ive got some really crappy autolites that im afraid to even have in my 85 FB
my friend went ahead and got me a set of 4 BUR7EQ plugs
is it best to run 7s/9s or just 7's or just 9's
or is it even alright to run those plugs in the 12A
i forgot to add i have the 1.1 carb 12A engine

 

The 12A is supposed to use the BREQ-14 NGK's. The 7's/9's are for the 2nd gen 13B's. You can probably use them but don't quote me on that.

 

MORE INFO

https://www.rx7club.com/1st-generation-specific-1979-1985-18/whats-best-spark-plugs-165434/

 

First Gens use BR8EQ-14 plugs for all 4 while the Second Gens use the BUR plugs. I use BUR7EQ's in the leading side because I have a 2nd Gen leading coil and use BR8EQ14's in the stock trailing. But when I got my SA it had BUR7 and 9EQ's in it and it worked just fine

 

BR* plugs = first gen plugs, for distributor-type ignitons

BUR* plugs = second gen plugs for direct fire type ignitons

the 7,8,9 are the heat ratings.

For the first gen, BR8EQ-14 in all four is what you use for city driving (they foul less) and BR9EQ-14 is what you use for mostly highway driving (they won't burn themselves out as easily)

In practice either one works in either scenario, one's just better than the other.

For the second gens, they use a different heat ratings in leading and trailing, whereas we use the same heat rating all around.

If you use the BUR* plugs instead of the BR* plugs it won't work as well. They'll work in a pinch but they're made for direct fire, so unless you have a 2nd gen ignition coil on your leading or DLIDFIS you want the BR* plugs

Jon

 

When I ordered plugs for a 79 engine from MAZDA directly, they gave me cooler plugs than for the FB engine'd cars. I don't remember exactly what it was, but for some reason 7 comes to mind.

 

The NGK heat ranges get hotter as the number goes down, so a BUR7 is hotter than the BUR9, etc.

 

run them since you got them. they'll do wonders for reducing carbon buildup on the plugs. start easier, better throttle response, less smelly/sooty tailpipe. but they were designed for direct ignition like others said.

i have used 4 BUR9EQ plugs A LOT and they were just too cold. fouled, poor start, poor throttle response for daily driving. worked better for dedicated road racing.