Normal
Light grey or tan deposits and slight electrode erosion
Carbon Fouling
Dry, soft black carbon on the insulator and electrodes
Symptoms:
Causes:
Symptoms:
- Poor starting
- Misfiring
- Faulty acceleration
Causes:
- Faulty choke - over rich air/fuel mixture
- Delayed ignition timing
- Bad ignition leads
- Plug heat range too cold
Pre-Ignition
A melted or burned center and/or ground electrode, blistered insulator and aluminum or other metallic deposits on the insulator
Symptoms:
Causes:
Symptoms:
- Loss of power causing engine damage
- Pre-ignition occurs when combustion begins before the timed spark occurs
Causes:
- Plug insufficiently tightened
- Engine insufficiently cooled
- Ignition timing too advanced
- Plug heat range too hot
Over Heating
An extremely white insulator with small black deposits and premature electrode erosion
Symptoms:
Causes:
Symptoms:
- Loss of power at high-speed or during heavy load
Causes:
- Plug insufficiently tightened
- Engine insufficiently cooled
- Ignition timing too advanced
- Plug heat range too hot
Mechanical Damage
Bent electrode and a broken insulator, dents often present on electrode
Symptoms:
Causes:
Symptoms:
- Misfiring
Causes:
- Plug nose is too long for engine head
- Foreign object (bolt/nut) in combustion chamber
Oil Fouling
Wet, oily black deposits on the insulator and electrodes
Symptoms:
Causes:
Symptoms:
- Poor starting
- Misfiring
Causes:
- Wrong piston rings, cylinders, and valve guides
- Fuel mixture oil content too high
Broken Insulator
Insulator is cracked or split
Symptoms:
Causes:
Symptoms:
- Misfiring
Causes:
- Severe detonation
- Incorrect tool/torque applied during installation or removal
- Careless gap setting
Torched Seat
Melted in the thread and seat area of the plug housing
Symptoms:
Causes:
Symptoms:
- Loss of power causing engine damage
Causes:
- Plug insufficiently tightened
WHICH SPARK PLUG IS RIGHT FOR ME?
Auto makers built their cars to be maintenence-free, and no prudent consumer in their right mind would buy a car with plugs that you have to change every 3000-5000 miles these days (unless it was a hand-me-down used car). Most modern day vehicles will use iridium, while most are using platinums.
Platinum plugs (and Iridiums) were introduced to provide longevity (60k-100k+) to vehicles compared to copper plugs which foul after 3000-5000 miles, but they do NOT dissapate heat fast enough (which leads to pre-ignition/detonation) and do NOT provide a "better spark" like they have claimed...with their "fine-wire electrode" (which only causes problems).
Copper is one of the best conductors of electricity and heat, but they just plain dont last. Using Platinum and Iridium plugs, the center electrode (fine-wire) thin, that under high boost, they get so hot, they will begin to "heat glow" and cause premature ignition in the combustion cycle (pre-ignition => detonation) unless they were properly designed to pull the heat. This is a problem for all of us turbo guys running high boost. Copper on the other hand, has a much thicker center electrode, on top of that, the copper material is able to dissapate heat from the combustion chamber fast enough to keep the combustion temperatures lower. Coppers use thicker electrodes simply based on the fact that they can easily jump the spark, whereas platinum and iridiums will require a fine wire to better direct the spark to prevent missfires.
Remember the two primary functions of a spark plug:
1) To efficiently ignite the A/F mixture without mis-fires (Gap, etc)
2) To pull heat from the combustion chamber into the head, where the cooling system should dissapate that heat. (Heat Range)
With those two in mind, coppers will work much better in these environments. For those thinking: "What If I just simple use a colder Platinum plug?" Well, for the kind of boost our A4's make with the Krispy-Kreme K03's, we will reach EGT's of over 900 degrees C (keeping in mind that pre-ignition can start to occur at around 870 degrees C). Once those colder platinums reach preignition temperature, it will take them FOREVER to dissapate that amount of heat (with the details about the material/design I mentioned above). A platinum/Iridium plug in a colder heat range usually runs just as hot as a copper in the standard heat range when under high stress. So many people will use a Platinum/Iridum plug TWO steps colder to counter that. But using a plug that is 2 steps colder, will lead to two things:
1) More prone to carbon-fouling on "normal driving" where EGT's are kept low. (Plugs must stay above 550C Deg to burn off excess carbon deposits to "self-clean")
2) As a result, loss of horsepower from a less efficient/inhibited spark.
