.018" is the gap you're looking to run. Seems most BR9ES out of the box are closer to .028", or maybe they're not set to a controlled gap at all?

A wider gap puts more strain on your charging system and potential for higher RPM missfire.

Not sure that it is a problem on the twin cylinder sleds, but the triples having another ignition coil do put a larger stress on charging components.

I've also run BR9ES out of the box gap doing trail side plug changes on 700 twins and haven't noticed an issue.

 

.018" is the gap you're looking to run. Seems most BR9ES out of the box are closer to .028", or maybe they're not set to a controlled gap at all?

A wider gap puts more strain on your charging system and potential for higher RPM missfire.

Not sure that it is a problem on the twin cylinder sleds, but the triples having another ignition coil do put a larger stress on charging components.

I've also run BR9ES out of the box gap doing trail side plug changes on 700 twins and haven't noticed an issue.

Can bad things happen being gapped too low? I mean say if one was .010? Just throwing out a number for example purposes.

Also, here http://accessngk.com/part_finder/Snowmobiles/results.asp?id=1147&type=std they say .020... because of the "C"? They was the electrode is designed?

Thanks

 

BR9ECS Is the factory spec plug that needs to be gaped at .018, the BR9ECS-5 comes pre-gaped.

Something to read from another thread:

Posted 04 December 2013 - 10:31 AM

Here you go... right from the horses mouth....

"

The Difference between ES and ECS Type Spark Plugs

Did you know many 2002-present Ski-Doo snowmobiles are factory
equipped with NGK BR8ECS, BR9ECS or BR9ECS -5 spark plugs?

It is very important that the same type of plug is used as a replacement on machines
that were originally equipped with this type of spark plug
.
The difference between the ES and ECS plugs is in the firing
-end design. For example, a BR9ES and BR9ECS will have the same thread size, hex diameter, thread length, and projection; however BR9ECS has a special low -
angle ground electrode. This low-angle ground electrode is
designed to be more resistant against vibration and the shorter ground electrode design
provides a faster path to transfer heat away from the ground electrode.

Failure to use the recommended ECS plug,
where specified,may cause failure of the ground electrode,resulting in costly engine damage.

Another frequently asked question is"What is the difference between BR9ECS and BR9ECS-5?"
The differencebetween the twois the preset gap of the spark plug. BR9ECS will come out of
the box gapped at approximately .032, " while BR9ECS-5 will come out of the box gapped at approximately .020".
Adjusting the gap of either spark plug is not recommended because ofthedesign of the ground electrode"

Staright from NGK's website.... Hope this helps.... I was wondering myself...
.

http://www.ngksparkp..._ ecs_plugs.pdf

 

BR9ECS Is the factory spec plug that needs to be gaped at .018, the BR9ECS-5 comes pre-gaped.

Something to read from another thread:

Posted 04 December 2013 - 10:31 AM

Here you go... right from the horses mouth....

"

The Difference between ES and ECS Type Spark Plugs

Did you know many 2002-present Ski-Doo snowmobiles are factory
equipped with NGK BR8ECS, BR9ECS or BR9ECS -5 spark plugs?

It is very important that the same type of plug is used as a replacement on machines
that were originally equipped with this type of spark plug
.
The difference between the ES and ECS plugs is in the firing
-end design. For example, a BR9ES and BR9ECS will have the same thread size, hex diameter, thread length, and projection; however BR9ECS has a special low -
angle ground electrode. This low-angle ground electrode is
designed to be more resistant against vibration and the shorter ground electrode design
provides a faster path to transfer heat away from the ground electrode.

Failure to use the recommended ECS plug,
where specified,may cause failure of the ground electrode,resulting in costly engine damage.

Another frequently asked question is"What is the difference between BR9ECS and BR9ECS-5?"
The differencebetween the twois the preset gap of the spark plug. BR9ECS will come out of
the box gapped at approximately .032, " while BR9ECS-5 will come out of the box gapped at approximately .020".
Adjusting the gap of either spark plug is not recommended because ofthedesign of the ground electrode"

Staright from NGK's website.... Hope this helps.... I was wondering myself...
.

http://www.ngksparkp..._ ecs_plugs.pdf

ski-doo told their dealers tech,s to run the ecs plug,s only.

 

Ever tried br9eya? I have ran 9es plugs forever and just switched to br9eya. Sled loves em. Told another buddy about them, and after fouling a few br9es he switched and said it was night and day. Both sleds are 670's

I check my plugs basically every ride and there paper bag brown.

Not really a performance gain, but they start and run when cold easier.