# FAQ - Audi R8 Red Ignition Coils - Are they Worth the Cost?



## SwissJetPilot (Apr 27, 2014)

*Audi R8 Red Ignition Coils - Are they Worth the Cost? - by FNChaos*

_"People often refer to red-colored coil packs as 'R8' coil packs since the R8 uses them. (However, red packs are not exclusive to the R8)

There is nothing particularly special about red packs vs black ones. There is no additional horsepower to be gained by changing from black to red. The real reason for upgrading is early coil pack revisions were unreliable / prone to failure and (at the time), the R8 used the latest rev. available.

So, replacing known good black versions for red Chinese knockoffs is foolish. Whereas replacing old rev packs with newer OE ones (regardless of color) makes sense.

Like a lot of OE parts, VW / Audi uses multiple vendors (NGK being one) and in some instances those vendor might manufacture the same part in multiple countries. The ones manufactured by Eldor in Italy are considered highly reliable and often recommended, but as long as you use legit Audi p/n 06E905115E or F (Red) or 06F905115F (Black) you'll be fine."_

Lots of forum members are running red coils packs w/o issue. If you have an older MK2 or plan on an ECU tune proactive replacement is recommended (but not required).

The following contains p/n's that were not part of Audi's coil pack recall (meaning there is no reason to replace them unless they actually fail)
_Note: info gathered from various web sources so take it for what it's worth..._

07K905115D
07K905115E*
07K905115F
06F905115F
06H905115
06D905115K
06E905115D
06E905115E
06E905115F
06E905115G
06F905115F

* 07K905715E ok to use but do not mix.

I suggesting than anyone considering a Stage1, 2 or 3 ECU tune should consider proactive replacement to avoid failure. ECU tuning increases the stress on parts and old coil packs have been known to fail shortly after tuning.










*A History Lesson on the Advent of Coil Packs*

Prior to the advent of coil packs, most cars had a single ignition coil (essentially a single coil pack providing energy to all of your spark plugs).

Your ignition system then used a '_distributor_' which was a mechanical device directly connected to your camshaft through a set of gears. As your camshaft turned a shaft within the distributor rotated.

As the distributor shaft rotated, an arm with a copper contact (rotor) would make / break electrical connections from the ignition coil to a series of contacts mounted on a 'distributor cap'. The energy from the coil was the _distributed_ (hence the name) through these contacts via a set of spark plug wires providing the energy to fire your spark plugs individually (visualize the hands of a clock making a connection at 3, 6, 9 & 12 as it rotates around the dial)

Problem with this design is moving parts wear out and the intensity of the spark would vary with wear.
(Spark intensity was controlled by the duration (dwell time) between opening & closing of the electrical contacts (aka points). Tune-ups partially consisted of adjusting the position of the contacts as they wore down.

Individual coil packs eliminate the problems associated with a distributor and spark intensity can be controlled electronically by your ECU.  Yeah!

So if you're still reading I'll get into the 'weeds' a little deeper.

Earlier I said coil packs are nothing more than a step-up transformer with a FET (field effect transistor) switching circuit in one package. So what is a step-up transformer you ask? Well, first some basic electrical theory.

1.) _When your apply electrical current into a wire a magnetic field will be produced around that wire._
Make a coil of wire, attach it to a battery and you have an electromagnet (probably did this as a kid in grade school)

2.) _When you move a wire through a magnetic field (or move a magnetic field past a wire) you induce current into the wire._
This is how an alternator or generator works. Take several coils of wire wrapped around an armature, spin them past a couple of fixed magnets and you produce current that can be used to charge your car's battery or power you home.

Now we take these two principles and combined them together...
If you make an electromagnet AND you put the electromagnet's coils in close proximity (not physically connected) to another set of coils you can induce current into the second set of coils IF the magnetic field moves in relation to the secondary coils.

Ah, so how do you move the magnetic field? By switching it on and off of course. Each time you cycle power the magnetic field grows and collapses causing it to move in relation to the coils

Ok, so now we can induce power from one set of coils into another set of coils what's the point, why not just route the power directly?

Well the interesting thing is you can increase / decrease the voltage in the secondary coil by varying the ratio of windings between the two coils. For example, if there are ten wraps of wire in the secondary coil for every one wrap in the primary voltage will go up ten times. 1000 to 1, get 1000-volts out for every 1-volt in.
(Of course there is no free lunch, can't make power out of nothing. In order for voltage to go up current must go down).

… So now the picture starts to become clear. Take a low voltage / high current source (i.e. car battery) apply it to a step-up transformer (aka coil pack) Switch it off & on quickly and you can send 30 – 40 thousand (low current) volts to your spark plugs with no moving parts. 

So what did we learn here? Coil packs are nothing more than wire and a electronic switch. The only way they are going to fail is if they are physically damaged by heat or vibration. Build quality is the key here.

Nothing magical. *Red* vs *Black* doesn't matter.


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