Chevrolet Cruze Forums banner

Hesitation...GONE!

496K views 1K replies 175 participants last post by  Johnny B 
#1 · (Edited)
UPDATE: For those that don't want to read through the 2348972347892 pages of this thread, we have found that the following plugs seem to work best in the 1.4-Liter engines:
-BKR8EIX-2668 (iridium plugs), expect ~10-15k regaps on these, ~40-50k overall life.
-BKR7E-4644 (nickel/copper plugs), expect 15-25K out of these plugs, with a regap or two required at 5-8k intervals on stock tune.


-FR7BHX-S (ruthenium) - this is the latest recommendation for a combination of long life and drivability.

Set initial gaps @ .028". Higher gaps will start to blow-out as the gaps increase.

So for what it's worth, some of you may remember that I was saying I had hesitation that felt like timing pull, even on 93 octane during winter months. I believe I got that one taken care of with a new stock ECU tune from Chevrolet, as for the most part, it behaved much better after that.

However, with the AC on fan speed 3, and especially 4, on a hot day (85+), and even sometimes just randomly when it's not that hot, I'd feel a strong timing pull from 1850-2750 RPM...jerky acceleration and the car just felt...slow. Pinging right off the knock sensor, about 3-4 times per gear under acceleration. With the AC off, it's fine unless I'm sitting at a light for a while.

I ordered the copper NGK version of the same heat range plug that's in the car (BKR7E) and dropped them in today. Perfect day to test - lots of traffic, lots of stoplights, AC on fan speed 3/4, and 94 F outside.

Once the ECU "adjusted" after a few seconds, I could not get the car to jerk WHATSOEVER. Very happy. Acceleration is smooth from a stop all the way up to 5500 RPM, and the car drives like what I feel like it was made to drive like.

I don't know why this made a difference, other than my experience that turbo cars do not like platinum plugs and perhaps iridium have the same effect on them. The old plugs look like they're burning just fine and are clean.

EDIT:
Many of us have found that the .035" gaps are a little bit optimistic - our cars will start to blow out after not too long as the gaps grow. I'd recommend starting in the .028-.030" range. Check your plugs again after 10,000 miles and readjust.




Old iridiums
 
See less See more
2
#51 ·
Blue Angel said:
So I'm going to pick up a set of Honda dirt bike plugs for my Cruze turbo next week, gap them to some crazy spec that will never work, drive so easy they will never get up to proper temperature, and try to set GOLD Hypercruzer status before they foul up. That sounds like just the right amount of dumb. Wish me luck.
I remember ordering light bulbs for a non-Honda vehicle through their dealers too for about 1/3 the cost.

LOL, good luck with that. Run em up to redline before you fill up and see how they do.
 
#52 ·
Yea those charts confused me lol I will test I'm going to datalog tonight with my stock plugs gapped at. 030 and then I have order the same plug just copper and I will gap to. 030 and log again.


Titan I need a new datalog veiw program that your created.

Sent From An Antique,
My Original Droid.
 
#54 ·
They sent me Autolite 3923 are those correct sorry I'm mlnot at a pc.

Sent From An Antique,
My Original Droid.
 
#57 ·
Ok so way bad lol ill send em back. So what part number should I get can't see thay picture


Sent From An Antique,
My Original Droid.
 
#60 ·
Ordered.

Sent From An Antique,
My Original Droid.
 
#59 ·
i am tuned and are looking to take out the stock plugs...what what ones should i put back in to try this time
 
#62 ·
Put em in today. Noticed the car doesn't sputter on start up any more. Low end RPM range is smooth and less jerky. Was too hot for testing power and I took my boost gauge off so I only assume I was at 22psi but revved to 5500 in 3rd and no cutout.

Plugs were gaped at 0.029 out of the box so I left them that way.

Stock plugs were pretty much burned out. I had them at 0.027 for the last ~15k and that was just too much for them. I'm driving 60 miles down then back up a 3000ft elevation change so I'll see how well they do later tonight when it's cooler.
 
  • Like
Reactions: jblackburn
#63 · (Edited)
When I had my 2004 Aveo 1.6L/Auto I threw in a set of NGK BKR6EIX laser iridiums. Those and a set of Magnacore 8.5mm wires sure woke that little car right up! Even well into 150000 miles when I gave it to my cousin the car still was performing fantastically. Never once though did I ever get over 30mpg/hwy. At least it was consistent.

