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so far, so good. these have around 500 miles on them and a significant amount of 3rd gear pulls. 93 pump and about 40% ethanol with about 600 cc of 100% meth. i am runnng off the wastegate spring at 15.9 psi about 500/535 hp. G40-1150.
calculated power is backed up my 72 to 100 mph elapsed time. just under 12 mph per second. and this is at 2650 altitude.
one observation is that the threads on the two lower plugs have oil on them. i purposely removed the crush washer on two of the plugs, the lowers, to compare to the plugs w crush washers. the top plugs have zero oil on the threads. going forward i will use the crush washers and not obsess on the plug depth. the rear lower looks like it may be running hotter as evidenced by the partially clean face. this jibes w my knock readings being higher in the rear. i have been running 10% more fuel in boost in the rear and for the last run lowered it to 5%.
the last run was a bit different in that i removed the ProMeth nozzles and swapped in two old fashioned M15s. my IAT dropped 125 F! meth does work i made 532 hp at 15.8 psi boost and 10.44 AFR on 32% ethanol.
i also now have a Radium Surge tank and lift pump. the prior run w 7.5 gallons in the tank i got a stutter from fuel starvation. now w the Radium setup that is gone.
will post a few graphs and further comment later today
Last edited by Howard Coleman; 04-18-23 at 02:36 PM.
I was thinking about a way to make the R6601 plugs fit perfectly. I have a friend that has a CNC machine and a plasma cutter, whichever would work best. Could I get him to cut back the steel collar on the plug by 2mm and use a tap to finish the thread up to the newly cut back collar. This would allow the standard washer or a new crush washer to be used. Since I don't have a R6601 plug right now, can someone who has one measure the collar length to see if 2mm can be removed and still have enough collar left to safely use the plug? What does everyone think? Would it work? If it does, he does do side jobs and I could get him to potentially make batches of them for sale if the needed volume was there.
Mike
that's waay too simple a fix, it needs to be more complicated... it might work. i will do a quick measure for you and post it. it might just be a nice biz opportunity for you. of course we won't know if it works til we give it a spin.
here's a comparison:
the 6601 has a four mm flange. you would not need to add further threads. i think it is quite possible that the removal of half of the flange would work fine structually... as to whether the mod would help combustion, it would just be give it a try.
if you do a set of 11s i would be happy to try them.
Last edited by Howard Coleman; 04-20-23 at 07:56 AM.
as of yesterday i hadn't gotten around to properly tuning the AFR at zero TPS decel. i generally see 9.0. while that is great for apex seal lube it is not so great for loading up the plugs w fuel... in this case 85% gas, 15% ethanol. i have around 500 miles on the 11 surface gap plugs and all was fine until yesterday. i encountered a red light at the bottom of a long hill near Sylvia on my way to the DGRR. when i pulled away it was clear i had lost fire in one rotor. it did clear and ran fine to Bryson City. really fine. on the way home all was well until i headed down a succession of lengthy declines. looking at the 9.0 raised my pulse a bit and i did eventually shift to neutral but found just N of Franklin i was back to one rotor. this time it didn't clear and i called wifey. about an hour later she arrived w sparkplugs and tools. i swapped in a couple of 7420s and had a happy motor. this isn't a knock on the 11 surface gaps, rather it is on me for not lightening up the fuel a bit on decel. thought you might like to know.
that's waay too simple a fix, it needs to be more complicated... it might work. i will do a quick measure for you and post it. it might just be a nice biz opportunity for you. of course we won't know if it works til we give it a spin.
here's a comparison:
the 6601 has a four mm flange. you would not need to add further threads. i think it is quite possible that the removal of half of the flange would work fine structually... as to whether the mod would help combustion, it would just be give it a try.
if you do a set of 11s i would be happy to try them.
Good news! My other friend, who runs a high-end machine shop that does work for ULA (United Launch Alliance-Delta 4 rocket people) as well as Marshall Space Center (NASA), said he should be able to machine down the collar on the 6601 plugs. He is going to do a test on a sample spark plug next week. If it works, I will order several new plugs and have him do a batch. Howard, I will send you 4 to try, If they work well, he would be able to do more. If others are interested, I could see if he would do this on a regular basis and make a small business of this.
