Spark plug heat ranges

[85Iroc]

I've been running NGK R5671A-7 plugs on motor and R5671A-9 plugs on nitrous. It seems to do fine with the -7 plugs on motor, and also fine with the colder plugs on nitrous, but it is really blubbery and doesn't want to run pulling to staging/doing burnout before a nitrous pass with the cold plugs.

Question is, since i have low compression (approx. 10.5:1) would it hurt anything, or possibly help, to run 1 step hotter plugs for motor and nitrous???

thanks

[Mike Stark]

Try the 8's for spray. Keep and eye on the strap and make sure it doesn't start to look glassy. Let me know how it runs on the juice.

[85Iroc]

thanks Mike.

It went a tenth and 2 mph faster on the 200 shot than before porting, but,..........my bottle pressure was about 100lbs low and it was very fat, went 6.26 @ 111 mph with a 1.36 short time. I don't have a bottle heater (next purchase) and it didn't 60' as well as before. Interestingly, the previous passes were footbraking and the short time fell off with the transbrake. I'll get a full bottle with the right pressure next time and it should pick up a good bit more, I hope.