88ZNX
Let loose the Boost!!
- Joined
- Nov 4, 2004
At least once a week I get asked what spark plug should I be using. First of all there is no magic spark plug. So I started researching this because it started making me second guess my self. After three days on the web reading and comparing and crossrefencing I made a chart of the plugs only for Buick V6s, I didnt get into other engine types to keep it simple. Because this info is based off of my opinion I invite anyone else's opinion also. This chart is for iron and allum. heads and the deferent brands and seat style. I chose the coldest number plug in each type because most racing applacions use a colder and stock plug and our engines are pushing 20,25,30,35 and 40 psi and an 8 to 1 compersion could be as high as 26 to 1 at full boost. You have to find the plug that works with your engine combo and tune. Will you be street driving mostly or track racing, cause an engine thats giong to be street driven on pump gas will need a medium heat rang plug if it only see boost every so often vs a hard core street and strip racer thats in the boost all the time, it will need a colder plug. But again according to the tune. Now the gap, this has been a rule of thumb thing a .035 gap plug should be closed up to around .025, then keep playing with it till you find the sweet spot. For example I allways ran .025 and wile on a chassis dino two yearys ago we pulled the plugs and closed the gap to .018 and picked up 36 RWH with no other change. That dosent mean yours will you just have to play with it.
Our iron heads only use a tapered seat with .450 leanth 14mm thread. There are several version of electrodes, counter sunk and extended, long groung straps and cut back groung straps. The cut back strap is for racing it exposes more spark to the chamber and has a tighter gap. There is a theory that the counter sunk electrode can with stand more boost with out loosing the flame vs an extended one cause it is more exposed to the tornado affect is the chamber. I couldnt find any thing to back this theory up. But it seam's logical.
Standerd counter sunk electrodes in the coldest heat rang I could find.
AC R42T AUTO LIGHT 144 AR132 CHAMPION 121 V59C NGK 5673-9
Extended electrodes in coldest heat rang.
AC R42TS AUTO LIGHT 23 AR55 CHAMPION V57C NGK 5674-10
After calling T/A and Champion I learned that T/A heads take washerd plugs and Champion will accept both tapered and washerd. The thread is 14mm leanth is .750
Standerd counter sunk electrodes with washers coldest heat rang.
AC ? AUTO LIGHT AR3932 CHAMPION C57CX NGK 5671-10 (4091)
Extended electrodes with washers coldest heat rang.
AC rapid fire 5 AUTO LIGHT 3910 3924 CHAMPION C57YC NGK 5672-10
Extended electrodes with tapared seat coldest heat rang.
AC ?? AUTO LIGHT 103 CHAMPION ?? NGK ??
Most spark plug manufacture heat rang is the higher number the hotter the plug. Example AC R42T is the coldest where the R45T is hottest. It seams only NGK is reversed. Example (4091) 5671-(5) is the hottest and 5671-(10) is the coldest.
Now that you know what is available you have to find out what your engine wants.
A plug that is to cold will normally foul out and miss fire but want cause engine damage in most cases. But a plug that is to hot can cause per ignition and detonation, and that will cause engine damage if not corrected.
Please fill in the gaps and give your opinion. List the plugs you are having good luck with.
Thanks Alan
Our iron heads only use a tapered seat with .450 leanth 14mm thread. There are several version of electrodes, counter sunk and extended, long groung straps and cut back groung straps. The cut back strap is for racing it exposes more spark to the chamber and has a tighter gap. There is a theory that the counter sunk electrode can with stand more boost with out loosing the flame vs an extended one cause it is more exposed to the tornado affect is the chamber. I couldnt find any thing to back this theory up. But it seam's logical.
Standerd counter sunk electrodes in the coldest heat rang I could find.
AC R42T AUTO LIGHT 144 AR132 CHAMPION 121 V59C NGK 5673-9
Extended electrodes in coldest heat rang.
AC R42TS AUTO LIGHT 23 AR55 CHAMPION V57C NGK 5674-10
After calling T/A and Champion I learned that T/A heads take washerd plugs and Champion will accept both tapered and washerd. The thread is 14mm leanth is .750
Standerd counter sunk electrodes with washers coldest heat rang.
AC ? AUTO LIGHT AR3932 CHAMPION C57CX NGK 5671-10 (4091)
Extended electrodes with washers coldest heat rang.
AC rapid fire 5 AUTO LIGHT 3910 3924 CHAMPION C57YC NGK 5672-10
Extended electrodes with tapared seat coldest heat rang.
AC ?? AUTO LIGHT 103 CHAMPION ?? NGK ??
Most spark plug manufacture heat rang is the higher number the hotter the plug. Example AC R42T is the coldest where the R45T is hottest. It seams only NGK is reversed. Example (4091) 5671-(5) is the hottest and 5671-(10) is the coldest.
Now that you know what is available you have to find out what your engine wants.
A plug that is to cold will normally foul out and miss fire but want cause engine damage in most cases. But a plug that is to hot can cause per ignition and detonation, and that will cause engine damage if not corrected.
Please fill in the gaps and give your opinion. List the plugs you are having good luck with.
Thanks Alan
