Spark plug suggestions?

#1

Any ones to avoid, or ones that I should get?

#2

I use Autolite Racing plugs AR52. They are a step colder than stock and seem to work okay for me… You can special order them at Advance Autoparts.

#3

I (and Chuck Baader) like Autolite AR 53 plugs on a pure race car. For a mixed duty car that sees street & track time NGK ZGR5A plugs are a better choice.

#4

Jim, thanks for the post. After checking the box on the plugs I installed last night, I use AR53s as well and not AR52s.

#5

I use stock bosch w8lcr. I avoid platinum. Has anyone tried iridium plugs?

#6

What are the benefits of the AR52’s vs the Bosch or NGK’s on a race only car?

#7

Driving our cars constantly at higher speeds and engine loads causes higher combustion chamber/cylinder head temperatures than on a street driven car. As a result, a colder plug is desired to keep the spark plug electrode in the proper operating range where they work most efficiently. The AR53s are one step colder than the stock plugs. Also, modern plugs last longer; the electrodes erode faster on the OEM copper tipped plugs like the Bosch. That being said, OEM plugs are $2 each vs $6 each for the racing plugs… Stock plugs are likely good enough, but it’s typical to run a colder plug like the AR53s in racing applications. If a plug were to get heat saturated, it could cause detonation. I of course do NOT have any dyno data to back up that racing plugs are in fact more efficient and produce more power, but run them anyway to be on the safe side.

#8

Sorry to resurrect an old thread. I just picked up a set of Autolite AR53’s. For OEM/stock plugs I’ve never really worried about setting the gap. Should I with these? And if so, what should it be set to?

EDIT: The Bentley says 0.07mm for “normal” plugs. Is this the right value for the AR53’s (or any other plug that might go in this engine) as well?

#9

Err… 0.7, not 0.07

#10

Gap them on the high side of the Bentley spec.

#11

Awesome, thanks! Believe the spec is 0.7 +/- 0.1, so I’ll shoot for 0.8.