boost sputter @ high boost

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b16stalyun

New Member
question, 2nd gear im at 13 lbs with creep up to 15. 3,4,5 gear i get a heavy sputter when i hit full boost. it does not do it in 2nd gear. only 3rd+ when i hit full boost. i thought i was hitting boost cut because of the boost creep. my boost cut is at 22.9lbs. I have a Motorola 2.5bar map sensor. which should be good to 35lbs. (1bar=14lbs) if im correct. so i lowered the boost in 3rd+ to 16.5lbs with a creep to about 19/20lbs depending on temp. it is still breaking up and not going near 22.9lbs.

what could be the problem? the weather is about 20degrees-40degrees outside.
plugs?
wires?
weather?
tune?
 
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keep in mind, at sea level, you're already AT one bar for the atmosphere... so, a 2.5 bar sensor gives you ~ 1.5 bar of boost to play with, or about 22psi.

but, breaking up sounds like you need more fuel and a better tune to compensate for the different burn of fuel in winter vs summer.
 
keep in mind, at sea level, you're already AT one bar for the atmosphere... so, a 2.5 bar sensor gives you ~ 1.5 bar of boost to play with, or about 22psi.

but, breaking up sounds like you need more fuel and a better tune to compensate for the different burn of fuel in winter vs summer.

Agreed. My car runs like ass when it gets really cold out. I had to richen it up a little to compensate for it.
 
update. i ran my car today. it was 65 degrees outside still had the sputter.

in 2nd gear my a/f is about 11.5~
in 3rd,4th at times it goes down to 10's
 
update. the boost sputter was due to spark plugs. changed em out, re-gaped em and they work fine
 
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