plug gap? - Boost Forum

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plug gap?
Tuesday, January 24, 2006 5:52 PM
just woundering what to gap the pulgs for the gm sc and what plugs do you think i could use?


<img src= "http://registry.gmenthusiast.com/images/will1026/thumbnail_oh%20my.jpg">
14.475@98.7124 at capitol raceway

Re: plug gap?
Tuesday, January 24, 2006 6:02 PM
im using the plugs that came with the kit gapped at 45. absolutely no problems whatsoever.



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- Sold my beloved J in April 2010 -
Re: plug gap?
Tuesday, January 24, 2006 6:39 PM
yeah i have those but i have a missfire in cylender 1 so am going to replace them



<img src= "http://registry.gmenthusiast.com/images/will1026/thumbnail_oh%20my.jpg">
14.475@98.7124 at capitol raceway
Re: plug gap?
Tuesday, January 24, 2006 9:44 PM
your gap should be .035 or .040




I was a retard, and now I'm permanently banned.
Re: plug gap?
Wednesday, January 25, 2006 12:42 AM
i had the gm plugs gapped at 50 and i was getting 8* KR at full boost
switched to #5's @ .40 and had 4-5* KR
now im going to try the colder plugs AC delco pn = #5614285 gapped at .40 and have my fingers crossed

btw this is the stock pulley and i see 6.2lbs of boost at higher rpms
and all KR is gone with the alky on but i want it gone period before i put the new pulley on



Re: plug gap?
Wednesday, January 25, 2006 5:44 AM
TR5@ .028 with waterinjection and a 2.5" pulley...

TR6@ .032 with a 2.7" pulley.

thats what worked best for me. everything else misfired.


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: plug gap?
Wednesday, January 25, 2006 7:13 AM
bluzr2 wrote:i had the gm plugs gapped at 50 and i was getting 8* KR at full boost
switched to #5's @ .40 and had 4-5* KR
now im going to try the colder plugs AC delco pn = #5614285 gapped at .40 and have my fingers crossed

btw this is the stock pulley and i see 6.2lbs of boost at higher rpms
and all KR is gone with the alky on but i want it gone period before i put the new pulley on


KR = knock retard?

I still don't get how people are getting so much boost with the stock pulley. I've never seen a hair over 5 psi and I've probably got one of the most restrictive setups here, which should build more boost with less flow.





Re: plug gap?
Wednesday, January 25, 2006 10:21 AM
Yea... for boost you don't want the factory plug gap. Definitely stay below .040




I was a retard, and now I'm permanently banned.
Re: plug gap?
Wednesday, January 25, 2006 11:23 AM
KR = knock retard? yes

wish i knew why the boost was so high also, i have a catback system w/ 2 1/4" pipe and a regular circle muffler(pretty quiet) had 2 glass packs on it for one day then removed for just a generic muffler. could actually be more restrictive then stock but i doubt it. one of these days ill get bored and weld up a turbo muffler or something see if that changes anything. btw stock exhaust manifold and cat.




Re: plug gap?
Wednesday, January 25, 2006 1:24 PM
Spotabee Racing (The Fake Z24) wrote:Yea... for boost you don't want the factory plug gap. Definitely stay below .040


Any idea why GM says to use 0.050 with the kit then?





Re: plug gap?
Wednesday, January 25, 2006 1:25 PM
Wild Weasel wrote:
Spotabee Racing (The Fake Z24) wrote:Yea... for boost you don't want the factory plug gap. Definitely stay below .040


Any idea why GM says to use 0.050 with the kit then?


That doesn't make sense considering the factory plug gap is .040




I was a retard, and now I'm permanently banned.

Re: plug gap?
Wednesday, January 25, 2006 3:06 PM
check out my post about rapid fire # 5's, the second page. get them ac delco plugs i talked about.


later






Re: plug gap?
Wednesday, January 25, 2006 8:09 PM
this post is cool

im currently at 45 gap w/ the stock charger plugs and stock pulley, and i've had no problems.

i will be going to the 2.7 w/ no alky though, so i might consider regapping my plugs. what do you all think? 40?

and if i have major problems, i might do this 2 step colder plug thing. although i really dont beat on the car much.

also, is knock retard the opposite of timing advance?



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- Sold my beloved J in April 2010 -
Re: plug gap?
Wednesday, January 25, 2006 8:17 PM
Viper98912 wrote:this post is cool

im currently at 45 gap w/ the stock charger plugs and stock pulley, and i've had no problems.

i will be going to the 2.7 w/ no alky though, so i might consider regapping my plugs. what do you all think? 40?

and if i have major problems, i might do this 2 step colder plug thing. although i really dont beat on the car much.

also, is knock retard the opposite of timing advance?


i'd do closer to .032 - .035




I was a retard, and now I'm permanently banned.
Re: plug gap?
Wednesday, January 25, 2006 8:28 PM
Spotabee Racing (The Fake Z24) wrote:
Wild Weasel wrote:
Spotabee Racing (The Fake Z24) wrote:Yea... for boost you don't want the factory plug gap. Definitely stay below .040


Any idea why GM says to use 0.050 with the kit then?


That doesn't make sense considering the factory plug gap is .040


actually, this post is not cool. i meant to type this in jake's rapid 5 post.

and actually spot, the n/a stock ld9 gap is 50, not 40.



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- Sold my beloved J in April 2010 -
Re: plug gap?
Wednesday, January 25, 2006 8:39 PM
OK. Well, then, that only furthers my point. The stock gap is .040 on the 2.2 sorry my bad. Why would you stay at stock gap (or go larger) for forced induction? You don't. And it makes no sense for GM to say that.




I was a retard, and now I'm permanently banned.
Re: plug gap?
Thursday, January 26, 2006 5:25 AM
ya... densor air= harder to ignite...

MOPAR wants .050 gap on the neons (AKA SRT-4) though.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: plug gap?
Thursday, January 26, 2006 1:13 PM
I thought that a bigger gap made a more powerful spark, but required more voltage to do so.




Re: plug gap?
Friday, January 27, 2006 5:34 PM
from the NGK website :

Always check that the spark plug gap is compatible with the engine manufacturers specification. A gap that is too small means that the spark duration will be very quick and the spark will be thin and weak. The consequences of this may be bad starting and high exhaust emission levels. This will result in an increase in fuel consumption. If the gap is set too large, the ignition system will not be able to cope with the demands and a misfire situation will occur. Some wide gap spark plugs have a longer ground electrode to accommodate a wide gap setting. These must be used where specified, as opening up a standard plug to a wider gap setting may result in the electrodes not running parallel to each other. This could result in abnormal and premature electrode wear.



14.82 @ 97 mph
Re: plug gap?
Saturday, January 28, 2006 11:41 AM
Right. So if GM says to use a 0.050 gap with the plugs they provide, isn't that what we should use unless we're getting misfires?

How can we tell if it's misfiring?





Re: plug gap?
Saturday, January 28, 2006 2:12 PM
^flashing check engine light at wide open throttle.

Team GREEN


Re: plug gap?
Saturday, January 28, 2006 3:33 PM
Ok, so if mine doesn't do that then my 0.50 is fine, right?





Re: plug gap?
Sunday, January 29, 2006 7:22 AM
^ should be ok. IF you get a flashing CEL, i would put the gap smaller on them gm s/c plugs and it will go away. like .030 - .035ish
I would pick up a set of them ac delcos i talked about in my other post and give them a try and see how your car runs. @2$ a plug it isnt much.

Team GREEN

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