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Spark Plugs

3942 Views 19 Replies 9 Participants Last post by  NickD
So my girlfriend has a bone stock 2012 cruze with the 1.4 turbo. Changing her plugs to try to reduce some of the turbo lag its horrible in warm weather with the ac on. I saw the hesitation sticky and is the BKR8EIX-2668 or BKR7E-4644 still the way to go? I saw this post was from a few years ago and I cant read through 115 pages. Thanks!
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Before you pitch the plugs, try running the tank almost to empty and refill with premium.
This little turbo motor pulls spark timing, a lot, anytime ambient temperature is above 65 degrees.....and as a result, a HUGE lag on throttle apply/re-apply.

The majority of members run premium in the summer.....runs normal, mileage improves.

Plugs are the next step if fuel doesn't resolve driveability to your satisfaction.

Robby thanks for the reply. I will try that and see what happens. It looks like the plugs in the car are the NGK IFR7X 7G
Yes, definitely try higher octane gas first.

I prefer the way mine drives with the BKR7E, but they are higher maintenance (frequent gapping). I actually need to do it at the moment. If it's an auto, I'd say just go with the BKR8EIX - they spend a lot less time below 2000 RPM than I do.
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Yes, definitely try higher octane gas first.

I prefer the way mine drives with the BKR7E, but they are higher maintenance (frequent gapping). I actually need to do it at the moment. If it's an auto, I'd say just go with the BKR8EIX - they spend a lot less time below 2000 RPM than I do.

That's one thing I read online was the BKR7E was definitely some maintenance. I was doing some looking into the BKR8EIX. It just seemed most people with either of those plugs are in manuals not autos. She has an auto. So I didn't know which would be the best route. If it runs better I don't mind spending the $50 or whatever.
The manuals just become a chore to drive in summer on the stock plugs, so that's why you see a greater number switching. Autos are less noticeable, but the earlier years still hugely benefit from higher octane gas as a starting point.

If you're still unhappy with it after a tank or two, go the route of the BKR8 Iridium plugs (or try out the el cheapo BKR7E for a month or two and upgrade to the iridium plugs if you like the way it feels).
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Don't let the price throw you off, if you must shop online for them. Coppers were spot on for me but gapping was a bit much for how I drove when I was tuned.

What's wrong with reading 115 pages? LOL everyone wants the answers to the test instead of 2 hour study groups. There was a shorter thread that summarized it in cliff notes but can't for the life of me remember what it was called.
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Mine is also an auto trans. The premium fuel makes a big difference in my car, and doesn't cost that much more. I just looked at my gas log spreadsheet, and it has only cost me $136 more in the 2.5 years I have had the car.

I have also tried the BKR7EIX, BKR8EIX and the BKR7E plugs. They do make a difference with my car. The power feels more consistent and it seems to pull more reliably. I also get fewer days where the car feels like it is lagging. It may not be as noticeable as the manual trans, but I still notice a difference.

I personally prefer the iridium EIX plugs. However, the iridium plugs still have a nickel ground strap, so I check the gap about once a year. These plugs are higher maintenance than the stock plugs, and I wouldn't recommend them to anyone who is lazy about regular maintenance.

If I had to choose between using premium fuel and replacing the plugs, I would choose premium fuel.
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AS others have said about the premium gas it is definitely a bonus when it comes to performance. If you are interested or considering, you could tune but that is more expensive. Also another thing not helping is this heatwave we are experiencing
Try the premium first and see if the car doesn't pick up some.
Well guys her car has alomst 70K and were going to go ahead and swap plugs along with premium. Shes almost empty so that's perfect. So should we go back to the stock ngk or try out the BKR8EIX? I thought that plug didn't have to be regapped once a year unlike the BKR7E?

I just need to try to do something quick so I can get the plugs ordered and done as its extremely hot here.

What I am currently thinking is trying the BKR7E and see how it feels since I can get a set for $10. If we like that we can change out to the BKR8EIX later as these plugs are easy to get to.
Any plug that isn't the stock ones will be higher maintenance. Worth the benefits for increased maintenance is up to you.

