engine is going to be around12.5 to 12.8 to 1 so adding the 2 injectors and being able to lean it out considerably puts it will into the 400's whp

Mercier

iTrader: (15)

Sounds good. I am looking for 400-450 at the crank so should work out fine regardless of what I have now(though pulling heads this weekend and will check part numbers). Two more questions and I think I am sold. Will these require a different connector/adapter at the harness? Should I plan to do a soft rebuild on these or just throw then in?

Thanks!