MK5 Golf GTI

All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: ROH ECHT on June 08, 2011, 08:56:19 am

Title: Spark plug gap should be..?
Post by: ROH ECHT on June 08, 2011, 08:56:19 am: I had my plugs replaced under warranty not long ago. My mileage dropped from 28.5 mpg avg. to 26.5 mpg avg..
I read that on turbo cars that the gap should be tighter, say around .022". I pulled them and adjusted the gap to
.025" and the mileage went up to 28.0 mpg avg.. I'm wondering if, maybe, I should go ahead and pull them out again
and set them at .022", and what has been your experience with this issue?
Title: Re: Spark plug gap should be..?
Post by: chris s on June 09, 2011, 12:48:07 pm: I am about to replace my Plugs as part of my attempt to resolve a mapping issue, and was just going to put in the standard NGK iridium plugs without adjustment. Although, I've read various posts that the gap is important
Title: Re: Spark plug gap should be..?
Post by: Boothy on June 09, 2011, 12:51:22 pm: The NGK ones come pre-gapped for the GTI apparently.
Title: Re: Spark plug gap should be..?
Post by: ROH ECHT on June 09, 2011, 04:33:27 pm: Yeah, mine were supposed to be pre-gapped as well. When I pulled them, they were .030 and I adjusted them as I wrote to .025in.
I did notice that the engine immediately ran smoother. Then later that the mileage improved. I'm curious to know if anyone else has set
theirs at .022in and if that setting worked out for you. I have read that others set them at .022in. as that is where they felt the gap should
be set for the 2.0t fsi. I may just go ahead and try it because, not much different right?
Title: Re: Spark plug gap should be..?
Post by: bacillus on June 09, 2011, 05:12:56 pm: I have to confess that I never gap my NKGs... :ashamed:
Title: Re: Spark plug gap should be..?
Post by: chris s on June 09, 2011, 07:42:21 pm: Well just put my new plugs in, and didn't change the gap... will see how it goes now
Title: Re: Spark plug gap should be..?
Post by: Fizgti on June 12, 2011, 06:10:04 pm: How wud you measure the gap?
Title: Re: Spark plug gap should be..?
Post by: Boothy on June 12, 2011, 07:09:37 pm: Feeler gauge:

http://www.amazon.co.uk/dp/B0002BUJQM/ref=asc_df_B0002BUJQM3175336?smid=A3P5ROKL5A1OLE&tag=googlecouk06-21&linkCode=asn&creative=22206&creativeASIN=B0002BUJQM
Title: Re: Spark plug gap should be..?
Post by: Fizgti on June 12, 2011, 07:13:30 pm: Top tip mate pulling mine out later on and check
Title: Re: Spark plug gap should be..?
Post by: bacillus on June 12, 2011, 07:47:49 pm: Quote from: Fizgti on June 12, 2011, 07:13:30 pm
Top tip mate pulling mine out later on and check

If you have ngk iridiums then I advise against trying to physically re-gap them.
Title: Re: Spark plug gap should be..?
Post by: Boothy on June 12, 2011, 07:50:29 pm: Quote from: bacillus on June 12, 2011, 07:47:49 pm
Quote from: Fizgti on June 12, 2011, 07:13:30 pm
Top tip mate pulling mine out later on and check

If you have ngk iridiums then I advise against trying to physically re-gap them.

Whys that mate?
Title: Re: Spark plug gap should be..?
Post by: bacillus on June 12, 2011, 08:03:39 pm: The iridium tip is very brittle/fragile so is at risk of damage when trying to regap using a feeler guage.
Title: Re: Spark plug gap should be..?
Post by: Fizgti on June 12, 2011, 09:12:09 pm: Quote from: Boothy on June 12, 2011, 07:50:29 pm
Quote from: bacillus on June 12, 2011, 07:47:49 pm
Quote from: Fizgti on June 12, 2011, 07:13:30 pm
Top tip mate pulling mine out later on and check

If you have ngk iridiums then I advise against trying to physically re-gap them.

Whys that mate?

I never knew anything about re gapping then plugs