What is the benifit of running a hotter or colder plug.

[Leatherneck]

So I am looking at installing the BRk8EIS plug, irridium. See if there is a difference.

Saw this and thought I would add it.
http://en.wikipedia.org/wiki/Spark_plug

[Piledriver]

So I am looking at installing the BRk8EIS plug, irridium. See if there is a difference.

Saw this and thought I would add it.
http://en.wikipedia.org/wiki/Spark_plug

Iridium is a good choice, last ~forever vs copper plugs, are those hotter or colder than stock?
(An NGK "6" is equivalent to a Bosch "7" heat range, but I always have to Google which way is hotter or colder, as it depends on brand.)

[FJCamper]

Hi,

To take this to the extreme, on some very push-it-to-the-limit racing engines, you have to start and warm up the engine with a set of 'hot" plug and race it on "cold" plugs.

All this hot and cold plug business has become less important with evolutions in spark plugs that increase their hot-cold range.

We run NGK BP7 to BP9 12mm plugs in our racing engines, and they have performed well.

I'm old school and remember when Bosch rated their plugs in seconds to destruction. A street Bug took a W145. Spirited driving required a W175. Porsche 356's took W225's.

But then Bosch changed their rating system to something incomprehenible like Champions, and I went to NGK's.

FJC

[Piledriver]

One nice feature the MSextra devs added at my request is a feature GM (at least) uses to keep the "streetable" plugs alive on their blown motors: load/time enrichment.
(I know its in MS3, not sure if its in MS2E, have to look...)

Basically , you set up a curve on when to start adding more fuel and how much...above a programmed load.
(you set the load and time/fuel adder% curve)

Boosted GM motors run at <10:1 (progressively more vs time) at full boost after ~5 seconds of WOT. (they make more power initially, its a survival thing)

This keeps the "normal" plugs (and possibly valves...) from melting, which I at least consider a feature, even on a NA ACVW.

[Leatherneck]

So I am looking at installing the BRk8EIS plug, irridium. See if there is a difference.

Saw this and thought I would add it.
http://en.wikipedia.org/wiki/Spark_plug

Iridium is a good choice, last ~forever vs copper plugs, are those hotter or colder than stock?
(An NGK "6" is equivalent to a Bosch "7" heat range, but I always have to Google which way is hotter or colder, as it depends on brand.)

The 8 is a hotter plug with NGK. I run rich, can't get it to go away, change jets I go from rich to lean to running good to running crappy.

[raygreenwood]

One nice feature the MSextra devs added at my request is a feature GM (at least) uses to keep the "streetable" plugs alive on their blown motors: load/time enrichment.
(I know its in MS3, not sure if its in MS2E, have to look...)

Basically , you set up a curve on when to start adding more fuel and how much...above a programmed load.
(you set the load and time/fuel adder% curve)

Boosted GM motors run at <10:1 (progressively more vs time) at full boost after ~5 seconds of WOT. (they make more power initially, its a survival thing)

This keeps the "normal" plugs (and possibly valves...) from melting, which I at least consider a feature, even on a NA ACVW.

And a fun blast from the analog past is that this was also one of the primary functions of the frequency valve injector and Lambda circuit in CIS injection paired with the impulse vacuum valve. It allowed kind of a weighted curve of enrichment for the Saab turbo as temps went up. Ray