You need a plug that is actually "hot enough" to ignite the A/F mixture as hot as possible to get the most efficient combustion, as well as burn off carbon-deposits (~550C deg), and yet cold enough to prevent pre-ignition when compression is high (< 870C Deg).
Quick cross-reference guide for all the plugs listed above in heat range:
(VW/Audi Factory heat range in bold)
NGK - | 5 | 6 | 7 | 8 | 9 |
Denso - | 18 | 20 | 22 | 24 | 27 |
Bosch - | 8 | 7 | 6 | 5 | 4 |
Champion - | 11,12 | 9,10 | 7,8 | 61,63 | 59 |
OEM Range - Stock car with stock boost/timing, or mildly-tuned car in cold climates.
Recommended plugs in this heat range:
- NGK FR7S8EG (OE Platinum)
- Bosch FR6KPP332S (OE Platinum)
- Bosch F6DTC (Tri-Electrode)
- NGK BKR7E (Copper)
- NGK BKR7EIX (Iridium version of the same plug above)
- Denso K22R (Copper)
- Denso IK22 (Iridium version of the same plug above)
One Step Colder - Cars with basic performance upgrade (chip/intake/exhaust) - k03, k04, etc.
Recommended plugs in this heat range:
- NGK BKR8E (Copper)
- NGK BKR8EIX (Iridium Version of the same plug above)
- NGK R5672A-8 (Copper, Non-Resistor plug)
- Denso K24R (Copper)
- Denso IK24 (Iridium Version of the same plug above)
- Bosch FR5DTC (Tri-Electrode)
- Bosch F5DP0R (Platinum/Side Fire)**
Two Steps Colder - Cars with bigger turbos will benefit from these, whereas a regularly chipped car may foul these.
Recommended plugs in this heat range:
- Champion C59YC (Copper)
- NGK BKR9EIX (Iridium)
- Denso IK27 (Iridium)
** - Many members have found real good luck with the Bosch F5DPOR's, this is why:
Despite all the "con's" about platinums (poor conductivity, poor heat dissapation qualities), the engineers at Bosch has managed to engineer the F5DPOR's so that they are still able to fire the A/F as well as pull away enough heat. The F5DPOR's unlike conventional plugs, use a "Side-Fire" technology, where instead of a standard "projected" electrode into the combustion chamber, the ground electrode was placed on the edge of the plug so that it fires closer to the flame kernel. By doing so, the F5DPOR's are able to still keep a thick center electrode (to pull heat away faster) without having to go with a smaller electrode in order to fire. The F5DPOR's heat range is also equavalent to that of a NGK #8 (TWO steps colder than stock), in order to give the same effect as a #7. But because it is a platinum plug and not copper, they will not foul "as" easily where a copper would have. Because of these two important attributes, Bosch was able to use these plugs to both last like other platinums (up to 60k), while still function under more extreme environments. Platinums however, still do not compare to iridiums in longevity, as well as heat/electro conductivity.
QUESTIONS & ANSWERS SECTION
Question:
Originally Posted by jimrobbington
Originally Posted by kristokes
I got mine for $3 each so $12 for a set of 4.. For that price, it's worth trying them out yourself 
Originally Posted by jimrobbington
Originally Posted by kristokes
I gapped the plugs from it's specs (0.028") to 0.032" (do not go over). The minute I fired up the car, the exhaust tone became a LOT deeper. So I took the car around the block, then on the highway doing some 0-100MPH pulls - the car became a LOT smoother! The powerband of the turbo will now make boost past 5000RPM and the spool-up became noticeably quicker. The hesitation I used to experience at 5000RPM disappeared and the idle became a lot smoother.
By simply switching spark plugs, I would say that my "butt-dyno" pretty much felt another 5-10hp difference in power.
By simply switching spark plugs, I would say that my "butt-dyno" pretty much felt another 5-10hp difference in power.
