Tuning advice sought -

[ECMnut at aol.com]

Hi Jörgen,
I still have the factory shortblock, aside from SpeedPro rings & bearings.
  I think many of the turbo 4.3 engines are put into the grave early due to
 detonation.  I live 20 minutes from the track, and have hundreds 
of runs on my truck, most of them with the diacom connected. 
 If I show up when the track opens at 5PM Wednesday night, 
 I can usually get 15 runs in..  I watch the knock retard *very* closely.  
A gear-change boost-spike causing 2-4 deg of knock retard is the 
most I hope to see.  The rest of the time, it is zero.
  The boost spikes seem to be much worse than in the past,
while little has changed in my setup.. As soon as the rain lets
up, I'm going to try a bunch of wastegate parameter changes
in the chip to see what has the most impact.
    (Thank you Richard Tomlinson, wherever you are)
Mike V

 >  I am not sure if you can get rid of the boost spikes with the stock turbo
>  when the cap is open. Here in sweden we have a lot of typhoons and every 
one
>  that the catalyst is removed from has had broken ringlands and bent rods.
>  The stock wastegate can't control boost without the additional backpressure
>  from the catalytic converter. I guess that you have aftermarket pistons and
>  rods in your engine and don't need to worry about it as much.
>  
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