Replaced Spark Plugs with a step colder ones
05-15-2010, 05:48 PM
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2003 W211 E55, 2003 W220 S600
Replaced Spark Plugs with a step colder ones
My car was in need for some spark plugs, so i decided to get the LFR7AIX NGK Iridium IX spark. Stock heat range for NGK plug is 6, I went with a step colder to heat range 7.
It is a pretty simple job but it just takes time to replace 16 of them. You will need a 17mm open end wrench to pop the plug wires and a swivel spark plug socket. the torque setting is 28nm for the plugs.
Initial impressions the car idles smoothly, better than what it was. About MPG with a step colder plugs I will report back.
It is a pretty simple job but it just takes time to replace 16 of them. You will need a 17mm open end wrench to pop the plug wires and a swivel spark plug socket. the torque setting is 28nm for the plugs.
Initial impressions the car idles smoothly, better than what it was. About MPG with a step colder plugs I will report back.
05-15-2010, 07:54 PM
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cornfed gtr and m3
Nice. What does your car idle at now? Mine is pretty much steady at 540-560rpm after installing the plugs. Never been exactly a smooth idler.
05-15-2010, 08:00 PM
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2003 W211 E55, 2003 W220 S600
Exactly the same as your, idle is very smooth, let just say on the inside it feels like a lexus you can even hear of feel the engine running.
05-15-2010, 11:38 PM
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E63 P30, CL500 Sport
My car was in need for some spark plugs, so i decided to get the LFR7AIX NGK Iridium IX spark. Stock heat range for NGK plug is 6, I went with a step colder to heat range 7.
It is a pretty simple job but it just takes time to replace 16 of them. You will need a 17mm open end wrench to pop the plug wires and a swivel spark plug socket. the torque setting is 28nm for the plugs.
Initial impressions the car idles smoothly, better than what it was. About MPG with a step colder plugs I will report back.
It is a pretty simple job but it just takes time to replace 16 of them. You will need a 17mm open end wrench to pop the plug wires and a swivel spark plug socket. the torque setting is 28nm for the plugs.
Initial impressions the car idles smoothly, better than what it was. About MPG with a step colder plugs I will report back.
05-16-2010, 12:46 AM
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2004 E55,1969 300SEL6.3,2011 ML350 BlueTec Diesel,2005 ML400 CDI
Historically, NGK's have the widest heat range of any manufacturer. You may want to visually inspect the 7's after about 500 miles to see how they are doing. How did the 6's look when you removed them? I replaced my 6's with 6's after about 25,000 miles as they showed a perfect pattern.
Last edited by AgSilver; 05-16-2010 at 12:49 AM.
05-16-2010, 03:51 AM
#6
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Historically, NGK's have the widest heat range of any manufacturer. You may want to visually inspect the 7's after about 500 miles to see how they are doing. How did the 6's look when you removed them? I replaced my 6's with 6's after about 25,000 miles as they showed a perfect pattern.
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05-16-2010, 12:31 PM
#14
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i also recommend the 7's if you're modded, otherwise stick with oem. you won't see an improvement in power or mpg's and the improved idle is simply due to new plugs. this mod is just an extra measure against detonation with increased boost and crappy pump gas.
Last edited by chiromikey; 05-16-2010 at 12:34 PM.
05-26-2011, 03:27 PM
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e55
bump, im putting these in as we speak.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
05-26-2011, 03:48 PM
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Evo VIII/E55 AMG
bump, im putting these in as we speak.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
Some of mine were a little rough. Spray pb blaster down the chamber and let it soak for a few mins. Then Start to loosten, and tighthen (go back and fourth to work the penatrant through the threads. Then you should be good to pull them out.
Make sure you apply anti seize on the threads of the new plugs to avois having to do this again 
05-26-2011, 03:49 PM
#19
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bump, im putting these in as we speak.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
The stock spark plugs are being a biotch and feel awfully tight to loosen, so much so, that I quit right now to come ask. How hard should I be yanking on these to loosen them. Im putting significant force on them and they barely move and lord knows I dont want to snap one.
BTW I've been running this plug for the last 30k miles and haven't noticed any problem. Car idles very smooth. For the record though, I didn't notice any problems with the stock plugs either.
05-26-2011, 04:01 PM
#20
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Im looking at plugs and wires in a few months, just a question. I know you say to run oem plugs if you are stock, but what if I run a colder (7 HR) plug anyways? will the engine and exhaust temp be cooler?
05-26-2011, 05:20 PM
#22
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No performance benefit to colder plugs. In fact may lose some cylinder pressure, but good extra security for a modded car. I have run the 7's since the day I put the pulley on the car. Car is smooth and still makes boatloads of power. Pulled one to look at after 5 K and they were fine. I have injectors and plugs as part of my engine protection insurance plan!
