I have bought a set of HKS Iridium Plugs for my 96 RX7.

I fear that I have may have bought the wrong heat range (Heat Range 10) for my car.

Should I have purchased the 9 Range plugs instead?

Many Thanks....

 

10's are fine... but don't let your car idle for long periods of time. They might foul. I also use an entanol based gas to keep the plugs clean. But with the highest octane.

 

Thanks for the reply Racer RX.....

Do the plugs foul up because they don't reach their proper operating heat range?

Judging by your reply am I right in thinking that the use of higher octance fuels helps keep this problem at bay?