spark plugs for track use
there’s no shortage of people to hang out with in the won’t take heed to sound advice club
how they look is meaningless in a rotary; whether they fire or not under high load is all that matters
you probably have them gapped too wide anyway since nobody thought to bring that up, especially if they’re the RX8 rotary specific plug ...
how they look is meaningless in a rotary; whether they fire or not under high load is all that matters
you probably have them gapped too wide anyway since nobody thought to bring that up, especially if they’re the RX8 rotary specific plug ...
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Hey did you ever do the dyno tuning with Steve? Results?
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I tapped them and will be going colder once I am able to get the plugs. Especially for the longer tracks with more wide open straights. I tapped them myself after using a search on here cause I didn’t want to be that guy.
I know rotary’s can’t be read like normal plugs hence why I said for what’s its worth which isn’t much.
Steve has not got back ahold of me. He said they had some dyno issues and that got the shop backed up a bit. So just waiting to hear from him.
I know rotary’s can’t be read like normal plugs hence why I said for what’s its worth which isn’t much.
Steve has not got back ahold of me. He said they had some dyno issues and that got the shop backed up a bit. So just waiting to hear from him.
Good discussion. One other thing you should look at with plugs is coils & leads... with ~20 track days per year I figured I needed plugs once per year and coils+leads every two years.
Or get aftermarket coils, but then you need to do more research on what really works.
Based on this thread I should probably be running colder plugs though. I've been running NGK RE7C-L + RE9B-T and can't say I've noticed an issue with running hot on track aside from the set that came out of a failed motor that I probably left in too long.
For tuning, MazdaEdit worked on my series 2.
Or get aftermarket coils, but then you need to do more research on what really works.
Based on this thread I should probably be running colder plugs though. I've been running NGK RE7C-L + RE9B-T and can't say I've noticed an issue with running hot on track aside from the set that came out of a failed motor that I probably left in too long.
For tuning, MazdaEdit worked on my series 2.
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another one to consider for those losing grounding straps, available in -8/-9/-10/-11 heat range and only 19mm deep
I think Motorsports only carries -11,
-10 is the recommended minimum, -11 is preferred
https://www.ngk.com/ngk-4586-r6601-11-racing-plug
.
I think Motorsports only carries -11,
-10 is the recommended minimum, -11 is preferred
https://www.ngk.com/ngk-4586-r6601-11-racing-plug
.
Last edited by TeamRX8; Jun 1, 2021 at 11:13 PM.
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PM sent.
I red this on racing beat web page regarding the spark plug gap recommended for high RPM/track use. Looks like they gap down their plugs to .015" ? Can NGK 7420/6725 even be gaped?
When using our Racing Beat recommended spark plugs in street applications we find a gap of .020" to be a reasonable compromise. When using the following plugs for performance applications: BR7EIX, BR8EIX, BR9EIX, and BR10EIX - we recommend a gap of .015". We recommend that a drop of engine oil be applied to the threads, and using our Thin Wall Spark Plug Socket.
I also checked RockAuto and they have above mentioned Denso iridium plugs in stock in 9 leading and 10 trailing heat range - these are equivalents of NGK R7440-9 and 10. They also have NGK R7420-10 and R6725-10.5 in stock as well. Out of those I can only get R7420-10 by Friday, rest next week.
I red this on racing beat web page regarding the spark plug gap recommended for high RPM/track use. Looks like they gap down their plugs to .015" ? Can NGK 7420/6725 even be gaped?
Spark Plug Gap/Torque
Virtually all modern stock engines use relatively large plug gaps for good idle and emission purposes. However, as power and RPM increases, large plug gaps require more and more ignition energy to fire reliably. There is no exact relationship, but expect to reduce plug gap as power and RPM increase. In all high output race engines we use a gap of .015". If the gap erodes to .020" or more, power loss usually occurs.When using our Racing Beat recommended spark plugs in street applications we find a gap of .020" to be a reasonable compromise. When using the following plugs for performance applications: BR7EIX, BR8EIX, BR9EIX, and BR10EIX - we recommend a gap of .015". We recommend that a drop of engine oil be applied to the threads, and using our Thin Wall Spark Plug Socket.
I also checked RockAuto and they have above mentioned Denso iridium plugs in stock in 9 leading and 10 trailing heat range - these are equivalents of NGK R7440-9 and 10. They also have NGK R7420-10 and R6725-10.5 in stock as well. Out of those I can only get R7420-10 by Friday, rest next week.
edit, it shows up as " NGK 5501"?
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another one to consider for those losing grounding straps, available in -8/-9/-10/-11 heat range and only 19mm deep
I think Motorsports only carries -11,
-10 is the recommended minimum, -11 is preferred
https://www.ngk.com/ngk-4586-r6601-11-racing-plug
.
I think Motorsports only carries -11,
-10 is the recommended minimum, -11 is preferred
https://www.ngk.com/ngk-4586-r6601-11-racing-plug
.
but it appears that the 8 and 9 heat ranges are NLA...
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would any of those plugs work for this mix?
on my white rx8, i used oem plugs for 4 years with this sort of mix. not saying i didn't do any damage, but i didn't foul and it ran pretty good overall.
Last edited by hufflepuff; Jan 19, 2022 at 11:45 AM.
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just change out the plug at the event? it's not that big of a deal to change out leading plugs. and just run oem trailing plugs all the time. do you keep your track pads on for daily driving also?
the rotor housing plug holes likely had a lot of cracks and the apex seals were jumping and flying off of the overheated spark plug mountain pretty good.
Last edited by TeamRX8; Jan 17, 2022 at 11:02 AM.
85 cylinders, 6 rotors...
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Can you describe how the spark plug heat range contributes to this in a rotary? Is it detonation, or the fact that the plugs are recessed, and the overheated tips cause local hot spotting in the aluminum? I understand what a too hot plug does in a piston engine, but I can't understand how these characteristics, which I know exist in race/high power use, can be attributed to plug choice in the rotary. Since you have been racing this engine longer than anyone here that I know of, I know you have researched this thoroughly. Please let me know.
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i plan to tear down my white car engine in the near future and will take detailed notes and pictures to share with the community.
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welp, i bit the bullet and ordered the NGK R6601-10, part number 4017. NGK.com actually had them for <$21/ea and free shipping. i am hoping the -10 heat range will work well for my dramatically variable usage. will report back...
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i suspect i will probably foul them before the nickel electrode wears out, but we will see!