better flow

[pound_feet]

Hi, thanks for putting up a site like this, though I am not sure if I am in the right place, seems like this can be my last chance to find answers online.

I am into cars, and I made my on exhaust systems. I am trying to avoid the aftermarket band wagon for some reason, anyway, so my question is about the exhaust flow.

If all variables are the same (temp, design, materials, engine, etc etc), what will be the better pipe to use to get the faster flow rate? A circular pipe? An oval pipe? A squared pipe? A rectangular pipe? Given that all the pipes in question are all straight, made of same material (say stainless steel), same cross sectional area and same external conditions are applied.

I know a circular pipe is the easiest pipe to use because we can bend them, but what if I am not gonna be bending the pipe? Can I, let's say, get a faster flow rate using a same cross sectional area oval pipe instead or a squared pipe?

I hope you can spare some patience understanding my query...and hope to hear from you soon, thanks a lot guys. More power!

[admin]

Honestly I have never looked that way, as circle cross section is always better to use due to less material required for the same cross section area. On the other hand, for thin wall channels square or rectangle is also good. One thing might be in favor of round shaped pipe - in rectangle channel, in the corner area, zone of intensive turbulence may influence flow reduction - just thinking...

[pound_feet]

Thanks. I was also thinking of the turbulence flow factor. I was reading up on laminar and turbulence flows and seems that a circular/cylindrical pipe is the best option. Thanks again for clearing up my mind. More power and cheers!