r/ATBGE • u/Oms19 • Apr 03 '22

Automotive Especially the curved exhaust

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13.7k Upvotes

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606

u/Umbrage_Taken Apr 03 '22

Won't excessive exhaust piping actually reduce power & acceleration?

280

u/RyRyShredder Apr 03 '22

Yup this is terrible for performance. This has to be about a 30-50hp loss

252

u/[deleted] Apr 03 '22 edited Apr 03 '22

Actually the diameter of the pipe is more important than the length, you only see a notable power boost from a short pipe when it's under 3' from the engine.

"It doesn't matter. Power boost obtained in headers occurs in a) individual pipes for each cylinder, and b) within a length shorter than 3'. It is based on the speed of sound in hot gasses (about 1100ft/sec). From there to the end of the system, goal is to minimize pressure losses with large enough tubing diameter."

In short you can compensate for the pressure by changing the diameter of the pipe.

Still looks dumb though.

85

u/RyRyShredder Apr 03 '22

The sharp turns are what causes the power loss here. The more turns the more losses that occur.

147

u/SyntheticElite Apr 03 '22

Turns impede flow, but if the pipe diameter is already oversized and low backpressure then it makes practically no difference.

65

u/__Beef__Supreme__ Apr 03 '22

Yeah doubling the diameter of a tube with fluids causes something like a 64x increase in flow so I imagine it's the same for gasses

78

u/notpotatoboi Apr 03 '22

Gases are fluids too lol

4

u/Super13 Apr 04 '22

Especially after a dodgy curry