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Need advice on plug gap with the posted modifications


Latinwrlord

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I know it's like beating a dead horse. But I was up till 2 am. Researching plugs and plug gaps etc. Have a major migraine. He is the issue the car runs fine till I hit full boost. Partial boost is fine but once I get down on it I have to back off right of way. It detonates or misses. I was told to change the plugs. The car is a 09 GT500. It's has mild modifications like 2.5 VMP upper pulley, 15% Innovators West lower, 127me JLT CAI, 72 me L&M throttle body with L&M high flow elbow and the S/C mouth was port match to elbow. Has full length headers with high flow cats and stinger axel backs. With a Diablo Sport Trinity tuner with performance tune. Driving me nuts. Want to drive the car on Easter. So went and bought NGK BR7EF plugs and so many forums you read state gap them from .028-.039. Looking for advice. There is a lot of knkwledgable people on this site. So please advise, please?

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I know it's like beating a dead horse. But I was up till 2 am. Researching plugs and plug gaps etc. Have a major migraine. He is the issue the car runs fine till I hit full boost. Partial boost is fine but once I get down on it I have to back off right of way. It detonates or misses. I was told to change the plugs. The car is a 09 GT500. It's has mild modifications like 2.5 VMP upper pulley, 15% Innovators West lower, 127me JLT CAI, 72 me L&M throttle body with L&M high flow elbow and the S/C mouth was port match to elbow. Has full length headers with high flow cats and stinger axel backs. With a Diablo Sport Trinity tuner with performance tune. Driving me nuts. Want to drive the car on Easter. So went and bought NGK BR7EF plugs and so many forums you read state gap them from .028-.039. Looking for advice. There is a lot of knkwledgable people on this site. So please advise, please?

 

What plug are you running now have you checked any?

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Those mods are not so mild, with a 15% over lower and 2.5" upper it will be making approximately 20 -21 lbs of boost.

Hopefully you have some fuel system mods as well, your combination is at or beyond stock fuel pressure / injector limits.

I am running a 10% lower with similar intake mods, but also running as dual VMP pump boosters and FRPP 56 lb injectors.

For plugs I am running 1 step colder Ford Motorcraft plugs that are gapped at .032, part number SP-471 AGSF12FM1

With my latest power increase mods (beyond 750) I will be dropping the gap to .030

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