I am well aware of spark plug heat range/ gap and how it affects the motor. What i am wondering is what spark plug seems to work the best with the high cr motors +/- 13.1 with a standard B-series ignition and 93 octane? I am presently using and have had good luck with regular old NGK V-power plugs. Is there another alternative to the old reliable V-power that may yield better spark? If more details are needed to answer my question thoroughly let me know. Any suggestions are noted and greatly appreciated.

I have experienced no issues, just going for a retune in three weeks and want to freshen everything up. Last tune was on 91octane.

 

No. Not really. At 13.0:1 you're looking at least BKR7E or BKR8s (7 or 8 Heat range).
Stick with NGK/Denso, and you'll be fine.

 

Thanks for your suggestion Shodan. Lots of people looking at the thread, but no comments. Hmm

I called King Motorsport today and asked the same question. Mike L's response was to use the BKR7/8 or if you want a plug that will last a little longer use the Iridium. Kinda figured I would stick with the old idea of "if it ain't broken don't fix it". But, due to technology always advancing there may be something new on the market. Guess I'll just stick with the $2 V-power.

For others who may wonder.... I am presently using a NGK V-power R5671a-8 gapped @ .040 and right at 12.8:1cr in hot Florida. This a non resistor plug.

 

i prefer the NGK Iridium plugs, in the stock ITR number - BKR6EIX-11.

they did smooth my idle out compared to the platinum version NGK.

i'd look for them in the 7 or 8 range as stated, or try the 6's and see if they are too hot for you...

 

Interesting to hear the Iridium plug smoothed the idle over the platinum. Good input.

 

yup, they did...

and i'm not in the 13+ C/R either, just a measly 12-ish... hence why i can still run the 6 plug and not see any difference between it and a 7.

 

I have had very good luck with Autolite 3923 as I saw a gain on a few customers cars with a couple HP on the dyno back to back with iridiums,but I havent used them on more than 12-1 CR.

 

Wow, never thought I would hear of an Autolite plug being used on a Honda.

After more research a few people have claimed glitches with electronics when using non-resistor plugs. One person even said "do NOT use non resistor plugs with Hondata S300", but did not state why. Guess that rules out the V-power Racing plugs.

 

I find this interesting because when I first ordered new plugs for my car obviously they gave me the 6 heat range looking it up on the computer. Then I realized the JDM motor came with 7 heat range.

I said eh the 6's run fine why bother. So I pulled the plugs just to make sure they looked ok with the 6 heat range. It was easy to see that the plug was too hot for the motor at 11.1:1 compression. It wasn't melted or anything but it was a bit too white to my liking.

I said what the hell I have some BKR7EIX (Iriway's from Japan) in a box in the garage. Put them in and instantly noticed a difference. It seemed to run just overall smoother especially up top! Did a plug check and they were a nice tan color. Now the 10,000 mile BKR-6EIX-11 are the spare plugs. Just to verify I wasn't crazy I through the 6's back in there and said WTF I had no idea the heat range could be that noticeable.

Looking at the heat ranges for plugs, I think it said if the cylinder temperatures are 200 degrees hotter,making 100HP more all motor, and/or the motor spends a lot of time at higher RPM's for long durations then the next heat range should be used. Mind you ignition timing advance makes more heat and usually when we tune or modify a car that is one of the things we change.

 

mine come out tan like they are supposed to...

i don't run any crazy ignition timing, and a fairly conservative tune as well...

my next engine, however, will probably require a much cooler plug...

 

I am sticking with a 8 heat range plug because of my CR. I've decided to use the bkr8eix to install just before my fresh tune. 9's were just a little too cold for daily driving. Dead of summer and on the road course they were fine.

As I said before I've had no issues in the past. Simply retuning for 93octane (currently 91) and a different climate. Anyone have input on 91vs 93 octane tuning?