No its not. It is the opposite.

With synthetic, you pay more, but get more heat resistance/less breakdown, but in any case you should be changing often.

With platinum plugs, the tradeoff is longer life, but with more resistance. Since we don't need the longer life, because we change plugs more often, we are paying more for more resistance, which is stupid.

I'll have to remember this, and "just say no to platinum".

 

All the info mentioned above re: durability of platinum/iridium vs copper, that is considering the longevity of the electrode, right? Since the rotary fires each plug twice as often as a piston engine, the electrodes should wear out twice as quickly. So that's why we either change our plugs more often, or spend extra money on the iridium plugs in order to lengthen the time between plug changes.

How do carbon deposits factor into all of this? I haven't changed my plugs yet (though I am probably going to do so this week, after reading this thread), are the rotary's plugs often carbon-fouled? I doubt the iridium would be any less susceptible to carbon fouling.


-s-

 

/\ twice as often? also fouling has more to do with the heat range of the plug and our rich mixtures than the electrode metal

 

Iridiums work fine and there are some ir motorcycle plugs that work great at about $7 ea, pick your heat range from 7 - 10 or higher.

I have run the NGK rotary race plugs at $30 ea and find a huge improvement over the stock style plugs, huge. The $7 iridium motorcycle plugs run near same as the $30 NGK race plugs.

 

^ err, ehem

You are saying you have used a motorcyle spark plug in the 3rg gen'?

 

Yes, the $7 Iridium motorcycle/snowmobile plug is the BR_EIX series. For instance, I use the BR10EIX in my 7.

Do a forum search and you will see it is not uncommon.

 

Again, more info on this on my site. There seems to be a lot of questions here that my site answers and they keep on coming. I really suggest taking a look. Fouling for example often occurs before the electrode wears out. Platinum is also normally only a coating over the electrode and can burn off quickly in our cars. Platinum is rare and expensive so the core of the plug is still normally copper.

I have tested platinum side by side with non-platinum and couldn't see a difference in electrode wear or fouling. I also tested the expensive iridium plugs offered by HKS/Denso and had very bad fouling problems.

I'll be testing the Rx-8 and motorcycle/snowmobile plugs soon. Right now I am testing BRISK plugs.

 

Any updates on the RX-8 and snowmobile plugs yet? Thanks.

 

There was another thread on this in the single turbo section. Apparently the motorcycle/Snow mobile cold race plugs are way cheaper even in iridium but you will need the thin socket from Racing Beat to install/remove them.

 

I'm will be using motorcycle plugs in my 1st gen.. NGK.. I dont remember the plug code.. but they are heat range 10 all around. they are copper and resistor core. think they where ~$5-6


-Zach

 

BTW you can grind the lip off your housing and not need the socket too. (i didnt need one anyway with mine)

 

Many of the high power FDs are running either the NGK BnEGV or BRnEIX type of plugs. They do require a thin wall socket, or have the protective ridges around the plug holes ground off. They just fire better than the BURnEQ/P types.

Go to
https://www.rx7club.com/showthread.p...hreadid=316066

 

okay I read the whole thing, but what's the "Theory" behind NGK's design with the ring, and 4 Slots... why do rotary engines have such different spark plug design than piston engines !? with the little arm and "gapping them" is thers some sort of uneven burn created by the arm !? And is the fact that we cannot gap ours and the reason why we have to buy new ones, greed by NGK ??

 

I appreciate the link. Thanks.

 

whoa, my thread is still alive
kris

 

the equ if i remember right is

Ep = 2(pi)A