looking for a 10 degree spark plug with resistors. i have only found the 10eix plugs which are iridiums and not good for the rotary. is there any plug made that is 10 degree with say a copper or platinum center? any imput appreciated.

 

Why are the Iridium BR10EIX no good for the rotary?

That is what I and many others on the forum use. $7 each!

 

I thought Iridium was a supior spark plug to copper or platinum lol. It's what they use in the expensive racing plugs (for rotaries).

thewird

 

br10eix cant take the heat and wind up falling apart. check out the last post on the first page of this thread..

https://www.rx7club.com/showthread.p...ighlight=b9egv

 

I've used iridium NGK plugs before. No issues regarding the plug material or life, just a weird gap issue.

Why is iridum no good? Worked well for me.

 

there's the NGK R6725-105's, they're 10.5 degree rating, but they seem to hold up well, and are resistor.

 

R6725 Ngk also come in 9 and 10 heat range also.

 

Get the Greddy Race Plugs.

rhdjapan.com have them

They are the BEST plug for high HP PERIOD. THey last 5-6X longer then your average plugs.

 

The NGK R6725-xxx and R7420-xxx are the only plugs NGK makes in the proper reach (.846", same as stock), are resistor plugs, and are offered in the 10+ heat range. The R6725 and the R7420 are the same plug with the difference being that the R6725 is a platinum plug and the R7420 is iridium. The R7420 is apparently the same plug as the Greddy Race Plug.

I've used the EIX with good results as well as the EGV (non-resistor) with good results. However, both of those plugs only have a .750" reach so the tip is retracted around .010". Does that matter and if so how much and in what circumstance?

 

good to know about the 6725's, it'd be awesome to rock a 9 and 10 heat range together.

 

Good news to whoever wants the R7420's, they are trying to do a group buy at a killer price. ---> https://www.rx7club.com/jkl-engineering-271/gb-ngk-iridium-racing-plugs-power-cable-racing-plug-wires-701009/




.

 

I did lose a ground strap on a BR10EIX once during a series of detonation events so bad it felt like fuel cut.

However, I have never had any issues with the porcelain, though I run low EGTS under load.

 

Are you sure about the NGK R7420 plug being the same as the greddy race plug cause that would be cool

thewird

 

I wouldn't doubt it Marco, there's only so many companies that make plugs....its like turbos.

But I've never held a Greddy plug so I can't say for sure, but I could tell though since I've had (got) lots of R7420's here

 

Has anyone modified, C-Bored the spark plug holes on the rotor housings, to extend the EIX or EGV plugs further into the chamber? It would be a fairly simple job to do during a rebuild, especially if you were modifying the housing to use a regular plug socket.

 

From rockauto.com. Worked good and cheap.

 

B10EGV is the way to go. someone sells a socket to use.. dont remember who.. or you can just make your own.

 

www.KGParts.com

Keith Gibbons is the man

 

Well, I did say apparently. NGK does make the Greddy plug and it "looks" just like the 7420. Don't know why it would be very sweet though because whichever you choose is still very expensive.

 

Would be sweet because the greddy plugs are more easily aquired and are a bit cheaper too.

thewird

 

"R7420-X" is stamped on the side of the GReddy race plugs that I got off of an engine from Japan

 

Thanks

 

You're welcome!

To be completely correct mine say "R7420-9", I can only assume that they would say whatever number heat range they are, hence the X.

 

I have broken the porcelain on the BR10EIX plugs from detonation. I simply cannot afford the NGK r7420 ... Would stock BUR9EQ's be ok if I can keep pre turbo EGT's to 1500 degrees F ?

 

the correct resistor plugs can get quite pricey. i usually change my plugs 3-4 times througout the summer. i have currently been using ngk R5671A-10. very similar to the B10EGV but they cost half the price, and i have had great luck with them. i found them years ago by another member who swore by them. they are also a 5/8" socket size so no need for a special socket.

** how many have been running non resistor plugs with hks twin powers? the only reason i ever think about getting resistor plugs is to keep from hurting the hks box.