Charles,
Yes and No (IMO)... A restriction will cause flow separation at the outlet
and inlet and reduce the velocity of the gases (kinda like a muffler) But if
it is just an orifice (sudden transisition in wall with no effective length)
then the total restriction say of a 2.5 " neck in a 3" pipe is less than if
you had a solid 4' run of 2.5" pipe coming from your Cat to the atmosphere.
The longer the restriction, the slower the velocity of the gasses through it
due to boundry layer development (gas has no velocity at the wall of the
pipe, no matter what the velocity in the middle)...the boundry layer is the
layer of gas that is not at the same velocity as the gas in the effective
middle of the pipe...
But, I think Hanson will "enlarge" the cat outlet by removing the pipe a
little too close to the case... at least Ive seen this done in magazine
articles...You definitly want a particular velocity in your exhaust system
though based on engine displacement and desired RPM range of operation. Too
big a pipe will reduce performance by reducing the scavanging effect of the
flowing gasses among other things...
BKB
-----Original Message-----
From: Ican2u7176@aol.com [mailto:Ican2u7176@aol.com]
Sent: Wednesday, February 03, 1999 7:32 AM
To: dakota-truck@buffnet.net
Subject: Re: DML: Paint Update now exhaust restiction:cat
In a message dated 2/2/99 11:27:16 PM Eastern Standard Time, srp@home.com
writes:
<<
1 Replace the 2.5" with a Flowmaster and 3" from CAT to Tip (oem
location)
2 Replace the 2.5" with a dual outlet Flowmaster and 2- 2.5" pipes
exiting on
both sides (one oem, the other a mirror location on driver's side)
or
3 Replace the 2.5" with a dual outlet Flowmaster and 2-2.5" pipes
exiting through
the ROLL PAN with ROLLED Chrome TIPS....on boths sides of the
license plate
section. VERY COOL!!!! >
Isnt only as good as the 2.5" outlet in the cat? it doesnt matter if you put
a
6" cat back set-up on, you are only as good as the tightest point(2.5" cat
inlet and outlet)
Charles Smith
99Dak R/T
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