( * OK, 52.7 MPG US = 4.5 L / 100 km... but who's counting?)
Filled the MPGiata yesterday for a new best tank for the car!
It's always a bit of a surprise when I calculate the tank MPG, because the MPGuino rarely lasts an entire trip without resetting, so it doesn't save accurate tank data.
I was extra surprised this time because it included a couple of longer trips where the car wasn't at its optimal weight or shape (see above pic).
Mods in place for this tank:
(in no particular order)
- MPGuino fuel economy computer
- 50 PSI
- zero-toe alignment
- cleaned & regapped spark plugs (the gap was 0.010 wider than spec!)
- air conditioning delete (removed components)
- power steering delete (belt removed)
- ignition timing advance
- air dam, with...
- partial grille block
- half size radiator, and...
- one of two factory cooling fans deleted
- smooth wheel discs
- taller gearing (larger diameter rear wheels/tires)
- side mirrors delete/relocated inside
- LRR tires on the front, narrower than stock: 165/65R14 Dunlop Enasave
- wiper delete
- synthetic motor oil: 66% 5w30 + 33% 10w30
- weight reduction (goal: 100 lbs / 45 kg is attainable)
- MAF / open loop AFR adjustment
- synthetic lighter weight transmission oil (50% lightweight GM Syncromesh + synth 75w90)
- synthetic differential oil
- WAI - warm air intake
- reduced disc brake drag (serviced calipers/sliders this year)
- tonneau cover
Details of these mods in the build thread:
"MPGiata" modding thread: aiming for 50 MPG with a 1990 Miata
Driving style/environment:
In a word: optimal.
One of the reasons I'm able to get such stellar fuel economy from all my cars is because I'm lucky to live in a part of the world with pretty laid-back drivers and nearly empty scenic rural roads that I usually use instead of the freeways. And I rarely have to drive in busy city traffic.
Almost all the driving for this tank was on MPG-optimal scenic/rural roads, with a max limit of 80 km/h / 50 mph or below. Conditions: warm, dry, and not a lot of wind. Techniques: driving with load on hills, when it doesn't hold up following traffic. Engine off approaching most stops/turns. Maximizing conservation of momentum in curves, because that's so much fun in this car!
Needs more!
It needs more mods: Coolant/transmission heater, springs on the brake pads, lower coil springs, belly pan, rear fender skirts/rocker extensions... I probably won't do anything more to it this year, but with some of these additional tweaks, it seems like a 55+ MPG tank (4.3 L/100 km) is a realistic goal for next year.