Another spark plug thread? NGK 4586 r6601-11
 

I was looking through the competition parts on my mazdaspeed account and came across this.


0000-10-R601-11 @ NGK SPARK PLUG/11.0

Notes: R6601-11 S&P PORT

RX-7
RX-7 TT $21.30

then did a search on here and found NOTHING, Zero, zip, nada. How the eff can i search the rx7club and not pull up this NGK plug?

Sparkplugs.com specs say:
Plug Specifications

Thread Size: 14mm
Hex Size: 5/8" (16mm)
Reach: 19mm (3/4")
Seat Type: Gasket
Gap: .016" (0.4mm)
Heat Range: 11
Terminal Type: Solid
Resistor: Yes
Brand: NGK

Center Electrode

Type: Standard
Material: Nickel
Size: 2.5mm
Projection: Non-Projected

Ground Electrode

Type: Semi-Surface Discharge
Material: Nickel
Quantity: 1

NGK 4586 R6601-11 Nickel Racing Spark Plug



why has this plug not been beat to death in discussions?

and the noob question, would it be good to push the limits of the stock FD ignition on this plug 14-18psi? 93 or 110+?

I think a lot of people are hesitant to try things without seeing results first. I've run almost all the plugs I can think of and even did some extra work compiling a bunch of plugs that fell within the specs that we could potentially use. But at the end of the day.... I didn't try any of them if I hadn't seen them been used before. Not worth it to try something imo. Especially since I've come across nothing better than the NGK R7420's. I'm damn near 7 Events on them over a 9 months to a year and havn't noticed any idle stumble or break up in the higher rpms. I'm definitely interested considering the price.... But let me know how it goes =-)

Interesting plug, I have a set coming to test out in the trailing position in place of the fine wires. Looks like they also have them in a 10 heat range, that might be a good candidate for an e85 plug.

I dont see them lasting too long in a rotary thats modified. The nickel electrode will wear out.

The R7420 Is a far better plug and will last much longer. Now if your car is not too modified then I suspect the r6601 will be fine.

Ok excuse the threadjack and forgive the ignorance, but what are the limits of the good old standard BUR9EQP and BUR7EQP and are there better options for 400whp, and why?

What fuel are you running?

98ron petrol (pump)

so i have been running the heat range 10 version of these plugs for a few months.



I drive my car 2 days a week to work with a rich tune and 10-12 psi. when in traffic for a while is when other plugs would start to foul. but these act just like the BUR9s and stay pretty crisp.

one thing to mention is that these plugs are alot shorter and my ignition wire almost didn't reach. I have noticed that the knock readings on my PFC have been crazy since i switched, but the readings increase perfectly with RPM, including free revving.

sorry no HC type test on these. they have seen 15psi and 9 AFRS on stock coils with old and used 2nd gen rx7 ignition wires with no issues.

Now someone else give these a shot and make a better review and take all of the glory that comes with another spark plug thread lol.

Check autolite ar3931. They work great and only 5.00 a piece. Been beating mine for about a year still working great.

I'll never use another Autolite plug on any car I own.

Why is that? Ive used the autolite racing sparkplugs at over 500whp and the car ran better with them and ign1a coils then with the ngk7420. Id like to see more feedback on the autolite plugs.

Thank you,
Jose Nieves

I've been using the Autolite AR3933X. These are the equivalent of an NGK #9 heat code. For about a year now the same set of plugs have approx 3000 miles of street driving and abuse. The diaphragm on my FPR failed and I cracked a rear iron and had to open the engine up. The housings had more scortching around the plugs than when they went in before, so I would probably step up to the AR3932X. Overall the plugs have been good, they light off about everything I throw at them with stock FC coils and ~13psi on a GT4088R.

Yup. I actually know someone who dynoed 748 with the ar3931's and has been abusing them for over a year and still firing with no issues. I've never tried the 3933 or the 3932's but I can totally vouch for them. I haven't been able to properly tune my car yet but mine are still firing strong whit all the fuel that's been dumped to them

Anybody run Autolites with water injection?

I have been running them with water injection and no problems. The car def runs better with them on. Every situation is different tho. I switch plugs from the autolites to ngk7420 to see if it was just old plugs or me and my engine likes the autolites.

Jose

Awesome, thank you :)

Howard Coleman is now recommending this plug in the trailing position. SPARK PLUGS


I still have the same set in my car from 2015, they have lived through a coolant seal failure and rebuild, and a weak battery, probably only a couple thousand miles and well under 10lbs of boost.

Thinking out loud.

First observation: Correct me if I'm wrong, but the idea of the fine wire with small gap R7420 iridium is that it takes less effort for the spark to bridge the gap allowing it to light off under extreme conditions. The gap on those R6601 look as wide if not wider than the OEM BUR9EQ. Looking at these R6601 I would think they would blow out easily under high boost & water/meth injection In the +500hp range.

Just speculating, but If the R6601 in the trailing fail to light, it could explain the reduction in knock that was observed. The old anti detonation device mod essentially.

It would be nice if these turn out to be a good fit for the trailing as they are relatively inexpensive and look to not function as glow plugs which has been my concern with the R7420s from day one.

I have 900 miles on a pair being used as trailing plugs. All is well so far.

Those plugs will put the highest voltage stress on leads and coils of any design type due to field shape. I guess it doesn't matter if it's working but there are a lot of people running effectively with fine wire irridium at high power.

the ground strap on the 7420 is thicker per some photos I posted on another spark plug thread on the forum somewhere. I assumed it was specifically intended for turbo FD3 applications. Which included photos of the 7440 Renesis specific iridium plugs with their thinner ground strap for demonstration purposes. Which are likely only intended for NA applications.

I agree with you hypothesis on the 6601 plugs though. Because they more or less is similar to an HEI coil test plug. Except the test plug accentuates that voltage jump more imo per the photo below:


https://cimg4.ibsrv.net/gimg/www.rx7...36a8fa9575.jpg
.

"Howard Coleman is now recommending this plug in the trailing position."

i am not "recommending" the plug.

i am passing on a comment i received in a private email from someone whom i hold in HIGHEST regard. if he is kind enough to provide a warning and guidence i welcome and accept it.

here again is his statement:

"With any decent inductive ignition you need to run a full surface discharge plug in the trailing. If you don’t, you will get knock over approx 500hp."

i am breaking in my new setup and the plugs are onboard. i have an engine customer that has a twin to my setup and has now been running them for a few months around the 500+ level. his experience is they run just like the fine wires he took out but his knock is 15% less.

i am simply sharing some relevant info. make your own decision on this. i have made mine.

I'd love to see back to back dyno and knock log of fine wire, surface and no trailing trigger/ spark at all. I suspect it's because the trailing plug is doing very little but without torque figures it's only guessing.

Any issues with the 19 vs 21mm reach? (Not only for these for for any plug we use?
How about in the leading position? Does a 2mm less reach a affect the heat transfer from housing to plug and the possibility of spark plug hole crowning / cracking due to heat?

For the $50 in plugs and a little extra dyno time, this might be a valuable test for my final tune dyno. Hopefully more than...