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Cant boost past 6psi without knock


AutostradaVR4
03-21-2010, 09:47 PM
this board's been dead lately, so i dont feel too bad about such a nooby post lol.

So I finally got my MBC put on today. I was just looking to get back to the 12-14psi (stockish) boost level for now...didnt think i'd have too much trouble, but i can't seem to get past 6 or so with out knocking. It's an ebay MBC so i was playing it safe...had my wife in the car with the logger watching knock as i gradually turned it up. It's fine at 6 but when i went to 8-9psi i got 3-4 knock counts (around 3500 revs...and not even WOT!:crying:), so i backed off.

Just re-did all my vac lines today, so i dont think i have any boost leaks...but i have yet to pressure test the system. Would a boost leak cause this? (I have the vac redux and EGR delete done...so my vac system's pretty clean)

Plugs are NGK Iridium/Platinum's, stock heat range, ungapped (.044...the box said "DO NOT GAP"..). They're new, only a few hundred miles on them. Plug wires are Stock Mitsu wires, about 10K on those. The rest of the ignition is original AFAIK, so about 110K. I do know that my VSS need to be replaced...so my best guess is that between the oil in the cylinder from the bad VSS and the .044 plug gap that's causing spark blowout.

Would a fuel problem cause knock?

Also, i've got the screw on my Greddy RS about half way...i didnt think that would make a difference but as you can tell im still learning.:rolleyes:

Let me know what you guys think!

cHo
03-22-2010, 02:34 AM
I personally would start off by regapping the plugs down to 32-34. Also boost leak test the system and make sure there are no leaks. Check your intercooler and make sure the fins are straight and nothing is bent or damaged..
Now that we have all the free things taken care of..
When was the last time you replaced your fuel filter? fuel pump? also a faulty fpr could cause random knock in partial throttle situations.. Also make sure your oil is good..
Try the free things and post up what you find..

LandoAWD
03-24-2010, 02:35 PM
BLT the car FIRST.

Iridiums in a boosted car? I know the EVOs do it, but I'm 99% sure 3kGTs are not to use anything but copper.

AutostradaVR4
03-24-2010, 04:54 PM
...u know the stock plugs are plats right?

Stealthee
03-24-2010, 04:55 PM
Iridiums are actually stock in a 3s.

Even though the box says do not gap, gap them.

AutostradaVR4
03-24-2010, 04:57 PM
Even though the box says do not gap, gap them.

Word. Yea i plan on regapping them this weekend.

LandoAWD
03-25-2010, 07:59 AM
I said 99%...

;)

I've read Platinum, Iridium, and copper, but It looks like only one is right.

Igovert500
03-25-2010, 02:01 PM
I always heard plats were stock. Some people run iridiums, some plats, I personally prefer copper gapped to .28-.32...they are easy enough to replace, and if they get fouled out, i'd rather be out $1.60

Re: original problem. Boost leaks could cause you to run too lean, causing knock. Could also be fuel pump not getting enough voltage, hotwiring it would solve that. I'd start with pressure test though, it's free.

LandoAWD
03-25-2010, 02:05 PM
Hell, if copper works, people should use 'em. All that snake-oil BS with plugs drives me nuts. I spent 20 minutes arguing with the Auto-Zone guy about why I run motorcycle plugs (NGK copper BR8ES) instead of 20 dollar apiece 97 tip, platni-ridi-moon rock plugs.

He has a muffler welded to his Honda's stock exhaust...perhaps I should have listened?

Stealthee
03-25-2010, 06:17 PM
Hell, if copper works, people should use 'em. All that snake-oil BS with plugs drives me nuts. I spent 20 minutes arguing with the Auto-Zone guy about why I run motorcycle plugs (NGK copper BR8ES) instead of 20 dollar apiece 97 tip, platni-ridi-moon rock plugs.

He has a muffler welded to his Honda's stock exhaust...perhaps I should have listened?
I bet he used the Bosch 4+ plugs. :lol:

My cousin bought a set of those years ago for his Integra. They actually made the car run WORSE.

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