Exhaust quiery

[Toms 50th Ani]

A mate of mine was telling me the other day that the exhaust pressure (or flow) descreases itself from the end of the extractors right down to the exhaust tip therefore there is an uneven balence of pressure along the pipes.

He said by installing a Venturi that is half an inch smaller than your exhaust pipe just after where the extractors join up (collector i think), it equalises out the exhaust pressure to the exhaust tip and giving more airflow therefore providing more power.

This Venturi isn't big or anything, think of it like a bowtie where the pipe goes from 2.5inch (at the collector) then only a few CM's down it shrinks down to 2inch then expands back to 2.5inch for the rest of the exhaust system.

I know your thinking that this is restricting airflow and that was my immediate response too but he claims its only at a cirtain point (right after the collector) does it provide any beneficial gain and anywhere else along the pipe will cause a decrease in power.

Apperently in Nascar racing, this was a ruling to limit the cars power and after experimental testing, this is what they found.

ya thoughts?

[Reaper]

Hmmmm that one doesn't have the ring of truth to it. Think of it this way - do you fart any better with a cork up your arse? What a lot of people do is install a balance pipe between the two pipes which does have some merit.

Reaper

[Not_An_Abba_Fan]

OK, in NASCAR it limits the power of a car, so how would it increase a street cars performance.

The design of extractors does exactly what you are describing that the venturi does. Each exhaust pulse travels down the header pipe and when it gets to the collector it s dragged along by the pulse in front of it. If you know anything about high and low pressure reactions then you will understand the principle of this. As the pulse gets 'sucked' into the mainstream exhaust, it 'extracts' more exhaust from the head, hence the name 'extractors'. By fitting anything just after the collector, you are slowing down the exhaust pulses and making their scavenging less effective. This is what reduces the power of the NASCAR cars.

A venturi is used to suck a second element into the flow of the first, eg a carburettor, a venturi is used to suck the fuel in through a jet. There are many applications that a venturi is used, but in an exhaust system it would only restrict the flow.

[Jesterarts]

Hmmmm that one doesn't have the ring of truth to it. Think of it this way - do you fart any better with a cork up your arse? What a lot of people do is install a balance pipe between the two pipes which does have some merit.

Reaper

hahahahaha! with a cork up my arse i get a comical "pop" sound...lol

I think that this thing would do more harm than good... it would interupt the flow and cause turbulence... reducing the scavenger effect like Not_An_Abba_Fan said and your engine would have to use more effort to clear the exhaust cause of this back-log of gases...

Thats what i recon anyway