5.7L -> 2.0L MPG N00B checking in!!!

[BlownEarDrums]

Hello, this is my first time attempting to modify a car for more MPG not HP . I have a 95 Caprice Impala SS clone and a 98 Escort ZX2 5spd. The best MPG I have managed to get out of the escort is about 28MPG with about %80 highway driving. I"m hoping to squeeze about 35 out of it. The forums look good with a wealth of knowledge. I'm hoping to find out just what RPM to drive the car at on the highway since the car screams at 3200 at 70MPH. Hopefully some people on here have modded the ZX2. Anyway, hope to get some questions answered here. Thanks, hope to hear from some of you on the forums.

Brad.

[SentraSE-R]

Welcome to EM, Brad. You're going to get your best mpg down at 2000-2200 rpm, where your Brake Specific Fuel Consumption map gives peak fuel economy v. power. For your gearing, 2285 rpm = 50 mph. That's pretty convenient in terms of aerodynamic drag, too, as you're below the major drag hit that comes above 55 mph. Unfortunately, 50 mph is a bit slow for freeways, but you might try finding some country roads with 55 mph PSLs, and see what your Focus can really do.

My wife had an AT Focus that got 26 mpg at 72 mph. It got 36 mpg at 55-60 mph. Slow down for a tank, and you'll see 35 mpg.

[Tygen1]

There are a couple of us ZX2 guys here. You can swap in the Escort Sedan 5th gear to bring you highway rpms down a little lower, search TeamZX2.com for the swap instructions. I am ATX so I don't suffer from the excessively high highway rpms.
The ZX2 is a very capable mpg car, check my gas logs. In pure highway driving I expect more than a 50mpg average and 30+mpg in the city. On my typical commute to work I expect 43mpg. I started out in the 28mpg range with my car also.

For mods, I'd suggest a grill block to close off 80% of your lower grill. A Home Depot 5" lawn edging front air dam under the bumper and some rear wheel skirts to round out the aero package. I'd estimate those mods have benefited me by about 4 mpg on my commute.
Under the hood I wouldn't worry to much about performance mods. Just toss the stock cold air intake, it's drawing from behind the fender. Cut off your snorkle and tape up that fender hole so you can pull in underhood air that will be warmer than ambient. It would be good to try and get warmer air, in the 120-140 range would be best if you can find a way. Pull the plug on your knock sensor, do it right now and enjoy, it's free, safe and easy, again see TeamZX2 for instructions. A scangauge will pay for itself, buy one and enjoy the ride.

Edit: Oh yea, slow down!!!! I average 50mph on the highway, it is a great benefit. Just do this safely.

Welcome to Ecomodder!

[BlownEarDrums]

Some great info so far. I wish I could "safely" slow down. Here in Miami, the average highway speed is about 75. Everyone speeds. When I first got the car I thought I was going to die because it was such a huge difference from the v8 ex-daily. I used to go about 80-85 in that for its best economy. I will try to slow done this week and see what happens. I'll have to leave at about 5:30 if I do 50. So I think I'll beat most of the traffic at that time. Now is it safe to pull the knock sensor after letting the engine run hotter and take in warmer air thus running leaner? I know that the PCM will use the knock sensor to pull timing if the sensors senses detonation.

Thanks for the info, Keep it coming!

[moorecomp]

Glad to have another ZX2 on the forum. The knock sensor being disconnected will not cause any problems. Lots of guys over at teamzx2.com have done this and have had no issues. Ford even recommended this be disconnected on a TSB. I have had mine disconnected for over a year, run the cheapest 87 octane gas I can find, run a warm air intake and have never had any knock issues. Tygen and I have even been experimenting with a controlled air intake leak to force our engines to run lean and still no knock. I drive 52 miles one way to work and it has many ups and downs and average over 40mpg in the summer months and am doing 34 to 36 in the winter. I am not doing any EOC now because of the icy roads, and the winter blend fuel combine for most of my losses. I have an MPGuino installed and have found on my car that I get better mileage at 57mph than I do at 50mph. I guess it is to do with fuel schedules in the ECU. When the snow melts here, I am going to do some more aero mods and make a better WAI. Good luck.

[redyaris]

What I did on my car [Toyota Yaris] was use clothe dryer 3 inch aluminum flex vent hose to duct hot air from the exhaust area to the air filter box. this vent hose cost about $5.- I get 140F intake air temperature with this system according to my scan gauge II with ambiant air temperature at 85F. You may want to install some form of temp monitoring system before you modify.

[Tygen1]

Reducing speed will probably be the most important, ie. highest percentage improvement. Try following what Moorcomp said. The vacuum leak thing is a more advanced thing, but it has been very effective for me.
Now go outside and pull that knock sensor. I've had mine pulled for years with only side effect being Joy!
There are some cheap to free performance mods on teamzx2, you can do them and not suffer any mpg loss and you will gain some driving pleasure.

[ex-x-fire]

Make sure the tune up parts are good, clean your maf senser, & make sure the engine has a good t-stat in it. Cooler running efi engines use more gas. Have your injectors cleaned, I got a canister inj. cleaner set up, total investment under $150, most shops that I know charge around $100. When I first started doing my car & truck my neighbor asked what I was doing, I ended up doing his too, made some $$ back.

[90crxHF]

I'm interested in the controlled air intake leak...