Mike
good move i will be happy to run them. it is neat to do something that hasn't been done. i can't imagine why they wouldn't be better. PM me and i will send you some $ for the plugs/shipping.
Just wanted to add that the NGK 6601-11 with the factory crush washer in the trailing are working out exceptional well for me! I am not sure anyone would need to do anything fancy, at least in the trailing location. I'm using Denso Iridium 5722 IRE01-34 11 in the leading gapped to .023. Power is really clean. Tuner mentioned it was much cleaner then my older setups and knock was extremely quite. Very very easy 600 whp on E85 with quite a bit more in it. Also limited it to 8k. I only stopped because my CPR motor only has about 1300 miles or so on it. Highlights of my setup are CPR built motor (thanks Howard!), Motec M150, M&W CDI and BW 9180SXE with 1.10 AR.
there is an old pre-Mazda design where the plug is in the rotor, huge advantage as then the gap is actually in the combustion chamber...
bad part is that to change plugs engine comes apart
This is describing a real Wankel rotary engine (DKM), what we use is his assistant Paschke's (KKM) rotary engine because materials science was not advanced enough for the Wankel rotary to even be as reliable as Paschke's rotary.
To change spark plugs on a DKM one removed a cover plate on the stationary housing and rotated the engine so that the spinning rotor housing exhaust port aligned with the spark plug on the spinning rotor face and removed the spark plugs through the exhaust port.
The centershaft was stationary and also the intake . Because all the rotation was cocentric they tested it up to 26,000rpm without issue.
The DKM Wankel rotary engine could not be a viable production engine at the time as the steel rotating rotor housing kept warping. Ceramics would solve this issue.
I've confirmed I'm running well with a standard Denso Iridium 11 in the trail (color looks perfect after a fair amount of mixed miles), so will be giving the 6601's a try in near future. What would I look for to confirm they are performing similarly well or better?
typing from my smaller surface while my laptop keyboard is getting replaced... i typed a response yesterday but just as i finished i managed to delete it.
just to review there are two considerations in play here.
heat range
surface gap
heat range
IMO is settled. run the coldest plug that works for you. colder plug =s less rotor housing distention. this applies to everyone, whether you are running the stock twins or doing crazytown. i have built over 180 13BREWs and other than the 10 or so which were new blocks all arrived with an elevated spark plug boss. mostly lower but always a small amount upper. a really good ignition system has always been important because the motor at any stage of output develops high combustion chamber pressure. often misfires (the result of inadequate ignition) are not noticeable unless you have a dyno plot at zero tuning. the second reason for having a really good ignition system is so you can fire colder plugs. colder plugs = less apex seal wear.
surface gap plugs
Mazda delivered our cars with special spark plugs that did NOT have a single ground strap. the reason being the risk of pre-ignition and detonation from a glowing ground strap. has anyone on this board broken the tip of an OEM apex seal... detonation was the culprit. surface gap plugs eliminate the ground strap and give the spark 360 degrees to find the easiest ground. while this is all the theory, and i buy it, the reason i made the switch is because a person i value, and have valued during the last 15 years says they are absolutely necessary to reduce detonation/pre-ignition at 500 or above. i bet they will contribute positively at any power level. further, since i posted this numerous people have come forward to say that they have been running the 6601s at all 4 positions and they have observed less knock as well as other positive metrics.
theory, check.
practice, check.
sign me up.
Peter, good for you for swapping in the 11s. as to the next step and your question: i of course traveled the same road a few months ago... the how do i know road.
11 surface gaps in all four positions. warm up on a cold day initially was just a little ragged. i did a bit of work leaning warm up a bit and now find they start cold no different than my 10s. i found, similar to others, that my knock readings were a bit lower. since they lack the traditional ground strap there isn't a way to read temperature. color seems similar to a traditional plug. if you do find yourself on a dyno of course you would want to look at zero smoothing for misfires. i did make 539 rwhp at 15.9 psi w my setup (G40-1150) so they do make power which wasn't a surprise... so my takeaway, so far, is similar to others who have run them. i did learn that it is best to leave the crush washer on the plug... i wasn't particularly surprised to learn this... the washer seals any leakage through the threads... i found oil on the threads.
i did foul one of the lead plugs driving thru the mountains. my fault, not the plug. my AFR was 9.0 on decel and i had some prolonged coasting down hill. easily fixed by retuning that small portion of my fuel map. i had driven with the plugs for more than 1000 miles w no fouling... it was the prolonged decel from some lengthy downhills that did it. just an FYI.
