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  • 1996 - 2004 SN95 Mustang -General/Talk-
  • SN95 4.6L Mustang Tech

Spark Plug Gap with cams

  • Thread starter Thread starter Cobra123089
  • Start date Start date Dec 11, 2008

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 11, 2008
#1
  • Dec 11, 2008
  • #1
Just trying to get opinions on spark plug gap. I'm running the stock .054 gap but from previous experience with my GTI the general rule was -.002 for every 20hp gain. What do you think?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,166
17,860
224
Massachusetts
Dec 12, 2008
#2
  • Dec 12, 2008
  • #2
For N/A applications, stick with 0.054"

If you upgrade the ignition with high performance coils, then you can try increasing gap until you expierence misfire.


I've never heard of opening the gap based on HP levels. Without ignition upgrade, you'd get misfiring.


The GTI has a turbo right? Different rules apply there with forced induction. For N/A though, gap stays same. If anything, you want to increase it to expose more spark to the air/fuel mixture.
 

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 12, 2008
#3
  • Dec 12, 2008
  • #3
it just feels like a slight miss on cold starts. if i index the plugs i should make sure it faces the intake valve right?
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
43,166
17,860
224
Massachusetts
Dec 12, 2008
#4
  • Dec 12, 2008
  • #4
Correct, towards the intake


You can try closing up slightly

Technically the range is 0.052" - 0.056", so try setting them to 0.052" and see if it makes a difference and you would technically still be in spec
 

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 12, 2008
#5
  • Dec 12, 2008
  • #5
ill try doing that tonight, after i degree the cams, i go in for a dyno tune after x mas and i was everything tip top.
 
S

Smokeurhonda

New Member
May 1, 2003
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Maryland
Dec 12, 2008
#6
  • Dec 12, 2008
  • #6
you really only need to start closing the gap when you go with a power adder. .052 should be fine for your set up
 

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 13, 2008
#7
  • Dec 13, 2008
  • #7
just got a pm from tim at mph he recommends .048
 

bhuff30

Founding Member
Dec 11, 2001
6,037
35
129
Olathe KS
Dec 13, 2008
#8
  • Dec 13, 2008
  • #8
Do you really think it matters that much? I've probably got 70,000 miles on my plugs, so the gap has probably openned to .07-something just from use. The car still runs fine and doesn't miss. In fact, it still makes great power and I made some of my best 1/4 miles times on these 'old' plugs.

If you run a power adder, close the gap. Otherwise, anything near stock will work just fine. A wider gap is better, so don't close it unless you get a miss at WOT. This isn't rocket science. Long as you don't have a miss, it doesn't really matter what the plug gap is.
 
P

PAzYearazzUP

Banned
Dec 12, 2008
33
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0
Dec 13, 2008
#9
  • Dec 13, 2008
  • #9
The larger the gap, the longer the spark, the more contact with a molecule is micro bits of all that gap. I would extend the gap wider and I am sure the stock coil can jump a spark especially when the gap is all messed up is a spark hunting for a sharp edge. So, with 70K on a set of plugs as mentioned, I think the wider gap can take some gap at the plug is max the gap as wide as a 70,000 mile plug = Just to be safe.

And Indexing is like the same gap in the same spark is the same-same is a waste of time is just a smoother fire if you want all things equal. I doubt you made any HP is the same fuel and air entered the chamber and how can you increase HP if you can cook more fuel is make more pressure over the piston dome.
So, you have carbon build up on the threads is they have to spin out to line up? You want carbon to fire off before the spark? Save your head and forget it is, Justmy2Cents is.

Edit: I just thought of a slight loss of compression as the plug moves out of the chamber. So, there is HP loss is you can go index is see you at the end of the 1320 is gonna pay me late tear, is don't come crying to me is warned chews.
 
S

Smokeurhonda

New Member
May 1, 2003
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Dec 13, 2008
#10
  • Dec 13, 2008
  • #10
PAzYearazzUP said:
The larger the gap, the longer the spark, the more contact with a molecule is micro bits of all that gap. I would extend the gap wider and I am sure the stock coil can jump a spark especially when the gap is all messed up is a spark hunting for a sharp edge. So, with 70K on a set of plugs as mentioned, I think the wider gap can take some gap at the plug is max the gap as wide as a 70,000 mile plug = Just to be safe.

And Indexing is like the same gap in the same spark is the same-same is a waste of time is just a smoother fire if you want all things equal. I doubt you made any HP is the same fuel and air entered the chamber and how can you increase HP if you can cook more fuel is make more pressure over the piston dome.
So, you have carbon build up on the threads is they have to spin out to line up? You want carbon to fire off before the spark? Save your head and forget it is, Justmy2Cents is.

Edit: I just thought of a slight loss of compression as the plug moves out of the chamber. So, there is HP loss is you can go index is see you at the end of the 1320 is gonna pay me late tear, is don't come crying to me is warned chews.
Click to expand...


WTF did you just say? I can't understand a single sentence in that statement. am i really that hungover?
 

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 13, 2008
#11
  • Dec 13, 2008
  • #11
i did nt get it either
 

CobraRed_96_GT

Active Member
May 20, 2006
1,421
4
39
UCSD/La Jolla
Dec 13, 2008
#12
  • Dec 13, 2008
  • #12
You close it for more power, you close it for more compression.
 
P

PAzYearazzUP

Banned
Dec 12, 2008
33
0
0
Dec 13, 2008
#13
  • Dec 13, 2008
  • #13
You aRE kidding me, right? You draw the cc down moving the threads out of a chamber.
You made no HP if the BTU is set to burn so hot and the spark gap did not make any difference no matter what angle is the compression and spark is gonna blow some power if you index your finger up is your rear end is did that stop the farting around your french tip?
 

bhuff30

Founding Member
Dec 11, 2001
6,037
35
129
Olathe KS
Dec 13, 2008
#14
  • Dec 13, 2008
  • #14
WTF is going on in this thread? Half the posts are either complete non-sense or complete
 

Cobra123089

Member
Sep 30, 2006
94
0
7
Broomfield CO/ Laramie WY
Dec 13, 2008
#15
  • Dec 13, 2008
  • #15
i think just one guy is complete non sense
 
S

Smokeurhonda

New Member
May 1, 2003
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0
Maryland
Dec 14, 2008
#16
  • Dec 14, 2008
  • #16
PAzYearazzUP said:
You aRE kidding me, right? You draw the cc down moving the threads out of a chamber.
You made no HP if the BTU is set to burn so hot and the spark gap did not make any difference no matter what angle is the compression and spark is gonna blow some power if you index your finger up is your rear end is did that stop the farting around your french tip?
Click to expand...


Dude I don't know who you are, or who your pretending to be, but do me a favor and cut the crap. Convenient how you joined 2 days ago.
 
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