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Old 17th November 2007, 17:21   #1
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Default Correct heat range determination

hey people

always wondered and then i found this ows pdf not sure where so i cant post the link but will copy paste the important stuff

ÜBER POWER IRIDIUM spark plug heat range is designed according to spark plug tip and insulator nose
operating temperature. ÜBER POWER IRIDIUM spark plug center temperature is fixed at 600C, therefore we
call it no. 6 heat range.

Spark plug’s location means exposure to extreme combustion temperature. Spark plug heat range is measured
by the spark plug tip and insulator nose’s ability to remove heat from combustion chamber. It is determined by
several factors, spark plug tip (and length) and insulator nose construction (and length) since they are the
hottest parts of spark plug.

It is important to choose the correct heat range in order to maintain spark plug tip & insulator nose temperature
between ranges 450C to 850C. At operating temperature from 450C to 850C, spark plug insulator nose and tip
has the ability to burn off carbon deposits so we call it "self cleaning temperature".

If temperature exceeds 850C, it may cause the spark plug nose tip to over heat and spark plug electrode may
begin to melt. In the case of Iridium tips, the tip will not melt but heat removing process is too slow. The spark
plug nose and tip temperature still remain high, and this condition may lead to pre ignition / pre detonation and
will cause engine damage.
If temperature is below 450C, the insulator nose and spark plug tip will not become hot enough to deter fouling
and carbon deposits. This condition will cause spark plug misfire.

i know that electronic tools are used abroad in performance cars to determine the correct heat range requirement

but what do we do????

my ows plugs came to N1 a week back but ::it came with a bottle of slime which exploded and ruined my plugs

now i believe i will get my plugs from the man himself at the MUMBAI autoexpo

any gyaan anyone???


Last edited by cyneverdie : 17th November 2007 at 17:26.
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Old 18th November 2007, 12:29   #2
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To Add my query also- What should be the Heat Range for My XETA running on CNG, If I go for Iridium plugs will it help, currently using Denso after the OEM bosch went bad after 17,000 KM- Went to the store and found a new Boch plug with 4 tip,but won't it be difficult to adjust Gap incase required in such a plug ???
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Old 19th November 2007, 14:04   #3
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Generic heat ranges to be used:

Normal Cars : Typically run on 7 heat range plugs
Modded cars and High compressions: 8 min
Nitrous: 8-10
Turbo: 8-10

Multi point plugs do not need adjustment as they have multiple gaps alreadys preset from the company.
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