Date: Tue, 26 Jan 1999 21:43:39 GMT From: keithnopsamick.freeserve.co.uk (Keith Warnell) Subject: Re: more HP- free!!!!!!!!!!1
I've just done this too, I found that turning the K put all the way clockwise keeps the boost on longer but it does back off I think caused by the knock sensor. I've been warned about adjusting the F pot for knock detection but will probably try backing about 1/4 turn to reduce the sensitivity this weekend. A crazy mod I tried for a while was drilling a 3/16 hole in the pipe from the solenoid to the wastegate. this just slowed down the opening but the net effect was that the boost pressure came on very quickly all the way to the limiter and sometimes blew most of the hoses off the manifold! 0-60 in 5.4 though............. Where can you jumper out the pressure sensor? on my 89 T16S (UK) its behind the glovebox and a major dismantling job. Can thi sbe done on the APC box or its connectors? Also "boost enrichment system" what is this? On Sun, 03 Jan 1999 11:11:27 GMT, Riff <turbospgnopsamsouth.net> wrote: >from stefan bolin- >Tweaking the control unit! > >Extreme caution should be taken when adjusting the control unit since >there are three adjustment. If you adjust the wrong one, you might as >well >throw the control unit away since the chances of getting it back to the >original setting is practically impossible. If you feel brave, dig in, >it's not >difficult. > >First you'll have to take the four screws out of the top of the box. >Remove the top cover >from the box. You will see three holes in the top circuit board that >gain you access to >the three adjustments inside the box. Some of the earlier control units >have the >adjustment screws obviously marked with the letters K, F, and P (Knock, >Frequency, >and maximum boost Pressure). If you don't have one of the earlier units, >you'll have to >look a little deeper to find the markings. Some units may not be marked >at all. On my >control unit, the screw on the right was marked with the letter P. I >turned the screw 1/4 >turn clockwise and test drove the car. There was a modest increase in >boost pressure. >I turned the screw another 1/4 turn clockwise and test drove again. >Again a bit more >boost. Finally, I turned the screw about 1/16 of a turn all the way to >it's limit. This gave >me about what I was looking for. The boost went right to the end of the >gauge. This is >about 14-15 psi. > >To get rid of the boost taper, you'll have to consult one of the major >Saab tuners and >ask them about their modified control units. > >If That's not enough... > >If that's not enough boost pressure for you, try jumpering the wires for >the pressure >transducer so that the APC control unit doesn't know what the boost >pressure is and >will rely solely on knock. I tried this on my car and did not like the >results, however, >several people who I know run their APC systems this way and have >experienced no ill >effects. One certain '86 Saab 900 turbo is running up to 20 psi with >the transducer >jumpered and a boost enrichment system. > >For those of you with Garrett T-03 turbos, 16-17 psi is about where the >efficiency of the turbo goes away and the air coming out begins to get >really hot, so running the system with the pressure transducer may be >advisable. > >Another thought... > >Another thought I have had is to bleed off the pressure to the >transducer with a small bleed-off orifice to let the boost pressure get >up to about 17 >psi. You'll have to experiment with this idea. > >Putting a resistor in series to the transducer won't work because as the >pressure goes up, the resistance goes down. You could possibly install >a variable resistor in parallel with the transducer though.
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