Exhaust: Do we really need back pressure?

[peter at thescirocco.com (Peter)]

...That back-pressure is probably close to the resistance the exhaust flow 
deals with going through the bends in the exhaust system.

Peter - 302.832.8989
http://thescirocco.com
----- Original Message ----- 
From: "brad boston" <boston813roc@gmail.com>
To: "Cory Langford" <Cory_Langford@bcit.ca>
Cc: "Scirocco list" <scirocco-l@scirocco.org>
Sent: Thursday, February 15, 2007 6:36 PM
Subject: Re: Exhaust: Do we really need back pressure?


> If you are running a 2.5 inch pipe from the headers back with no turbo you
> will need to richen up the air fuel mixture a bit from stock.
>
> Also, a straight through muffler/resonator (if correctly tuned) will cause
> back pressure due to the resonating pressure waves bouncing around inside
> the resonator
>
> Brad
>
> On 2/15/07, Cory Langford <Cory_Langford@bcit.ca> wrote:
>>
>>
>>
>> Just finalizing the exhaust set-up and I was wondering what the opinion
>> was
>> on running a completely free flow exhaust.
>>
>> One of the tracks has a noise restriction, and one does not.  So I 
>> figured
>> the simplest design was from the header to 2.5 inch pipe straight back 
>> (no
>> cat, res. etc).  I figured I would have a removable muffler that can 
>> slide
>> in when needed, and a straight pipe when not.
>>
>> But I have seen some talk on the vw engines needing some back pressure to
>> keep the exhaust gasses hot enough to travel quickly through to the end.
>> So I was wondering if a simple straight pipe would have any down sides to
>> it (beside noise)?
>>
>> Cory
>>
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