Time to chime in on this thread. I think everyone is in agreement that
being able to alter the factory programming is the best route. Cost of
doing so seems to deter most from this route. I'm not sure why nobody
is talking about an even better (and much cheaper) alternative. I'm
talking about a totally different computer to COMPLETELY control both
fuel and spark delivery. I'm talking about a non-Mopar alternative. It
simply boils down to spark advance/retard and controlling fuel injector
pulsewidths for the appropriate conditions (be it twin cylinder, 3, 4,
5, 6, 8, or even 12 cylinders, boosted or NA, nitrous, water injection,
cam, stroked, etc). Total control can only come from a fully
programmable non-Mopar controller. While the aftermarket controllers
can do all this - they are a bit costly over the short-term but not
long-term when compared to multiple re-flashes of factory PCM or
multiple piggy-back devices (that I agree are just band-aid fixes). I'm
talking about the $100 Megasquirt controller. Check out
http://www.bgsoflex.com/megasquirt.html or the Megasquirt yahoo group.
The build-it-yourself version is about $100 while fully pre-built and
tested versions are around $200. Add a MegaSpark box (the same hardware
with different code and only 4-wire hookup) and you can have total
control of spark and fuel delivery for a minimum of around $200. Add a
DIY-WB controller and go closed-loop with wide-band control for another
$150-$200. It would be equivalent to having unlimited custom PCM
re-flashes and unlimited dyno time all while cruising down the highway
for less than $400.
Of course you could keep paying $500-600 for PCM re-flashes and costly
dyno time and still be left with a rough guess at what your motor is
really needing. Personally, I'm utilizing the $100 solution for
datalogging and confidence building and will soon be hooking up the
injectors to full MegaSquirt controll on 4 of my vehicles (including my
$22,000 Harley Dyna Wide-Glide w/V-Twin motor).
Shane
Bernd D. Ratsch wrote:
>Don't get me wrong here, I don't disagree with Bob that custom PCM
>programming is the best route, but consider that it's for your specific
>vehicle, the Dyno time, and cost of the PCM programming...and you can
>hit $800+ in a one-day tuning session (easily). $400+ for PCM
>programming + Dyno Time (minimum 2-4 hours with A/F).
>
>If you modify the MAP signal (as in this case), yes...the PCM will try
>to correct itself to keep itself within factory parameter. Under Closed
>Loop operation, the PCM wants to keep things at a 14.7-15.0:1 ratio.
>However, if you're running larger injectors, bigger cam, modified heads,
>etc., the MAP input signal (vacuum signal) and fuel output (O2) is
>altered already and the PCM will try to compensate...sometimes too much
>and can go out of range. This is where the APEXi unit (and a few others
>similar to it) comes in handy. You can modify the signal to the PCM and
>get it close to 14.7-15.0:1 again without having to reprogram. This
>way, and under Closed Loop operation, the PCM stays happy. Sure, there
>will be a little adjustment on the PCM's side, but this is just to keep
>things ratio within the 14.7-15.0 ratio. In general they work very well
>but there are cases where compression, cam profile, vacuum and other
>custom engine build-up factors put you out of the realm of readily
>available (and budget oriented) fuel tuning devices and you may need to
>consider either aftermarket programming and/or aftermarket programmable
>piggy-back (or stand-alone) systems.
>
>Another simple way of looking at things:
>
>Input = What the PCM is "reading" from the sensor(s).
>Output = What the PCM is "telling" the fuel/timing to do based on the
>inputs
>
>Under Open-Loop operation, O2 is ignored and reverts to a baseline. You
>can adjust things without any problems at all.
>
>This was verified with a Dodge Master Tech (and not just some paper-work
>certified tech but also a fellow racer with a modified '01 Dodge Ram),
>with an internal (PVO) Dodge source, and two "Chip" manufacturers (one
>being a Superchips tech).
>
>- Bernd
>
>-----Original Message-----
>From: owner-dakota-truck@bent.twistedbits.net
>[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bob Mankin
>Sent: Thursday, May 29, 2003 11:53 PM
>To: dakota-truck@dakota-truck.net
>Subject: RE: DML: Re: RE: Re: Re: Re: Re: Superchips Dyno Results
>
>Ron, if you'll retrace the thread, I was asking that you dyno before and
>then a few weeks after so we all might learn something from the
>exercise, myself included. Trying to be objective here.
>
>Not sure why Bernd feels the need to so strongly defend the product
>based on his word alone. I'm simply looking for hard data. As I said, I
>personally believe there are better options out there but I won't make
>assumptions on your motivations for the purchase decision.
>
>Good luck with the box.
>
>Bob
>
>
>
>
>
>
This archive was generated by hypermail 2b29 : Fri Feb 06 2004 - 11:46:22 EST