spark plug gap spec and procedure question!
Dec 2, 2009, 06:44 AM
#1
Evolved Member
Thread Starter
iTrader: (3)
Join Date: Mar 2007
Location: Connecticut / Vermont
Posts: 562
Likes: 0
Received 0 Likes
on
0 Posts
spark plug gap spec and procedure question!
Ok so for the last couple of months I have been rummaging around the forums searching for some answers on specs of what to gap spark plugs to specifically for the EVO VIII.
There are quite a few old threads about this subject. Mostly from back in 2004-2006 or so. There is a lot of good information on these threads especially about what heat range plug one should be running. Wich i have concluded that the stock 7 heat range is good up until 24psi or so then one might think about changing to one step colder. An 8 series plug. So the copper part #'s for NGK are BPR7ES and BPR8ES. This again is NOT for an IX this IS for an EVO VIII. Through my searching i saw a lot of people getting confused about what plugs to use for their IX. The two engines use completely different plugs.
So heres my question. I have been told for average boost (23psi) 0.022, 0.025-0.027, also the factory gap 0.028-0.031. OK now which do I use? I have tried these different sizes and my car seems to run the best with a larger gap. like around 0.030. But I have not seen to many people talk about running a gap this large. only one person so far.
A quote from this thread --> spark plug gap
And is post #5 by Jamie@WROKS
Interesting....Heres another thread with some other information that is interesting
https://www.evolutionm.net/forums/ev...p-1-5-bar.html
Some pulled quotes from this thread
Post #13 by mitsuorder
Post #14 by QuantumEVO
Contradicting information. I realize all of these threads are super old. For instance this last one is from 2003. So There may have been new proper values established since then....If so I cant find it. All i find for info on this topic is 5+ years old. I know people don't like to bring back old threads so I didn't post on them...
Heres another controversy. The value for 0.028 for example is un inches i assume? Some people are writting in values like 0.028 and other are saying 0.0028 and others... are saying 0.28.
These are all very different values. Id like to take a micrometer at work or something that i know is accurate to gap these properly once i know what value to set these guys too. But its hard to tell what the correct numbers are with all of this misinformation.
ANOTHER issue i have. I have to gapping tools at home. One is made by the brand "OEM" purchased from autozone. Its the wire type. Note that i did see the issue with the bad batch of wire style gapping gauges. This is not one of them. The other style is a Champion gauge. Its circular and a bit larger in diameter then a silver dollar. Maybe and inch and a quarter in radius. 0.025 on my wires gauge is more like 0.035-0.037 on the champion wedge style gauge. Which one is right? Also when using the champion gauge where are you taking the measurement from... meaning which side of the plug's electrode will you use to line up to a measurement mark. The lower side? or the higher side? Or maybe the middle of the electrode? Its all unclear to me. I have included a picture of a gauge similar to mine. (below)
Here is a picture of the wire style gapper (below)
Is this guys technique correct? Or should he be perpendicular to the electrode instead of parallel to it as shown. There is a difference because of the bends on the corners of the "u" part of the wire. Try it and you will see what i am talking about. I have seen both ways online in different areas.
For anyone that actually reads my entire post / rant
and has some valuable information to share.. THANK YOU. Sorry about all of the text but this issue has been bothering me for a while and I cant find any answers to such a simple question....
Thanks!
-Ethan
There are quite a few old threads about this subject. Mostly from back in 2004-2006 or so. There is a lot of good information on these threads especially about what heat range plug one should be running. Wich i have concluded that the stock 7 heat range is good up until 24psi or so then one might think about changing to one step colder. An 8 series plug. So the copper part #'s for NGK are BPR7ES and BPR8ES. This again is NOT for an IX this IS for an EVO VIII. Through my searching i saw a lot of people getting confused about what plugs to use for their IX. The two engines use completely different plugs.
So heres my question. I have been told for average boost (23psi) 0.022, 0.025-0.027, also the factory gap 0.028-0.031. OK now which do I use? I have tried these different sizes and my car seems to run the best with a larger gap. like around 0.030. But I have not seen to many people talk about running a gap this large. only one person so far.
A quote from this thread --> spark plug gap
And is post #5 by Jamie@WROKS
Originally Posted by Jamie@WROKS
WORKS recommends the OEM plug gapped to factory specs: .028-.031 You shouldn't need to go a range colder with the P2 boost settings.
In my own EVO, I use BGK BPR7ES gapped at .028 (I've used these plugs for years in my previous vehicles without issue).
