Spark Plugs- NGK 5RE 11 vs 6RE 11

[Subarunation 713]

1999 2.2 Legacy. My manual calls for a 5RE but I can't seem to find them locally. I did a search and found TONS about spark plugs but I didn't find anything on the 5 vs the 6. There was one thread where the question was asked but I didn't find the answer.

 

Am I splitting hairs?

 

IIRC I put 6REs in a while back but I wouldn't bet my life on it. If I put 5REs in I can't remember where I got them. You folks who use 5REs, where do you get them?

 

Thanks,

Greg

[nipper]

1999 2.2 Legacy. My manual calls for a 5RE but I can't seem to find them locally. I did a search and found TONS about spark plugs but I didn't find anything on the 5 vs the 6. There was one thread where the question was asked but I didn't find the answer.

 

Am I splitting hairs?

 

IIRC I put 6REs in a while back but I wouldn't bet my life on it. If I put 5REs in I can't remember where I got them. You folks who use 5REs, where do you get them?

 

Thanks,

Greg

 

Whats the difference? heat range?

[Subarunation 713]

Whats the difference? heat range?

Nipper,

Here is what I found on the NGK Web site:

 

How do I find a colder or hotter plug?

 

First, consult the NGK numbering system page,(listed on the bottom left of the 411 info page), you should be able to see which digits identify the heat range for your spark plug.

EXAMPLE: The heat range for a BCPR6ES-11 is the "6" (ignore the -11, it is the gap)

After you have identified the numbering system for your plug, merely raise or lower that number to change the heat range.

REMEMBER, NGK PLUGS GET COLDER THE HIGHER THE NUMBER, HOTTER THE LOWER THE NUMBER.

 

Say you are starting with a BKR6E-11

if you want a colder plug, you would use BKR7E-11

if you want a hotter plug, you would use BKR5E-11

(again, on non-racing plugs, the number after the "-" refers to the gap)

 

So if I use a 6 it is "colder" than the 5. For normal conditions will one step make a hill of beans?

 

Thanks,

Greg

[OB99W]

[...]So if I use a 6 it is "colder" than the 5. For normal conditions will one step make a hill of beans?

A colder plug may tend to foul a bit more (which can lead to misfire, etc.), but it's dependent on other factors. If your driving is primarily highway, the effect of one-range colder plugs probably won't be very noticable. However, it's possible that with low-speed stop-and-go driving, especially if the engine tends to run rich or burns a little oil, there could be some fouling.

[Subarunation 713]

A colder plug may tend to foul a bit more (which can lead to misfire, etc.), but it's dependent on other factors. If your driving is primarily highway, the effect of one-range colder plugs probably won't be very noticable. However, it's possible that with low-speed stop-and-go driving, especially if the engine tends to run rich or burns a little oil, there could be some fouling.

Thanks OB99W,

I was reading Josh's comments when I did my search and his warning is what made me ask my question because the temp range sounded pretty serious. I checked RockAuto.com's Web site. They had a 6RE as the plug reccommended through 5-99? Just one more thing to confuse my simple mind :-)

Greg

 

btw-most of my miles are at 65-70 mph going down the highway. Countryside around me is moderately flat to low rolling hills.

[nipper]

You will be ok. A cooler plug is perfect for highway driving. ALso if thats what you had before, i wouldnt worry about it.

 

nipper