Charlie944

Has anyone ever tried "non-projected" tip spark plugs such as: NGK BR7ES? I have read a couple books on auto ignition performance; one of them by Dr. Jacobs of Jacobs Electronics. He and others bring up the point when using forced induction, or N2O to use a non-projected tip to reduce the chance for creating hot spots. This situates the spark ~1/16" into the combustion chamber, versus a projected tip that situates the spark an additional 1/8" into the combustion chamber. I know these plugs are commonly used in motorcycles and snowmobile engines. Do you think throttle response would suffer?
TIA!

hacker-pschorr

Bump - did a search on this topic, didn't find very much.

Curious what your thoughts are.

My friends 928 with 951 pistons (about 8:1 compression) and 15lbs boost is running br8es plugs with no fouling.

A friend of ours who is an AEM guru uses the BR8ES plugs on every high HP car he builds. His daily driver is an Eclips with 718 wheel hp (AWD) does 10.6 in the 1/4. He was suprised when he found out we were using standard protuding electrode spark plugs in our cars under boost.

I was searching the 951 forum for spark plug info to see if any of you guys wer running the non-P NGK plugs. Since my 928 is the 16V, I have the same heads as the 951 (just smaller valves). I plan on running the BR7ES plugs until I turn up the boost.


I originally bumped up this thread:
https://rennlist.com/forums/944-turbo-and-turbo-s-forum/248525-high-hp-spark-plugs.html
Until I realized who started it - removed my post.

Charlie944

Hacker, I did run BR7ES's for a while in my Callaway turbo. I noticed a significant drop in EGT's
(over 50C). I was starting to foul some out though due to some blowby though so I went back to a projected tip plug. I might play around with them again though when at the track this season. Last year I was suffering from really high EGT's (900-950C+) but I feel this was in part due to my clutch was slipping and I was having to run partial throttle although higher rpm's. All of which are recipies for higher EGT's. I have been looking more into a water/meth injection kit to help with higher EGT's.

I might have to go to a dyno and play around with my TEC2 EMS to get the timing spot on too.

The spark plugs are fairly cheap Hacker so go ahead and play. I would suggest getting a EGT gauge if you have not already to monitor your temps.

hacker-pschorr

Thanks Charlie - suprised this isn't a popular topic around here. Maybe it's just me

What plugs are you running now, the BPR7ES? Same plug with the regular tip?

What is the stock NGK number for a 951? I would assume #6 heat range (same as 928).

10 of these at Fleet Farm are $16

Charlie944

I am currently running BPR6ES (951 stock heat range) due to I was running the car into late fall last year. I do have a BPR5ES (944 NA heat range) in cyl # 1 to help it from fouling out sometimes in low rpm traffic. During the summer I played around with BPR7ES's and while they do help a tad with EGT's it was certainly not as helpful in lowering them as the non projected tip plugs. I might try and go with some BR6ES or a BR5ES too. I want to find my balance with no fouling plugs and keeping EGT's safe. Ultimately I need my timing looked at and I still may go with a Water/Meth Injection.