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Thread: 10 psi question

  1. 09-29-2007 08:50 PM #1
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    the_jester
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    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.
    2008 Trailblazer SS LS2, K&N CAI, flowmaster 40 series, hp tuned
    2004 Trailblazer 4.2, K&N CAI, hp tuned
    2002 Camaro Z28 5.7 ls1, lid, slp loudmouth, bbk longtube headers, ory, hp tuned, tr224 cam, ported 243 heads, moser 12 bolt w/ 3.73's and full spool, and a 100 shot just in case. 463whp, 458 wtq 11.32@ 120 1.52 60' on motor no spray times yet
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  2. 09-29-2007 09:00 PM #2
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    I would not risk it.
    99RCSB Broke because I wasted thousands and thousands of dollars on my truck.
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  3. 09-29-2007 09:22 PM #3
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    Jamest
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    I think you need bigger injectors to run 10 psi. I bet the 28s are way maxxed out.

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  4. 09-30-2007 09:47 AM #4
    Ramsey
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    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.
    mods:2004 sierra ext sb,20s ,big brake kit w,hawk pads,air bagged,2006 6.0 lq4 swap,vortec supercharged10psi, air to water intercooled w/ dual electric fans on it ,snow meth injection kit,60lbers, e-fans ,big radiator swap ,cam 218 /222 548/550 comp .hardened prs .1.85 comp roller rockers ,guideplates ,crane double springs,trans 4l65e built .pacesetter l/ts true duals w/x pipe and magnaflows,14 bolt rearend swap ,3.73s,aroemotive fuel pump system w/elec.fuel controller and bypass regulator a/n fittings, taylor 10.5s interceptor gauge,aem w/b a/f ,autometer boost/vac NELSON 93 OCTANE TUNED .
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  5. 09-30-2007 02:50 PM #5
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    Eventually, you will end up with this feeling...

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  6. 09-30-2007 04:51 PM #6
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    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?
    2008 Trailblazer SS LS2, K&N CAI, flowmaster 40 series, hp tuned
    2004 Trailblazer 4.2, K&N CAI, hp tuned
    2002 Camaro Z28 5.7 ls1, lid, slp loudmouth, bbk longtube headers, ory, hp tuned, tr224 cam, ported 243 heads, moser 12 bolt w/ 3.73's and full spool, and a 100 shot just in case. 463whp, 458 wtq 11.32@ 120 1.52 60' on motor no spray times yet
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  7. 09-30-2007 04:59 PM #7
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    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.
    2008 Trailblazer SS LS2, K&N CAI, flowmaster 40 series, hp tuned
    2004 Trailblazer 4.2, K&N CAI, hp tuned
    2002 Camaro Z28 5.7 ls1, lid, slp loudmouth, bbk longtube headers, ory, hp tuned, tr224 cam, ported 243 heads, moser 12 bolt w/ 3.73's and full spool, and a 100 shot just in case. 463whp, 458 wtq 11.32@ 120 1.52 60' on motor no spray times yet
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  8. 09-30-2007 05:53 PM #8
    RedHeartbeat
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    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.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
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  9. 09-30-2007 06:41 PM #9
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    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
    2008 Trailblazer SS LS2, K&N CAI, flowmaster 40 series, hp tuned
    2004 Trailblazer 4.2, K&N CAI, hp tuned
    2002 Camaro Z28 5.7 ls1, lid, slp loudmouth, bbk longtube headers, ory, hp tuned, tr224 cam, ported 243 heads, moser 12 bolt w/ 3.73's and full spool, and a 100 shot just in case. 463whp, 458 wtq 11.32@ 120 1.52 60' on motor no spray times yet
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  10. 10-01-2007 08:40 AM #10
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    SCIV
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    Quote Originally Posted by the_jester View Post
    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
    Mine were maxed, but I wasn't running meth. I went to 60lbers.
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