FAQ: What are the correct spark plugs for my B6/B7 S4?

[diaftia]

These cars came with more than one type of plug depending on when they were made. It could be an NGK based plug or a Bosch based plug. This can cause some confusion when looking at them because there are variations between manufacturers and what options are available. There are things to consider such as metal, electrode, heat range, etc.

There is some debate over whether or not to use a single electrode sparkplug or a 4 post plug. There are some people that say the cars were designed to use 4 post plugs by Audi engineers and some that say that is garbage. The counter argument is that an electrical current will travel the shortest path and all the 4 posts do is offer a bit of redundancy if there is a failure. You will also find that some people will say use a German plug in a german car, japanese plug in a japanese car, etc. Bottom line is that people have seen good results with both.

In the list below you might ask why some are 6's and some are 7's with regards to heat range. The heat range numbers used by spark plug manufacturers are not universal. That means, a 10 heat range in Champion is not the same as a 10 heat range in NGK nor the same in Autolite. Some manufacturers numbering systems are opposite the other, for some manufacturers (Champion, Autolite, Splitfire and Bosch), the higher the number, the hotter the plug. For othe manufacturers (NGK and Denso), the higher the number, the colder the plug.

4 post plugs are generally used to get more life out of a plug. You are not going to get more spark because the energy is going to flow a single path and that is going to be the path with the least resistance. 4 post plugs just give the energy 4 paths to travel and as one wears out it will flow a different path. So you generally get longer life out of a 4 post plug.

Here is a chart from sparkplugs.com regarding heat ranges:


OEM (4 Electrode) Replacement:
Bosch (7406) FGR7KQE0 Nickel Electrode +4 (listed on 034's and Bosch's website)
Bosch (4417) FGR7DQP Platinum +4 (listed on JHM's website)
NGK (3199) BKR6EQUP OEM platinum replacement (listed on JHM's website)
NGK (5767) BKR6EQUA OEM non-platinum exact replacement (NGK and 034's website)

Single electrode Alternatives:
Denso (5304) IK20 Iridium (sparkplugs.com and various Audizine members)
NGK (6418) BKR6EIX Iridium (listed for 2004 S4's only on sparkplugs.com)
NGK (7092) BKR6EGP Single electrode nickel core platinum plug (NGK's site)

Torque specs for spark plugs are 22 ft lb or 25 Nm.

[SquiddyB6S4]

To answer your question about multi-lash plugs, the lash on the plug, as well as the electrode itself, get hot during each combustion event. The better those parts can resist heating up, or give off their heat before the next combustion event, the better. The worst case scenario is that these parts hold too much heat, and cause the fuel/air mixture to auto-ignite before the spark is actually given (this is how diesel engines work, which use glow plugs instead of spark plugs, and they are intended to do this every cycle). Now, I am by no means saying that a multi-lash plug will do this. But a multi-lash plug is much more likely to do this, as the extra lashes make the plug harder to cool, since they add material that would also need cooling, and block airflow across each other, also keeping them from cooling as effectively as a single lash plug.

The ONLY reason to have multiple lashes is to make the plug last longer, as all four lashes will have to wear down instead of just one. That being said, iridium plugs are supposed to have a 60k change interval, and I have personally used them to almost 90k before without even seeing any wear. And no, the electricity will not jump to all four lashes at once. Electricity follows the path of least resistance. Besides, if it did jump to all four at once, you'd have four REALLY weak sparks.

So now you know

[jfunkey]

To answer your question about multi-lash plugs, the lash on the plug, as well as the electrode itself, get hot during each combustion event. The better those parts can resist heating up, or give off their heat before the next combustion event, the better. The worst case scenario is that these parts hold too much heat, and cause the fuel/air mixture to auto-ignite before the spark is actually given (this is how diesel engines work, which use glow plugs instead of spark plugs, and they are intended to do this every cycle). Now, I am by no means saying that a multi-lash plug will do this. But a multi-lash plug is much more likely to do this, as the extra lashes make the plug harder to cool, since they add material that would also need cooling, and block airflow across each other, also keeping them from cooling as effectively as a single lash plug.

The ONLY reason to have multiple lashes is to make the plug last longer, as all four lashes will have to wear down instead of just one. That being said, iridium plugs are supposed to have a 60k change interval, and I have personally used them to almost 90k before without even seeing any wear. And no, the electricity will not jump to all four lashes at once. Electricity follows the path of least resistance. Besides, if it did jump to all four at once, you'd have four REALLY weak sparks.

