V6 Vortec to V8 Vortec Conversion

[JANETSKY, ALBERT (AIT)]

ahhh... a reply!  I've realized that in 98 GM started using passlock 2.  I
think I'll set the 98 PCM on the shelf and see if I can completely reprogram
96 v6 PCM for a v8.  

I'm feeling like I might have stumbled into something that I'll find very
little support for.  Essentially zero support for the obd-ii systems on the
web.  

I think I can figure out how to interface the obd-ii interface with my pc...
but haven't stumbled upon any applications out there that can communicate
with it.

AL


-----Original Message-----
From: Len Sabatine [mailto:sabatine at epix.net]
Sent: Thursday, August 16, 2001 10:35 AM
To: gmecm at diy-efi.org
Subject: Re: V6 Vortec to V8 Vortec Conversion


     While the PC Dyno program may be giving some cool gross HP numbers ,
     I would be looking at the shape of the torque curve more closely , 
especially
     with an OBD2 PCM. Overall , a LT1 F-Y Body production cam w 1.6 rockers
     will drive better and be easier to get up and running.
     A '96 Vortec PCM is not identical to a 98  Vortec PCM , just close.
      Len

>Hello All...
>
>My name is Al Janetsky.  I'm a Systems Engineer with a telecommunications
>organization... and for fun I'm converting a 1996 GMC Sonoma sportside
>equiped with the 4.3L Central Sequential Fuel Injected Vortec to a 5.7L V8
>Vortec. I'm hoping to keep the truck streetable with occasional runs on
>Saturday nights at the local drag strip (for fun).
>
>The donor motor, wiring harness, and PCM is out of a 1998 3/4 ton GMC
>Sierra.
>
>I currently have the engine at Kendricks of San Antonio for my machine
work.
>
>Modifications include porting and resurfacing the Vortech heads.  An LT4
Hot
>cam package... 1.6 roller rockers, and upgraded valve springs.  The specs
on
>the cam are 218/228 at .525/.525
>
>I plan to swap out the v6 pcm for the v8 pcm... (even though they are
>identical except for the programming).  I plan to use the existing v6
wiring
>harness and run a few of the pinouts from the pcm to the fuel injector
>assembly. I've already traced the pinouts from the ecm to the injectors,
and
>think that it will be a fairly straight forward swap.
>
>There are a couple of major concerns that I have regarding my project.
>First off -  Does anyone think this cam is too large for my conversion.
The
>vehicle should weigh in at about 3275 after the v8 is installed.  Gearing
on
>the vehicle is a 3.08 locker, and the transmission is a 5 sp New Venture
>3500 that I just rebuilt.  I know that I can give up some low end torque...
>and it looks like this cam will make gobs (in comparison to existing) of
>power way up in the rpm range.
>
>A computer program at the machine shop speced out about 330HP with the use
>of small tube headers and somewhere near the 400 ft/lbs of torque mark.
I'm
>concerned that the PCM will not be able to handle all of the duration.
>
>Some other areas that I would like to address are the identification of the
>98 OBD-II PCM and how I might be able to custom program the system to be
>more compatible with the modifications... (including tach, gearing, manaul
>trans, etc. etc.)
>
>I'm willing to spend time doing the research... but so far it appears that
>most of the information on the web is related to older efi systems.  I've
>considered the hypertech solution... but to me, it's only a duct tape
>solution being that I can't fine tune the system to my needs.
>
>I'd really appreciate any information about the 98 pcm, communication
>protocols, etc that would get me started in the proper direction.
>
>Thankyou,
>
>Albert Janetsky
>aj5242 at txmail.sbc.com
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