up'ed the boost, problems

[sl87]

Got a MBC and boostin 12 psi on T25. Sometimes when i go full throttle it will hit 12 then hold 11. During this process, at some points of the Rpm, it will do little backfires and bog. I got 255lph fuel pump, 300zx fuel filter. Stock Injectors and FPR. Also, on the way home from work, the turbo was lagging (4-5psi). 10 mins after, started boosting fine. Any opinions are appreciated. Thanks.

[playbass311]

Sounds like you're running too rich. What type of BOV are you using, and more importantly are you reciruclating it? At that much boost your dumping a lot of fuel and if you're not recirculating or have some kind of tuning its going to cause you to bog. Also, 12 psi on a T25 is a little high, especialllly if you dont have a front mount. Just be careful man and IMO you should consider turning your boost down to like 10 psi or so, especially if it is your daily driver. Oh, you should also check for any vacuum leaks and make sure your MBC is tightened down well.

[Silverbullet]

It dosn't matter if the BOV is recirculated or not while the driver is on the throttle.

How sure are you that its backfiring?

The first thing i thought of when i saw the title of the thread is it might be breaking up whch is a common thing if your spark plugs are not gapped properly or if one of ur coilpacks is dying.

[sl87]

well i do have FMIC and hks bov (non recirculated). My plugs are the denso iridiums, which your not supposed to gap. Im pretty sure that they come gapped at .040. Does it have to do with my car not being tuned when i upped the boost? I thought i wouldnt have any problems with the setup i have. Stock FPR and injectors, z32 fuel filter, 3.5 inch exhaust, HKS BOV and intake, Hybrid FMIC.

[slow s13]

silverbullet is dead on, Remember the more boost you run the harder it is for the spark to jump the gap and your gap is a bit above the spec of .36 I gapped my irridiums to .32 and run 12psi on a front mount with no probs just be carefull when you gap them. If your scared to gap them go buy some cheapie coppers and gap them down and see if your problems go away.

[Silverbullet]

next time you buy plugs, buy the cheap copper plugs. Not only do copper plugs provide the best spark but they are cheap. 0.40 is a really high gap. I personally stick with 0.25. I know ppl who swear by 0.28, and 0.30. It depends on your motor really, but give those lower numbers a shot and you should have fixed ur problem.