rbastedo Posted July 25, 2008 Report Share Posted July 25, 2008 I had to install a Sigma bike speedo as the tunnel on my Midget doesn't allow enough room to connect up a speedo cable. Besides being able to tell just how fast I've been driving... I also learned that adding up your trips in your head and calculating your fuel economy isn't incredibly accurate. :eek: So I filled up this Tuesday and drove all week. With a couple side trips to the grocery store & whatever the trip meter said 137 miles as I pulled in to fill up this afternoon. That's way more than I would have guessed, due to not really adding up all the little places I go during the week. It took 4.3 gallons. The Sigma also records top speed, for the week it was 78mph. So pretty much driving like a madman and taking a lot of little short trips I'm getting 31.86 mpg. I wonder how good it would be with a rebuilt carb? I wonder how good it would be if I could drive 55? The world may never know... :cool: Quote Link to comment
Bleach Posted July 25, 2008 Report Share Posted July 25, 2008 are you sure the speedo is accurate? Quote Link to comment
rbastedo Posted July 25, 2008 Author Report Share Posted July 25, 2008 are you sure the speedo is accurate? Yes, I've calibrated it. My car only weighs about 1600 pounds. The Carb is thrashed, currently I just don't have time to rebuild it. I'm considering just buying a rebuilt, but who knows if it would be better than what I already have? Quote Link to comment
Bleach Posted July 25, 2008 Report Share Posted July 25, 2008 depends. Atomizing the fuel better should produce better torque which in turn will increase economy under all driving conditions. Given enough torque, a 5-speed will increase your cruising economy even more. Quote Link to comment
rbastedo Posted July 25, 2008 Author Report Share Posted July 25, 2008 I'd love to have a 5 speed - but that isn't what I've got and right now I have little time & space for such projects. Besides have you seen the going price of a good Datsun 5 speed lately? Quote Link to comment
ppeters914 Posted July 27, 2008 Report Share Posted July 27, 2008 I'd love to have a 5 speed - but that isn't what I've got and right now I have little time & space for such projects. Besides have you seen the going price of a good Datsun 5 speed lately? A good Datsun 5-speed isn't expensive. A good Datsun 5-speed for an A-series engine -IS-. :D Quote Link to comment
DRIVEN Posted July 29, 2008 Report Share Posted July 29, 2008 My 1200 has an A15 / 5-speed combo (dogleg). With 3.90 gears and stockish diameter tires it turns 4000 rpms +/- at freeway speeds. It only gets about 30mpg. I never got a chance to run it with a stock carb. It was missing when I bought the engine. Now it has mikunis off of a motorcycle. I think the jetting is pretty close and it runs great. Throttle response is awesome and it pulls strong. If you are pulling those kind of numbers with a 4-speed -- I don't think i'd mess with it. A series 5-speeds are ridiculously expensive thanks to those MG guys:lol: What kind of rearend gearing you got? I only weigh a couple hundred pounds more. I know my motor is tired and if I jet leaner it runs poorly. I want to know your secret. Quote Link to comment
ggzilla Posted August 2, 2008 Report Share Posted August 2, 2008 5-speed works. Datsun 1200 4-speed: 38 mpg highway (A12 round port engine) Datsun B210 5-speed: 50 mpg highway (A14 round-port engine) Datsun 210 5-speed: 47 mpg highway (A14 round-port engine) Quote Link to comment
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