The 1.6L Corolla got something like 33mpg while my 1.8L gets ~38 mpg driving it "normal". Different drivers and different cars, but my sister drives the 1.6L one now so should be interesting to see what kind of mpg she can get with it (if she tracks it). Using public sourced data supports my experience too. The engines might be almost identical, but the cam profiles and such make them act so much different. My 1.8L feels like it has power and it feels good in the corolla, the 1.6L feels overly high geared and sluggish.
I suspect there's a little more involved than just heat losses in the combustion short stroke vs long stroke. Just the stroke length difference is effectively changing the "gear ratio" of piston travel vs crank turn. Also the pressure is pressed on the piston for longer, so I'd expect more energy to be turned into movement from the long stroke. My uneducated mind would guess roughly 10% for the 1.6L to 1.8L difference. Maybe make the 1.8L into a 2.0L just by a longer stroke and get another 7% and loose some max rpm.
Another interesting thing that I've noticed is when I travel and get to hilly areas, my mpg goes up a little. I suspect it's simulating pulse and glide a little with the rolling hills.
Also, update on the echo, the gas tank leaks at the seam (1/2 tank or fuller), yay for Michigan rusty vehicles. Also the main support for the rear end on the passenger side is rusted out quite badly. I'll have to weld some plate steel in before winter. If I saw that before I bought parts for the car, I probably wouldn't fix it up and just look for another beater around winter time, but the car's design is simple enough it shouldn't be too hard to fix the rust and I'm not super worried about looks and such (it's under the car anyway).
I know people like photos, so here's some of the little beater. Kind of what you get for $250 in Michigan when the vehicle runs and kinda stops (drums and shoes worn out, no adjuster in it's design). Don't mind the broken concrete, working on getting a base setup for my driveway. Got a person coming over so using the car so they don't go cranking into the drive way too fast. Also, yes I have the rear bumper, plan to put it back on so it doesn't draw attention from the wrong people.
Resonator from a Camry works quite well for a muffler on this little thing. Not too loud, but loud enough to hear it to drive (no tach).
Rust... what rust? Bottom left part of the pic is where the rear suspension attaches to the body.
Yep it has the weight reduction in the trunk too.
Anyway, I knew the car was going to be bad, just wasn't expecting the rust to be quite that bad. Trunk is no big deal, ez to patch up. The main unibody frame rail will be a bit more involved. Clearly the car was never undercoated, once it's fixed up good enough to be safe and everything, I'll be undercoating the body. $20 or so of grease can make that car body last another 3-5 years atleast I'd guess. Solid test to see how well it stops rust since I never undercoated anything before, but the logic of it makes sense.
The only down side to that car is the suspension design, it attaches to the body right where the rust is normally. On the "upgraded" cars (corolla, camry, lexus etc) it has a sub frame and independent suspension so the attachment point is much closer to the center of the car so it can rust out a lot more before the physical integrity of the vehicle is in question.
Not sure if I should start a new thread on the echo, or just mix it in with the diesel truck talk. Not planning too much for crazy mods, just fix rust, and smooth the underside of the car out and remove any plastic catching wind.