I like your current thinking.
I tried the BRK8EIX plugs and went back to the BKR7E copper. Reason was simple - cost. My BRK8EIX only lasted about 30K miles, which is two sets of the copper plugs but at $32 (8EIX) vs $21 (copper).
If its just checking gap once a year or so I don't mind it on this car. Like I said its easy to get to the plugs. If it was like some other cars where intake manifolds have to be removed or other stuff that takes hours I would feel completely different. Well I am going to try the BKR7E then at .28 -.30
You do have to check the gap, but the plugs also wear out faster and have to be replaced more often. I don't know how long they last because I have changed mine several times trying out different options. I haven't kept them in long enough for them to wear out.

The OEM plugs have an iridium tip and a platinum spot on the ground. Because iridium and platinum are very hard these plugs last a long time, but platinum also has higher resistance and doesn't provide as good of a spark.

The 7E plugs have a nickel tip and a nickel ground. Nickel is very soft and wears out quickly. However, some people believe these are better than the iridium versions. One reason is that they have a larger surface area on the tip, which might give a better spark. The NGK website rates these lower performance than the EIX plugs. I personally think the NGK engineers know what they are doing, so I believe them. Other people might disagree.

The EIX plugs have an iridium tip and a nickel ground. The tip lasts longer, and iridium has lower resistance than nickel. The tip is a very fine point. The nickel ground will wear out as quickly as the 7E plugs.

With either of those plugs you will notice that the ground will get a large pit in it after a while. With the 7E plugs you may also see wear on the tip.

Also, try to gap all four plugs as identically as possible. And, if you use the EIX plugs, be careful not to break the tips. Don't put pressure on the tip. My car runs much better at 0.28 than at 0.30.
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Put the BKR7E plugs in last night. Gapped right about .29 I tried to get all of them as close to one and other as possible. But we all know its tricky. We also put in a full tank of premium. I haven't talked to her today yet to get any results. But she has a 10 mile one way highway trip in traffic to work and back. So I will update later tonight or tomorrow.
By doing the plugs and fuel grade change together you won't know what really resolved the issue.

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Ha, an old GM 455 CID would get you home if only 3 or 4 out of 8 plugs were firing and most people didn't even know the difference. Sure didn't have to worry about burning up your catalytic converter, didn't have any. PCV wasn't a problem returning crap back to the combustion chamber, because returned to a bare intake manifold. no injectors in there to have their faces plugged up with carbon. And the AF ratio for each cylinder would remain the same because there was no O2 sensor to go nuts with the new stuff.

One little misfire, O2 sensors, oh my God, seeing oxygen, the fuel must be lean, better enrich it, so even more raw gas goes into the cat to burn it up. Talk about a self destructive machine.

When spark plug wires were used, some were over three feet long generating lots of EMI where the major inference was with an AM radio, screw the radio, want a hot spark so would use solid copper wires. What they were doing was taking a piece of grocery store string and dipping this in carbon that with engine heat would cake up and causing arcing within the carbon. This was where your spark was going certainly not across the electrodes in the plugs where it belongs.

But with my 454 left that carbon in there idiots were using an insulation displacement spark plug terminal just making a point contact at one point to that carbon, how stupid can you get? So on each end of each wire, jammed in a piece of 20 AWG plated single strand wire two inches into the carbon to vastly improve the conductivity. Resistance of this wire was 2K ohms per foot, made darn sure a three foot wire was 6k ohms, and this was checked every time I had to clean or replace the plugs.

And this was quite frequent because back then not only had conductive carbon on that center electrode insulator shorting the plug to ground but lead as well, new plugs were about 40 cents each back then. Least now, just carbon, also cleans off much easier, use walnut shell powder in my blaster to clean them. To deal with PCV dump in a can of Seafoam in a full tank of gas every 5K to clean up that carbon. But instead of doing this around every 4K miles, getting by with 15K miles now, and only use top tier gas.

Who ever gets my Cruze will find four brand new plugs in it, just replaced the before it was rear ended, I don't get it back, insurance company gets to keep it thanks to our crooked laws protecting the insurance companies, and screw you consumer.

