747 Timing Calc

[don.broadus at exeloncorp.com]

I would say that the 13 degrees (crank)  would make the engine such a dog, I
believe you are calculating distributor
degrees, so multiply the 13 X 2= 26 degrees (crank) . The 26 degrees at the
crank is what my 82 305 LG4 T/A engine had
going to non ECM Hei with 36 degrees (crank) really ,made a difference  

> -----Original Message-----
> From:	rr [SMTP:rrauscher at nni.com]
> Sent:	Thursday, June 21, 2001 9:05 AM
> To:	gmecm at diy-efi.org
> Subject:	Re: 747 Timing Calc
> 
> 
> The ALDL spark gets added when the ECM is in ALDL mode.
> I believe this is the 10k resistor across the diag
> terminals. Scan tool can also be used to do this.
> 
> As for the 13deg, hard to say. I haven't tuned many lo-po
> motors. Gm needs to take into account emissions, cat-con
> survival and warranty claims. Hopefully someone with more
> experience in this area can add.
> 
> C2500, a heavy truck maybe? Low timing to keep ping at
> bay while towing and engine is hot (220f).
> 
> BobR.
> 
> On Wed, 20 Jun 2001 17:46:02 -0400
>  "Brent" <wildkat at paonline.com> wrote:
> > I assume that I did the calculation correctly.  I really
> > wasn't sure whether
> > to include the "ALDL/CL adv " or not.
> > 
> > Amazing yes and confusing.  I don't understand why it
> > only needs 13d @
> > 3200rpm WOT.   I thought the older iron heads had a slow
> > burn rate as
> > compared to newer alum heads and required more WOT
> > timing...
> > 
> > Seems to indicate the mixture is burning very rapidly or
> > end combustion is
> > taking place in the exh manifolds.    Thoughts?
> > 
> > Regards,
> > Brent
> > ---- Original Message -----
> > >
> > > Amazing isn't it?
> > >
> > > BobR.
> > >
> > > Brent wrote:
> > >
> > > > I'm having trouble figuring out how the 7747
> > calculates timing.  This
> > stock
> > > > bin is for a '91 Chevy C2500, 350, auto, 3.73.
> > > > http://www.paonline.com/WildKat/arjt000.bin
> > > >
> > > > Lets run the engine at 3200RPM, PE mode, 100KPA, 75d
> > C coolant temp.
> > I'll
> > > > assume there is no knock retard.  I used WinBin to
> > find the values.
> > 
> > 
> --------------------------------------------------------------------------
> --
> To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
> in the body of a message (not the subject) to majordomo at lists.diy-efi.org


************************************************************************
This e-mail and any of its attachments may contain Exelon Corporation
proprietary information, which is privileged, confidential, or subject 
to copyright belonging to the Exelon Corporation family of Companies. 
This e-mail is intended solely for the use of the individual or entity 
to which it is addressed.  If you are not the intended recipient of this 
e-mail, you are hereby notified that any dissemination, distribution, 
copying, or action taken in relation to the contents of and attachments 
to this e-mail is strictly prohibited and may be unlawful.  If you have 
received this e-mail in error, please notify the sender immediately and 
permanently delete the original and any copy of this e-mail and any 
printout. Thank You.
************************************************************************
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org