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View Full Version : GT500 Spark Plugs


Justin@VMP
July 20th, 2009, 05:40 PM
There is a lot of talk about changing spark plugs, even on mildly modified cars, in my experience it is a waste of time to change plugs if your stock plugs are not worn out.

There are a lot of myths out there about plugs, such as plugs that make more power, or plugs that increase MPG, or plugs having an effect on A/F. None of that bogus BS is true.

If your car has 10-20k miles on it and is driven like a GT500 should be, then I would replace the stock plugs when you do mods, as they are getting close to being worn out at that point.

If you run more than 16psi I would replace stock plugs.

When you replace plugs you can go to a copper plug that is colder like the TR6 and gap it down to .035" (stock is .045"), but also keep in mind they will need to be replaced more often, I only get about 3000-4000 miles out of plugs on my GT500 due to the high output and all the abuse it sees.

If you are running 16psi or less and don't have a ton of miles, I would not worry too much about plugs. The 4v chamber does not benefit from a super cool plug like some other less efficient chambers.

If you don't need the plug change then I would not waste the time or money on it, and that is the case with most GT500s that just have a tune/cai/pulley.

Black09
August 4th, 2010, 05:06 PM
So, a stock plug is fine running 2.65 pulley / intake / and tune?

Thanks,
Jason

Justin@VMP
August 6th, 2010, 10:35 AM
So, a stock plug is fine running 2.65 pulley / intake / and tune?

Thanks,
Jason

Yes.

2008gt500nl
November 5th, 2010, 12:20 PM
What is the suggestion for the gap for the stock plug.

Justin@VMP
November 8th, 2010, 10:13 PM
stock is .045", which is fine for 13psi, around 15-17psi i would drop down to a .035" gap

2008gt500nl
November 9th, 2010, 01:59 AM
Justin,

What would you suggest (I have no idea about the amount of PSI) for a CAI and Pulley with tune.

And I assume that 0.035" is inches (-:

Dris

Justin@VMP
November 9th, 2010, 04:27 PM
yes, inches, right now your car makes about 12-13psi

2008gt500nl
March 22nd, 2011, 12:19 PM
What would be the recommandation with the TVS and upper pully

what plug
what cap

Thanks