Are projected tip plugs more prone to detonation, as compared to the equivalent non-projected tip plug?

Probably depends on the combustion chamber design. I use the extra projected, extra wide gap plugs on my pump gas engines. Same part number that the factory puts into the modern engines.

Not if you get the heat range and timing correct for that motor
I like and always use them on all my N/A motors
you should always strive to get the spark as close to the center of the piston as possible

I use this type in my 512, they work great. the spark is not shrouded by the ground strap.

Thanks for the feedback. Anyone see value to iridium plugs? I know the OEMs use them for longevity, but the fine tip seems to produce a well concentrated spark. Would that be beneficial to power production?

those are interesting. whats the part number on those?

bkr6ek & a step hotter bkr5ek NGK I run the 5 in my 9.5to1 512 street car. 4000 miles on them & some track passes, no missfires & they still look great. no signs of detonation.

Regular NGKs at $20 a set.Especially when you reading plugs!

Ill check those out. Thanks

In NGK's, the higher the number the COLDER the plug unless that weird sukka is different...........

yep,they follow the same as all NGK.

An NGK "5" would scare me. I'm not sure I'd use anything hotter than a "7" even for a regular street car, but a lot of that is based on my experience with too-hot heat ranges used in motorcycles.

x2, especially with BB Mopar heads that have the plug sitting almost back to the cylinder wall.

I'm sure I've posted this picture before but here are three plugs I tested in my 470 with the Trick Flow heads. These are all the same heat range and the same brand. Standard, projected and super projected. I use the super projected just because it seems like it should be better but I did not notice any difference on the dyno between the three plugs.

Went 9.79 @ 135+ several years ago first pass ever w/the new combo and a # 7 and my carb was lean as in the 14's up top and saw a tiny bit of peppering so now I run 8's at 12.1.1 comp.........

I think CR plays a big factor. I was using regular tip NGK -7 plugs in my 10.3:1 470 street car, and have been having an issue keeping them clean and would have sporadic misfires driving around town. I changed to some used Autolite 3923 (projected tip) and the plugs look better and I don't notice misfires now. I need to get new plugs and have been pondering what to get. Given my recent tests, I plan on going with -6 but still need to decide exactly which type to get. The "super projected tip" plugs look interesting. Also thinking about trying the fine tip iridiums as an experiment.

Sure would like to see a comparative timing strap read on those three plugs after a good pull. Sure seems that the projected plugs would be risky in a power adder situation.

I run the NGK BKR6E in my 505 , same plug in my 440 . 505 is 11:1.
Never any issues . Under 10:1 NA I would run -5
These are projected plugs.
Only thing with NGK's is they hate being over fuelled .

Tex

That's good info and I like the fact that you race it and get real world tested info which is helpful for some of us in a similar scenario.......Dyno stuff for sure has it's place especially a chassis dyno in a real world load zone simulating going down the street or track but, I still have tried adding more fuel, timing air pressure and launch/suspension settings to get more out of my car and a few others along the way............

Maate !
I am only a slowpoke compared with most on here .

Tex