Last edited by Howard Coleman; 05-31-23 at 09:36 AM.
came across this plug in a rotary engine drag car video with a mega ground strap, used in blown alcohol hemi drag engines, 19mm reach, non-resistor and nickel electrode though, but only $10
a twin to the Autolite AR3932. /19 mm, sort of no shroud on the center electrode. and also a non resistor. non resistor often shuts down the ECU. the AR3932 has been Autolite's highest volume racing plug for many years. i really like the fact that the 6601s are resistor and the spark has a 360 degree option to reach ground.
R6601 spark plugs are at the machine shop to have the collars cut back by 2 mm. Should have them back next week if everything goes well. Howard, PM me your address to ship 4 plugs to you once I get them back. I will post a picture of the altered plugs once I get them back.
Mike
FWIW I got a box of those copper washers that somebody shared early in the thread. They are super thin, and certainly thinner than any regular crush washer is going to get. I haven't tried them yet but worth remembering perhaps.
pm'd you, looking forward to lighting them up. we do need to retain the crush washers.
We could not keep the crush washers that came with the plugs. We could not get them off without hurting the threads. We need to use aftermarket washers.
Mike
If they work and it lessens knock and helps prevent the rotor housing from deforming along the spark plug holes from excess heat, why not? Who wouldn't spend a couple extra bucks on plugs rather than the cost of a prematurely toasted engine or prematurely worn apex seals leading to an early engine rebuild. $10-$15 more for each plug vs. $5,000-$6,000 for an engine. I'll take the plugs, please. LOL
Mike
I can't imagine any local machine shop doing this for $10-$15/plug where I am. Hopefully if these work some source steps up and machines and stocks large batches that can be readily available. Would also be interesting to sell plug wire sets with ends that are sized for them.
Since we are looking at existing plugs, figured I would post mine too. I just swapped these stock 9s for the new R6601-9s. Have about 1500 miles on these plugs. Looks like I might be able to put a colder plug in the trailing? Interesting how the trailing are half white/black. Would like to hear feedback from smarter people than I on the plugs.
Regarding the new plugs, I installed all 4 9s without the crush washer. Started the car and let it warm up. Unfortunately its cold and rain today, so I was not able to drive the car at all.
I did notice that idle with the accessories on seemed like it was actually rougher than with the previous plugs. I did notice that my AFRs do seem richer than before swapping the plugs. I will have to go back and look at my PFC logs. I try to shoot for 12.7-13 at idle and with the accessories on it dipped into the high 11's a few times. Maybe the extra fuel is causing the slightly rougher idle. Could be from the car coming off of fuel and enrichment for startup.
Side by side. R6601 without washer Front Leading Front Trailing Rear Leading Rear Trailing
Your tune is VERY far off if your plugs look like this.
The following remarks with PowerFC screenshots, knock, etc are a result of the possible injector imbalance and possible lean tip-in that you're experiencing. All of this should be resolved before testing plugs.
The sad part is your little PFC Tweak tool saying that you're 92% dialed in and this looks like worse than a first startup map in terms of accuracy.
the OE plugs primarily show the path the spark took to ground. the spark will always take the easiest route. the OE plugs provide 4 paths. of course the path of most resistance shows carbon. it is colder. the tan ground segments show where the spark actually traveled. they are hotter and carbon free.
combustion chamber swirl, or lack thereof, has lots to do with where the spark travels. ports are significant factors as to creating swirl/optimum atomization. see my new section on ports.
normal plugs w a fixed ground strap may or may not offer the easiest landing spot for the spark. (of course the odds are against.) OE plugs are better but the surface gap 6601s are the best as they offer a 360 degree option for the spark.
as to the picture w the 3 plugs... the porcelain is too white on the plug tagged as best. tan porcelain is happiest.
04-12-23, 02:57 PM
i made 532 hp at 15.8 psi boost and 10.44 AFR on 32% ethanol.
