Any e36 318's being built for ITA???

[Andy Bettencourt]

As a test, how about the OEM header, extrude honed and then an ID and OD coating?

That would an interesting comparision during a dyno day.

[Doc Bro]

As a test, how about the OEM header, extrude honed and then an ID and OD coating?

That would an interesting comparision during a dyno day.
[/b]

Explain the extrude honing process and if possible where to get it done, please. I'm up for the test Andy. I'll provide the header and dyno time. You provide the extrude honing and coating. :P

Also, what are advantages to internal coating?

R

[Andy Bettencourt]

Explain the extrude honing process and if possible where to get it done, please. I'm up for the test Andy. I'll provide the header and dyno time. You provide the extrude honing and coating. :P

Also, what are advantages to internal coating?

R [/b]

It's basically 'abrasive flow machining'.



Look here for more info:

http://www.gethoned.com/news/headers.php

The purpose of coating is two-fold as I know it. 1. to reduce underhood temps and 2. to keep the exhaust gasses as hot as possible while they exit through the exhaust. This 'scavenging' is reduced as gasses cool. So an ID and an OD coating provide maximum heat retention of the gasses while providing the lowest underhood temps.

AB