Re: Oil press switch ground overboost

[steveb@falcon.kla.com (Steven Buchholz)]

>  Steve , Orin.... I got this mod from a lister named Martin Slotterback. How
> it works..... It uses the ground from the oil pres switch to supply a ground
> to fuel pump relay . the good part is     no oil pres(ie. engine stall) no
> ground. I have been running  that way since I got the  spring from charlie
> smith last march.   That mod is still in place. I have not installed the
> resister yet  just the knob. I wanted to make sure the plumbing was right.
> Will I get any difference with the resister?
> 
... you'll have to talk to Paul about that stuff.  I just want to urge you 
to move forward with caution ... you have an engine that IMHO is well designed
for self preservation and are deliberately disabling those capabilities!  The
ECU has three mechanisms that it can play with to try to avert disaster.  The
first one is playing with the timing ... you haven't done anything to affect 
this.  The second one is the control of the wastegate pressure ... here you 
have done 2 things, one you have installed a Charlie Smith spring, and 2 you 
have installed the Shrappnel Knobben (R).  If the computer detects a fault it 
can no longer decrease the pressure on the top of the WG to open the WG and 
reduce the manifold pressure.  The last mechanism is the fuel pump shutdown 
... the ECU's option of last resort.  The only thing that will cause the pump 
to shut off now is when the engine stops running ... probably too late in the 
event of a problem!  

IMHO the RDH/S Mockry/Orin technique is the one I prefer ... and the way I
will go when I have the chance.  Rather than trying to work around the ECU
we should be trying to adapt it to do what we want.  We still have to ack-
nowledge the fact that we are increasing the risk of damaging the engine, 
but if there is some failure the ECU can still exercise its options for 
self protection.  I have no issues with the techniques that Charlie Smith 
and Paul have been using, but when you are pushing things as hard as you 
are (0.9 bar is over 13 PSI of boost) you must keep in mind the possible 
negative effects.  The main reason I am posting this response to you is 
because you said that your engine is pinging under boost ... this is one 
of the only warning signs ...

Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)