New plugs, less boost? please help - SRT Forums

Mr Magna-Mopar Man · 06-21-2008, 03:58 PM

I just changed my plugs to ngk iridium's (LZTR5AIX-13) some people told me they are pre gapped others said to gap them to stock specs. i dont have too many mods so the stock gap is fine with me. Under the hood the sticker sais the stock gap is .050 so i checked the new plugs and they were less than that , they were around .040 so i gapped them to .050 when i pulled out the old plugs which i think were the origional plugs they were not gapped to .050 more like .065 ... so i put the new iridiums in gapped at .050 and idle was very smoothe i took her for a rip and everything looked fine but it feels like the turbo is not as responcive, its like it needs ore throttle to get even up to 10 psi.. not sure whats goin on but any info/help would be great.. thanks guys

SRT4SINA · 06-21-2008, 04:35 PM

you probably have a vacuum leak coming from the plugs since you installed them yourself. Did you change them with the engine being completely cold? Are you getting any codes?

BTW, You don't need Denso Iridiums; all you need are some NGK 4306s or some Champion 570s gapped to about .45 (which is what I run).

HCCAFan · 06-21-2008, 04:36 PM

I don't think it's plug related.

stxsrt · 06-21-2008, 04:38 PM

just retourque the plugs, there probably loose. x2 you dont need denso's. I run 25 psi on my ngk's gapped @ .48

HCCAFan · 06-21-2008, 05:25 PM

He said he is using NGKs

Mr Magna-Mopar Man · 06-21-2008, 08:26 PM

Quote: Originally Posted by SRT4SINA

you probably have a vacuum leak coming from the plugs since you installed them yourself. Did you change them with the engine being completely cold? Are you getting any codes?

BTW, You don't need Denso Iridiums; all you need are some NGK 4306s or some Champion 570s gapped to about .45 (which is what I run).

it wasnt fully cold, maybe this is the problem i know the engine was still pretty hot when i changed them.. what can this do? i tightend them right untill they were not turning anymore but not over tight.. i have never had any boost issues untill i changed the plugs

Mr Magna-Mopar Man · 06-22-2008, 09:10 AM

so i put the old plugs back in and still feels like ive lost some power and some boost.. wont really go over 10 psi for some reason.. I always tighten plugs by hand without a torque wrench ... it seems like i can tighten the plugs by hand with the extension untill the point where it wont get any tighter, then i put the socket wrench on and tightend it a little more.. is this correct or are the plugs not tight enough they are to the point where they wont really get tighter without alot of force butnot too tight.. please help

reddy · 06-22-2008, 09:50 AM

Quote: Originally Posted by Mr Magna-Mopar Man

so i put the old plugs back in and still feels like ive lost some power and some boost.. wont really go over 10 psi for some reason.. I always tighten plugs by hand without a torque wrench ... it seems like i can tighten the plugs by hand with the extension untill the point where it wont get any tighter, then i put the socket wrench on and tightend it a little more.. is this correct or are the plugs not tight enough they are to the point where they wont really get tighter without alot of force butnot too tight.. please help

that is what I do...... get a cheap set of champions
dielectric grease (usually at the counter) and replace them.......

I have tried other plugs and had weird problems, so I always go back to those darn dependable champions

SNOOPALOOP · 06-23-2008, 12:32 AM

NGK or Champions.. either one should work. Boost leak test too