# Best Spark plug and Gap settings



## WhiteAndBright (Mar 4, 2013)

I use the Autolite Coppers.. Gapped to .028


This extraordinary insight brought to you from the confines of my iPhone..


----------



## obermd (Mar 3, 2012)

If you don't plan on ever checking them again until replacement at 60,000 miles, set them to 0.028". If you don't mind pulling them out and checking periodically set them to 0.034-0.035". The original spec for this car was 0.033-0.037" but GM came back after XR queried them about the gap and the fact that there was a lot of inconsistency and most plugs at 0.025" or less and said 0.028".

In my opinion, the reason for this discrepency is that spark plug gaps grow over time as the electrode wears down from use. Extrapolating from the increased gap size I measured in Janary gives a max gap of 0.029" to start. The Cruze's engine will start experiencing spark blowout around 0.040". Also, when checking your plugs remember to straighten out the ignition coil springs before reinstalling the coil pack. The other thing a couple of us have noted is that the gaps don't grow at the same rate, so don't be surprised if you see one gap larger than the others.


----------



## MassCruzeLTZ (Mar 30, 2014)

WhiteAndBright said:


> I use the Autolite Coppers.. Gapped to .028
> 
> 
> This extraordinary insight brought to you from the confines of my iPhone..



I will check those out. I thought I had seen a debate about the Iridium plugs vs copper!


----------



## obermd (Mar 3, 2012)

If you go with copper plugs you'll need to check your gap every six months or so.


----------



## 555hp (Mar 21, 2014)

Welcome fellow 2014 LTZ RS owner (did the extra $1000 sun discount do you in as well)?

We just re-gapped our 0.024 gap factory plugs to 0.032. I did not think it would make much of a difference, though was surprised that it actually did...don't expect much though. A bit smoother idle and low rpm torque and maybe another 1 highway mpg.


----------



## WhiteAndBright (Mar 4, 2013)

I agree I have noticed a difference at idle.. It feels a lot smoother, I also had Trifecta bump up my idle to 850 as I run the a/c 100% of the time when it's over 65*.. I am very hot natured.. After I had that changed it is a night and day difference at idle..


This extraordinary insight brought to you from the confines of my iPhone..


----------



## sx sonic (Nov 25, 2013)

Just set gaps to .028" and call it a day. It's what Trifecta Vince recommends and I believe what the updated service manual specifies.

Plugs. Well NGK or O.E.M. iridiums (or one heat range colder). Coppers may interest you as many members here like them


----------



## WhiteAndBright (Mar 4, 2013)

sx sonic said:


> Coppers may interest you as many members here like them


I am going to stay with the coppers, yes you have to replace them sooner than you have to replace the oem but they cost like 8 bucks.. I will spend the extra money to have a smoother idle.. Just my 2 cents..


This extraordinary insight brought to you from the confines of my iPhone..


----------



## winks79 (Dec 20, 2013)

MassCruzeLTZ said:


> What is every ones opinion on what is the best spark plug to use for my 2014 LTZ RS? And I'm seeing a lot of gap questions but I'm unmodded engine wise so what gap is best??


I have a 13' model identical to yours, no mods. My wife drives this car. I changed the iridium out to NGK coppers with a 7 heat range. Set gap to .030. Did not tell her that I did it, and a couple of days later she told me that the car seem to be running better than it did previously, smoother on acceleration. I don't drive it enough to compare, but I don't think she would lie to me for no reason. I think I gave around $9 for the plugs, and they are very easy to take out and regap when the time comes. I figure I will check them again after she puts around 10k on them and see what they look like.


----------



## Vetterin (Mar 27, 2011)

If I haven't changed......regapped my plugs at least 20 times now....I am a liar! I've tried the Autolite iridiums (just put them back in Tuesday), Autolite coppers and NGK coppers with gaps ranging from .028 to .035 and to ME (while the differences aren't staggering) the best set up is the Autolite coppers @ .030. I'll probably put the coppers back in this weekend. YMMV!


----------



## Merc6 (Jun 8, 2013)

winks79 said:


> I have a 13' model identical to yours, no mods. My wife drives this car. I changed the iridium out to NGK coppers with a 7 heat range. Set gap to .030. Did not tell her that I did it, and a couple of days later she told me that the car seem to be running better than it did previously, smoother on acceleration. I don't drive it enough to compare, but I don't think she would lie to me for no reason. I think I gave around $9 for the plugs, and they are very easy to take out and regap when the time comes. I figure I will check them again after she puts around 10k on them and see what they look like.


LOL adding 93 would have made her think you did something to the car.


----------



## Shmigelz (Sep 9, 2012)

Factory ac- Delco, gapped at .28


Sent from AutoGuide.com Free App


----------



## Slammed2014Eco (Feb 13, 2014)

I'm running the 7E Vpower on mine @ .28 but I'm also tuned, Love my copper plugs tho no issues at all other than tearing a boot when replacing ;'(


----------



## ehagendorff (Mar 7, 2014)

I'm running NGK BKR7E's at .30. Car runs much better with them so far.


----------



## Cruzado (Sep 9, 2012)

Check the Hestitation Gone thread. I switched to the Autolite coppers and they were ok...except didnt last too long...so I went with NGK V Power at .30. I like these better. The improvement was best noticed in low RPM response...such as stop n go traffic... That thread has a ton of good info.


----------



## AZCruze (Nov 3, 2014)

Last night i swapped mineon my 2012 1.4t lt to the ngk v powers @ 0.029 and wow smooth idle no more little lag in the lower rpms, the shift seems smoother and firm when it goes threw very easy to swap out... car only has 1k on it i am goingto run them for another 5k or so and then check them out. I wanna see how the mpg's change.


----------



## Slammed2014Eco (Feb 13, 2014)

AZCruze said:


> Last night i swapped mineon my 2012 1.4t lt to the ngk v powers @ 0.029 and wow smooth idle no more little lag in the lower rpms, the shift seems smoother and firm when it goes threw very easy to swap out... car only has 1k on it i am goingto run them for another 5k or so and then check them out. I wanna see how the mpg's change.


That's a good choice, I did the same with my 2014 as well I swapped them at about 6500 miles just wait until you get tuned and it just gets better if that's a route you're looking at =>


----------

