[V8] 3.6 convert to 4.2 and other silly questions.

[Tony and Lillie]

Ok, to add a little knowledge to this......

The 4.2 uses a true sequential fuel injection system. The 3.6 uses a "batch" 
system. Not quite like batch systems of old, where they fire all the 
injectors at once (like in all VW digifant systems, for instance) but it 
still fires two at once. So, the 4.2 has a slightly more sophisticated 
system. The 4.2 ECU uses inputs from the TCU to determine some of it's 
parameters. The 3.6 does not. So, if you use a manual trans with a 4.2 and 
it's ECU it will actually be down on power compared to the same setup on a 
3.6 ECU/manual trans. You have to source a 4.2 manual ECU for ideal running 
with a manual trans. Otherwise, the ECU will run in default mode, thereby 
retarding ignition timing/etc and reducing engine power.

This is why it is thought that the 3.6 ECU is more agressive than the 4.2. 
Becuase most of those opinions are based on a manual swap into a car with a 
4.2 auto ECU running in default mode. And, that is then compared to a 3.6 
ECU running in it's "normal" mode.

In your situation, the guys are dead on. Use the 3.6 headers, 3.6 intake 
manifold. It will run similarly to the stock 3.6, just with more torque/hp 
due to the extra displacement. Years ago I worked on a '90 V8Q auto with a 
4.2 swap done just as described, and it was a very nice car to drive. Much 
pepier off the line than a 3.6. Ideally, you want the 4.2 ECU/wiring, etc. 
However, in your situation, I think what you have lined up is perfect. And, 
it does sound like he is charging you a fiar price for the work/price, IMO.

HTH, and............
this advice is worth every penny you paid for it ;-)
Tony

----- Original Message ----- 
Subject: Re: [V8] 3.6 convert to 4.2 and other silly questions.


>I believe that it should bolt right in like Chris says.  It is not 
>"exactly"
> the same but the few differences pretty much only act in your favor in 
> terms
> of more power.  You may want to use the exhaust headers from the 3.6 
> though
> because they flow better and don't have the air pump that the 4.2 might 
> have
> on it.  Supposed, the 3.6 ecu has a bit more aggressive engine timing
> parameters too.  All in all it should be pretty straight forward.  Most
> others who have done this though have done it in conjunction somehow with 
> a
> manual transmission.