[V8] standalone

[George Tur]

On Wednesday 21 February 2007 20:59, Andrew Schlueter wrote:
> Ok guys I need your knowledge. I am looking at a standalone system. I
> was going to do just fueling and leave the stock timing up to the ecu.
> Now how important is it to control my timing based on fuel. I have tuned
> standalone on turbo cars and timing is way important, just I don't know
> about NA ones...
>
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I don't have any info about the application of aftermarket control systems for 
the 4.2 or 3.6 V8, but a while ago Jorgen Karlsson posted the following on 
the list here. You might want to contact him to see he can give you more 
information specific to the earlier V8s.

> Jorgen, out of curiosity. For the ABZ engine transplant that you
> did, what
> sort of engine management system did you use? Can the motronic
> control unit
> in the V8 handle an ABZ, or would a new control unit and wiring
> harness be
> required?

I used an aftermarket Autronic SMC engine management system for the ABZ. I
already had the SMC and it's more flexible then the motronic, it's full
sequential just like the V8 and A8 engine management systems and it is well
suited for turbocharged engines.

When used on a V8 I only have one user controllable output, on the I-5 the
three unused injector drivers are user programmable. The Autronic SM2 is a
better match for the ABZ. Anyway; after hooking up the idle control I can't
control the variable intake, in my particular case with a 2850lbs car I just
locked the variable intake in the high rpm position. This makes the car more
fun to drive and the low end grunt is still quite impressive. The low rpm
setting provide more 'power under the curve' but the top end feel a bit lame
in that setting.

I would say that the variable intake should be used on the heavy type 44. A
MSD rpm activated switch will do the trick. If its left in the low rpm
setting it will pretty much emulate the stock intake on the PT or ABH.

The more interesting problem is using the PT engine management system for
the ABZ. This will take a few hacks.

First of all the distributors from the PT will fit the ABZ, I have actually
used a PT distributor to create trigger signal for the Autronic before I had
the flywheel modified.

The flywheel from an ABH will fit the ABZ, but I am not 100% sure about the
longitudal alignment. It looks good though and in any case it even clears an
early 016 with a few modifications to the throw out linkage. The trigger
assembly may require some fabrication. I don’t know anything about that
since I have never examined the PT trigger console. I don’t know if the
62degree pin will clear the ABZ, that’s vital.

Another problem is the Mass Air Flow sensor, this is integrated in the PT’s
intake and the ABZ’s MAF is a separate unit. Electronically they may or may
not be compatible.

The PT intake will most likely fit the ABZ with a few modifications, it
looks like the studs are in different locations but that can be fixed with a
drill and thread tap (direct translation from Swedish, but I am sure that
you get it.). I will know more about this before spring as I will build a
new intake for the ABZ.

With the PT intake on the ABZ you may find that the PT injectors are to
small for the ABZ, I’m not sure about their capacity but I think that they
are marginal.

If the stock engine was an ABH you will be home after installing the ABH
intake on the ABZ.

Fitting the ABZ injectors will require modifications to the MAF bypass; this
is almost impossible since the bypass is the intake itself.

The PT MAF assembly can be fitted in a piece of tube of the right diameter,
this way you can choose your injectors quite freely by changing the tube
diameter.

Comparing part# for the intake, injectors, and MAF sensor between the PT and
the ABH will most likely provide a solution.

In a V8 I would keep the ABZ intake, controlled by a MSD rpm switch, I would
keep the ABZ injectors, install the PT MAF assembly in a tube of suitable
diameter. I would also fit an aftermarket fuel pressure regulator to be able
to make adjustments to the alignment. The design of the ABZ regulator would
make it necessary to fit the fuel pressure regulator in series with the
stock unit. This would make it impossible to compensate for a MAF bypass
smaller then the ideal size.

Let me know if you have more questions, I’m only in this Audi business for
fun, not for money.

Jörgen Karlsson
Gothenburg, Sweden.
Audi 80 4.2Quattro -83