Motor Swap Questions - Low EFI Content

[Frederic Breitwieser]

>	My weird-o LT-1 into Audi swap is moving forward again.  I have a
>couple questions and I hope the minimal EFI content will be excused.

This is not wierd.  I'm building a mid-engined car (from scratch), using a
twin turbo Buick V6 mated to an Audi 5000 transaxle.  That's wierd :)

>1)	I'll be hooking up the Painless Wiring harness here in a couple days
>and I wanted to know what would happen if I didn't hook up a VSS.  The car
>wil be using a 5-spd manual.  I know how to get an adapter, but I would like
>to know if it's really needed.

Its not really needed for street use, as the computer will use other
sensors to compensate.  Not necessary in an ideal fashion, however it will
compensate.  Mine compensated somewhat, but consistantly ran a little lean,
especially under full throttle (this is before the turbos were installed, I
ran it N/A for a while to test the mechanical connection between the Audi
and the GM).

Dakota Digital makes adaptors, however getting the speed from the transaxle
is not necessary that complex.  The deal is to find out the number of
pulses per mile the ecm is expecting (4000 pulses per mile I think?  Sorta
guessing), then calculate how many rotations your differential/axles will
make based on your tire diameter per mile, and create a little wheel with
either magnets or an optical LED sensor.  Feed it into the ECM, and you're
done.  The Audi transaxle (certain ones anyway) have a sensor where the
speedo gear went in older models, that pulses 2192 times per mile, very
complex to use... 

>2)	Can GM PCM modules be exposed to the elements inside the engine bay?

No, they are not hermetically sealed, in fact, not even sealed with a
gasket.  Its best to shove the harness through the firewall and mount it on
the inside.

>3)	Motor Mounts:  I am looking for a good motor mount setup that will
>reduce some vibration.  The position of the engine limits me to look for a
>mount that will only allow 0.5" of verticle movement at the mount point.
>Anyone know of a rubber type or maybe even something like Delryn that I can
>adapt to this project?

If you want to remove vibration, you can use the OEM rubber mounts that
were designed to mate to the engine (they have a .75 or 1.00 inch thick
rubber plate), and make a simple bracket off your existing frame to attach
to the mount.  Poly mounts tend to last longer.  Since i"m not concerned
with vibrations (mid engined sports car) I'll be using solid steel mounts
I've fabricated.


Frederic Breitwieser
Bridgeport, CT 06606

Homebrew Automotive Website:
http://www.xephic.dynip.com/

Wanted - RWD Buick Flywheel that fits the 3.8L / 4.1L!
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