s/c fuel question

[Joe]

What would i need technically to run a fmu??? I dont know if I trust the programming anymore on my truck, I am not having any pinging that i can hear, b ut I dont think a truck with 13,ooo miles is worth blowing the engine. Anyway, do I need something to control the timing with the fmu??
thanks.
Nick

[LilYellowZQ8]

You will need 7psi or more to "need" an FMU. The stock setup will support up to 6psi.
All an FMU does is cut off the fuel return to the tank to keep pressure up at the injector(s). It uses vaccum to open or close a diaphram to regulate how much fuel is returned to the tank. It's basically a bandaid, but it still works. The computer will retard the timing if it sences knock, so timing is still going to be controlled by the computer. The only thing you can do for your timing is to get an MSD 6BTM to retard the timing a degree or two depending on how much timing you want taken out per pound of boost.

[Joe]

So if i took the programming out of my truck, and ran an fmu only than I would be fine???, I know that the knock sensor would adjust my timing, but did not think that would have enough taken out for boost.

[03 Rado]

Leave the programming alone, its set, otherwise you'll need a MSD BSTM and set it for one degree pulled per pound of boost.
A FMU is fine alone, but I wouldnt run anything over a 4:1 otherwise you'll have the same deal others do, a never ending tuning session and ruined cats etc.
I'd water inject the prick to protect it if I was worried.
Your getting all caught up in old school myths that say you MUST HAVE UNDER 13:1 air fuel ratios. Today we are injecting a fine mist spray not pulling droplets of fuel in and hope it atomizes to that MYTH should be buried!

[lamerboy]

Stock from the factory at wot the a/f ratio is richer than 13:1. in no way is it good for your engine with 91-93 octane fuel to run that lean with 6psi of boost or more.

If you want an fmu get a cartech 2025 and a wideband so you can adjust for when conditions change.

[biglouie_underpressure]

Stock from the factory at wot the a/f ratio is richer than 13:1. in no way is it good for your engine with 91-93 octane fuel to run that lean with 6psi of boost or more.

If you want an fmu get a cartech 2025 and a wideband so you can adjust for when conditions change.
you sound like you blew a few head gaskets in your time.I would go Alky before i did and fmu,hell i run alky.

[lamerboy]

you sound like you blew a few head gaskets in your time.I would go Alky before i did and fmu,hell i run alky.

No Ive never blown a HG.. If I ran 13:1 a/f ratios for the last 50,000 I bet I would have.

Theres really no need for alcohol/meth on my truck because its got an air/air intercooler. I would consider it if I ran about double the boost though. The only time I'd consider running my truck that lean was on a dyno run or a quick drag race. Other wise for longevity sake I'd run 11.8:1 just like everyone else who wants their turbocharged/supercharged car/truck to last. Its really not worth the few extra hp to me.