So now you know

Man once again most of this is wrong and completely incorrect. unforchionattly it seems you once again have no clue how certian parts of the motor work. I've now come to the conclusion some members just post so people will have something to read

To make this simple. Many people have tested the single post plugs on or motors and found the car seems to loose power. The multi post plugs have many many befits over the single post plugs in or application. Sticking with the 4 post is a solid move.

To further adress a completly inncorect statment.

To answer your question about multi-lash plugs, the lash on the plug, as well as the electrode itself, get hot during each combustion event. The better those parts can resist heating up, or give off their heat before the next combustion event, the better. The worst case scenario is that these parts hold too much heat, and cause the fuel/air mixture to auto-ignite before the spark is actually given (this is how diesel engines work, which use glow plugs instead of spark plugs, and they are intended to do this every cycle). Now, I am by no means saying that a multi-lash plug will do this. But a multi-lash plug is much more likely to do this, as the extra lashes make the plug harder to cool, since they add material that would also need cooling, and block airflow across each other, also keeping them from cooling as effectively as a single lash plug.


So now you know

NONE of this is correct.

You can get your plugs to the point where they will melt and they wont pre or auto ignite the fuel.

The multi post plugs have little or nothing to do with the heat of the plug as to its use or design. while It might have a benifit of less heat that isn't why its used.

I personally almost fell out of my chair when I read this one.

(this is how diesel engines work, which use glow plugs instead of spark plugs, and they are intended to do this every cycle).

So now you know

Oh my dear. god as if squiddy hasn't been super wrong in the past. This is getting real imbarising for me to keep having to correct someone that THINKs they know but are so clue less.

Glow plugs only serve for the purpous to help heat the cylinder. before start up then they are not activated again. THEY DO NOT STAY ON NORE ARE THEY INTENDED TO DO THIS EVERY CYCLE. OR EVEN during the start up.

The only exception is new Desel motors keep the glow plugs on till 200deg has been reached to try and help emmisions. The motor is self dosn't even need them on.

MAN... SO NOW YOU KNOW. As you clearly didn't

[Justincredible]

To answer your question about multi-lash plugs, the lash on the plug, as well as the electrode itself, get hot during each combustion event. The better those parts can resist heating up, or give off their heat before the next combustion event, the better. The worst case scenario is that these parts hold too much heat, and cause the fuel/air mixture to auto-ignite before the spark is actually given (this is how diesel engines work, which use glow plugs instead of spark plugs, and they are intended to do this every cycle). Now, I am by no means saying that a multi-lash plug will do this. But a multi-lash plug is much more likely to do this, as the extra lashes make the plug harder to cool, since they add material that would also need cooling, and block airflow across each other, also keeping them from cooling as effectively as a single lash plug.

The ONLY reason to have multiple lashes is to make the plug last longer, as all four lashes will have to wear down instead of just one. That being said, iridium plugs are supposed to have a 60k change interval, and I have personally used them to almost 90k before without even seeing any wear. And no, the electricity will not jump to all four lashes at once. Electricity follows the path of least resistance. Besides, if it did jump to all four at once, you'd have four REALLY weak sparks.

So now you know

Oh. Gosh. I have to say this is horribly inaccurate, Ill leave it at that.


OEM (4 Electrode) Replacement:
Bosch (7406) FGR7KQE0 Platinum +4 (listed on 034's and Bosch's website)
Bosch (4417) FGR7DQP Platinum +4 (listed on JHM's website) <- - Can someone confirm this. My research points to that this is a plug for a 2.8L Audi Motor.
NGK (3199) BKR6EQUP Platinum Premium (listed on JHM's website)

I believe this is all true. I know JHM uses the 4 electrode plugs. Ive had great results from them. They actually do make a difference over the single

[diaftia]

My local shop carried the Bosch (4417) FGR7DQP which are iridium. I am going to give the a shot today. FYI the NGK 3199 are purely platinum.

[dparm]

Multi-electrode plugs are used for longevity, quite simply. This is why we can go well over 50k without changing them.

You can run single-electrode with no negative consequences other than having to swap them more often (maybe every 20k, depending on the motor and driving style).