V8 clutch pipe diameter...

[cweeden]

Hi All,

Is there any reason why the clutch pipe on my V8 is 1/4" while all the brake lines are 3/16" ? 

I wouldn't expect 1/16" change in pipe diameter to have an appreciable impact on the operation of the clutch in terms of pedal feel or operation, am I missing something from my physics education?

Finding M10 x 1 male fittings for 1/4" pipe is quite a challenge (especially in stainless steel).

cheers

-Chris

[fjmuurling]

The amount of fluid which has to travel trough the pipe is only dictated by the bore of the master cylinder and the (pedal) stroke. and  is independent of the volume of the pipe.

A smaller pipe is a little more restrictive flow wise.

Why not just make up a mockup (won't brake the bank) and see if it works?

[Escape]

Going from 3/16" to 1/4" is a 77% increase in section, so the difference in resistance at higher flows will be considerable. Also worth remembering the clutch needs more fluid displacement than the brakes, as the brake pistons only move a little bit as it's the pressure increase that provides the braking force. And there are (usually) more brake lines, one for each corner with ABS.

Not to say 3/16" wont work, just that there is some reasoning behind the larger diameter clutch pipe. That is the case on a lot of cars btw.

Filip

[cweeden]

Thanks for the feedback.

The body is off the chassis so I don't want to fit the wrong something that is easy to do now but will be much harder to replace once the body is back on, no room for experiment I'm afraid. 

The 77% increase is more than I'd realised because I've been too lazy to do the maths (or think about it, doh!) and yes more movement too, so now this is starting to make sense. 

I'll stick with 1/4", thanks. 🙂

cheers

-Chris