I searched but couldn't really find any RELIABLE information regarding higher boost and colder spark plugs (and gaps). I am running the factory plugs at the factory gap with my mods listed in my sig. I have 28,000 miles on them. In the spring, I plan on changing to the NGK 1 step colder plugs. I have a few questions regarding this:

1. What is the benefits of doing this with my modifications?
2. What gap works best with my mods and these plugs?

I will be using the copper plugs and will change them out every 20k or so (**** iridium plugs). Any factual help will be appreciated.

Thanks!

 

I can't comment on copper plugs but i went with 2 step colder ngk's and gapped them at .035 and my car runs good.

 

Is the 2 step colder the BKR7E or is that the one step colder. I forgot...

Mine runs OK but in the low RPMs it bogs and chugs like no other (1500 and below). Would the colder plugs fix this?

 

Here you go http://www.ottperformance.com/Cobalt...duct_info.html

 

Yeah, I was thinking of going with the 7E's though since I only have a 3" pulley and 42's.

Anyone else?

 

The 7e is perfect for what you need. I personally ran this plug and step colder autolites. The autolites were on the 2.5" m62 the ngk's were on the 2.75" tvs. .035 always worked well for me.

 

1. Using colder plugs reduces the combustion chamber tempuratures. The higher compression generated by smaller pullies creates more heat during the combustion process. Typically as a rule of thumb for every 50 - 75 crank HP you should drop a plug heat range (unless you are porting the head which can help to reduce tempuratures due to better flow, but no need to go into that).

2. The only way to tell what gap works best, is to try different gaps. You always want to have the biggest gap possible without having spark blowout. The best thing is to start at say .040 then see if you have an hesitation at WOT. If so then drop to .039 and see if you get hesitation. You can continue this until you find a gap that works best. I wouldn't go smaller than a .035 gap and probably no wider than .040. Chances are, if any, that you will need a smaller gap and not a larger one.

 

Thanks guys! I am gonna try the 7e's at .035 and go from there.

 

remember guys we already have a boosted plug...

alot of you guys thinking you need to go two steps from stock thats really like three

the bkr7 are like 2 steps colder already considering a stock plug would be a bkr6 which is already 1 step colder...


bkr7e FTW gapped at 32...