Re: Turbo="easy"? (long)

[Dan Bubb <jdbubb@ix.netcom.com>]

The biggest negative about the SDS <www.sdsefi.com> is that it will not
let you enter discreet values for ignition advance on a load vs. RPM
graph. This can make it difficult to impossible to mimic "vacuum
advance". i.e. advance under low load cruise conditions. It also
requires a jury rigging of ignition set values if you have a wild cam
with really poor idle vacuum. As SDS says, their system is for racing
and isn't good at these particular functions. Also, the lack of an
interface with a PC is a negative from my perspective. You can only look
at one engine set point (load vs. RPM) at a time and it will not data
log.
That said, the TEC II doesn't have these problems.
As far as fuel control, the Haltech requires input for each load vs. RPM
point. The TEC II uses what they call the "theory of linear
thermodynamics." (SDS uses essentially the same approach) This assumes
that load as determined by a MAP sensor is proportional to fuel
required. So, to tune the TEC II you essentially determine the height
and slope of a fuel delivery "curve" (actually a straight line) then
apply a volumetric efficiency overlay. This isn't a bad approach, but it
does assume the engine's volumetric efficiency vs. RPM curve is the same
for all loads. This isn't necessarily true, especially for engine with
turbos, variable cam timing or variable intake manifolds. This may not
seem like much and the error may never be very large, but it's still a
limitation.
For tuning the Haltech with all it's discreet points, I will mimic the
TEC II and assume "linear thermodynamics" for the initial data entry,
then tune from there. I don't think it's going to be much more painful.
Ignition tuning is essentially the same with the Haltech and TEC II.
Cost is also an issue. I intend to use the stock KS Hall effect
distributor, coil and ignitor triggered by the Haltech. The TEC doesn't
come as a fuel only unit so the cost is significantly higher, plus one
of their less devoted dealers immediately steered me away from the TEC
II towards MoTec ;-).
As you can tell I already have the Haltech. Maybe I'm just ignorant, but
I'm not too intimidated by the tuning. I think the hardest part will be
just getting the engine started. After that it should be patience,
datalog, analysis, data entry.....patience,datalog, analysis, data
entry.....
Hope this isn't too obtuse.
Dan

"Scott F. Williams" wrote:
> 
> Okay, why do you prefer Haltech over TEC? Haltech has mappable outputs to
> control everything but your girlfriend. However, this is all very costly to
> implement and tune. So... what are the other benefits that you see?
> ______________________________
> Scott F. Williams
> Account Manager
> GENUiTY - Eastern Region
> 100 Wall Street, 10th Floor
> New York, NY 10005
> Voice: 212.416.1745
> Cell: 917.648.2256
> Fax: 212.618.5160
> scott.williams@genuity.com
> 
> > -----Original Message-----
> > From: owner-scirocco-l@scirocco.org
> > [mailto:owner-scirocco-l@scirocco.org]On Behalf Of Dan Bubb
> > Sent: Monday, August 06, 2001 10:42 AM
> > To: Scott F. Williams
> > Cc: Neal Tovsen; Gary Huff; Patrick Bureau; scirocco-l@scirocco.org
> > Subject: Re: Turbo="easy"? (long)
> >
> >
> > Haltech!
> >
> > "Scott F. Williams" wrote:
> >  Its all about
> > > the SDS or TEC-II in my book.
> > >
> > > Have checkbook ready and buckle in tight...
> > > --
> > > Scott F. Williams
> > > NJ Scirocco nut
> > > Golf GTI 16v rallycar
> > > Mazda 323 GTX turbo assault vehicle
> > >
> >
> > --
> > Email LIST problems to: scirocco-l-probs@scirocco.org.
> > To unsubscibe send "unsubscribe scirocco-l" in the message to
> > majordomo@scirocco.org
> >
> >

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