Originally Posted by matthewb2795
Originally Posted by kristokes
Originally Posted by Jake@JHM
UPDATE:
We noticed right away when we started the development on our JHM 2.0T Tuning some months back that my A4 was being a bit hesitant and misfiring as soon as the car would start boosting above 10psi. Our first instinct was that there was an issue with my spark plugs based on our years of firsthand experience with turbo Audis in our shop. After removing my spark plugs, we checked the gap and they were all at .045 which is why I was getting the misfire. The plugs that came out of my car were Denso PK20PR11 plugs, and looking at their website it shows that those are the plugs that Denso recommends for the B7 A4 2.0T, yet they come at their recommended gapped of .044. However, Audi recommends that the plugs be gapped at .028 which is quite different than a .044 gap, so always make sure your plugs are at the right gap before you install them as whoever installed these plugs in the car before I purchased it, did not. The increased gap over stock (recommended is .028 by Audi) adds more resistance for the coil to fire across the gap. This is okay sometimes when boost levels are stock since the engineers have to factor in spark plug wear. However when you add boost it increases the resistance to jump the gap and it is just like increasing your gap even more, hence the misfires. My car most likely would have been okay if the installer of the Denso plugs would have regapped them to spec. However we do not believe in using plugs that aren’t a close to stock gap since they were most likely engineered for a non-boosted application.
Denso Plug:
I replaced my Denso Spark Plugs with the OEM Bosch Spark Plugs we have on our website HERE! I made sure they were gapped at .028 prior to install for our tuning development purposes. This was because we have to make sure that everything is functioning 100% perfect at the stock plug gap for those people who would be purchasing the tune and still on their original plugs (I know the gap size will increase over time as they get used, however we have seen quite a few very low mileage 2.0Ts). Needless to say we would have been okay with the off the shelf gap of .032, but they would have .004 gap less to work with as they wore down with mileage.
Spark plugs are essentially the center of your car’s ability to run and make power. When you increase your boost, you are increasing your cylinder pressure which makes your coil packs have to work harder to jump the given gap. The shorter gap will also help insure a better fire with more consistency. Considering that your plugs can fire over 100 times a second, making sure that you keep the best gap for your application is a must. That way you will always have a proper burn and not have a spark plug caused misfire. That being said, a .028 (Factory spec) gap is going to be much less strain on the coil packs/motor than .044, hence why I was misfiring when my cylinder pressure increased.
In addition, the spark plug works as a heat exchanger by pulling the unwanted thermal energy from the combustion chamber. The heat range given to a spark plug defines the spark plugs ability to dissipate the heat. Both Bosch and NGK are popular spark plug manufacturers and their heat range designations both utilize a number between 1 and 10 and are often times confused with each other. NGK goes down a number every time the heat range gets HOTTER and Bosch goes down a number every time the heat range gets COLDER. For the 2.0T the OEM Heat Range for NGK is “7” and the lower the number for NGK, the hotter the heat range is (like stated previously). For example, the BKR6E is going to be hotter than the BKR7E. The OEM Heat Range for Bosch is “6” and the lower the number, the colder it is (like stated previously). For example, the F5DPOR is going to be a colder plug than the F6DTC. The rate of heat transfer for the spark plug is determined by a few things; the length of the insulator nose, gas volume around the insulator nose, the material of the center electrode, and the construction of the porcelain insulator. Keep in mind, the spark plugs heat range has no relationship to the actual voltage that is being transferred through the spark plug!
There is a lot of information to take in to understand sparkplugs, and at time can be quite confusing. That is why we have done the research for you and are here to supply you with the correct sparkplugs for your application.
OEM Replacement Spark Plugs:
There are two different spark plugs that came in the B7 A4 2.0T. Therefor both choices will be a direct replacement for your vehicle. We have had great experiences with both of these manufactures and choice will ultimately come down to preference.
Bosch - FR6KPP332S Long Life Platinum (Heat range 6)
Click HERE for more information!
NGK - PFR7S8EG Laser Platinum (Heat range 7)
Click HERE for more information!
Higher Boost Applications:
The following plugs are pre gapped at a perfect width to keep misfires away on high boost applications. We use these plugs in our race cars and customer’s cars with great success.
Bosch - F5DPOR Platinum Sidefire (Heat range 5, one heat range colder than stock)
Click HERE for more information!
Bosch - FR5DTC Tri-Electrode (Heat range 5, one heat range colder than stock)
Click HERE for more information!
Bosch - F6DTC Tri-Electrode (Heat range 6, same heat range as stock) Note: This is a good lower cost replacement for stock cars or cars mostly stock with just a tune.
Click HERE for more information!
NOTE: The spark plug torque spec is 30nm or 22 Ft-lbs. Remember to use Anti-Seize on the threads for easy removal and corrosion protection.
If you have any questions please feel free to ask. I am here to help!
