Turbo Talk... & HKS Controllers

[Mark Taschek]

> 
	Well on  my 87 900t if the guys at frenches who raced 900t
	were write the APC unit would modulate the control valve and
	you now have full boost controle. 
	
	
	
	
	
	
	
	
	

> >       ... The system will monitor the engine for
> > 	knock and if your running good gas and have boost with no knock
> > 	then the system will let you boost even more untill you 
> > 	start to knock and then will slowly drop the boost untill
> > 	knock is low and the it will start to increase the boost again
> > 	untill it starts to knock.. 
> 
> If memory serves re: an '86 system we used to have, the
> APC unit is a completely separate add-on with its own controller
> and wire harness appropriate for DIY.  There is a knock sensor and
> a solenoid that opens a turbo bypass valve that routes some of the
> air coming out of the compressor side of the turbo back upstream
> of the intercooler.  The solenoid is simply open-close with no in
> between settings. So there are two boost settings - the upper
> setting limited by the wastegate setting with the bypass closed
> and the lower setting set by system geometry when the bypass valve
> is open.  I think that in that early unit the APC control just
> opens the bypass valve when it detects knock and then closes it
> again after a delay.  It was effective.  Given the price of old
> 900Ts you should be able to get the pieces cheaply.  I could be
> wrong about some of this but I'm pretty sure that is the way that
> system worked.  Newer integrated systems monkey with timing etc.
> 
> Peter
> 
> -- 
> Peter Dufault (dufault at hda.com)   Realtime Machine Control and Simulation
> HD Associates, Inc.               Voice: 508 433 6936
>