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.

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

... 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

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.

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.

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............

What's w/those ashy deposits.........

I am currently running Denso iridium plugs for a Toyota Tundra in my 10.9 compression 493 with Indy EZ heads and they run perfect all year long.
I have considered using the twin ground plugs but it runs so well with the iridium plugs why change

Gus

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

All else being equal, Yes!

I had a REAL hard time getting the transfer slots, cruise AFR to lean out, I should have asked you for help its all good now.

OK, this is the first voice with a clear contrary position. Can you share your thoughts on this? Do you think the projected tip is hotter than a standard plug and can act like a hot spot (that was my original thought)?

I'll say this, I do NOT shoot for lean cruise afr's cos we are not efi we have carbs and WET manifolds so richer mixture work/run way better for me and many others I build for. Now I don't mean cruising in the 11's or low 12's but cams w/duration and overlap need to be richer and if I want mileage, I cruise my Ranger..........

What type of plug did you run prior to the iridiums? Did you notice anything on the change?

No matter what the heat range numbers say for a particular plug ( or comparing different brands of plugs), the farther the porcelain and tip is from the plug housing, the hotter it is going to run. The hotter it runs, the more prone to detonation it is going to be. Just because you can't hear it or see aluminum flecks on stuff, or melted ground straps, etc, doesn't mean your engine isn't running in some degree of detonation. Long before there were knock sensors on engines, I worked in a knock lab ( late 60's ) for a large oil company. An eye opener regarding engine detonation. I wouldn't be surprised if over half the build claims I see on this sight ( running outrageous CR's on pump gas )are running in some degree of detonation. It's just not enough to see / hear or to break stuff - but can be enough to negatively affect performance - and definitely enough to shorten engine life. Hence, knock sensors on all late model performance cars from the factory. KNOCK KNOCK, WHO'S THERE -----------. Hey Thumper, how's tricks?

So should I cut back on the octane booster or just see how the RN9Ys look after some road time?

No matter what the heat range numbers say for a particular plug ( or comparing different brands of plugs), the farther the porcelain and tip is from the plug housing, the hotter it is going to run.

I know of another guy in SO CA that worked in a knock lab also, he lead me to use the projected tip spark plugs in iron headed B and RB motors as well as all of the Mopar hemi motors for drag racing and street use
Same information, different conclusions
I had low compression(true 8.5 to 1) pump gas 350 Chevy boat motor that pinged, knocked, on regular pump gas with a Champion J12Y and quit knocking with a Champion J11Y
I worked in service stations a long time ago before they became gas stations only and I have seen many stock motors that needed the spark plugs heat range changed for the driver
Around town only grandma drive differently than there hot rodder grand kids did
Colder is always safer than a tiny bit to hot when it comes to gasoline and different driving conditions and fuel used

You had the same experience that a lot of racers and hot rodders have, they don't hear it until the motor quits or starts smoking
I learned to look at the plugs frequently until I knew the tune up was safe
On my stock 415 HP M.W. on the old 100+ octane high lead pump fuel in 1971 to 1973, it liked the stock J11Y, not the J10y or the hotter J12Y spark plugs. I could hear the difference in idling right away, I could see the differences in on the plugs with one full WOT blast down the street
As far as heat on the plug tip the center porclyn determines what the tip temperature will be, retracted or projected
More porclyn around the center electrode less heat transfer

Same piston exposed to detonation. BTW, never heard it until the damage was done.

Not apples to apples in a power adder situation and I've been using projected tips forever w/zreo issues as long as the carb/timing are where they need to be.............

True. Can't remember for sure, but with the boost I was running the static CR figured out to be around 17 -18:1. Projected tip plugs don't live there.

Plug electrode heat build up transfers through the porcelain to the plug main body. The farther it is from the main body, the less heat transfer there will be and the hotter the electrode will run. What I was always taught.

Smokey Yunick invented the projected tip plug--it has been std equip for 40-50 years now?? They are supposed to idle cleaner and better
I have been a hot rod nut and engine guy all my life --I have never had a better plug or better plug company than NGK--quality is unsurpassed--tech line answers phone on first rings and if you give correct info--all ya need is correct compression ratio--fuel type--and the proper thread engagement stuff like always They will put you ON THE MONEY first time if you give correct info Then you order off Ebay with free shipping and no sales tax and get the best for less--I tell this tale again and again but folks fight it and always have other opinions---
Yes Autolite race plugs and Champion race series are good plugs but tech is almost non-existent and price is just stupid compared to NGK on Egay
Just try call NGK tech which you can Google
These are the best quality plugs available Japanese made --superior quality--Amazing tech support--and best price of all the quality units available
Quit fighting City Hall and try em will ya???

I'd like to see some ACTUAL results from using different brands of the same heat range plugs. I would guess that there wouldn't be much difference to measure. I would have to say yes to the original question. At some point sharp edges and projectile tips will retain more heat in the combustion chamber. Common sense.

Just ordered a set in a 6. See how those do. I put ngk race 7's in and had an intermittant misfire.

Dont know but definitely had more misfires on the race 7's than the projected tip 5's. Could be that running on the edge of rich may not clean off the 7 like it does the 5's. Gonna leave the 7's awhile and see how they work out.

Just to interject something I know doesn't answer the question. The most detonation resistant plug I've seen with in car, and on dyno experience is an NGK 6061-10. That is against autolite AR series, and champions true race series plugs.

Can't copy the pic, but look at the electrode, and strap arrangement in the link.


http://static.summitracing.com/global/images/prod/large/NGK-5962_w.jpg