Exhaust System Info! Choosing Your Exhaust!


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This is a Formula 1 exhaust manifold.

You can see how each port from the engine has a unique length runner, mathematically calculated, so that the pulses can pull the next pulse out with ease. Chucking a fan in here, would need to spin much much much faster than the engines 18,000rpm limit to extract the gases out without introducing any restrictions



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engine revs 18,ooorpm WOW!!:astonished:

Only way to really find out if what I suggested will work is to make one and try it out. Unfortunately I cant.
If someone has an old had it turbo with a blown compressor, remove the compressor and block it off and stick the modified turbo still spinable down the other end, maybe that would give us an idea if it will work.


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Thanks for the correction donki and the time and thought you have put into your replies.
I have read that issues with extractors are less of an issue with a turbo fitted. As far as drag of the fan is concerned. There will be less as it will now, not be driving a compressor. So momentum would be greater.

Forget external power its never been in this equation.

An idea that was popular years ago was an exhaust tip with a surrounding megaphone facing forwards channeling air into the exhaust stream. Hopefully with an extraction effect?
Possibly all it did was scoop up dirt or ouch! on a low depression.
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This thread fascinates me. So much of the same thing said in so many different ways and addressing the various aspects of the same problem, whats best varies dependent on whats wanted together with
what its applied to. Scavenging, flow rate, back pressure etc: etc: gets back to each individual application. Even the experts wouldn't be able to give a generalized rational answer to these multiplicity of problems.
Without specific calculations and trials for each individual supplication and regarding as to the ratio of torque to kilowatts required and is the more important.

Re flow rate for a given situation? back pressure? scavenging? etc? Smaller diameter pipe higher pressure faster flow rate! Larger diameter pipe less pressure slower flow rate! nothing no pipe, no header,
no catalytic converter, no muffler= ? A hell of a lot of noise. Like this thread. Haha :blush:

More noise added here!!!:smilingimp:


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I would suspect that the flanges may be different since the diameter is different, but nothing that would be too difficult to correct


A question for someone who has used RPW 4-1 extractors (4g15): How low do they sit compared to stock? Is the ground clearance reduced by a lot?