Up-pipe restricter.

[chook]

Just bought a set of stainless Kando headers and up pipe from a fellow forum member and just wondering why there would be a smaller diameter pipe inside the up-pipe just before the bung hole! Is this to regulate flow? I thought it would be more of a restriction.

Any ideas?

See crappy photo, that faint line inside the pipe is the edge of another pipe! What the?

[bass_straitener]

It's there to cause a slight narrowing to increase/maintain gas velocity. Helps turbo spool up.

You can google the more technical answer but that's basically the theory. Try googling velocity stack or velocity chamber.

Or this thread has some answers too.

http://www.rexnet.com.au/forum/index.ph ... ge__st__20

[chook]

It's there to cause a slight narrowing to increase/maintain gas velocity.

You can google the more technical answer but that's basically the theory. Try googling velocity stack or velocity chamber.

Thanks buddy just had a good google read very interesting, I would have thought the lip of the pipe would create some disruption in the flow as its only tack welded in three places, might fully weld it then give it a hit with the die grinder to give it a smoother transition.

Thanks again!

[bass_straitener]

If you really want to make efficient you'd probably look at port matching them as they seem a bit hit and miss a lot of the time and any lips etc will cause unwanted turbulence.