alas! i _do_ have the 2 pre-cats...but headers arent in the picture for a
while...but thats what i said about a cat-back and i might have it by this
weekend...
-adam
----- Original Message -----
From: "Stlaurent Mr Steven" <STLAURENTS@MCTSSA.USMC.MIL>
To: <dakota-truck@dakota-truck.net>
Sent: Wednesday, May 29, 2002 2:48 PM
Subject: RE: DML: Exhaust bottleneck?
>
> Before I forget, if you have the PRE-CATS installed on your truck the gain
> from JBA shorty headers are only 9HP. If you don't have the Pre-CATS,
then
> the long type headers are up to 21HP gain. These were the figures given
to
> me from JBA engineers while they prototype the headers units.
>
> --------------------------------------
> Steven St.Laurent
> C4i System Engineer
> C4i Engineering Branch, PSD, MCTSSA
> MARCORSYSCOM, U.S. Marine Corps
> Office (760) 725-2506 (DSN Prefix: 365)
> "Never be content with somebody else definition
> of you. Instead, define yourself by your own beliefs,
> your own truths, your own understanding of who
> you are. Never be content until you are happy with
> the unique person GOD has created you to be."
>
> -----Original Message-----
> From: crm [mailto:tb.crm@verizon.net]
> Sent: Wednesday, May 29, 2002 11:52 AM
> To: dakota-truck@dakota-truck.net
> Subject: Re: DML: Exhaust bottleneck?
>
>
> 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