IcemanG17

Okay I understand that mandrel bent exhausts are better since the area where the bend is remains the same diameter and the straight sections allowing better airflow....but very few muffler shops have a mandrel bender......

So lets say a mandrel bent dual 2.5" exhaust flow 100cfm (random #).....I would imagine that a standard bent dual 3" system would flow at least that much...

How much airflow loss does standard bending do compared to mandrel bending??? Is it worth the extra expense?

Thanks

Daymon66

a 3" "standard bend" will flow more.
the air flow (volumn) loss between the two methods (same size pipe) is not worth mentioning.
although standard bent does reduce the diameter some the flow disturbances it creates is an issue as well.

a problem with standard bend method crimps the inner wall and in turn thins the outer wall.
this creates thinner material on the outside of the bend and a turbulent flow pattern because of the crimps on the inner wall.

i'll be happy to run some real life "models" and analysis to give you accurate numbers but rest assured your flow rates at the end will not be enough to cause concern unless you are installing them on the Space Shuttle...

jpitman2

Mandrel bending will also thin the outer wall (there is no option when you stretch the material), but leaves a smoother inner bend skin, and doesnt change section much - depends on the die supporting the exterior of the tube. We bend hydraulic fittings at work - up to 2.5" dia 1/4" walls (annealed steel, turned from bar), and you can see the marks from the edge of the dies. If they are not annealed properly they crack in a couple of places.

jp 83 Euro S AT 51k

Marine Blue

2.5" has a weight advantage.....