One step colder plugs???
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2006 E55 AMG
One step colder plugs???
I know this topic has been discussed a while ago and I'm hoping more members have tried them. My spark plug change is coming soon and more then likely I'll be going to the one step colder plugs. I'm looking for any type of feed back good or bad.
I'm not sure what should be considered when trying colder plugs but I figure since I'm making more hp than stock the extra protection against detonation would be helpful. Here are a few specific questions I have. (1) Since I use ice at the track will this be problem (2) In cooler weather are members noticing any kind of drive-ability issues (3) Is there a chance of losing any kind of performance gains
Like I said, I know this has been discussed before but some time has passed I'm hoping for a little feedback. I also spoke to a couple of member and they seem to think it's a good idea.
I'm not sure what should be considered when trying colder plugs but I figure since I'm making more hp than stock the extra protection against detonation would be helpful. Here are a few specific questions I have. (1) Since I use ice at the track will this be problem (2) In cooler weather are members noticing any kind of drive-ability issues (3) Is there a chance of losing any kind of performance gains
Like I said, I know this has been discussed before but some time has passed I'm hoping for a little feedback. I also spoke to a couple of member and they seem to think it's a good idea.
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From: Tempe, Az
CLS55 AMG 030
I just did 1 step colder like a month ago ,and my car seems to like them a lot. It seems a lot smoother ( I could of have bad plugs before) but to me I dont see any harm in doing it so why not?
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From: Lafayette, IN
2008 ML63 2009 SL63 2010 Alpha 7 GTR
Just bought them too, I have always heard more boost, step colder, same with N2O. It can't hurt. I have heard that most tuners, mech, only run factory levels. I do not think any testing has been done yet? Mine are still laying on my desk.
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2006 E55 AMG
Yep and that's why they're going on my car but I would still like to hear what some of the others have to say. Even though it sounds like the most logical thing to do with our modded cars I still wonder why only a few are doing it.
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From: Fort Lauderdale FL
2006 ML500
You know never ran colder plugs on a benz but I used to be a VW Corrado guy and had a 22psi supercharger on my car which can stock with a 12 psi charger. And VW had Bosh make a colder plug just for 1990 to 1992 G60 Corrado's. They were 25.00 a plug and really were nothing great. Just a colder plug really so am sure the a same would work for you guys... The fear always was you never wanted to run to lean so that was something I had to watch all the time!
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haters crazy
I'm running 2 steps colder than stock but my car came NA and Kleemann recommends 2 steps colder for my car. I've been running 2 steps colder for years (not the same set of plugs obviously lol)
Edit: I have a CLK55 and not an E55 so take it for what it's worth
Edit: I have a CLK55 and not an E55 so take it for what it's worth
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From: THE Orange County, California
2024 C8 Z06- 2025 BMW CS- 2022 Porsche 992 GTS
Dont know how much you will gain from a low boost car but on my Turbo which boosts around 1.3 bar the 1 step colder plugs with the upgraded supra coil packs brought the car some added butt dyno hp. 
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From: Minnesota
2005 S55 1982 300dt
The stock plug is NGK ILFR6A. Colder would be ILFR7A which doesn't exist. Luckily there is Denso Iridium. Stock for the E55 is IK16. Colder would be IK20 (which does exist), followed by IK22 which is even colder(brrrrr). Why can't NGK make it so easy. The A in the NGK part stands for Construction---Special Design, wonder what that is??
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From: Tempe, Az
CLS55 AMG 030
The stock plug is NGK ILFR6A. Colder would be ILFR7A which doesn't exist. Luckily there is Denso Iridium. Stock for the E55 is IK16. Colder would be IK20 (which does exist), followed by IK22 which is even colder(brrrrr). Why can't NGK make it so easy. The A in the NGK part stands for Construction---Special Design, wonder what that is??
Item model number: LFR7AIX
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From: Jacksonville, Florida
2006 E55 AMG --old cars -- E39 M5, 2.7tt Audi S4, E36 M3 **Ducati 996, 748
excellent -- So, i need 16 of these ?
