Does anyone know if the stock plugs are adequate for the supercharger? I know that on civics and stuff we had to swap them out for colder plugs. If this is true, which do u guys recommend?

 

Chris,

While I don't have a supercharged S2K, my CRX is blown and I've had a lot of time to experiment with plugs.

I originally was using the colder of the two recommend copper factory plugs. However, that really wasn't cold enough (9.1:1 compression, 8 psi of boost, racetrack conditions). That forced me to go to some expensive ($13 each) platinum plugs from Japan that were one heat range colder. Cured me of any heat related problems, but no performance increase (mild durability increase).

Recently, it was time to put in new plugs again and I decided to try the new Denso Iridium plugs, mainly because I could go 1-2 heat ranges even colder. I also liked the fact that they require less voltage to arc for a given mixture/engine/etc.

I put them in the car and went about my way, didn't really notice anything. However, over the next couple of days the car really seemed smoother in almost every situation, and it seemed to pull harder at high rpms/high boost. I also got rid of a hot misfire that occasionally showed up, always at 6000 rpm. I haven't dyno'd (and it wouldn't have been fair unless I compared new platinum and iridium, used to new doesn't work), but the car has never run this smooth. With the stock ignition and boost, you're pushing the limits of what you can ignite. There is a certain range of pressures and mixture that can be ignited for a given voltage. Go too high, too low, too rich or too lean and you misfire. I'm betting that I've reduced misfires on my CRX now. Even if I went from 1% to 0.5% misfires, that would be good for 1-2 hp.

Whatever the case, I'm sold on the iridium since I don't have to order them from Japan and they're cheaper than what I was using before. I'll try them on my NA S2K, although I don't expect any gains. In your case, I'd recommend going at least one heat range colder than stock, maybe two, and try the Densos, I was really surprised.

UL

 

I just installed the Denso Iridium plugs in my supercharged S2K. The difference is very noticable. The car seems smoother and seems to do better off the line and all around. I would highly recommend them. Note however, if you are considering an aftermarket ignition (MSD, Jacobs, etc) don't use these plugs. Denso says they will work, however, the tuning shops I have talked with say differently.

 

Can u tell me the part # for those plugs so I don't have to dig up that info? I'd help speed up the process for me.

Thanks

 

Chris,

I used Denso iridiums part number IK22. I'm sure you can go colder if you desire (don't have those part numbers). So far the IK22's seem great. I ordered them from Monarch Products (cheapest I could find and they have the plugs in stock). They can be reached at 909.672.8501 or from outside CA at 888.800.9629.

For piece of mind, I would recommend you check out the Denso web site at www.densoiridium.com.

Best of Luck!

 

IK24's are the next colder
order direct from Denso

 

Being fairly ignorant in the area of spark plugs, can someone please define what a "colder" plug is and why there are multiple steps. Why is colder better for SC/Turbo apps and so on?

Its always been a mystery to me.

 

Thanks guys... i orderd my denso's today. Their web page also describes the diff's between hotter & colder setups.

 

so what'd you get, short or long insulator? (a small test to see if you really read the stuff on heat ranges )

 

The application guide shows to get the IK22's. I'll start w/ their recommended plug before going colder (shorter)