I believe my spark plug heat range is too hot now.....

Hey all,

Since I installed the super zap ignition system, my plugs have been incredibly clean. Possibly too clean. I am using BP6ES, but am thinking of going a step colder to BP7ES. What might be the advantages/disadvantages be?

Jetting is 135 main with 170 a/c. Great WOT a/f around 13:1.

 

I will clarify a bit regarding what is running through my head.

After a WOT spark plug check (or any for that matter), the plugs are bone white. The ground strap is tan but the ceramic portion is brilliant white. I am thinking if I go down one heat range, the plugs may load up a tiny bit at idle but they won't get so blazing hot at higher rpm which may even out my flat spot.

 

see the "reading spark plugs" thread ... I'm running 12:1 compression also ... I had an issue and I thought it was plugs ... I had 6's and 7's in my motor and did not blow it up running it in the red all the time ... I was looking for a reason to run expensive plugs and haven't found it yet but I don't have a dyno to tinker with .... only the track

you need to cut the plugs apart or need a good magnifying glass to see the dark ring at the base but 13:1 sounds lean to me at WOT (I think ... my motor hasn't blown up yet )



cheers

 

Hey I have it in the upper 12.7ish range for most of the upper rpm range but it does hit 13 way up high. 140 mains is a bit too phat. I am thinking of trying maybe a 180 a/c with 140 mains and see if that gets it in the low 12s

 

Dude ... you know more than me about plugs ... my knowledge is limited to the "reading spark plugs thread" and the last few years of experimentation ... before that all I knew was the bloody wall chart at Kragen .


cheers

 

I have a NGK catalog and the recommended plug is a BP7ES with .6mm electrode gap.My newly bought GT4 has 8's which I will be changing!
Geoff