Here is the plug serial number if you want to run 1 step colder NGK's from amazon they are $7.85 thats were I ordered mine and like them a lot. I had to do a lot of searching on the forum to finally find the plug I was looking for. Hope this helps
Item model number: LFR7AIX
Item model number: LFR7AIX
Last edited by guysandiego; Apr 10, 2010 at 12:41 AM. Reason: typo
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From: Orange County, CA
GMC - Miata - Trek - P-Car
The stock plug is NGK ILFR6A. Colder would be ILFR7A which doesn't exist. Luckily there is Denso Iridium. Stock for the E55 is IK16. Colder would be IK20 (which does exist), followed by IK22 which is even colder(brrrrr). Why can't NGK make it so easy. The A in the NGK part stands for Construction---Special Design, wonder what that is??
The ‘A’ in the OE NGK ILFR6A plug designation refers to their relatively unusual 26.5 mm/1.04 inch reach.
Be aware that Denso’s IK16/20/22 variants have only 19 mm/.750 inch worth of threads.
They’ll screw in just fine, although ignition efficiency will be dramatically reduced.
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From: Tacoma WA
Bicycle
One step cooler plug should be a move in the right direction, Our cars are sensitive to knock as it is. One concern I have is the over leangth of our plugs, I had the chance to talk to someone that had the heads off and got some mesurements. This is what they said
"Plug sticks through .350 on the deepest part (center of piston chamber) . About .290 on other side of plug.. Looks like about one thread comes through the chamber.."
One steel thread in the chamber is a No-No from a performance stand point, One of the main objectives in keeping knock down is reducing sharp edges in the chamber, If you have heated metal up you will noticed the what gets hot first is the thin edges and points, same thing happens in the chamber, when it gets hot enough that edge will ignite the fuel instead of the spark plug. Now in the real world I cant tell you if this happens in our car with one thread sticking through or not but I can tell you I run what some woulds say is a "short plug" in mine with no notice of imparied drivablity.
"Plug sticks through .350 on the deepest part (center of piston chamber) . About .290 on other side of plug.. Looks like about one thread comes through the chamber.."
One steel thread in the chamber is a No-No from a performance stand point, One of the main objectives in keeping knock down is reducing sharp edges in the chamber, If you have heated metal up you will noticed the what gets hot first is the thin edges and points, same thing happens in the chamber, when it gets hot enough that edge will ignite the fuel instead of the spark plug. Now in the real world I cant tell you if this happens in our car with one thread sticking through or not but I can tell you I run what some woulds say is a "short plug" in mine with no notice of imparied drivablity.
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From: Lafayette, IN
2008 ML63 2009 SL63 2010 Alpha 7 GTR
RenntechE55’s LFR7AIX recommendation is sound.
The ‘A’ in the OE NGK ILFR6A plug designation refers to their relatively unusual 26.5 mm/1.04 inch reach.
Be aware that Denso’s IK16/20/22 variants have only 19 mm/.750 inch worth of threads.
They’ll screw in just fine, although ignition efficiency will be dramatically reduced.
The ‘A’ in the OE NGK ILFR6A plug designation refers to their relatively unusual 26.5 mm/1.04 inch reach.
Be aware that Denso’s IK16/20/22 variants have only 19 mm/.750 inch worth of threads.
They’ll screw in just fine, although ignition efficiency will be dramatically reduced.
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E55
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From: Lafayette, IN
2008 ML63 2009 SL63 2010 Alpha 7 GTR
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From: Bay Area
2015 E63S, 2018 E63S
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From: Southern Cali (Ontario)
good thread..
I need plugs soon..
NGK LFR7AIX is 1 colder step than stock...
16x $7.85 is not bad for something that does not need replacing for another couple of years.
Amazon has them.. but wondering if a better price is available.
I need plugs soon..
NGK LFR7AIX is 1 colder step than stock...
16x $7.85 is not bad for something that does not need replacing for another couple of years.
Amazon has them.. but wondering if a better price is available.
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2006 E55 AMG
Here is the plug serial number if you want to run 1 step colder NGK's from amazon they are $7.85 thats were I ordered mine and like them a lot. I had to do a lot of searching on the forum to finally find the plug I was looking for. Hope this helps
Item model number: LFR7AIX
Item model number: LFR7AIX
colder plug and it's time I listen. I'll keep ya guys posted.
Thanks again for all the input!!! Good stuff guys.
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From: Tempe, Az
CLS55 AMG 030
