Spark Plug question
#1
02-24-2007 | 10:11 PM
Thread Starter
|
1st Gear
Joined: Nov 2006
Posts: 47
From:
Spark Plug question
Well my car is nearing its 90,000 mile mark, and I noticed that sometimes I get a bouncy tach at idle, almost as though the car was misfiring or something... I think I should probably change my spark plugs but I'm not sure what to get as my car is completely stock. I plan to get an APR 91 octane chip soon, and I dont want to have to change my plugs AGAIN as soon as I get the chip.
Any suggestions?
Any suggestions?
#4
02-24-2007 | 10:40 PM
I'm make believe
Joined: Dec 2006
Posts: 17,587
From: In my head
RE: Spark Plug question
Spark Plugs
[ul]
OE Plugs: NGK PFR6Q - .032" gap
For Stock Cars - .032" gap:[*]NGK BKR6E[*]Autolite 3923[*]Denso Iridium IK20
For Chiped Cars - .028" gap:[*]NGK BKR7E[*]Autolite 3922[*]Denso Iridium IK22
[/ul]
**Avoid all non copper plugs, reommend to change every or every other oil change to keep from misfiring.
General Rule of thumb: For every additional 50HP over stock, a general rule is 1 heat range colder and gap shrinks by .004
--So, a chipped 1.8T would make good use ofa plug one range colder gapped to .028
>Tightening torque 30Nm (22 ft-lb)
>Tightening torque for Coil Packs 7ft lbs
[ul]
OE Plugs: NGK PFR6Q - .032" gap
For Stock Cars - .032" gap:[*]NGK BKR6E[*]Autolite 3923[*]Denso Iridium IK20
For Chiped Cars - .028" gap:[*]NGK BKR7E[*]Autolite 3922[*]Denso Iridium IK22
[/ul]
**Avoid all non copper plugs, reommend to change every or every other oil change to keep from misfiring.
General Rule of thumb: For every additional 50HP over stock, a general rule is 1 heat range colder and gap shrinks by .004
--So, a chipped 1.8T would make good use ofa plug one range colder gapped to .028
>Tightening torque 30Nm (22 ft-lb)
>Tightening torque for Coil Packs 7ft lbs
#8
02-25-2007 | 01:51 AM
2nd Gear
Joined: Sep 2006
Posts: 1,436
From: San Diego & Santa Cruz, CA
RE: Spark Plug question
If you run a colder plug on a non-chipped car you are likely to foul the plugs prematurely. Here is some info from the 1.8T FAQ on AW.
Stock spark plugs NGK PFR6Q stock gap .032"
--Common replacements
Autolite 3923
Autolite 3922 (one heat range colder)
Denso Iridium IK20
Denso Iridium IK22 (one heat range colder)
Bosch F7LTCR
NGK BKR7E (Race plug, one range colder)
*avoid BKR7E-11 as the factory gap is too large, .042*
For every additional 50HP over stock, a general rule is:
--1 heat range colder
--gap shrinks by .004
So, a chipped 1.8T would make good use ofa plug one range colder gapped to .028
Reference: From NGK's FAQ: Spark Plug Gap
"Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005"."
Torque Settings for your plugs
(referenced from the Autolite website)
Thread Diameter......................Aluminum Heads
.................................Pound Feet........Newton Meters
14mm Crush Gasket...15 - 22 lb. ft.........20 - 30 nm
From Bentley Manual :
GAP
0.80 mm max.(0.031in)
Tightening torque 30Nm (22 ft-lb)
Tightening torque for Coil Packs 7ft lbs
How to read your plugs
As you change your plugs, it's a good idea to look over your old plugs to get an idea of how your engine is running and to help asses what your next plugs should be. Mostly your making sure your in the right temperature range, and that everything is consistant in all four cylinders.
-light brown/tan/gray in color they are the right heat range and A/F ratio
-white and you want a colder plug, likely running too lean i.e.: too much air, not enough fuel. (too much boost...)
-black (Majority of faulty plugs fall into this category)
---black and dry, you want a hotter plug
Dry fouling refers to the accumulation of carbon on the firing end of the plug which decreases the insulation and finally leads to miss-fire.
---black and Wet, you want a hotter plug
Wet fouling refers to the black and shiny state of the firing end covered with carbon and fuel which decreases the insulation causing the engine to mis-fire
-Often simply need to simply drive harder, add a freeway run into your short commute or something (quit being a spode and DRIVE the darn thing)
-The fuel setting (A/F ratio) is rich (chipped often run slightly rich)
-dirty air cleaner elements.
-Idling for a long time.
-The heat range of the plug is too cold (using a MBC and no chip(stock))
-reddish could indicate fuel system degredation troubles,iron content, rust?
--Common replacements
Autolite 3923
Autolite 3922 (one heat range colder)
Denso Iridium IK20
Denso Iridium IK22 (one heat range colder)
Bosch F7LTCR
NGK BKR7E (Race plug, one range colder)
*avoid BKR7E-11 as the factory gap is too large, .042*
For every additional 50HP over stock, a general rule is:
--1 heat range colder
--gap shrinks by .004
So, a chipped 1.8T would make good use ofa plug one range colder gapped to .028
Reference: From NGK's FAQ: Spark Plug Gap
"Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005"."
Torque Settings for your plugs
(referenced from the Autolite website)
Thread Diameter......................Aluminum Heads
.................................Pound Feet........Newton Meters
14mm Crush Gasket...15 - 22 lb. ft.........20 - 30 nm
From Bentley Manual :
GAP
0.80 mm max.(0.031in)
Tightening torque 30Nm (22 ft-lb)
Tightening torque for Coil Packs 7ft lbs
How to read your plugs
As you change your plugs, it's a good idea to look over your old plugs to get an idea of how your engine is running and to help asses what your next plugs should be. Mostly your making sure your in the right temperature range, and that everything is consistant in all four cylinders.
-light brown/tan/gray in color they are the right heat range and A/F ratio
-white and you want a colder plug, likely running too lean i.e.: too much air, not enough fuel. (too much boost...)
-black (Majority of faulty plugs fall into this category)
---black and dry, you want a hotter plug
Dry fouling refers to the accumulation of carbon on the firing end of the plug which decreases the insulation and finally leads to miss-fire.
---black and Wet, you want a hotter plug
Wet fouling refers to the black and shiny state of the firing end covered with carbon and fuel which decreases the insulation causing the engine to mis-fire
-Often simply need to simply drive harder, add a freeway run into your short commute or something (quit being a spode and DRIVE the darn thing)
-The fuel setting (A/F ratio) is rich (chipped often run slightly rich)
-dirty air cleaner elements.
-Idling for a long time.
-The heat range of the plug is too cold (using a MBC and no chip(stock))
-reddish could indicate fuel system degredation troubles,iron content, rust?