In my own EVO, I use BGK BPR7ES gapped at .028 (I've used these plugs for years in my previous vehicles without issue).
https://www.evolutionm.net/forums/ev...p-1-5-bar.html
Some pulled quotes from this thread
Post #13 by mitsuorder
Originally Posted by mitsuorder
ok, gapped my NGK BPR7ES's at about 31 today, car is ******** some ***, man did my stock plugs look nasty, all that running rich from the factory I guess, just realized I totally forgot to apply the antisieze stuff that o'riely gave me to the threads. should I go back and apply that stuff? is it bad to back the plugs out after the copper crush washers have already been compressed? with an aluminum head will I be ok without the antisieze stuff till the next time I do my plugs? thanks for any answers in advance!
Originally Posted by QuantumEVO
Ok to remove and reinstall. I never use antisieze.
1.5 is too much boost on stock turbo even with 93 (which is the minimum octane for that level). You aren't making any more power at that level. 20 psi is a good level for 93 octane with FMIC, exhaust, etc.
.030 is too much gap. .020 is too little. One will cause misfires, etc and the other will not make as much power as you could.
1.5 is too much boost on stock turbo even with 93 (which is the minimum octane for that level). You aren't making any more power at that level. 20 psi is a good level for 93 octane with FMIC, exhaust, etc.
.030 is too much gap. .020 is too little. One will cause misfires, etc and the other will not make as much power as you could.
Heres another controversy. The value for 0.028 for example is un inches i assume? Some people are writting in values like 0.028 and other are saying 0.0028 and others... are saying 0.28.
These are all very different values. Id like to take a micrometer at work or something that i know is accurate to gap these properly once i know what value to set these guys too. But its hard to tell what the correct numbers are with all of this misinformation. ANOTHER issue i have. I have to gapping tools at home. One is made by the brand "OEM" purchased from autozone. Its the wire type. Note that i did see the issue with the bad batch of wire style gapping gauges. This is not one of them. The other style is a Champion gauge. Its circular and a bit larger in diameter then a silver dollar. Maybe and inch and a quarter in radius. 0.025 on my wires gauge is more like 0.035-0.037 on the champion wedge style gauge. Which one is right? Also when using the champion gauge where are you taking the measurement from... meaning which side of the plug's electrode will you use to line up to a measurement mark. The lower side? or the higher side? Or maybe the middle of the electrode? Its all unclear to me. I have included a picture of a gauge similar to mine. (below)
Here is a picture of the wire style gapper (below)
Is this guys technique correct? Or should he be perpendicular to the electrode instead of parallel to it as shown. There is a difference because of the bends on the corners of the "u" part of the wire. Try it and you will see what i am talking about. I have seen both ways online in different areas.
For anyone that actually reads my entire post / rant
and has some valuable information to share.. THANK YOU. Sorry about all of the text but this issue has been bothering me for a while and I cant find any answers to such a simple question....Thanks!
-Ethan
Last edited by ethan169; Dec 2, 2009 at 07:07 AM. Reason: I suck at HTML and had to fix a few tags....
Dec 2, 2009, 06:53 AM
#2
i read ur hole post.. i have evo 8 24psi dd. im running the br8es plugs gapped to .025. i have never use the wire gapper but i used the circluar one and all i do is start at the beginning and slide the plug up untill the center of the electode is at where i need it to be.. hope that helps. im sure many people do it different ways. i say whatever works best for you and ur car is the right way
Dec 2, 2009, 07:10 AM
#4
Evolved Member
Thread Starter
iTrader: (3)
Join Date: Mar 2007
Location: Connecticut / Vermont
Posts: 562
Likes: 0
Received 0 Likes
on
0 Posts
i read ur hole post.. i have evo 8 24psi dd. im running the br8es plugs gapped to .025. i have never use the wire gapper but i used the circluar one and all i do is start at the beginning and slide the plug up untill the center of the electode is at where i need it to be.. hope that helps. im sure many people do it different ways. i say whatever works best for you and ur car is the right way
bluebanana23 every time i tried anything below 0.025 my car seemed to have noticeably less power.
Dec 2, 2009, 10:04 AM
#5
Evolved Member
iTrader: (1)
Join Date: Mar 2005
Location: Mesoamerica/ SF Bay Area
Posts: 7,905
Likes: 0
Received 5 Likes
on
5 Posts
I don´t like either the wire gapping tool, or the ¨coin¨type tool. The better option is the steel blade type feeler gauge. They are more accurate. First they are ground and then polished to much tighter tolerances.
Dec 2, 2009, 10:08 AM
#6
Always gaped plugs to .026 on both BR7ES (stock turbo and when I was on the 20g) and BR8ES (Now on the 61mm). Never break up all the way to 8200rpm stock 120k mile ignition
Oh and always use the cheap circle tool. Works like a charm I'm old school
Oh and always use the cheap circle tool. Works like a charm I'm old school
Thread
Thread Starter
Forum
Replies
Last Post
2005, bpr7es, evo, evolution, gap, gapping, lancer, mitsubishi, oem, plug, spark, spark plug, sparkplug, spec, specifications
