[V8] 5 spd conversion: 3.6 vs 4.2

[Ed Kellock]

This is wonderful to hear.  I believe I'll hold on to this email as a reminder...


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From: DasWolfen at aol.com
Date: 2004/03/05 Fri PM 02:27:41 MST
To: ekellock at adelphia.net,  v8 at audifans.com
Subject: Re: [V8] 5 spd conversion: 3.6 vs 4.2

In a message dated 3/5/04 1:55:20 PM Eastern Standard Time, 
ekellock at adelphia.net writes:

> I was interpreting it as a comparison between a 4.2 car converted to a 5spd 
> versus a 3.6 5-speed converted to 4.2.  
> 
> Maybe I misinterpreted.  Give the above, I would think there'd be no 
> difference really.

 A 4.2 converted 91 5 spd could be significantly quicker than a 4.2 car 
converted to a 5 spd.

 Some may remember that about 2 years back I swapped a low mileage 4.2 into a 
former lister's 90 V8 while retaining the 3.6 electronics. The results of 
that swap were surprising. The car consistantly posted 1/4 mile times that 
computed back to 330 hp when corrected for altitude and temp. Only John J's 93 has 
been able to match or exceed those numbers. The 90 is Stebro equipped, in all 
other respects it's stock, the 93 is ported, cammed, chipped, and breathing 
through a Scorpion exhaust.

 This leads me to believe the 3.6 ECU may have more aggressive timing maps 
than the 4.2 unit. The one area I was really worried about is leanout at full 
throttle when the 3.6 ECU switches to open loop operation. Leanout would be 
indicated by engine knock. The car never once gave any indication of knock 
problems despite my admittedly brutal testing (no comments from the peanut gallery!) 
and the current owner has reported that he's had no engine or electronic 
problems at all. The lack of any leanout problem at all indicates that the Motronic 
is capable of recognizing the increased displacement as an increase in 
volumetric effeicency and has enough flexability in the programming to account for 
it at full throttle.

 Bosch's little silver box may not be quite as stupid as we think!



 

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