10 psi question

ok, i have a 10 psi pulley sitting on my counter and its killing me. now my silverado is running 9psi, on stock injectors, with the boost pump raising the fuel pressure, and FMU regulating. my wideband is showing perfect air to fuel ratios right up to redline. now heres the thing, i am putting a bung on the sub tomorrow so i can switch my wideband back and forth between the two trucks. if i put my 28lb injectors back in and get a new tune will i be able to run 9-10 psi as long as i watch my a/f ratios. or do i need a pump and FMU. i think if i keep an eye on things and keep my meth working for safety.

I would not risk it.

I think you need bigger injectors to run 10 psi. I bet the 28s are way maxxed out.

Jamest

anything over9 i would go bigger 42 lbers from the 8.1liter im pushing 12 psi of boost and im starting too run out at 6200 rpm.dont chance it !good luck.

Eventually, you will end up with this feeling...

:puke:

well, I'm running 9 psi on the stock 21 lb in the silvy, but i know what you mean. damn it. that pulley is calling my name. well, if i get some 42's will the stock pump put out enough to run them? because i am getting LT's and ORY, and i know from the silvy that you have to richen it up after adding headers. so with 42's and headers will the stock pump still be up to it?

well, im hard headed so i went to iroczone and used their injector calculator to find out exactly what size i need. and at 450 hp at the crank it says i need 42's to run under 80% duty. so i guess everyones right. i just need to suck it up and get some.

IROCs run 43 psi of fuel pressure unlike our 50-58 psi regulators. We get even more flow from the injectors than they did. I'm not sure what calculator you used on their site.

i just used the 43.5 that was set thanks for the info. i'll check it out with our pressure. how big do you think i can go on 42 lber's

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Originally Posted by the_jester

i just used the 43.5 that was set thanks for the info. i'll check it out with our pressure. how big do you think i can go on 42 lber's

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Mine were maxed, but I wasn't running meth. I went to 60lbers.

If you buy the 60lb'ers that means you can 15psi, heheheh

but can my stock internals hold 15psi, hehe thats the real question, injectors are cheap, blocks not so cheap.

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Originally Posted by the_jester

but can my stock internals hold 15psi, hehe thats the real question, injectors are cheap, blocks not so cheap.

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It is a calculated risk. You are already pushing past what it was designed for.

Hell no! A stock bottom end can't handle 15 psi. Ok, yes it would--for like 2 WOT runs--then BOOM! You'd throw a rod through the hood! You can run 10 psi reliably... Anything past that, and you are rolling the dice...

I think JJ will chime in and disagree, lol.
His truck has seen 20psi a few times, and has been running on the same engine with 15psi for about 2-3years, many, many passes at the track and lots of street driving.
I hope I just didn't jinx his truck, hahah

you're right though, 10psi is fine, but 15psi is pushing it, you constantly have to monitor when running that much boost.

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Originally Posted by the_jester

well, I'm running 9 psi on the stock 21 lb in the silvy, but i know what you mean. damn it. that pulley is calling my name. well, if i get some 42's will the stock pump put out enough to run them? because i am getting LT's and ORY, and i know from the silvy that you have to richen it up after adding headers. so with 42's and headers will the stock pump still be up to it?

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I was seeing 110-115% duty cycles on my stock 28# injectors at 10psi even with a 10:1 FMU. (With the 10:1 disk in it I've seen it peg my 100 psi fuel pressure gauge.) Probably the only thing that saved me from damaging something was the fact that I was spraying meth.

I now have 42# and they run about 80% duty cycle. I still have the FMU but dropped back to a 6:1 disk in it. It barely moves my fuel pressure now. I may see 65psi at full boost.

IMO you need at least 42# injectors.

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Originally Posted by farmtruc

...JJ...has been running on the same engine with 15psi for about 2-3years, many, many passes at the track and lots of street driving...


you're right though, 10psi is fine, but 15psi is pushing it, you constantly have to monitor when running that much boost.

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Damn, JJ has a stock bottom end?

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Originally Posted by txarkitekt

Damn, JJ has a stock bottom end?

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Ya, stock block and internals, well an LS6 cam only.

Heads have never been off, no gaskets leaking, doing pretty good so far.

Wow, good work Allen! That is amazing that thing is still tight. That brings up my confidence on the stability of the LS block for FI...