Sent from AutoGuide.com App
 
#69 ·
I put the BKR7E plugs in today, gapped at .038" with no plug resistors.

J, I owe you a beer.

I can't believe how much smoother it runs at low rpm... below 1500 is where I do the vast majority of my driving and I'm still not sure why it makes such a difference, but it does.

I can lug this little 1.4 down to 900 rpm and it doesn't shudder at all! Nice and smooth the whole way down. I drove down part of my commute route as a test, and this area has several spots where I usually have to work hard to keep it happy in 6th by keeping my speed up. Now it just pulls up those inclines without protest where it would be shuddering and vibrating before. It even feels like it has more torque down low than before. This is now one happy little motor!

I haven't done any WOT pulls yet as I'm currently HYPERCRUZING my way through this tank, but if what I feel below 1500 rpm is any indication there won't be any issues up top.

For $12 with tax I can't imagine anything else giving a bigger bang for the buck other than properly gapping your plugs for free.


Sent from AutoGuide.com Free App
 
#70 ·
I can lug this little 1.4 down to 900 rpm and it doesn't shudder at all! Nice and smooth the whole way down. I drove down part of my commute route as a test, and this area has several spots where I usually have to work hard to keep it happy in 6th by keeping my speed up. Now it just pulls up those inclines without protest where it would be shuddering and vibrating before. It even feels like it has more torque down low than before. This is now one happy little motor!
Nice - the low RPM drivability improvement is the first thing I noticed as well. I've even found with the cool weather we've been having (50s-70 max), it's running smoothly on regular gas @ low RPMs too. I may consider running it all winter if it holds true down to lower temps as well.

Turn on the AC or drive in 80's, however, you get some timing pull there on 87, so I'll go back up a grade on the next tank.
 
#75 ·
All I know is I replaced my iridiums with coppers yesterday gap is .032 and no blow out. I'm happy

Sent From An Antique,
My Original Droid.
 
#78 ·
So for what it's worth, some of you may remember that I was saying I had hesitation that felt like timing pull, even on 93 octane during winter months. I believe I got that one taken care of with a new stock ECU tune from Chevrolet, as for the most part, it behaved much better after that.

However, with the AC on fan speed 3, and especially 4, on a hot day (85+), and even sometimes just randomly when it's not that hot, I'd feel a strong timing pull from 1850-2750 RPM...jerky acceleration and the car just felt...slow. Pinging right off the knock sensor, about 3-4 times per gear under acceleration. With the AC off, it's fine unless I'm sitting at a light for a while.

I'd changed out the plugs in the winter last year for coppers, and thought I was still running those. I'd actually changed them back out for the iridiums and the coppers were put into another car and then completely forgot about it.

Ordered the copper NGK version of the same plug (BKR7E) that's in the car and dropped them in today. Perfect day to test - lots of traffic, lots of stoplights, AC on fan speed 3/4, and 94 F outside.

Once the ECU "adjusted" after a few seconds, I could not get the car to jerk WHATSOEVER. Very happy. Acceleration is smooth from a stop all the way up to 3500 RPM, and the car drives like what I feel like it was made to drive like.

I don't know why this made a difference, other than my experience that turbo cars do not like platinum plugs and perhaps iridium have the same effect on them. The old plugs look like they're burning just fine and are clean.

FWIW, .032" gaps on both. Somewhere between .028"-.035". Experimented around with multiple gaps on the iridiums back in the winter - no real difference with hesitation, but performance improved at higher gaps.
Looking at the picture of the spark plug, the electrode in the centre doesn't look right? It looks pointed whereas shouldn't it be flat on top?
 
