NGK Iridium BKR9EIX Condition After Two Seasons

B8 S4
#1

Let me know what you think. I swap to these at beginning of summer and take out when it gets colder. Last two track visits I was dealing with some major “false” knock. Swapping to 8 series heat range as we speak. Will report back with findings. I know the knock cost me big time for my runs. I still ran “ok” best run of 11.73@118.9

New plugs Gapped to .25

http://images.tapatalk-cdn.com/15/10/28/79bc179a11fa9a186b37528512d6d3c8.jpg

http://images.tapatalk-cdn.com/15/10/28/e08b361948112454441f71bae9ac212f.jpg

http://images.tapatalk-cdn.com/15/10/28/2f8806b5281e3e09464933b2770d11c4.jpg

#2

Old Gap vs New Gap .34 vs .25

http://images.tapatalk-cdn.com/15/10/28/4e7dd6c00119f5340066cac5e8194a83.jpg

#3

So excuse my ignorance…is the decrease in gap (.25 from .34) due to the change in heat range or due to the wear of the old plugs? Im new to this whole heat range thing…

#4

Nice thread. I was just about to change my plugs. I was going to stick with factory (9?) heat range, and gap them to 0.28 as recommended by APR. I guess I need to look into this a little more. What are your thoughts on these plugs versus the factory Bosch or NGK’s? Why’d you go to 0.25? Not questioning you at all, but just trying to get some ideas.

#5

Heat range is basically the defined characteristics of a given plug relative to the other plugs in the series. As you can see, the new plugs in this photo have more of the insulator exposed to the environment (combustion chamber), the 9 series plug has little of the insulator exposed. This allows more heat to be absorbed and generally the plug runs a little bit warmer overall.

I chose to gap lower because I didn’t realize my existing plugs (9x), we gapped so high. When cylinder pressures are higher (boosted applications) you can have spark blow out, which is where the spark has trouble jumping from the electrode. Gapping smaller means less distance to cover and less likely hood of spark blowout

This is a general informational post. Under certain conditions practices can change.

#6

Factory is platinum 8 cold range Jran.

Honestly, I gapped to .025 just on advice of my tech and to try something. I am spraying methanol and pushing the limits of pressures in this motor so we will see the results.

#7

Thanks for the info.

#8

Not sure where I got the 9 heat range from. I do see the factory double platinum NGK’s are an 8…

#9

Thanks man…I am familiar with gapping and why we open or close them but was not aware of the benefits or needs for going warmer or colder in heat ranges or even how to tell the difference…really appreciate the info!!

#10

Keep in mind that bosch and ngk use ass opposite numbering system for heat range. So if you want a cooler plug be aware when selecting between the 2 brands.

For illustration

http://images.tapatalk-cdn.com/15/10/28/245065cd675d2994e9daea44f08caa05.jpg

#11

Jones did you try gapping the plugs different to see how that effected knock. we saw this on the 4.2 some plugs would have more ghost knock then others. Also you could see if you degreed plugs with the strap at 12 oclock it helped. The best plugs were the multi electroid plugs. .25 is very short on the gap. .28 and .25 is a big difference. Stock is .36 right

As for the plugs the tips look like they have white on them so they look like they are running clean

#12

Stock is 0.032 I believe.

#13

I to am going to replace my plugs also as a precaution. I went to the stealership and the part number was
mfg# 101-905-661-G
https://www.ecstuning.com/Audi-B8_S4-Quattro-3.0T/ES2539202/

These are NGK PFR8S8EG.

I think I will try a gap .028 and see how this goes. I am trying to understand plug gap, older plugs, etc. However from what I hear and read.
“reduce .004” for every 50 hp you add" or “every 75-100 hp you add, you should go one step colder on the spark plug’s heat range”

Seems like a bit much to gap every .004 for every 50hp?? however I am noob on the spark plug scene. I think I will run with reducing stock by the .004 total.

PS, I am sure most of you guys are well versed in the DIY. But I came across this guys vid after reading Saxons thread over at AZ.

https://www.youtube.com/watch?v=wmZI42A-JPA

#14

We have coil pack ignition system so you can open up the gap a little more. The closing of the gap was to originally help keep from plug blow out. But thats just about a thing of the past. The voltage our electric system builds and how much the coil packs puts out makes for less of a concern.

Closing the gap too much can cause ghost knock due to a smaller point of burn. The larger the gap the more the plug spark will arch and give more area for the center of the burn. You dont want to open the gap too much because this too can cause a delay in the arch.

Stock on the 4.2 is .36 I pull it back to .34 and step down a temp. Pulling the colder plugs is a big help as it pulls out heat and helps keep a good burn.

#15

some good plug stuff

http://audirevolution.net/forum/index.php?topic=106.0

#16

So I wanted to do the .028 however. The wire spark

#17

Knock issue has been fixed. Will try and make track again this weekend.

#18

With just the plug change?

Good luck this weekend.

#19

According to my logs, unbelievable.

Those 9 cold range iridium’s were two years old which totally escaped me when I started running this fall.

#20

Well, good to know.

I’ve got 4 years, but only 22k miles on my plugs. I’m going to go ahead and replace them soon. I probably don’t need to, but it can’t hurt. I’m just trying to decide between the factory NGK double platinums, and the NGK iridiums you are using… I think either will do on my car, and I’ll probably stick with the factory 8 heat range with the 0.028 gap.