did a search about iridium spark plugs, and got even more confused. im in a need for a tune up, badly, and well im looking at iridiums, i got the money but dont know if i want to spend it on that. i know it makes minor differences like smoother idle, and a bit more power, etc. ive been hearing about the BR10EIX model type, that goes on some bikes. i thought rotary sprak plugs had to be flat at the end, does it not have to be? anyway heres my question:
-why should i pay $30-35 for special rotary iridium spark plugs, when i can just get the BR10EIX for $7?
-would 10 be the best heat rating for my list of mods? ill also be getting an exhaust soon.
-and what kind of gap should i use if i use the BR10EIX?

 

unless you've got more than 400 to the wheels, you'll be fine with either stock plugs or all trailing.

 

thank but can anyone else answer the other questions? if i can get the $7 iridiums, or pay$4-5 bucks for regular, im going with iridium. but is that the right kind i should get, BR10EIX? and is this heat range fine?

 

the 10's might foul out. also, they're the conventional style-which shrouds the spark from the combustion area making it a little harder to ignite and slightly less efficient.

 

so i should go with the ones that are made for the rotary, the flat kind? and i should probably get a 9 then?

 

what do your plugs look like now--are you burning them out?

 

havent pulled them out yet, they were slightly used sparkplugs from my old motor, and then i a rebuilt turbo motor, and i have a about 10k on the motor, along with whatever else i had from the first motor. and its starting to drive a bit rough.

 

10k??
i change mine every other oil change. LOL

seriously though, take a good look at them and see what they look like. i'm thinking you'd be ok with stock plugs though--at least for now.

 

Installing the RX-8 Iridium plugs over new stock plugs on a mildly modifed S5 TII was worth 4 hp on the dyno. Idle and top-end was slightly smoother too.
These plugs cost $280 Cdn at the dealership... that's about $200 USD for all four.... However, they don't seem to be showing signs of wear near as quickly...

 

that's $50/hp!!!

 

HKS also makes iridium plugs for the fc's.

 

Cause the reach on those bike plugs are not as long as the rotary specific ones...


-Ted

 

afaik iridium plugs don't make much difference performance wise, the main advantage is longer life of the plug because of the conductor material being harder to burn away over time. I wouldn't bother going much more than oem plugs, heat range you should check the plugs condition (fouled or overheated?) before you decide what heat range to use.

 

but the insulator still goes away...and broke off on 2 of mine when i tried them.

 

Talking to my local Rotary guru, I am in the process of placing 4x RX8 plugs in my Series 7..
However I have managed to get them for $20 aus each which is about $14US each...(Considerably less than the $50 US each quoted above...)

 

The best value I've found - good for ~4 oil changes.
(leading) NGK BUR7EQP - platinum - from Advance Auto Parts - $6.95 each.
(trailing) NGK BUR9EQ - standard - $4.95 each.