Originally Posted by Stein (Post 353371)

Should I start out with the BKR6E's or go to the 7E's?

Only 8PSI, so thinking 6E's but I don't know anything.

Yes, I searched, but found people using both.

Originally Posted by Saml01 (Post 353391)

Go make a thread in the meet and great before your thread gets locked and you get banned.

5 min of searching.
https://www.miataturbo.net/forum/t29001/

Originally Posted by Saml01 (Post 353468)

^ Bullshit.

One step colder is the general rule of thumb on any engine, I have read that on more then just this site.

Originally Posted by patsmx5 (Post 353473)

1.6's ran BKR6E's from the factory. So they should run a 7 right? My 99' had BKR5E's from the factory, and also has higher compression.... I call you and raise you 20. :giggle:

Originally Posted by cueball1 (Post 353482)

Does running COPS make a difference in the heat level you can run though?

Originally Posted by cueball1 (Post 353482)

Does running COPS make a difference in the heat level you can run though?

Originally Posted by y8s (Post 353495)

it might improve your chances of not fouling a colder plug by having more juice behind it.

Originally Posted by y8s (Post 353495)

it might improve your chances of not fouling a colder plug by having more juice behind it.

Originally Posted by Braineack (Post 353501)

true dat.

IMHO, run stock or one step colder. One step colder will help prevent any chance of pre-ignition while not going too cold and sacrificing the plug itself and any chance of a weaker burn/ignition from pulling out too much heat.

The heat range is selected for two reasons: maintaining a high enough temperature tip to prevent fouling and removing heat from the chamber.

Originally Posted by Braineack (Post 353501)

The heat range is selected for two reasons: maintaining a high enough temperature tip to prevent fouling and removing heat from the chamber.

Originally Posted by ZX-Tex (Post 353515)

Plugs do remove heat from the hot gas in the chamber, and transfer the heat to the cylinder head.

Originally Posted by NGK Website

Heat range

The term spark plug heat range refers to the speed with which the plug can transfer heat from the combustion chamber to the engine head. Whether the plug is to be installed in a boat, lawnmower or racecar, it has been found the optimum combustion chamber temperature for gasoline engines is between 500°C–850°C. When it is within that range it is cool enough to avoid pre-ignition and plug tip overheating (which can cause engine damage), while still hot enough to burn off combustion deposits which cause fouling.

The spark plug can help maintain the optimum combustion chamber temperature. The primary method used to do this is by altering the internal length of the core nose, in addition, the alloy compositions in the electrodes can be changed. This means you may not be able to visually tell a difference between heat ranges. When a spark plug is referred to as a “cold plug”, it is one that transfers heat rapidly from the firing tip into the engine head, which keeps the firing tip cooler. A “hot plug” has a much slower rate of heat transfer, which keeps the firing tip hotter.

An unaltered engine will run within the optimum operating range straight from the manufacturer, but if you make modifications such as a turbo, supercharger, increase compression, timing changes, use of alternate racing fuels, or sustained use of nitrous oxide, these can alter the plug tip temperature and may necessitate a colder plug. A rule of thumb is, one heat range colder per modification or one heat range colder for every 75–100hp you increase. In identical spark plug types, the difference from one full heat range to the next is the ability to remove 70°C to 100°C from the combustion chamber.

Originally Posted by y8s (Post 353791)

plugs removing heat from plugs.

otherwise you will have a diesel