Best Spark Plug for 1P57?

[Blueboy5000]

The 1P57 runs slightly hotter than the 157. It also produces more power and slightly more oil pressure.

So basically I have questions:

1) What is the best plug for a 1P57?

2) Would a colder burning plug decrease performance?

3) Is there really a difference in Iridium and Platinum plugs that is significant? Both should run slightly cooler than conventional plugs, and be harder and thus more resistant to warping and distortion than conventional plugs.

I know platinum and iridium are the bee knees for 2t engines, with iridium being clearly superior to platinum, is this also gospel for 4t engines?

Any info appreciated1 Thanks Dawgs! ;D ;D ;D

[rscotth]

I have a 1P57 as well with a ported and shaved head which theoretically raised my static compression 1 point. I am still using the CR7HSA with no issues. I would comment on the iridium CR7HIX but I'm still waiting on it to arrive with my backordered gasket set.
I really don't see a platinum or iridium plug running "colder" if it has the same heat index. The way spark plugs are made to run cooler or hotter is from the insulator nose length and that corresponds to the number on the spark plug (NGK's) CR7XXX. Lower the number the hotter the plug CR6XXX. The higher the number the cooler the plug CR8XXX.

3) Is there really a difference in Iridium and Platinum plugs that is significant? Both should run slightly cooler than conventional plugs, and be harder and thus more resistant to warping and distortion than conventional plugs.

Iridium and some platnum plugs have a very thin, long conductor. This electrode design heats up and cools down very quickly in response to changes in engine load. This may be what your refering to with them running cooler.
Everyone loves them on the GY6 and claim easier starting and smoother idle. I have one on order.......

www.ngksparkplugs.com/tech_support/spark_plugs/p2.asp?mode=nml

[sprocket]

Use a standard CR7HSA and side gap it.. better than iridium.. more spark visibility to the combustion chamber.

easy to do.. good tutorial here

scroll down
www.sr20-forum.com/naturally-aspirated-all-motor/16898-how-side-gap-spark-plugs.html