Date: Mon, 06 Jan 2003 23:22:04 GMT From: "Scott" <mtnbikernopsamete-nospam_triad.rr.com> Subject: Re: SAAB 2-strokes: how polluting are they?
These are all good ideas - thanks. I agree that the later oil injected motors are the way to go, though I suspect they will be the hardest to track down in the States. John brought up an interesting point about the exhaust: > > .... I have never heard of a two stroke car that had > > such a sophisticated exhaust - maybe someone could correct me > > here...Did the rally Saabs use a tuned pipe? I recalled seeing something of this sort in my research and a bit of digging turned it up again. At www.classicsaabracing.com they offer a PDF tuning manual that they developed in working on their 93 (apparently - my Swedish doesn't go much past 'skol') and in it there is a photo of what certainly looks like an expansion chamber hooked to the exhaust headers. It's a bit different from other examples I've seen in that it vents from the side - not sure what this might do to the performance of the chamber but it's worth a look. The PDF itself is at: http://www.classicsaabracing.com/Laddahemprov.pdf The plumbing must get a bit complicated but if the chamber is shaped properly you'd get an exhaust gas recirculation system and a supercharger all without adding any moving parts. Very much in the spirit of 2-stroke motors in its simplicity. It would again suggest taking Dave's advice on a later engine - probably with the toughest set of pistons you can find. Think this might raise the combustion temperatures in the chamber and create more NOx if I recall the chemistry of emissions correctly but you'd reduce the other polluting emission gasses. >Someone who looks an awful lot like John Davies <johndaviesNOSPAMnopsam.net> wrote: >Start with a oil injected engine, go with a synthetic 2-stroke oil like >a yamalube - it's a good start. Lots cleaner burning than the original >oils were 30 years ago. Check. >Someone who looks an awful lot like John Davies <johndaviesNOSPAMnopsam.net> wrote: > In case you were not aware, most manufacturers of off-road equipment > are drifting to four stroke engines. Honda and others are producing > four stroke outboard motors. It is only a matter of time before the > two stroke is dead. Actually this might not be true - it's possible we may yet again see a 2-stroke SAAB coming out of the factory. There is an Australian company that has developed a new type of two stroke motor that apparently injects the fuel-air mixture into the cylinder after the piston has passed the exhaust port. According to their Web site ( www.orbeng.com.au ) SAAB is participating in testing this new engine. I think the fuel delivery system will have a huge impact as well - if we are looking at the later 850cc motors what carburetor set-up will be most efficient? I haven't found anything describing the standard equipment on these motors but I'm assuming some sort of side-draft Weber is an option. Am I correct that they never went to fuel injection on the 2 strokes?