What plug (Autolite or otherwise) do you'll like to run in a Stage 2 TA SE head with 12.5 compression and for drag racing only. Thanks; Jim N.
Autolite AR3934 OR NGK R5671A-9 is a hot plug NGK R5671A-10 is a cold plug These are the plugs I have used with the best success. The NGK's have typically given a little better et and better consistency.
Thanks everyone for the info. I been doing a lot of research on this. I'd looked at the Autolite AR 3922 and AR 3911 which are extended tip and the AR 3932 which is regular tip. The AR 3932 is a real cold plug that some use for Nitrous. I'm not sure how cold I can run and not foul but I want to be as cold as possible. Thanks again JIm N.
The NGK have a projected tip verses the AR Autolite have a recessed tip design for heavy nitrous and/or piston dome clearance. I would say the -7 NGK is the one recommended for most N/A guys but I could see an -8. I ran #8's spraying 350HP of nitrous Autolite AR3932 same as #9 NGK I gap them at .025-.030 depending on the amount of nitrous I was spraying.. I think the part # is R5671A-10-Advance $1.98 each the AR3934 is a 8. AR3933 is a 9 and a AR3932 is a 10 R5671A-10 is generally recommended for @500hp nitrous -9 for 300-400HP nitrous -8 for 200-300HP nitrous If you want to know if you spark plug is right heat range for the combination you are running then match the fuel ring on the plug to the inside of the header tube. If the ring on the plug shows a good tune-up then your header tube on the inside should be medium grey or brown, depending on the fuel. If its white or real light grey, then you need a hotter plug and need to richen up the mix some. I enclosed a pic of a AR3933 to show the fuel ring that you can't see very well unless it's cut away. The mix shown is pretty close but a tad rich. It will depend on the combination. Jim, I would think your a little cold using the -9 or -10 plugs but it they aren't fouling then o No: your right with NGK being better since they have a projected tip that puts the spark more in the chamber.
Rick: Thanks for the help and the pic. I've got a couple of different sets of Autolites coming. I will try some NGK's too. I'm trying to get this thing together and to Flordia for the first race in April. I just want to start cold and work my way up a little. I'd always ran AR 12s in my iron Stage 1 heads, was not sure where to start with the Stage 2 deal. Thanks again and hope to catch you somewhere this season. Jim Netherland
Cross reference More plug info AR3932 or AR3933. And if you want an extended tip, AR3910 or AR3911 respectively. I like the Autolite AR plugs as they have a copper core.
I have used the AR plugs for several years with good success. Got my pushrods from Scott Brown today and now maybe I can get it running this weekend. JIm N. P.S. Bet my neighbors will love me breaking in the cam Sat. morning!!
