Re: Intercoolers and Digital boost control

[Orin Eman <orin@wolfenet.com>]

> This unit is adjustable such that two boost levels are available and
> selectable by switches.  I have them set at 1.8 and 2.2 bar or about 14 and
> 18 psi.  And, yes, I've grounded the fuel shut off relay.  A word here to
> those struck with horror at the idea of defeating a factory initiated
> 'safety' device.  These cars are carefully designed by engineers and
> lawyers to be successfully driven by idiots.  And these idiots may
> encounter a vast array of conditions and failures which may escape their
> notice.  Those of us who are more in tune with the physics of our
> surroundings will no doubt notice the difference between normal
> acceleration and if our car should suddenly accelerate like an F-18 on a
> catapult shot.  If it does, then something in the system is behaving
> abnormally,  _take appropriate action_!  If you are modifying your car for
> increased performance then take responsibility for same.  If your engine
> blows to bits as you reach Mach 1 between stop lights then don't
> complain... you knew something was different.  Machinery may have complex
> or intermittent problems, but machinery in never capricious or moody. 
> (Yeah, yeah, I know.)  Pay attention... and enjoy the improvements to your
> car.

You forget the other function of the fuel pump relay.  If the engine
stops turning, the ECU turns it off.  Did you see the pictures of
the burnt out 200?  Do you really want the fuel pump to keep running
in the case of an accident?

It's too easy to do it right and modify the ECU boost cutoff tables
and install a 2.5bar pressure sensor than to take this risk.

> I find that running at these boost levels can reveal new challenges.  I
> find that 2.2 bar at WOT I have a miss/power loss that I can't explain. 
> Scott Mockry fixed my WOT switch at Thunderhill but I've not found the rest
> of the problem.  Suspecting that the knock sensor is chopping the ignition,
> this afternoon I added two gallons of 115 octane racing gas to the tank and
> was greeted with a nice strong pull in ranges where only stuttering had
> previously occurred.  Looks as if I now must address all potential causes
> of detonation.

I'm not surprised.  Stock timing is far too advanced even for 1.8 bar.
You _will_ start knocking _below_ 1.8bar on premium gas, usually around
4800 rpm.  There are those around who can fix this, but it will cost
$$$.

I'll leave it up to the turbo experts to point out that at 2.2 pressure
ratio, your turbo is running really inefficiently and generating
a lot of heat...

Orin.

BTW, out of diaphragms at the moment; try Ned, Scott or Ivor.