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I see a couple of other folks have worked older VWs into CNG conversion. I have an old 1980 Dasher, formerly a diesel but alas the old 1.5 has decided that a couple pistons and the crank would become one with the block through the delightful process of corrosion.
My present intention, for something interesting, different, and quite possibly unique, is to power said Dasher with VW flat-four power, tuned for economy rather than power. I intend to use a TIV base engine if I decide to go completely aircooled, but at the moment I'm leaning toward a 1.9/2.0 waterboxer. Retaining real heat will be a definite plus, and the waterboxer will let me use the Dasher's stock heat exchanger and climate control system.
Either one will be running a turbocharged Atkinson/Miller cycle to improve efficiency (and emissions, incidentally).
For those not familiar, Atkinson cycle gives you an effectively longer expansion stroke than compression, giving your fuel-air mixture more time to burn at a sacrifice of some displacement. Miller cycle uses forced induction to make up for this loss of displacement.
Since she's well outside of any emissions testing requirements (being nearly thirty will do that), I figure it's the perfect vehicle to play with.
I don't intend to aspirate/carburete for fuel introduction, but will probably be using a programmable EFI computer and distributor-less dual plug ignition (The latter for a high quality spark and to combat the wide bores those flat-fours run. Up to 104mm, ugh!), along with water injection under hot and heavy loads to help keep temps and NOx formation down.
Because of the rarity of CNG refueling stations, I'm also on the fence with respect to CNG or LPG; is the latter a taboo to discuss here? My State runs incentives and has a very good tax structure to deal with legally running LPG on the road. I'm given to understand the biggest technical differences between these is on the fuel storage end, and after the regulator things are much the same, yes?
One of my other stumbling blocks is finding vapor injectors; I could probably use Civic GX injectors, but they are incredibly expensive new. I'm not familiar enough with other OEM, small displacement engines to find other sources; anyone want to throw me a bone or two on that topic?
My present intention, for something interesting, different, and quite possibly unique, is to power said Dasher with VW flat-four power, tuned for economy rather than power. I intend to use a TIV base engine if I decide to go completely aircooled, but at the moment I'm leaning toward a 1.9/2.0 waterboxer. Retaining real heat will be a definite plus, and the waterboxer will let me use the Dasher's stock heat exchanger and climate control system.
Either one will be running a turbocharged Atkinson/Miller cycle to improve efficiency (and emissions, incidentally).
For those not familiar, Atkinson cycle gives you an effectively longer expansion stroke than compression, giving your fuel-air mixture more time to burn at a sacrifice of some displacement. Miller cycle uses forced induction to make up for this loss of displacement.
Since she's well outside of any emissions testing requirements (being nearly thirty will do that), I figure it's the perfect vehicle to play with.
I don't intend to aspirate/carburete for fuel introduction, but will probably be using a programmable EFI computer and distributor-less dual plug ignition (The latter for a high quality spark and to combat the wide bores those flat-fours run. Up to 104mm, ugh!), along with water injection under hot and heavy loads to help keep temps and NOx formation down.
Because of the rarity of CNG refueling stations, I'm also on the fence with respect to CNG or LPG; is the latter a taboo to discuss here? My State runs incentives and has a very good tax structure to deal with legally running LPG on the road. I'm given to understand the biggest technical differences between these is on the fuel storage end, and after the regulator things are much the same, yes?
One of my other stumbling blocks is finding vapor injectors; I could probably use Civic GX injectors, but they are incredibly expensive new. I'm not familiar enough with other OEM, small displacement engines to find other sources; anyone want to throw me a bone or two on that topic?
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