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[MY2NDCVO]

Q. Why are there different heat ranges? Which one should I use?

A. Part of your spark plug’s responsibilities, in addition to firing a spark, is to remove heat from the combustion chamber. This is accomplished by channeling the heat through the insulator material and metal housing. From there, the heat is transferred to the cylinder head where the engine cooling system can go to work. A spark plug’s heat range is its ability to dissipate heat. The “colder” the plug, the more heat it can channel out of the combustion chamber. In a performance application, colder heat ranges may be necessary to handle the extreme temperatures brought on by higher compression ratios, forced induction, and high RPM’s. While “Colder” plugs may seem to be the way to go, please remember that the spark plug must achieve its “self-cleaning” temperature where it can burn off fuel and carbon deposits. Otherwise, the plug could “foul out” where it is prone to misfiring and poor acceleration. A plug that is too “hot” can overheat, also causing power loss, detonation, pre-ignition, and possible engine damage. A good, general rule of thumb is to start with the factory recommended heat range. For every 75 to 100 hp you add to your engine, you may go to the next colder step. DENSO heat ranges move up as they get colder; 16 would be our hottest Iridium Power plug, 34 would be our coldest (ranges; 16,20,22,24,27,31,34)

[tennisman]

This bit is even better than the re-usable oil filter that will increase your output power by 6%....

[eleft36]

From Wikipedia, the free encyclopediaJump to: 
"Sophist" redirects here. For the work of Plato, see Sophist (dialogue).

Sophism has two different but related meanings: In the modern definition (from Plato), a sophism is a specious argument used for deceiving someone. In Ancient Greece, the sophists were a category of teachers who specialized in using the tools of philosophy and rhetoric for the purpose of teaching aretê — excellence, or virtue — predominately to young statesmen and nobility. The practice of charging money for education, and providing wisdom only to those who can pay, led to the condemnations made by Plato"s Socrates who also regarded their profession itself as being 'specious' or 'deceptive', hence the modern usage of the term

Al

[07 CVO Road King]

Hi Forum and Merry Christmas. 

What plug do you all recomend for a basically stock 110" motor?  Maybe its best to stay with the stock Harley.  I'm sure there is alot of different thoughts expecially based on the main post here.  The iridium's do sound cool but I don't think I believe they would cause any major cooling.  But hell I don't know much.  I think this time of year the heat is welcome by me. LOL

[Indenial]

Seems like peas when compared to the heat given off by the transmission case and pipes. Heat comes from more than just the heads.

[willyB]

My bike runs significantly cooler after I installed the Shreiver #7664-T79. It was a very simple installation process and only took about 5 hours. The kit includes 5'-0" of copper tubing, the main heat disapating unit and the centrifical air movement system.

I can now run my bike for 30-40 minutes at idle without any heat build up. For the low introductory price of $499.99 I am completely satisfied. Plus, they included two special micro fiber polishing clothes, a high tech ultramicro polish and a year's supply a paper bags so that I can hide my head in shame for buying any product that claimed to keep my air cooled VTwin cool.

[dlaws01]

plugs by 2 heat ranges and that will decrease the combustion chamber temp by 70 to 100 degrees C or 212 degrees Fahrenheit.


Since my average oil temp is approx. 215 to 220 degrees F then if I change plugs my engine will actually start acting as an air conditioner. 

[AXIL]

  well i guess i will here some bravo Serra from this statement but..... there is no magic in spark plugs! having said that let me say..most street engines should keep the plugs 
stock and tune the carb./injection  to the engine. if something is not running right changing the plugs(unless its fouled) is a band aid.     
 
 my two cents     axil

[Fired00d]

  well i guess i will here some bravo Serra from this statement but..... there is no magic in spark plugs! having said that let me say..most street engines should keep the plugs 
stock and tune the carb./injection  to the engine. if something is not running right changing the plugs(unless its fouled) is a band aid.     
 
 my two cents     axil

Amen!!!... I do just that and change them every 5k... Lot cheaper and bike runs just fine.

 
Ride Safe,
Fired00d
 

[AXIL]

  firedood i keep saing the same thing and most tuners agree. thanks chiming in.  axil

[Twolanerider]

Just did my holiday charitable contribution.  Contributed 69 cases (because 69 is my favorite number [proper citation to Messrs Bill and Ted]) of Iridium spark plugs to UN-STUPID-ASS-STGGW (United Nations Study Team for the Understanding of Planetwide Industrial Development And Social Sensitivities Study Group for Global Warming).  They're going to screw two spark plugs each (counter indexed of course) into 138 lighter than air balloons lifted to thermally stable elevations perfect for the Iridium plugs to remove enough heat from the atmosphere to cure global warming.

The world can thank me later (as I'm humble about such things).

The whole plan is dependent on killing all the seagulls first though.  Because if just one of those phukking birds chits on a spark plug ignitor the entire heat exchange chain reaction goes to crap and we all die.

[martys]

Just did my holiday charitable contribution.  Contributed 69 cases (because 69 is my favorite number [proper citation to Messrs Bill and Ted]) of Iridium spark plugs to UN-STUPID-ASS-STGGW (United Nations Study Team for the Understanding of Planetwide Industrial Development And Social Sensitivities Study Group for Global Warming).  They're going to screw two spark plugs each (counter indexed of course) into 138 lighter than air balloons lifted to thermally stable elevations perfect for the Iridium plugs to remove enough heat from the atmosphere to cure global warming.

The world can thank me later (as I'm humble about such things).

The whole plan is dependent on killing all the seagulls first though.  Because if just one of those phukking birds chits on a spark plug ignitor the entire heat exchange chain reaction goes to crap and we all die.

Is that really true Don  or are you just makin' dat chit up 

[grc]

Hi Forum and Merry Christmas. 

What plug do you all recomend for a basically stock 110" motor?  Maybe its best to stay with the stock Harley.  I'm sure there is alot of different thoughts expecially based on the main post here.  The iridium's do sound cool but I don't think I believe they would cause any major cooling.  But hell I don't know much.  I think this time of year the heat is welcome by me. LOL

Your first impression is correct, running the iridium plugs isn't a valid way to reduce high engine temps.  This entire idea is just a bogus attempt by some undereducated marketing putz to sell more of the high priced plugs, period.  Consult a real  engineer with experience in such matters if you want the truth, not some clown in some magazine repeating what an advertiser told him.

If you plan to change your plugs on the regular Harley schedule of 10k miles, or even more often, then there is no advantage to using anything other than the standard spark plugs.  The platinum or iridium plugs main advantage is longevity, since the electrodes erode much slower than the standard materials.  This is what allows your car to go 100k miles between spark plug changes.  If you use the platinum or iridium plugs but still change them at 5k or 10k miles, you would be just throwing money away with no measureable improvement in performance.

If you happen to suffer from preignition problems and rapid erosion of the center electrode, along with blistering of the insulator nose, then you might need to go to a colder plug (and check your tune).  Otherwise, stick with the factory recommendation for normal street riding.


Jerry

[Twolanerider]

Is that really true Don  or are you just makin' dat chit up 

Make chit up?  Me?   

[AXIL]

  love ya 2lane. you kill me man.