Question 1.
Which is the better plug for forced induction applications?

p600b blower 10 psi max boost, meth/water inj, 9.7:1 compression, lloyd elliot 224/236 114 LSA cam. 1 3/4" long tubes; stock bottom end.

these would be on afr 195 eliminator comp port heads that I am installing.

thanks.


Question 2.
I also see they make an AR94 - which im assuming is a cooler plug.

However, I dont know if I need that one. I guess the car ran fine (old ported heads, and hotcam, w/ 11psi boost on the p600b, stock 10.5:1 compression w/ meth/water injection) on the TR6's.

Though I am putting in Lloyd Elliot cam and putting way better heads on....prob an extra 75 rwhp. Up to 545 rwhp-ish is my guess.

Would you go a heat range cooler than what worked before (NGK TR6)?

 

Neither. You need a gasketed plug with the AFRs. 3/4 reach.

 

Huh? Afr tech support (jason) recommended the autolite ar103.

What would you run?

What do you mean by 3/4 reach?

 

I'm pretty sure AFR heads have a 3/4" thick deck, not sure which plug they use tho

 

99.99% sure AFR, Trickflow, etc use a gasketed plug as opposed to a tapered plug la TR6.
Something like:

Autolite AR3923 - Autolite Racing Spark Plugs - Overview - SummitRacing.com

or

NGK Spark Plugs 6962 - NGK V-Power Spark Plugs - Overview - SummitRacing.com


Stock heads use the tapered plug.
I run a gasket plug, .75 reach in my Trickflows. A cold range 6 sounds fine.

Do a search on your heads and plugs.

 

The non-standardization of terms and enumerating heat ranges is maddening. I have rare Canfield LT1 heads on my car now and some TFS 23 LT1's that are about to go on. I asked around and found most references pointed to a AR3910 Gasket plug with .750 (aka 3/4" reach) length, 14mm thread. These plugs were $3.50 EACH and fouled in no time. After lots of reading, I found the Autolite 65's are the perfect plug for my turbocharged street car. It's a cheap plug(about $1.22 each), the color on them after 6 months is still a light tan.

 

That is a heat range 5. Isn't it too hot? They have an Autolite 66 which is a heat range 6 as well.

 

I pull my plugs for a visual inspection periodically and the color is a light tan. When I was using the colder plugs, they fouled fairly quickly. Black, sooty and it causes misfires. Now it's perfect.