excellent info Jay! i think after reading this and talking to a buddy up
here at work i'll wait till i can get the 3" cat-back. i figure that the
larger pipe might not do as much good now but down the road (after a couple
more mods) it will definitely be called for. no sense putting something in
that i'll have to replace a couple months later...
now i just need to decide on the muffler...the quote from the muffler shop
was for a $135 magnaflow, i guess i could knock $50 (or more?) off that
price if i took one in there myself.
thanks again guys!!
-adam
----- Original Message -----
From: "Woodruff, Jason P" <jason.p.woodruff@boeing.com>
To: "DML (E-mail)" <dakota-truck@dakota-truck.net>
Sent: Wednesday, May 29, 2002 12:18 PM
Subject: Re: DML: Exhaust bottleneck?
>
> Main exhaust bottleneck? In my opinion the whole thing.
>
> First I made a po'boy air intake Z tube, I felt a little more HP, probably
> mostly do o the colder air. Next I replaced the cat back exhaust system
to
> a single 3" and found that to increase throttle response AND torque
> substantially. Then I replaced the intake and Throttle Body with a real Z
> tube and F&B TB. Throttle response went way up, HP went up on anything
> above 2K RPM, but low (really low) end torque diminished a bit. I
wouldn't
> recommend that last one if your looking to tow a lot. I have a set of JBA
> headers in my bed room that I'm not sure if I'll ever get to put on, but I
> suspect they'll have the same effect as the TB change.
>
> I think there's 3 cats on 4.7Ls (except 2000 non-cali daks). one on the
end
> of each header then one further downstream after they've merged.
>
> Jay W
> 505/287 Dakota
>
> >Date: Wed, 29 May 2002 10:02:01 -0500
> >From: "crm" <tb.crm@verizon.net>
> >Subject: DML: Exhaust bottleneck?
> >
> >Hello all,
> >
> >Can someone pinpoint the main exhaust bottleneck for a 2001 Dak QC with a
> >4.7? After doing a lot of reading (here and elsewhere), I seem to be
> running
> >into 2 or 3 differing points. One the one hand, many seem to suggest a
new
> >muffler will really free up the exhaust. One the other, I have heard that
a
> >new muffler wont do much because the main bottleneck is at the cat. And
> then
> >on the 3rd "hand", I have read that if you dont replace the stock 2.5"
> pipes
> >with a 3" catback, neither hi-flow muffler nor hi-flow cat will help. And
I
> >guess to round it all out (4th hand), I've heard that the 3" pipes will
rob
> >you of low end torque, which is what you need for towing and the like
> >correct?
> >
> >If it makes a difference, I dont use the truck for towing. Mainly for
> >driving to work and around town and the occassional day trip. No racing,
> >other than the normal youthful exuberance on the freeway or at the light.
> >Basically, I am not looking to build a mean street rod or anything, just
a
> >truck that can sh*t and git if I tell it to.
> >
> >I dont want to spend money for the same thing 2 times, so I want to make
> >sure I do it right the first time. I just ordered a Z-tube last night and
> if
> >I can figure out what's best I hope to get some exhaust work done this
> >weekend. I'd like to use stock pipe if possible and avoid getting a whole
> >new catback system until later on.
> >
> >Also, is it correct that the 4.7 Dak's have 2 cats? Like a pre-cat and
then
> >a main cat?
> >
> >Thanks in advance!!
> >
> >- -adam
> >
>
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:04:36 EDT