2nd Gen RX7 Spark Plug Wires

[waynehussey]

Looking to purchase a set of spark plug wires for my 2nd Gen RX7, any recommendations with regards to brand and size (i.e., 7mm)?

thanks

[lateapex911]

perhaps my response won't be too helpful, (sorry) but the gold standard for the 1st gen has been the Racing Beat wires. expensive, (relatively) but high performance and good longevity, they are well made and robust.

[seckerich]

Wayne we have had excellent luck with the Magnacore wires. Not had a set fail yet if you wipe them down occasionally and do not let oil mist rot them.

[Chris Taylor]

I've gotta put a vote in for Taylor wires in 8mm, and not just because my name's on them.

(I don't actually get anything if you buy them, but perhaps I should seek the opportunity to claim we're related for a wholesale discount...)

[waynehussey]

Thanks Guys!

[C. Ludwig]

I use MSD 8.5mm custom sets pretty much exclusively. I like the custom wires as it seems all off the shelf wires for the 2nd gen are WAY too long. Taylor and Magnecore also have a great reputation.

[Chris Humphrey]

I've gotta put a vote in for Taylor wires in 8mm, and not just because my name's on them.

(I don't actually get anything if you buy them, but perhaps I should seek the opportunity to claim we're related for a wholesale discount...)

That is what I got from Mazdaspeed. If I remember correctly they were $46 for my 1st gen.

[mbuskuhl]

Looks like I will be ditching those stock 6 month old NGK wires I have. Along the same line, how about plugs? NGK 7 and 9's or? I had tried some other NGK's but saw no change on the dyno.

[seckerich]

7 plugs are too hot for racing unless you have conservative timing advance. 9's are borderline. Need cooler plugs. 10.5 or 11.5 is the norm.

[C. Ludwig]

7 plugs are too hot for racing unless you have conservative timing advance. 9's are borderline. Need cooler plugs. 10.5 or 11.5 is the norm.

Not true at all. I've ran 7s in both leading and trailing without issue. On the dyno I've cranked timing way past MBT without issue. So all 7s will work. But you only need to run a plug hot enough to eliminate fouling. If you can get away with 9s then do it.

We don't step to a 10 heat range plug until we pass 400 whp and over 1 bar boost on the turbo cars. That combination is wayyyy more detonation and/or pre-ignition prone than any ITS engine. That cold of a plug simply is not needed as a measure of safety for an ITS engine.

I've just never seen the hp claims of the high dollar R6725 plugs proven out. If someone wants to spend $33/plug, have at it.

[Chris Wire]

I use MSD 8.5mm custom sets pretty much exclusively. I like the custom wires as it seems all off the shelf wires for the 2nd gen are WAY too long. Taylor and Magnecore also have a great reputation.

+1

I even had a circle track engine builder tell me that he tested several of the popular brands for resistance and found the MSDs easily beat the others.

[mbuskuhl]

Hmmm... two very different opinions on plugs.

Eckerich - 10.5 -11.5
Ludwig - 7, maybe 9

I'm picking up the Magnecor 8.5mm wires but am lost as too what plugs now. The "other" NGK plugs I had tried were some that were supposed to sit deeper in and required a special spark plug socket that had been machined down just to get them tightened. On the dyno, they did nothing and I did back to back testing. I would prefer not to buy and test more plugs. If 7's and 9's like stock is not ideal, then ???? Some part numbers would help, I have the ones for 7's and 9's but not others.

[seckerich]

Thats what is so good about this site Mark. You get various opinions that are worth exactly what you pay for them (mine included). There are so many variables that can effect your choice. I tend to run the coolest plug that makes the power and have some insurance in pocket. Others run the hottest they can looking for 1 HP (possibly) until that 90+ day and a little bad gas takes out a motor. We ran for years with 9's lead and trail with no problems. We made some changes that made a 10.5 better. The computer I sent you to run made best power with the 9's. Not a huge deal if what you have is working. Read the plug and see if it is breaking down. Good luck!!

[C. Ludwig]

I tend to run the coolest plug that makes the power and have some insurance in pocket.

Best advice yet.


A hotter plug won't make power unless you're fouling plugs by running a cold one in the first place. The only thing a hotter plug is doing is holding more heat in the insulator to ward off fouling. Use the coldest plug you can while avoiding fouling issues. In some detonation prone race engines that requires warming the engine on a hot plug then replacing them with a cold plug for high load racing conditions. This has just not been my experience with an ITS engine. You're just not loading it highly enough to require a colder plug than stock to ward off pre-ignition or detonation.

[Chris Wire]

Best advice yet.


A hotter plug won't make power unless you're fouling plugs by running a cold one in the first place. The only thing a hotter plug is doing is holding more heat in the insulator to ward off fouling. Use the coldest plug you can while avoiding fouling issues. In some detonation prone race engines that requires warming the engine on a hot plug then replacing them with a cold plug for high load racing conditions. This has just not been my experience with an ITS engine. You're just not loading it highly enough to require a colder plug than stock to ward off pre-ignition or detonation.

So not even the 7s, just all with the 9s all around?

[tdw6974]

http://cgi.ebay.com/ebaymotors/Parts...3756.m14.l1318 Anyone try any of these? 10.2 mm Bigger is better?? Theory looks good.

[mbuskuhl]

Interesting article on ignition wires - http://www.magnecor.com/magnecor1/truth.htm

Also found this on rx7.com "For stock or mildly modified cars, use two #7 leading plugs and two #9 trailing plugs. Heavier modified cars may need to consider using four #9 plugs, for cooler plug temperatures."

[seckerich]

Wanted to bring this thread to the front again. I just pulled yet another motor with a recent rebuild with sucked apex seals. Motor was running Bur 7 and BUR 9 stock plugs. Do what you want but running hot plugs is just a ticking time bomb. You have no margin for error on the tune.