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How Do I Find a Colder or Hotter Plug?

Typically, the heat range is indicated within the manufacturer's part number for each plug. Examples have been provided below for some of the brands we supply. Once you have decided on a number, test to see if it exists by typing it into the search box. If it exists, you can add the part to your cart. For additional assistance contact our tech team at 888-800-9629.

Autolite:

Autolite indicates the heat range with the last digit of the part number. For example, 3923 has a heat range of 3. The higher the number, the hotter the plug. The lower the number, the colder the plug.

Starting with part # 24 (heat range 4), if you want a colder plug you would use part # 23 (heat range 3), for a hotter plug you would use part # 25 (heat range 5).

Autolite Heat Range Example

 

Bosch:

Bosch indicates the heat range in the middle of the plug number. For example, FR6DC+ has a heat range of 6. Bosch plugs get hotter the higher the number, colder the lower the number.

Starting with part # FR6DC+ (heat range 6), a colder plug would be # FR5DC+ (heat range 5), a hotter plug would be # FR7DC+ (heat range 7).

Bosch Heat Range Example

 

Champion:

Champion indicates the heat range in the middle of the plug number. For example, RV15YC6 has a heat range of 15. (The 6 at the end of this part indicates the gap setting.) Champion plugs are hotter the higher the number, colder the lower the number.

Starting with part # RCJ7Y (heat range 7), a colder plug would be # RCJ6Y (heat range 6), a hotter plug would be # RCJ8Y (heat range 8).

Champion Heat Range Example

 

Denso:

Denso indicates the heat range in the middle of the plug number. For example, SK20PR-A11 has a heat range of 20. The number at the end of the part indicates the gap.

Denso Iridium Power plugs feature the heat range at the end of the part number. For example, IK20 has a heat range of 20. Denso plugs get colder the higher the number, hotter the lower the number. 

Starting with part # IK20 (heat range 20), a colder plug would be # IK22, a hotter plug would be # IK16.

Denso Heat Range Example

 

NGK:

NGK indicates the heat range in the middle of the plug number. For example, BCPR6ES-11 has a heat range of 6. (The number after the “-“ is the gap.) NGK plugs are colder the higher the number, hotter the lower the number.

Starting with part # BKR6E-11 (heat range 6), a colder plug would # BKR7E-11 (heat range 7), a hotter plug would be # BKR5E-11 (heat range 5).

NGK Heat Range Example

EXCEPTION: NGK Racing Plugs: (Any NGK plug that begins with the letter “R”)

For NGK Racing Plugs, the heat range is located AFTER the hyphen. 

Example: R5671A-10 has a heat range of 10. A colder plug would be # R5671A-11 (heat range 11), a hotter plug would be # R5671A-9 (heat range 9).

Some NGK Racing Plugs are also available in half heat ranges. These are displayed as a 2 or 3 digit number after the hyphen. For example, R6120-85 has a 8.5 heat range and R6120-105 has a 10.5 heat range.

 

Pulstar:

Pulstar indicates the heat range by the number "1" or "2" in the plug number.

  • Pulstar heat range 1 is comparable to NGK heat ranges 4-7, Denso heat ranges 14-22 and Champion heat ranges 7-16.
  • Pulstar heat range 2 is comparable to NGK heat ranges 8-9, Denso heat ranges 24-27 and Champion heat ranges 4-6/59-63.

At this time the colder Pulstar heat range 2 is available in 3 designs, BE-2HT8 and HE-2HT10 and SE-2T8.

 

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