schematic question

[brp914]

In the Haynes schematic diagrams (which may be copied from factory manuals), a wire may be indicated as 4.0 RD. "RD" ofcourse means red, but what about the "4.0". I used to think it was about amperage, but now I wonder if it is cross section in mm2. Anybody know?

[Flat6pac]

Its the size of the wire.
Bruce

[brp914]

Thanks Bruce. By the way, I've got your motronic mounted on my engine and it's about to go in. Problem is, I've never seen a 3.2 in a 911 and my 911 is a '77. I'm confused about some of the vacuum and other air tubing. Hopefully you can help. I'll try to post some pics later in a separate thread.

[Flat6pac]

You ve got a PM and a phone number.
Bruce

[nreed]

Originally Posted by brp914

In the Haynes schematic diagrams (which may be copied from factory manuals), a wire may be indicated as 4.0 RD. "RD" ofcourse means red, but what about the "4.0". I used to think it was about amperage, but now I wonder if it is cross section in mm2. Anybody know?

Yes it is mm^2. See the following link for converting back and forth between awg and mm^2

Wire Gauge calculations