Jake
We noticed right away when we started the development on our JHM 2.0T Tuning some months back that my A4 was being a bit hesitant and misfiring as soon as the car would start boosting above 10psi. Our first instinct was that there was an issue with my spark plugs based on our years of firsthand experience with turbo Audis in our shop. After removing my spark plugs, we checked the gap and they were all at .045 which is why I was getting the misfire. The plugs that came out of my car were Denso PK20PR11 plugs, and looking at their website it shows that those are the plugs that Denso recommends for the B7 A4 2.0T, yet they come at their recommended gapped of .044. However, Audi recommends that the plugs be gapped at .028 which is quite different than a .044 gap, so always make sure your plugs are at the right gap before you install them as whoever installed these plugs in the car before I purchased it, did not. The increased gap over stock (recommended is .028 by Audi) adds more resistance for the coil to fire across the gap. This is okay sometimes when boost levels are stock since the engineers have to factor in spark plug wear. However when you add boost it increases the resistance to jump the gap and it is just like increasing your gap even more, hence the misfires. My car most likely would have been okay if the installer of the Denso plugs would have regapped them to spec. However we do not believe in using plugs that aren’t a close to stock gap since they were most likely engineered for a non-boosted application.
Denso Plug:
I replaced my Denso Spark Plugs with the OEM Bosch Spark Plugs we have on our website HERE! I made sure they were gapped at .028 prior to install for our tuning development purposes. This was because we have to make sure that everything is functioning 100% perfect at the stock plug gap for those people who would be purchasing the tune and still on their original plugs (I know the gap size will increase over time as they get used, however we have seen quite a few very low mileage 2.0Ts). Needless to say we would have been okay with the off the shelf gap of .032, but they would have .004 gap less to work with as they wore down with mileage.
Spark plugs are essentially the center of your car’s ability to run and make power. When you increase your boost, you are increasing your cylinder pressure which makes your coil packs have to work harder to jump the given gap. The shorter gap will also help insure a better fire with more consistency. Considering that your plugs can fire over 100 times a second, making sure that you keep the best gap for your application is a must. That way you will always have a proper burn and not have a spark plug caused misfire. That being said, a .028 (Factory spec) gap is going to be much less strain on the coil packs/motor than .044, hence why I was misfiring when my cylinder pressure increased.
In addition, the spark plug works as a heat exchanger by pulling the unwanted thermal energy from the combustion chamber. The heat range given to a spark plug defines the spark plugs ability to dissipate the heat. Both Bosch and NGK are popular spark plug manufacturers and their heat range designations both utilize a number between 1 and 10 and are often times confused with each other. NGK goes down a number every time the heat range gets HOTTER and Bosch goes down a number every time the heat range gets COLDER. For the 2.0T the OEM Heat Range for NGK is “7” and the lower the number for NGK, the hotter the heat range is (like stated previously). For example, the BKR6E is going to be hotter than the BKR7E. The OEM Heat Range for Bosch is “6” and the lower the number, the colder it is (like stated previously). For example, the F5DPOR is going to be a colder plug than the F6DTC. The rate of heat transfer for the spark plug is determined by a few things; the length of the insulator nose, gas volume around the insulator nose, the material of the center electrode, and the construction of the porcelain insulator. Keep in mind, the spark plugs heat range has no relationship to the actual voltage that is being transferred through the spark plug!
There is a lot of information to take in to understand sparkplugs, and at time can be quite confusing. That is why we have done the research for you and are here to supply you with the correct sparkplugs for your application.
OEM Replacement Spark Plugs:
There are two different spark plugs that came in the B7 A4 2.0T. Therefor both choices will be a direct replacement for your vehicle. We have had great experiences with both of these manufactures and choice will ultimately come down to preference.
Bosch - FR6KPP332S Long Life Platinum (Heat range 6)
Click HERE for more information!
NGK - PFR7S8EG Laser Platinum (Heat range 7)
Click HERE for more information!
Higher Boost Applications:
The following plugs are pre gapped at a perfect width to keep misfires away on high boost applications. We use these plugs in our race cars and customer’s cars with great success.
Bosch - F5DPOR Platinum Sidefire (Heat range 5, one heat range colder than stock)
Click HERE for more information!
Bosch - FR5DTC Tri-Electrode (Heat range 5, one heat range colder than stock)
Click HERE for more information!
Bosch - F6DTC Tri-Electrode (Heat range 6, same heat range as stock) Note: This is a good lower cost replacement for stock cars or cars mostly stock with just a tune.
Click HERE for more information!
NOTE: The spark plug torque spec is 30nm or 22 Ft-lbs. Remember to use Anti-Seize on the threads for easy removal and corrosion protection.
If you have any questions please feel free to ask. I am here to help!
Jake
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