DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 01-14-2009, 01:51 PM
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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.
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Old 01-14-2009, 01:54 PM
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Just a datapoint. I'm running bone stock NGK coppercore, with stock heat range and gap at 15psi with Sav's COPS.
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Old 01-14-2009, 02:15 PM
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Originally Posted by Stein
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.
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/
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Old 01-14-2009, 02:25 PM
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Originally Posted by Saml01
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/

I specifically read that thread and saw people using both. I didn't know if my lower boost would push me one way or the other.

I sure hope it didn't take you five minutes to find it. You started it!

Besides, you can't ban me yet. Only five people have paid for more frame rails. Let a few more pay before you do that!
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Old 01-14-2009, 02:32 PM
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7's as a precaution. Won't hurt anything else. I run them and they stay plenty clean actually. Running a 6 would be like running mid grade when you tuned for premium.
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Old 01-14-2009, 04:05 PM
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^ Bullshit.

One step colder is the general rule of thumb on any engine, I have read that on more then just this site.
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Old 01-14-2009, 04:11 PM
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Originally Posted by Saml01
^ Bullshit.

One step colder is the general rule of thumb on any engine, I have read that on more then just this site.
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.
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Old 01-14-2009, 04:21 PM
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Does running COPS make a difference in the heat level you can run though?
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Old 01-14-2009, 04:37 PM
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Originally Posted by patsmx5
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.
Unless you for some reason now have a higher chance of incurring pre-ignition from a hot spark plug, then no you wont be running anything colder then one step.

Originally Posted by cueball1
Does running COPS make a difference in the heat level you can run though?
No
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Old 01-14-2009, 04:37 PM
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Originally Posted by cueball1
Does running COPS make a difference in the heat level you can run though?
it might improve your chances of not fouling a colder plug by having more juice behind it.
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Old 01-14-2009, 04:56 PM
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Originally Posted by y8s
it might improve your chances of not fouling a colder plug by having more juice behind it.
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.
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Old 01-14-2009, 05:04 PM
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Originally Posted by y8s
it might improve your chances of not fouling a colder plug by having more juice behind it.
Originally Posted by Braineack
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.

If you compare the amount of energy from the sparkplug sparking that goes into heat (some % of the total energy, dunno how much) and compare that number to the amount of energy released during the combustion process, it's hard to fathom that the ignition system could affect the fouling-ness of a plug. But I dunno.

It's my experience that plugs get fouled from running rich and cold. If you drive hard, I'd run 7's no question. If you drive it easy often and it runs rich, you could get some buildup on the plug. But I certainly wouldn't gauge what plug to get by thinking "I wonder if it will detonate with this hot of a plug" but rather, "I wonder if it will foul with this cold of a plug". Because I can't see the heat range of the plug really affecting performance.
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Old 01-14-2009, 05:14 PM
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Originally Posted by Braineack
The heat range is selected for two reasons: maintaining a high enough temperature tip to prevent fouling and removing heat from the chamber.
Ok seriously, where did you get this part? What exactly does the spark plug screw into? The chamber/head. You're the first I've ever heard claim the plugs help cool the engine...
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Old 01-14-2009, 05:37 PM
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Plugs do remove heat from the hot gas in the chamber, and transfer the heat to the cylinder head.
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Old 01-14-2009, 05:45 PM
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Originally Posted by ZX-Tex
Plugs do remove heat from the hot gas in the chamber, and transfer the heat to the cylinder head.
On some level, sure. But Braineack is saying that this should be considered when selecting what heat range sparkplug you want to run. I think the difference in heat transfer between a hot and cold plug is trivial.
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Old 01-14-2009, 06:05 PM
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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.
NGK.com
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Old 01-15-2009, 10:19 AM
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Yea I gotta agree with Pats here, plug removing heat from the combustion chamber, I think its bullshit too.
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Old 01-15-2009, 10:37 AM
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plugs removing heat from plugs.

otherwise you will have a diesel
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Old 01-15-2009, 11:30 AM
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Originally Posted by y8s
plugs removing heat from plugs.

otherwise you will have a diesel
No more misfires though.
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