Car Exhaust Diameter Flow Question

Forum about flow calculators available on pipeflowcalculations.com and how to find solution for your fluid flow problem.
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jere
Posts: 2
Joined: Fri Aug 06, 2010 4:17 pm

Car Exhaust Diameter Flow Question

Post by jere »

Salutations :D

We are having a debate on an automotive forum about optimizing flow rates from a turbocharged car exhaust and have not been getting anywhere. I come here for help in shedding some light on the debate. I am under the impression that the car exhaust will flow best when not to small and not too big in diameter. That the pipe size should be optimized to a specific size for best power because there is an exhaust gas velocity that should not be exceeded.

The other party insists that there can not be a too big of a diameter pipe for creating best power results from the engine. The other party also posted one of your flow calculators the air pressure drop calculators to try prove that larger is better because there is a higher rate of flow.

I am curious if there may potentially be other variables at work in the turbo exhaust that we are not looking at or are being accounted for with the calculator. And I would very much appreciate any other insight that may be available that may help us resolve our debate :?: :?
admin
Site Admin
Posts: 375
Joined: Mon Feb 08, 2010 7:47 pm

Re: Car Exhaust Diameter Flow Question

Post by admin »

My opinion is the best solution is to have no car exhaust pipe at all if you want highest power :)

Now as this is not a option, than you are trying to get close to it - which is pipe should be as big as possible, but,

Flow through car exhaust is by no means stationary - it is oscillating with time very much so that flow calculator can not be used with high accuracy. How this oscillation is effected with pipe diameter and how to achieve resonance between flow and pressure oscillation with pipe diameter is question for somebody else.

Anyway, as low pressure drop in exhaust, power will be higher and how to calculate pressure drop for that kind non stationary flow ...

The other point of view is the propulsion that you get with high mass flow and high velocity from exhaust, but this is other theme I should say.
Pipe flow calculations - since 2000
jere
Posts: 2
Joined: Fri Aug 06, 2010 4:17 pm

Re: Car Exhaust Diameter Flow Question

Post by jere »

Ha you are right best exhaust is no exhaust, everyone agrees about that :D

Thanks for your help
PipRoma
Posts: 1
Joined: Tue Jan 25, 2011 10:26 am

Re: Car Exhaust Diameter Flow Question

Post by PipRoma »

jere wrote:Ha you are right best exhaust is no exhaust, everyone agrees about that
Yeah..I guess not. There are a lot of good brands for exhaust such of this is the magnaflow, gibson and borland.

As for performance, changing exhaust doesn't GAIN power, it frees it up from pumping losses.
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