Never shed a tear when spark plug wires disappeared, one less problem to deal with, but sure prefer coil on plug over the module, if one is bad, just replace that, not the entire module. But carbon has not disappeared in that wire, was moved inside of the plug and does anybody check that resistance between the center of the electrode and the outside terminal? this kid does, should be 4,000 ohms, for all you know since you cannot see it, could be infinity.

Daughter's Kia has coil on plug, nice, but some idiot specified a 45 mil gap, didn't know they had crack in Korea. This was tricking trying to close a 45 mil gap down to 26, had to very carefully bend the ground electrode outward while closing the gap so those two infinitesimal iridium electrodes were in line. Paid off, averaging 5 mpg more in fuel economy and seeing power she never have before with that little 1.6 L. And her fuel is being burned in the combustion chamber and not in the cat, even more problems.

18 ft-lbs of torque is darn near standard, if using a six inch wrench, that jumps up to 36 pounds of force, not easy to judge, if you don't have a torque wrench, get one, but not a cheap piece of crap, get a good one. Still prefer analog, hate these clickers, when you hear that crack not sure if its the wrench or your head that cracked.

Springs inside the boots are a problem, get hung up on the shoulder in the boot, stretching them out about 3/8" solves this, or will have a heck of a gap in there. Need a very bright light, tipping the module toward you, make sure all four boots are centered over the four plugs, then tip it backwards while applying pressure.

One more thing, is you see carbon on the spark plug washer, getting blowby and if its there, also on the seat in the head. Have to attach a piece of lint free cloth to a wooden dowel, soak it in choke and carb cleaner and clean that off. If you don't, will never get a good seal.

Won't get into what kind of plug to use, too many different opinions on this subject and most of them are from guys that have not designed ignition systems for the last 40 years.
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Just a quick update - She has been driving it for the last week and its been pretty warm (90's) and she said she has been able to tell a difference. Iv'e driven it a couple times and I am happy with the results. The check engine light has come on once for about 10 seconds but it went away and we haven't seen it since.
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I also changed my sparkplugs this weekend because of a hesitation at ~3K RPM. Went with the OEM Iridiums again gapped at 0.028.

Glad I did the change at 60K mi rather than the 100K recommended in the 2012 Owner's manual! There was nothing left of the electrode.

She's running like new now!
These are hundred year old spark plugs from a Ford Model T, ha, really haven't changed that much.

Actually this fired very good, Ford used permanent magnets on the flywheel that generated a voltage that operated a relay wired like a door bell buzzer, so would get a series of sparks. But the major problem was contact wear on those vibrator contacts, not spark at all.

Kettering came along using battery voltage with an autotransformer and camshaft controlled ignition points, a capacitor was connected across the points and renamed the condenser. This was so bad either, because when the points open, that condenser would form a resonant circuit with the coil, so would get a series of sparks. But again, point wear.

This lasted until the 1972 model year where a transistor replaced the points, but unlike the points is a unidirection device, cannot take reverse polarity like points can, so that condenser had to go. The consequence of this is only getting just one spark. Using an SCR to drive a capacitor charged to 400 volts and discharging it through the coil generates a nice spark line. But way too expensive for the bean counters, also requires an inverter, so just living with one quick spark.

Cars are still burning carbon that is highly conductive on that center electrode insulator, in brief, grounds out that center electrode voltage to ground. So not only just one spark, but one that can also be grounded with no spark at all.

Looking at over a hundred year problem with spark plugs that still never yet was solved, well the diesel did, no spark plugs at all.

If you really want to keep your spark plugs cleaned and gapped properly, you have to do this yourself. One key reason why I really like a four cylinder engine. Ha, that Caddy V-16 I owned was a major job, all I had was an Exaxto knife and a piece of steel wool, in the 60's making a couple of bucks purchased a walnut shell blaster to ease this job, still have it.

Putting V-6's or 8's in a FWD was crazy, had to tip the engine, or remove a bunch of stuff even to find the plugs. Or mounting an AC compressor over a couple of plugs, another PITA to deal with. Is an absolute pleasure to clean or replace the plugs in the Cruze. But they still have to be cleaned and properly gapped.

With copper type plugs for years, could get more mileage out of them with a super fine file. tip of the electrodes had to be perfectly square with sharp corners to get a decent spark, basics of electrostatics. Platinum or iridium kind of solved this problem.
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