#86 · (Edited)
Today I finally had the time to pull out my spark plugs. I put in the NGK copper's in and it took about 15 minutes. I haven't driven the car anywhere but I will find out tomorrow what the car is like. I did start it briefly in the garage just to make sure all was well. For no good reason here is a picture of the old spark plugs. I'm just a quick side note here. The spark plugs which look newer were the ones that were replaced when the dealership replaced my whole turbo unit.
Spark plug Auto part Automotive engine part Automotive ignition part Suspension part


Sent from AutoGuide.com App
 
#89 ·
#92 ·
[h=4]i found this doing a search. when i had my supra...i had $100,000 in that car but spent $6.98 on spark plugs hahaa

Copper Spark Plugs
[/h] Copper spark plugs are generally considered to have the best performance of any spark plug type. This is potentially different from what advertising companies suggest, but the other metals are, unfortunately, not as conductive in general as copper is. Platinum and iridium plugs are more likely to overheat, which causes damage to the plug components and can compromise the delivery of the spark to the engine block.
[h=4]Platinum and Iridium Plugs[/h] Platinum and Iridium plugs perform at a lower level than copper spark plugs, because they are less conductive and they tend to overheat. However, the overall longevity of these two types of metal is better than copper plugs. In reality, copper has the best performance of all three and the worst longevity. Platinum has good longevity and the worst performance. Iridium has good longevity and a performance that is decent, which is why iridium plugs tend to be more expensive than any other type. Still, the difference between these plugs in terms of overall quality is minimal, as there is a trade off for each.
Most copper plugs need to be changed every 20,000 miles or so. Platinum and iridium plugs can often go for twice that before they require changing, but the overall performance will not be as good and you may have to deal with overheating of the plugs. This is potentially not worth the added cost of both platinum and iridium spark plugs, although the decision will depend upon your preference.
If you have any other questions about spark plugs and which are right for your vehicle, consult with a mechanic for more advice.
 
#94 ·
i found this doing a search...
I think there's a lot more going on here than just the conductivity of the materials. I've done a fair amount of searching, and the vast majority of the information I've come up with is far from what I would consider factual. Example; apparently the tip of a "copper" plug is actually some sort of steel, and it's just the conductive core of the plug that's made of copper.

Then there's arguments over whether it's the electrical conductivity or the thermal conductivity which matters. I tend to side with thermal conductivity since there are resistors in the plugs, so electrical resistance would not be that big of an issue?

Some people claim that copper plugs make their cars run better, and others claim their cars will not run well on copper plugs no matter what and a set of iridium plugs cured all their problems. Maybe there's a sensitivity to plug type based on the type of ignition coil setup?

Researching this topic has given me far more questions than answers... there's so much crap to wade through its hard to find any facts.
 
#95 ·
Example; apparently the tip of a "copper" plug is actually some sort of steel, and it's just the conductive core of the plug that's made of copper.
Yeah...these are nickel.

I think I had some Bosch's in the past that were actually copper.

I tend to side with thermal conductivity since there are resistors in the plugs, so electrical resistance would not be that big of an issue?
I think so too. The car is acting like it's pulling timing because it's igniting too early, not a misfire/weak spark.
 
#97 ·
Yeah...these are nickel.

I think I had some Bosch's in the past that were actually copper.


I think so too. The car is acting like it's pulling timing because it's igniting too early, not a misfire/weak spark.
wait which plugs are pulling timing...the stock ones??
 
#96 ·
so i looked to see if my advance auto parts store had them and they do.$1.69ea. and they have a 4 star rating . read the customer reviews and they say...88 supra 24psi "these plugs are the best" 93 supra turbo "i recommend these plugs for boosted cars jetta 1.8t" i am at 400hp turbo charged and these plugs work perfect" and polaris 600 twin. "Makes it run like a champ. Would highly recommend"
looks like i am getting them at lunch
 
  • Like
Reactions: jblackburn
#100 ·
#102 ·
... Kevin D. Junkins, where are you man, and why aren't you on here sharing your findings with us?
I am here. Shared my finding in the VIP section earlier using my user name - blk88verde.
 
#104 ·
So basically we are talking conductivity vs longevity. Whereas instead of having to change the plugs in a 100,000 miles we may have to change them at 50,000 miles but the benefit of this is that our cars will run better.

Sent from AutoGuide.com App
 
#105 ·
So basically we are talking conductivity vs longevity. Whereas instead of having to change the plugs in a 100,000 miles we may have to change them at 50,000 miles but the benefit of this is that our cars will run better.

Sent from AutoGuide.com App
Based on my last car, I would expect 30,000 miles maximum. After that, I started getting misfires @ WOT.

That car was driven ~20-30,000 miles a year, mostly commuting and long highway drives.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top