I just pulled the leading plugs out for a 10,000 mile inspection (IRE01-27). The center electrode shows very little wear. To say the least, I'm impressed. I've always run NGK 9s in the past. In contrast, with 10k miles, the center electrode on NGKs would be worn down to a nub.

Conclusion: these plugs are worth every penny, and seem to mitigate high end break-up as well (I'm pushing about 370 rwhp with no TP and stock coils)

http://www.sparkplugs.com/more_info....92485&pid=9119

 

do these require a thinwall plug socket? I wasn't happy with the NGK BR10EIX, they could not stand up to high exhaust temps

 

I don't think they need a special socket, but then again I use a extended spark plug tool from an old motorcycle kit. I think you mean "high combustion chamber temps", which is where iridium truly shines

 

Are you running any type of ignition amp? Also what heat range do these come in?

 

No.

Denso heat range 27 is equivalent to NGK 9. 31 is equivalent to NGK 10, and 34 ~ NGK 11. The ceramic on the leading plugs I pulled looked fine. I suppose if you're making over 400 hp you may want to try the 31s.

Apparently NGK does not make iridium plugs for the FD? I believe HKS does, although they are likely rebadged Densos

 

Yes they do, 7420s and greddy rebadged 7420s.

 

That appears to be a Japan-only racing plug. Old GB:
https://www.rx7club.com/jkl-engineering-271/gb-ngk-iridium-racing-plugs-power-cable-racing-plug-wires-701009/

 

The 7420s are rebadged under the greddy name as the RE super racing plug or something or nother. Its the same plug and the greddy ones even have NGK written on them haha. http://thmotorsports.com/greddy/gred.../i-177763.aspx

 

Oh and HKS does make a rebadged denso. Heres the cross reference.

HKS(Japan) DENSO

R45RE- IRE01-27
M50RE- IRE01-31
M525RE- IRE01-32
M55RE- IRE01-34

 

Those are a little cheaper than the Densos, I'll give them a shot on my next plug change. Based on my 10k inspection, I think I can get 30k+ miles out of these plugs, which is unheard of in a turbocharged rotary. The increased longevity alone is well worth the price of admission, I don't know why anyone would run standard or platinum NGKs after trying these....

 

totally agree and will be trying the same test also. Lets say the stock 9s are around 30 bucks and with my setup i go threw them before an oil change comes up and i change mine every 2000 miles! That means 5 plug changes in the course of 10k miles. If i can have one plug change instead of 5, im all for paying a hundred bucks for plugs.

 

You change plugs every 2k miles? That's crazy...

 

Yeah.... your tellin me, and when they come out they look terrible!!! rounded electrode worn to a nub.

 

You must be running an ignition amp, I've heard they're hard on plugs. What hp are you making?

Here's an initeresting question: where is all the metal particulate from the spent electrode going?

 

i've tried a full 3k but after even 1k miles you tell a difference, 2k and it isn't running as smoothly, and at 3k i'd say it's running pretty bad. This is with stock NGK 9s, with a twin power. I have purchased these greddy plugs to try, but waiting for them to come off of backorder.

 

no rice im on a fc1000 and new stock coils. I'm around 423rwhp at the moment but soon will be venturing to the 500 mark with some meth. With the regard to the burnt mater, thinking about might ruin my day haha.

 

Wow.....and I thought my spark plug life was bad with the stockers

 

Whats really crazy i was bored and reading every post i could come across last night on the forums. I read this one and shrugged my shoulders.

I went to rotorsports racing where my motor is being built, and out of the blue he asked if i had seen the plugs in my motor. I bought a j-spec from japan2la. The plugs were the denso units, i think he said 2-27's and 2-31's maybe. I didnt really pay attention,, but i will now. lol.

He said he liked how they looked and we will try them when my motor gets done.

Will let u guys know. Also has anyone heard of index-ing your plugs. Just heard that from a race motor builder. You use washers to get the desired placement of the electrode. So they all face the exhaust path. There is probably a better way to explain but you get the idea.

Look into it, might be worth the while, im gonna try it..

 

I have the same results with the same hardware. It's really quite amazing how the electrode gets rounded off so quickly.

The only good thing is I only put about 2k a year on her so I'm ok with changing plugs after 1k.

 

I bought the Greddys on Ebay for $28 ea plus shipping less microsoft cash back!

http://cgi.ebay.com/ebaymotors/GREDDY-RACING-SPARK-PLUG-PRO-IRIDIUM-RE-RE11-ROTARY-ENG

 

*free shipping!! http://thmotorsports.com/greddy/gred.../i-177763.aspx

 

Neit: I don't think you need a 11 heat range plug unless you're pushing 450-500 hp; iridiums seems to run a bit cooler anyway. I'm running the equivaent of an NGK 9 and they look good. The rule of thumb is +1 heat range for every 75-100 hp over stock. You run the risk of wet fouling the plug on the street, and it will idle like crap.

 

I've been using BR10EIX with a twin power until recently daily driving and it runs fine. I wanted 10 heat range but couldn't find them so I got the 11's.

I've been running the stock twins at 17+ psi sometimes and plan to tune them higher with the 11's, just to be on the colder plug side when pushing the little twins.

I'm using RX-8 iridium 9's all around right now, I might do a 9-11 combination depending on how the 11's work all around

 

Where do you get the equiviant heat ranges from? Denso's site? Looking at the sparkplugs.com site, it would seem they have listed leading and trailing for each plug type since there are 2 in each category for the classes of plugs they list. If 27 = 9 and 31 = 10 in the racing category for heat ranges, what is 29 and 31 = in the super category they list?

Just curious before I order any.

 

Equivalent heat ranges came from the Denso tech support line, (888) 963-3676

NGK Denso
8 - 24
9 - 27
10 - 31
11 - 34

All I can say is the ceramic on the 27s looks very similar to NGK 9s in my car, so it seems correct