Calpak and Boost

Alex C. Green alex at ravenet.com
Tue Jan 14 06:18:31 GMT 1997


Hi Peter.

----------
> From: peter paul fenske <pfenske at direct.ca>
> To: diy_efi at coulomb.eng.ohio-state.edu
> Subject: Calpak and Boost
> Date: Saturday, January 11, 1997 10:09 AM
> 
> Hi All
> 
> Just was interested if anyone had the eprom contents of the syclone
> calpak. If not ok just have to spend some money.

I have a copy of the Syclone mem-cal.  There were 3 versions released.  The
first and original one.  The second one was issued as per GMC's TSB
primarily due to poor/rough idle.  The 3rd one was issued for the Saudi
Syclones that were exported to Saudi Arabia.  It disabled the O2 sensor
among other things.  The Saudi Sy's didn't have a cat installed.  They came
equipped with an exhaust resonator, twin mufflers and twin tail pipes. 
Several other malfunction flags were disabled on the Saudi chip.  Plus,
there's also a handful of aftermarket mem-cals that were made available. 
Some better then others.

> 
> Also if someone can send me the 89 tpi prom I could have a look
> and see what it would take to disable the egr and vats for you
> guys.
> 
> With the syclone stuff I am getting serious about writing some
> code and adding it to the 730 tpi stuff. What I want to do 
> is interecept the map a/d reads using a 2 bar map instead of
> a 1 bar.

Huh?  Both the GMC Syclone and GMC Typhoon came with a 2bar map sensor from
the factory.  They never had a 1 bar map sensor.  It would be really nice
to recal the chip for a 3bar map sensor.  I for one could actually take
advantage of a 3bar map sensor.  Unfortunately, no-one has a 3-bar chip
yet.

> When pressure exceed baro or a calibrated value I intend
> to switch the open loop calibration to my own table.

Open loop doesn't last very long.  As soon as the 3 wire heated O2 sensor
warms up, the ECM goes into closed loop.  I'm confused.  What would be the
point in running another cal in open loop? 

> Also switch
> in an external driver for additional injectors when the boost
> from the vortech cuts in.

Keep in mind that the Sy/Ty engine is not a regular Vortec-V6 with a turbo
strapped on.  The heads are different.  They used the fast burn heads.  As
well as the pistons and connecting rods.  The pistons are the Corvette
Hypereutectic pistons.  Not to mention the entire intake is different too. 
And obviously, the compression is different.  There is a tech paper
published by SAE PN#910682 entitled "The Turbo/Intercooled Syclone Engine"
that can give you all the exact details about the motor, turbo, ECM, and
other related materials.

 This is similiar to what is done in
> the LT5 to switch in the extra injectors. 

Hmmmm.  Sounds like a good idea, except where are you going to install this
extra injector(s)?  Out of all the Sy/Ty owners I know, I've never seen
this done.  That's not to say that it can't be though.

> 
> I would like to see how the Map reads are done in the syclone.
> 
> Tnx everybody: peter

L8TR

--------------------------------------------------
Alex C. Green
1992 GMC Typhoon #1153 (Green/Gray)
Hockessin, Delaware
E-Mail: alex at ravenet.com
--------------------------------------------------




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