Date: Sun, 30 Sep 2001 14:29:25 -0400 From: Via Regia <hereslookinnopsamcom> Subject: Re: Back boxes and APC tweeking
Check out http://www.geocities.com/Baja/Cliffs/2661/apc/apcboxadjust2.html for a quick apc tweak (Read Kevin's apc theory, linked on that page). You might gain some boost (needle on turbo gauge will push a bit higher into red zone) if you play with the two pots (If you try this, remember to mark original pot position so you can always return to stock settings if results are not desirable - it is trial and error). On 900Ts many replace their 2.5 bar fpr with a 3.0 bar one (a 3.0 bar is used on non-turbo Saabs, 900S for example, and can be had for around $50 - Bosch makes them) Doing all the above will yield some, albeit slight, results (I have done this). The more reliable way is to spend around $350 for an aftermarket "red box" apc (made by spg9, Abbott, Performance6, and a number of other places). These boxes are upgraded with new chips, etc. and may swear by them. To really get considerable hp increases, people also upgrade to a raising-rate fpr (variable pressures to far above 3.0), change fuel injectors, mess with the wastegate adjustment (not recommenred unless you really know what you are doing), and finally upgrade to a larger aftermarket turbo, switch to lighter flywheel, and bore our cylinders. A good source of information on performance mods large and small is the bulletin board on www.saabnet.com (check the performance section of board). You will also find links to the many aftermarket performance shops where you can buy an upgraded apc box and anything else if money is no object. The Saab motor will handle moderate power tweaks fairly well. The same cannot be said for the transmission (in a 900 at least) - life will be shortened considerably by the extra torque. Have fun. Via Regia On Sun, 30 Sep 2001 12:14:57 +0100, "Roger Hyde" <rogerhydenopsamternet.com> wrote: >I have seen lots of contrasting advice on tweaking APCs to increase boost. >But has anyone here actually done it ? I have a 1987 9KT and fancy a bit >more Umph (especially since my pattern-part exhaust mid section has robbed >my motor of some torque... cant afford to change it yet). > >Do you actually need to increase fuel pressure with an uprated regulator. >What is a safe level of boost increase (if any) >does anyone know of a suitable back-box that will give a bit more torque / >power without sounding like a monster truck ? > >thanks > >
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