Learned a new trick today...

[David]

When putting together a turbo system, I always weld a little bead around the end of each pipe so that the clamps on the connectors have something to help them hold on. Like this:

Today, one of my redneck drag racing buddies pointed out that there was a cleaner way to do it. He has one of those tools (forget what they are called) that are used iin sheet metal work to form those crimps/ridges that help give structure. We ran one around the inside of the end of the pipe a bunch of times and ended up with this:

Nice and neat and probably works better as well.

[This message has been edited by David (edited 11 January 2003).]

 

[sjs]

Nice! Ask your buddy exactly what it's called and if he can suggest a source.

 

[grippgoat]

Wouldn't an approach that left the inside of the pipe completely flat/smooth be better for flow? Or does it not really matter?

-Mike

 

[supergreen125]

the tool is called a bead roller.

 

[sjs]

Originally posted by grippgoat:
Wouldn't an approach that left the inside of the pipe completely flat/smooth be better for flow? Or does it not really matter?
-Mike

A reasonable question. I'd be more concerned if something protruded into the tube, but any irregularity is likely to modify flow characteristics. It might be difficult to predict what impact this would have, though my first though is that it would be negligible especially on the pressure side. But that is not based on any great scientific insight, just past experience and comparing it to various other factors such and the “steps” between two such tubes joined by a piece of silicone hose as is commonly done.

 

[David]

Originally posted by grippgoat:
Wouldn't an approach that left the inside of the pipe completely flat/smooth be better for flow? Or does it not really matter?

-Mike

A good question. In theroy, you want it to be as smooth as possible, but the reality is that the ends of the tube never line up perfectly anyway. So, I don't think it really matters.

 

[true]

I don't know if I would call that a trick, but it sure does make the pipe look nice.

Interesting the way you put the bead in your original picture...this makes for turbulant flow as well. I'm used to doing it as follows:

Your new method will definitely cause un-needed turbulance, but as sjs above stated, it may be negligable. I prefer my method (as does all other custom fabricators I'm aware of) as this simply throws out a questionable variable that those other 2 possess. Air under pressure in that pipe will follow the direction in that dip....air will flow more freely with no obstructions.

[This message has been edited by true (edited 12 January 2003).]

 

[sjs]

I agree, the fewer factors of unknown impact the better, but as I noted above it seems less likely to be a problem even than the transition between the tubes and the connecting hose. As you know, smooth edges of a large radius are much less of a problem than sharp abrupt ones. So if you really want to clean up your example, taper those tube walls down to a fine edge.