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Discussion Starter #21 (Edited)
those where test run, its weird. i also tought that it wouldnt run with that much boost. but the gauge is sitting at 0 off and plugged into the intake so might be real number.... it seem like wastegate not doing it job as the more it rev the more it boost. thats 91 unleaded gas mixed with 87 lol.... might be a bad gauge ? sure thing it get his 10 psi at 1900 rpm. so that would be really fun it it could be real number
 

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Discussion Starter #23
yeah i dont feel like it was detonating, ive heard lot of v8 knock and its kinda easy to hear.
for scanning i got nothing to scan, bought a tune mail tune so... gage migh be off maybe ?

ima try to figure out why it dont idle, mass air flow housing might be too short , it idle well well i disconect it so...
 

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Discussion Starter #24
Little update today, after a few test it seem to idle really good with maf removed, i ended up making the maf housing longer and it did help, its still have a jumpy idle but it run better. seem like 3.5 might be on the big side ?

also tested with wastegate locked open and it still overboost, sound like ima have to mod it
 

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Discussion Starter #25 (Edited)
turbo 1 clutch 0 lol

i tripple checked the gage and number are real / 1900 rpm 10 psi and past that it just climb to 15 turbo creep power....

now i gotta find something that can hold power longer than a 300k clutch

 

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Discussion Starter #27
i think i might have to... or make it sit at 10 psi with a external wastegate ????

i wonder... 5 less psi must be near a million hp lost ....


either way i think i might be sucking too much fuel for the stock pump ? anyone else with 2006+ pump ? i wonder what is the actual limit of it
 

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Na keep it at high boost. Im sure the bigger clutch will hold the power. If I were to guess your probably making 330+ hp and that clutch would hold that np.

Im not sure but I think all of the fuel pumps are the same for the Colorados.
 

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Do you guys really think that 91 octane is adequate for 10-15PSI boost? I'll bet the PCM is fully retarded trying to prevent detonation. To get max power & performance I think you will need better fuel or you will risk burned pistons and blown head gaskets.
 

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Do you guys really think that 91 octane is adequate for 10-15PSI boost? I'll bet the PCM is fully retarded trying to prevent detonation. To get max power & performance I think you will need better fuel or you will risk burned pistons and blown head gaskets.
With the right spark tables, yes. I ran 91 octane and 15lbs boost for 50k miles.
 

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Discussion Starter #32 (Edited)
i think that those motor beeing full aluminium as well as having a camshaft retard system can take some compression before detonating...

either way im getting hp tuner tomorow, gonna do full log and see whats really happening in there.

precision 40 mm wastegate came in today, that should get rid of boost creep and internal leak.... but welll the thing still 12 psi at 1900 rpm lol
 

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Little update today, after a few test it seem to idle really good with maf removed, i ended up making the maf housing longer and it did help, its still have a jumpy idle but it run better. seem like 3.5 might be on the big side ?

also tested with wastegate locked open and it still overboost, sound like ima have to mod it
I have the 3.5 inch housing and my idle does the same thing. I reduced a ton by adding 10% to the lower part of the maf curve but is still there sometimes. May try making my housing longer aswell
 

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Discussion Starter #35 (Edited)
well thats a crap way to run. maf reading are same as oem and well corrected... and on mine it show rich trim error. there got to be a way to make it run without burning black.

i think it have to do with it beeing a returnless fuel system, going regulated or going with a 2 bar map would fix the overfueling when motor is in vacuum, would have to scale the tune but even then IT would be way better
 

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Discussion Starter #36
anyone ever tester fuel pressure ? i get around 56 not running and 64 running. im wondering cause injector are rated at 58 psi not 64, should i change injector data taking in acount running psi ?
 

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Discussion Starter #38
Well final story 80 injector are on the really big side. Modified fuel pressure in tank to 3 bar and referencing it trought intake vacuum (2.5 bar idle) bring me close to 12:1 afr at idle, anything under 1.2 ms pulse width in hp tuner just run rought and sputter. i guess deka 80 arent that good at low pulse width, or maybe would need some kind of avanced tuning that arent avaiable in this ecu. either way i think that 80 are overkill for that engine, ima be switching to 50-60 soon, trim are going into 40% negative with no effect, looks like deka 80 arent willing to shoot under 1.2 ms
 

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How much timing advance do you have?
I can only get about 10 degrees with 12# before KR on 93oct
Seems like that’s about where I was too.

Well final story 80 injector are on the really big side. Modified fuel pressure in tank to 3 bar and referencing it trought intake vacuum (2.5 bar idle) bring me close to 12:1 afr at idle, anything under 1.2 ms pulse width in hp tuner just run rought and sputter. i guess deka 80 arent that good at low pulse width, or maybe would need some kind of avanced tuning that arent avaiable in this ecu. either way i think that 80 are overkill for that engine, ima be switching to 50-60 soon, trim are going into 40% negative with no effect, looks like deka 80 arent willing to shoot under 1.2 ms
I believe there are quite a few guys running the Deka 80s with good results. Are you doing the tuning yourself?
 

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Discussion Starter #40 (Edited)
nah, i got the tune from someone, after 1 week and going trought brand new maf/o2/map/throttle body/fuel pump. i finaly bought hp tuner.

Got it working today,(tonight)
i tought that 1 ms pulse width was the problem. but it seem like injector have a "short pulse" that can fire way lower than minimal linear pulse... so i trashed that idea and moved along...

Ended up reducing maf/ve table by almost 40 %, now everything run really smooth at 14:7 stoich idle...

i found some really nice post on hp tuner forum explaining how to play around with the 63 lbs/h hard limit of the pcm (And why this tune isnt working).

Pcm thinking that he had 63 lbs injector whyle they are 80 (94lbs at 4bar)....

I noticed that injector limit was ajusted by voltage multiplicator (untouched tune pictures at the end). witch doesnt seem to work on my pcm since its hard coded to max 63 lbs hr. the tune was set at 63 with 1.5 ratio ending up at 94 lbs h "calculated" BUT it looks like the pcm isnt alowing anything over 63 lbs calculated.... now that i reduced the VE/MAF table, i get a really good idle and cruze, i also tried to input "fake" 120 lbs injector, and it dont even change afr. so pcm is really limited to 63. no mather what voltage multiplicator is in or data, its always 63 lbs max !

ive learned a lot on this one but im really disapointed with the tune error... i tought email order tune where pretty reliable. but ended up spending 500 buck and do it myself...

I think that the tune might has been made on the fly, like as if it was a 2.9 or so (who allow bigger than 63 lbs injector) but 2006- doesnt... as well as not removing evap and second o2 dtc ect... injector offset left as stock ....
i dont know what to say... if this wasnt for wasting an extra 2 week, i woulda probably just sent back the loaner and fill a paypal request.......

 
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