GLHS spark plugs

[87glhs]

Can anyone recommend a better replacement plug for the stock RN12YC?

I've been thinking of trying a set of the NGK V-Powers--any feedback on these? I see FWD recommends them on their site but am unfamiliar with the product. I'm running a standard/OEM ignition setup.

I have though tried a set of the NGK platinums in a Toyota p/u (2.4L FI) I drive but wasn't impressed at all with their performance or longevity.

Thanks--

[black86glhs]

I run the GR-4 or 5....can't remember off the top of my head which one. They are an excellent plug.

[GLHNSLHT2]

Autolite AR51's. Cut back electrode for better flame propagation. Just as cold as an RN6 but will make a stock engine run better than stock plugs.

[87glhs]

Well, I ended up trying a set of the NGK V-Power (GR-4's). The V must really stand for "Vvvrroomm" as these plugs increased my HP at least 5-7%. No kidding. I've never been into various manufacturer's theories about why their plugs are better--and still can't find any verifiable data other than testimonials--but they're a definite improvement over the stock RN12YC's.

I'm also anxious to try out a set of the Autolites, but will wait until next year.

Last, I tried a set of the NGK Iridiums on my Toyota p/u. It actually needed plugs--old ones were worn to .060"--so anything I put in there would have been an improvement. Surprised the old ones even fired. I've read that the iridiums are supposed to use less voltage to fire, promote better gas mileage and last longer than a standard plug, but I have doubts. I think a hot, fast spark would provide more power than a weaker, small one. Time will tell.

Thanks again for the info.

[Marcus86GLHS]

i run the NGK V-power plugs in my GLHS for years now and I have also found the car seems to respond better than when using Champion 9YC's. I set the gap at .030" since i run 18-20 psi boost.

[supercrackerbox]

What Marcus said, but substitute Charger for GLHS.

[shackwrrr]

I am thinking that you had some detonation that going to colder plug helped out.

[trannybuster]

Is setting the gap wise, its a big no-no on snowmobiles because the electrode is laser welded and bending it could crack that thin weld. I use the NGK br8ecs..wondering if the same applies for cars?

[supercrackerbox]

I am thinking that you had some detonation that going to colder plug helped out.

Me, or the original poster? I've always run those in the Charger since I've owned it, and the cross-reference catalog says the GR4 translates to both the RN12 and RN9 Champions.