Greetings from the Great American Desert
 

I hail from the corner of Kansas, Oklahoma, and Colorado. Flat, sparsely populated, and d### far from any big city. Nearest WalMart is 45 miles.

Just replaced my last project with a '96 Ford Escort LX. 1.9 engine w/ manual transmission. The last second gen Escort I owned was a '91 Pony model, got 39-41 mpg highway regularly. Where I live, almost all driving is two lane 65mpg highways, so this project is meant to be an efficient, reasonably comfortable long-trip highway traveler. Which means a/c is mandatory, but p/s and electric windows are completely unnecessary.

I took a 700 mile trip this past week, one leg was 39.7mpg(!) but that was probably tailwind induced. Average mpg was 37, with nothing done but oil change, new plugs, new filter.

Looking at the following basic mods:
lowering car
front air dam
Seal front fascia (BIG gaps between headlights and bumper/grill)
Wheel discs on taller wheels/tires (175/65-14 to 185/65-15 Goodyear Assurance Fuel Max) (If I put 2" shorter springs on I'll still be 1.25" closer to the ground)
MegaSquirt engine control w/wideband O2 (this will be my third MegaSquirt, first time playing with wideband)
Advance cam timing to lower power band
de-power power steering
underdrive pulley for alternator, a/c, since almost all miles will be at 65-70mph.
I'm gonna be happy with 45mpg, and do backflips if I can approach 50mpg regularly.

I'm gonna first establish some baseline coastdown numbers as soon as I figure out the most consistent way to do that. Kinda playing with using an Arduino board to build a coast-down data logger. Shouldn't be too hard to pull a vss signal out of the OBD-II socket. Anybody else done anything along those lines?

I like what I see here. You guys know a lot about what I'm gonna be looking for. Happy to be here!

I think you're on the right track with most of your ideas.

Have you considered changing your differential or 5th gear instead of tire size? Taller tires, when done within reason, don't seem to make a big difference for gearing/highway RPM on a small car.

Welcome to the site.

Welcome!

You might try data logging using Processing on a laptop rather than trying to use the Arduino. Very similar languages and I've become a huge fan of the pair. Alternatively, you could just grab the data from the Arduino and send it to the computer but the VSS is a 12v sensor like the computer serial port and the Arduino is 5v.

AFAIK the 5th gear and the final drive in this trans are the highest available. It's the same trans that Mazda used for several models with twin cams and higher rpm range, so the only gears that swap are actually lower (higher numerically) than what I have. Yes, I only have room for tires that are ~7% taller, but that is 7% more than I have now.

7% is better than 0%. :thumbup:

Oh, wow. You are my hero for the day. I knew there had to be something out there, and since I'm a Linux user, I assumed it would be open source, but I just hadn't found it yet. Gonna start playing!!!!

btw, my familiarity with the arduin board is because I'm using one to develop a freestanding egr controller for my latest MegaSquirt project.