Is it better to run 9's in all holes? If so....what is the benefit?

 

you can, but if your stock you won't see any benifits. colder plug also means you can't idle as long you WILL foul the plugs. me for instance i run 10's and 11's for driving on the street and 4 11.5's for race day!

 

Just running one frigging degree colder plugs doesnt mean you'll foul your plugs instantly... Upgrading to 9s all around is not only for performance, but for convenience too (instead of 2 9s and 2 7s, just 4 9s). Anyway, in Greece I cannt even find 7s, so I'm stuck with 9s or colder...And who cares if the car will idle 5% "worse", when you'll most definitely see differences up high (especially in a TII).

 

i did notmean they would instantly foul out, just the colder you go the less you can put around 9's are no big deal though you start with 10's and up u better have a heavy foot. i still stick to my opinion on runnig 4 9's on a stock motor will bring you no more performance, you need to run more boost then you should notice a difference

 

if you are using NGK brand spark plugs the heat range is backward form most other manufacturers, the higher the number the "colder" the heat range. an "11" is colder than a "9". so going from 11 to 9 will resist to a certain degree fouling at idle. for a stock motor there is no reason except for sustained freeway driving to lower the heat range of the recomended spark plug. even on my race only street ported motor I run the stock heat range.

 

what is this number rating you all speak of?!

 

It refers to the NGK part number for spark plugs for rotaries.

Stock setup is 2 each of BUR7EQ and BUR9EQ. So for conveinence and to run a colder plug, you would run BUR9EQ all the way around. The 9 is a colder plug than the 7.

 

Soul Assassin is right... I have ran 11.5 before and they don't last long, as they tend to foul up easy on the street. The reason why you would run colder plug in the first place it to prevent detonation at top end. Another drawback of a race plug is that you might have starting problems if you are in a colder climate.

 

How often do you guys recommend spark plugs should be changed??

 

i thought it was every oil change ...jk i think its around 60k

 

No, no, no. It's more like 15k, if you're **** 10k, if you're super **** and foul them up constantly it's 5k.

 

My 90 GTU eats spark plugs. I just replaced my leading plugs that were 8K miles old. They were worn to the point where I was losing power. The center electrode was completely rounded off and much smaller than it should be, and the gap was about double that of a spark plug. I cleaned them every oil change too.