Spark plugs
01-15-2009, 09:20 AM
#11
Senior Member
Join Date: 03-16-2008
Location: Cleveland, Ohio
Posts: 662
Comparative tests between brand new plugs of different design / manufacturers are generally not valid because:
1. The differences tend to be rather small, well outside the repeatibility window of a typical chassis dyno. A climate controlled engine dyno is not accessable to most of us.
2. Random changes in indexing angle will swamp any other factors in the test.
Plugs with small, pointy electrodes can initiate spark better under adverse conditions, such as bad ignition, wires, low voltage, extreme cold, etc. These differences tend to disappear when everything is working correctly.
Plugs with multiple ground electrodes, such as Bosch +4 are based on WW2 aircraft designs optimized for redundancy / reliability, not performance. Flame kernel propagation is usually very poor because it's buried under multiple electrodes.
I'm generally not a big fan of iridium plugs, especially for extreme racing / nitrous applications. While the iridium indeed has a higher melting point than other materials, what happens under extreme conditions is that the underlying metal the iridium "nibs" are attached to softens, and the nibs come loose, causing far more damage than an electrode that is simply burning up. Iridium's long life makes for appealing claims of 100,000 mile service intervals, but have you ever tried to remove a plug from an aluminum head after 100K? They aren't coming out without some dynamite, but your warranty's long expired.
While this is a different engine, LS1 owners generally agree that NGK TR55 plugs idle noticeably smoother than the OEM Delco/Denso iridiums. They are a copper center electrode with a groove cut into it. Of course they will want to be replaced much more often, but they're dirt cheap. Copper and silver have an inherently wider heat range than other materials.
Most of the "trick" plugs with secondary gaps, or highly capacitive wires claim to be perpetual motion machines, outputting more energy than is inputted. This stuff was all tried decades ago, and if it worked, OEMs would be all over it. Owners satisfaction and willingness to defend the "technology" of this stuff is directly proportional to the size of the dent it left in their wallet.
The only somewhat non conventional plugs that I feel have merit are the Brisk LGS plugs which are an extended tip, surface gap design that have no conventional ground electrode to shield the flame kernel. They are naturally self-indexing, which is very appealing to racers. Indexing plugs is about as much fun as a sticky doorknob.
1. The differences tend to be rather small, well outside the repeatibility window of a typical chassis dyno. A climate controlled engine dyno is not accessable to most of us.
2. Random changes in indexing angle will swamp any other factors in the test.
Plugs with small, pointy electrodes can initiate spark better under adverse conditions, such as bad ignition, wires, low voltage, extreme cold, etc. These differences tend to disappear when everything is working correctly.
Plugs with multiple ground electrodes, such as Bosch +4 are based on WW2 aircraft designs optimized for redundancy / reliability, not performance. Flame kernel propagation is usually very poor because it's buried under multiple electrodes.
I'm generally not a big fan of iridium plugs, especially for extreme racing / nitrous applications. While the iridium indeed has a higher melting point than other materials, what happens under extreme conditions is that the underlying metal the iridium "nibs" are attached to softens, and the nibs come loose, causing far more damage than an electrode that is simply burning up. Iridium's long life makes for appealing claims of 100,000 mile service intervals, but have you ever tried to remove a plug from an aluminum head after 100K? They aren't coming out without some dynamite, but your warranty's long expired.
While this is a different engine, LS1 owners generally agree that NGK TR55 plugs idle noticeably smoother than the OEM Delco/Denso iridiums. They are a copper center electrode with a groove cut into it. Of course they will want to be replaced much more often, but they're dirt cheap. Copper and silver have an inherently wider heat range than other materials.
Most of the "trick" plugs with secondary gaps, or highly capacitive wires claim to be perpetual motion machines, outputting more energy than is inputted. This stuff was all tried decades ago, and if it worked, OEMs would be all over it. Owners satisfaction and willingness to defend the "technology" of this stuff is directly proportional to the size of the dent it left in their wallet.
The only somewhat non conventional plugs that I feel have merit are the Brisk LGS plugs which are an extended tip, surface gap design that have no conventional ground electrode to shield the flame kernel. They are naturally self-indexing, which is very appealing to racers. Indexing plugs is about as much fun as a sticky doorknob.
01-16-2009, 12:39 AM
#13
Senior Member
Join Date: 01-13-2008
Location: Washington State, where it rains
Posts: 4,708
I remember when I work auto parts, at one time I had 4 different plugs in the left bank of my truck experimenting(it was a lean eng so I was playing with which one lasted longer).
Always went back to Ac 43TS, or a 42 TS for long trips. Burnt up a set of Splitfires in 7k,actually started backfiring and shutting off!JUnk! Noticed nobody mentioned (hack,hack) Champions!
Always went back to Ac 43TS, or a 42 TS for long trips. Burnt up a set of Splitfires in 7k,actually started backfiring and shutting off!JUnk! Noticed nobody mentioned (hack,hack) Champions!
01-18-2009, 06:46 AM
#15
Senior Member
Join Date: 11-07-2007
Location: Southside of Houston Texas
Posts: 1,613
Ask and you shall receive Steve: OE Laser Iridium IFR6V-10G ^ # --- .040
I had to look up the cobalt from 2007
I had to look up the cobalt from 2007
Last edited by gcsd3742; 01-18-2009 at 02:05 PM.
01-18-2009, 01:59 PM
#17
Senior Member
Join Date: 11-07-2007
Location: Southside of Houston Texas
Posts: 1,613
