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Factory E30 M3 Headers
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A multi-header comparison

Four factory headers

There were many headers made for the E30 M3 over the years. Some were installed by the factory on vehicles sold to the public. Other headers were only intended for racing, and were sold through the BMW Motorsport department via the Gruppe A catalogue.

In the U.S. we only obtained one type of header on the E30 M3's that were officially sold through our dealer network. This is the unit that most people call the "standard" header (or "series" header). But in Europe, several other types of headers were installed on E30 M3's sold through dealer showrooms. There was (a) the Evolution 2 header, (b) the header for 2.3L engines without catalytic converter, and of course (c) the Evolution 3 header. It is sometimes thought that the header fitted to the 2.0L S14 engine of the "Italian E30 M3" (aka 320is) was also unique, and that it had the largest primary and secondary diameters of any of the factory headers. But there is not agreement on this point, and other knowledgeable enthusiasts claim that the 2.0L header was the same as the 2.3L non-cat header. This latter assertion is backed up by the part numbers in the ETK as shown further down.


Four factory headers

The pictures in this article, as well as the header dimensions, come from Markus in Germany. Above we see again the four common factory headers for the E30 M3. The "standard" 2.3L header for cars with catalytic converter. The 2.3L header for cars without catalytic converters. The Evo II header, and the Evo III header. Note that the Evo II header is a two-piece design and has the same part number as the 2.3L Gruppe A header in the Gr A catalog. Similarly, the Evo III header has the same p/n as the 2.5L Gr A header. Click here for more information about factory E30 M3 header part numbers from a different page on this site.

As previously explained, some E30 M3 enthusiasts claim that the header from the "Italian 2 liter M3" is larger than any of the other common S14 headers. The Italian M3 is more accurately called an E30 320is. It had an S14 engine which displaced only 2.0L in deference to certain Italian taxes regarding engine displacement. As far as the ETK is concerned, the 2L S14 engine was equipped with the same header as the 2.3L S14 with no catalytic converter. This is demonstrated in the "snapshot" of the ETK shown in the following link:
Click here for an ETK snapshot of the E30 320is header part number

Click here for an ETK snapshot of the various E30 M3 header part numbers

Now it is time to dig into the actual dimensions of these headers...
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More Myths Part 1