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Unread 01-10-2013, 07:39 PM   #1
who_datjeep
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MaxComp Spark Plugs Any Good?

Time to change spark plugs. Has anybody had any good experiences with this brand?

http://www.maxcompsparkplugs.com

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Unread 01-10-2013, 08:25 PM   #2
chriskeenan
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Im going to call BS on the whole thing. Why would you want to raise CR? Higher CRs require higher octane fuel to stop pre-detonation, so any and all MPG gains are useless if you have to run the more expensive fuels. Also putting the plug deeper into the engine can cause the piston to impact it on the compression stroke, destroying the plug and possibly the cylinder head or piston.

Also all their dyno charts are for motorcycles or lawn tractors, seriously, a lawn tractor. All of these have small cylinders, the biggest bike listed, the VX1100, has a displacement of 275cc per cylinder, its hardly a big engine by Jeep standards. Your 4.0L has ~670cc per cylinder, more than double the displacement per cylinder.

Quote:
The Max Comp sparkplug increases the performance of all gasoline engines, which will increase the stress on some parts up to the same percentage of power increase. The Automotive average power gain of most Max Comp Sparkplugs is 3% up to 6%. All manufactures build their engines to exceed stress of 20% above normal.
And I'd love to know where they got that 20% figure.

Just get the standard Champion coppers and call it done.
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Unread 01-10-2013, 08:42 PM   #3
who_datjeep
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Just wondering. Sounded pretty good. They said they tried it on a Jeep too. One of the people that was with the maker said they put the Jeep on the dyno and it ran better. Oh well. Makes sense about the higher octane gas and hitting the piston head. What do you recommend, platinum or iridium and what brand?

Edit: Didn't see your bottom line.
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Unread 01-11-2013, 06:30 PM   #4
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For your XJ, just get the NGK plugs (I don't know part number right off hand - plenty of info on here).
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Unread 01-11-2013, 10:59 PM   #5
Azzy
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3-6% is in the range of change in temps, the guy on the bike in front of you had beans for breakfast, and the direction my hermit crabs went when they crawl out of their house in the evening.

Basically, its made for people who like to heal things with magnets and increase the quality of audio through fancy cables.
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Unread 01-12-2013, 12:00 PM   #6
who_datjeep
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Quote:
Originally Posted by scottmphoto View Post
For your XJ, just get the NGK plugs (I don't know part number right off hand - plenty of info on here).
What's better? Copper, Platinum, or Iridium?
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Unread 01-12-2013, 12:01 PM   #7
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Quote:
Originally Posted by Azzy View Post
3-6% is in the range of change in temps, the guy on the bike in front of you had beans for breakfast, and the direction my hermit crabs went when they crawl out of their house in the evening.

Basically, its made for people who like to heal things with magnets and increase the quality of audio through fancy cables.
That's interesting.
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Unread 01-12-2013, 01:25 PM   #8
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Quote:
Originally Posted by who_datjeep View Post
What's better? Copper, Platinum, or Iridium?
The 00-01 likes platinum.

Quote:
Originally Posted by chriskeenan View Post
Im going to call BS on the whole thing. Why would you want to raise CR? Higher CRs require higher octane fuel to stop pre-detonation, so any and all MPG gains are useless if you have to run the more expensive fuels. Also putting the plug deeper into the engine can cause the piston to impact it on the compression stroke, destroying the plug and possibly the cylinder head or piston.

Also all their dyno charts are for motorcycles or lawn tractors, seriously, a lawn tractor. All of these have small cylinders, the biggest bike listed, the VX1100, has a displacement of 275cc per cylinder, its hardly a big engine by Jeep standards. Your 4.0L has ~670cc per cylinder, more than double the displacement per cylinder.


And I'd love to know where they got that 20% figure.

Just get the standard Champion coppers and call it done.
Not true in all applications, tell me how the 2.0 in the Focus runs 12:1 on 87 octane.....factory?
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Unread 01-12-2013, 03:00 PM   #9
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Quote:
Originally Posted by who_datjeep View Post
What's better? Copper, Platinum, or Iridium?
Copper.
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Unread 01-12-2013, 03:10 PM   #10
chriskeenan
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Quote:
Originally Posted by RockRodHooligan View Post
The 00-01 likes platinum.



Not true in all applications, tell me how the 2.0 in the Focus runs 12:1 on 87 octane.....factory?
The direct injection has a lot to do with it. Those little engines are light years ahead of the Jeep 4.0L. And still, raise the CR much on that 2.0L and it'll still need higher octane gas, and probably a ECU retune.
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Unread 01-12-2013, 05:45 PM   #11
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Quote:
Originally Posted by chriskeenan View Post
The direct injection has a lot to do with it. Those little engines are light years ahead of the Jeep 4.0L. And still, raise the CR much on that 2.0L and it'll still need higher octane gas, and probably a ECU retune.
It's unrelated but..... Direct injection has everything to do with how they are getting that high of compression without detonation, for two reasons, 1) It allows for very precise timing of when to spray the injector because it's already where it's supposed to be, as opposed to trying to make sure it gets where it's supposed to be, when it's supposed to be there from several inches away, and 2)It sprays raw fuel directly into the combustion chamber, cooling it in the process.

Hell, the new C7 Corvette has direct injection, something like 11.5:1 compression on 87 octane, first time in a long time that a Vette with a decent amount of power (450-475 HP) has taken regular unleaded.

It's unlikely these plugs will raise compression huge amounts, enough to need to go with a higher octain fuel, theoretically by sticking the spark out closer to the piston could give a more controlled burn.... That said this sounds like snake oil to me.
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Unread 01-12-2013, 06:06 PM   #12
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From 38 years of wrenching on Jeeps, here is my recommendation for plugs for the XJ.

87-99: Champion Copper

00-01: NGK copper (Champion work okay, but the NGK gap holds up better over time because of the different ignition system).

No fancy Saturday morning commercial plugs needed for this very simple engine.......
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Unread 01-12-2013, 06:22 PM   #13
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And I use NGK coppers in everything.
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Unread 01-13-2013, 04:37 PM   #14
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I have 155K on my 99 4.0. I don't think the plugs had ever been changed, on two of the plugs the center conductor had eroded below the insulator. I expected great improvement after installing new gapped Champions. I wasted my time, I probably could have gone for the Guinness record and left them in for another 75 or 100 K

Just my experience.

Jim W
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Unread 01-13-2013, 04:50 PM   #15
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How's AC Delco?
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