I'm looking into replacing my clutch hose on my '02 M Coupe to get rid of the built-in CDV. I'm in agreement with many that the clutch feel on this car is extremely poor compared to other BMWs I own.

I've read a bunch of stuff here and elsewhere and it seems that there's support for using the AN-3 stainless steel hose for this purpose.

Here's what I've just discovered in talking to Earl's (the place that's making up my hose). AN-3 has an internal bore of 0.06", which equates to roughly 1.5mm. This is the same diameter as the restrictor that I'm trying to remove. I honestly don't see how those that have used AN-3 have solved anything.

According to the guy I spoke to, the hard lines for the clutch (if they're the same as those for brake lines, which I believe they are) have a bore of 0.095" (~2.4mm). So any hose beyond that bore size isn't necessary. AN-4 has a bore of 0.17" (~4.3mm), which is the next available size. This is what I just had Earl's make up for me. Note: I had read that Earl's couldn't use AN-4 with the proper fittings, but he had it made up for me by the time I finished the phone call.

So I'd really like to know... have those that used AN-3 really felt a difference? If so, the only explanation I can see is moving from rubber hose to SS hose... it's certainly not from removing the 1.5mm restriction.

Thanks,
Blaine