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Discussion Starter #1
the problem is that i ran 400 hp at 18 psi on my sp67gt, but it wont go past 18 psi, i turn my boost controller all the way up and it doesnt want to go past 18.8.. feels like its not pushing enough exhaust through to spool the turbo which would be from the spark plugs being fucked up a couple days ago... i sprayed out the engine bay with degreaser in select areas (i know i know, i was careful in most spots), but got some in the spark plug valley, well i didnt notice it and had to run it like that a couple days, but not far, maybe 10 miles total, sputtering and sounding like it had gigantic cams... i know it probably killed the spark plugs so i need some good replacements.

whats everyone else run, spark plug and gap to make high hp on high boost.??

running ngk iridiums currently, but they ran 380 hp at 16 psi on the upgraded ct-26 (60-1), so its definately something going wrong with the current plugs i think
 

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Autolite 3923s is the only thing i run. I dynoed 420 at 18psi with no problems awhile ago and im sitting around 450 to 460 right now with zero problems. I gap them to .31. Also i am running 21 psi right now and i have ran 25psi with no issues.
 

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Moderator, l337 M0d3r4t0r
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Just pull the plugs, get the water out of the vally by pulling all the plugs crank it over about 10 times so the water sprays out of the cylenders.. Reinstall the plugs, and check for a boost leak... Some times your turbo is actually making like 40 PSI but it's leaking all the boost which is why you can only get 18.8.. Check it out!
 

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Discussion Starter #6
boost leak = fuel cut though... what else could it be leaking from lol???

also ive got all the liquid out, after using towels to mop up the excess, then spraying a couple shots of electrical cleaner in there with all the connections, it still seems like its not pushing as hard as it should

ill put in some new plugs just to be sure and check out the ones in there, they arent costly, and ill check all my intercooler piping.

but how is it making 40 psi but leaking all the boost with no fuel cut happening?? fuel cut is around 21-22 psi for me right now with this setup, and if there was a leak in the intercooler piping the fuel cut would be dead on at 15-14 psi or lower.. right?? ive had the problem before but this is something new
 

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Discussion Starter #7
Just pull the plugs, get the water out of the vally by pulling all the plugs crank it over about 10 times so the water sprays out of the cylenders.. Reinstall the plugs, and check for a boost leak... Some times your turbo is actually making like 40 PSI but it's leaking all the boost which is why you can only get 18.8.. Check it out!
ok i still dont get this zazzn, a boost leak is going to cause premature fuel cut, especially when you are pushing the max boost anyway, like i said in my post before this one, just reviving and bumping the thread so i can get a clear answer. im putting insome new plugs today so hopefully that will solve it, but if anyone knows any other reasons why someone wouldnt be able to reach full boost besides not pushing enouhg exhaust gasses, it would be appreciated
 

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As far as spark plugs, as per NGK recommendation you should be running 1 heat range cooler (higher number) for every 75-100HP over stock you are running. In your case I would probably run an 8.

I have yet to run into any problem running NGK Iridiums, everyone will say this copper that copper. Most are simply lemmings.
 

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Discussion Starter #10
As far as spark plugs, as per NGK recommendation you should be running 1 heat range cooler (higher number) for every 75-100HP over stock you are running. In your case I would probably run an 8.

I have yet to run into any problem running NGK Iridiums, everyone will say this copper that copper. Most are simply lemmings.
i do like how the coppers work and iridiums too, problem is on the island of oahu, its hard to come across a place that stocks them up, bout to go out and find some. but where do you usually find the heat range on the plug?? in the number?? the V-power ones i ran were bkr7e... the 7 would be the number right? and the higher the number the cooler it runs? thanks alot, that really helps
 

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ngk 6097s..
 

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does that turbo have an internal wastegate?

oh and autolite 3923 are hands down the best plug for that car and to be honest this dosn't sound like a problem with the sparkplugs
 

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i do like how the coppers work and iridiums too, problem is on the island of oahu, its hard to come across a place that stocks them up, bout to go out and find some. but where do you usually find the heat range on the plug?? in the number?? the V-power ones i ran were bkr7e... the 7 would be the number right? and the higher the number the cooler it runs? thanks alot, that really helps
http://tinyurl.com/33xdjm

Some info on heat range (NGK specific, to a small extent.)
 

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Discussion Starter #16
ive read that little blurb on ngk's website, but cant seem to find anything in the 8 range... it shows in their pdf that they make up to 11. but havent seen anything past the bkr7e's, anyone know the temp rating on the 3923's from autolite?
 

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Multi electrode plugs are a gimmik the spark only discharges to one electrode so they have no performance benefit what so ever. NGK coppers are fine and cost pennies (or at least they do in England, 6 NGK BCPR7ES = 1 platinum NGK) there is no need to run platinums, the only reason Toyota specify them is because you only need to change them every 70,000 miles personally I would rather change my plugs every 10,000 miles.
 
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