Spark plugs for GN 1s

007gn

Active Member
Hello everyone my question is whats The best spark plug to use for my GN1s that are fully race ported & will be run at @ 28lbs Of boost and what to gap them at. I'm using a 6870 Turbo with 93 n alky on my 4.1. Thanks guys
 

BEATAV8

The Engine Whisperer
Good features to look for:
gasketed plug. gasket plugs are easier on the threads compared to tapered seat plugs. important for aluminum heads.
non-projected tip. non projected tips help to avoid detonation
resistor style plug. resistor style plugs have low EMI and are less problematic on EFI cars.

I like the NGK 5430 but I also run E85. But there's no reason it wouldn't work well for gas and alky.
 

forcefed3.8's

Buckeye Bullet
I run ar3932 but these are non resistor plugs, and some have interference problems with them. Gapped out of the box, which is tight. Any plug on e85, i gap to .025.
 

Nick Micale

Tech Advisor
Staff member
...... important for aluminum heads.
non-projected tip. non projected tips help to avoid detonation...............
I know Champion recommended 103 plugs for their alum heads when they were first introduced, and this was before 109 builds were into the 9's yet.

With alky injection, and now e-85 is also common, my opinion is NOT to use any projected spark plug as this will become the hot spot at higher boost and RPM which can, and does, bring about pre-ignition which will instantly cause damage.

It may take 2 or 3 times at WOT before it actually becomes a complete disaster.
 

whitehot1

Well-Known Member
Nick, thanks for the info. Definitely got me reconsidering my plug choice.
Me too. I've always used projected plugs and never had any problems. But it's hard to argue with knowledge and reasoning that makes sense and backed with experience.

I just ordered a set of 8 NGK 4554 non projected plugs off ebay and they will be here before Friday and that works well for me since i'm doing some things on the car right now. The price of the plugs are less than 1/2 of what they cost in the auto parts stores and free shipping included plus no tax.

I'll run the plugs and see how they work out.
 

whitehot1

Well-Known Member
I received my NGK 4554 non projected plugs today. They all checked out ok with a visual inspection, all are pre gapped at .030''

Will be installing them shortly.
 

BEATAV8

The Engine Whisperer
The NGK 5430 is the only resistor racing style plug I have been able to find.

If you find that you have loss of powerlogger connection when you build boost, try the 5430.
 

vacuum 6

I have chuckers
I run ar3932 but these are non resistor plugs, and some have interference problems with them. Gapped out of the box, which is tight. Any plug on e85, i gap to .025.

I use the ar3933. I believe they are one range hotter from the 32s, out of box gap. I'm running 93 with 10% e85 mix and spraying alky.
 

Heskahoka

Supporting Member
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