Noobie ready to start his project - first post/question!
 

First some background - My wife and I are in a Miata club and for the past 5 years I have been working on Red Beast (https://www.lightweightmiata.com/ ). She is a '91 Miata with 400 pounds of weight removed and 150% more horsepower. I am growing tired of the project and I would like to move on to something else. I think an 70-80MPG car would be just the thing to keep me busy for a while. I have regularly visited this site for the past few weeks and have spent the past 2 hours reading quite a few of the old threads. Anyway, for my first official post I want to ask a question:

I think an old Geo Metro would fit my project just fine. I see that the XFI's get really good mileage but they do not have OBDII or fuel injectors. I think part of the fun of the project will be keeping tons of data from a scangauge and fuel injectors don't scare me like an old carb does (you can clean injectors but I can't work on a carb). Anyone have any advice or guidance concerning starting the project with a 50MPG '91 XFI vs a 35MPG '97 LSI?

Is there a better car to start with? I am trying to locate my wife's old Chevy Sprint Metro that we sold for $250 about 8 years ago. The car probably doesn't exist (rusted out or crushed) but it would be fun to start with that one.

Anyway, thanks in advance for the help. Hopefully you guys will see more of me if I actually get started on this thing. As you can tell from my website, I have no problem documenting everything that I do and posting it.

I can't speak to the advantages/disadvantages of the car you choose. Yet you have to keep in mind that cheap and free are at the top of my list when picking cars that get high MPG!

I do suggest considering running your car without an alternator connected. I have had great success doing this on my Jeep. The Jeep has a range of 45 miles on a Group 24 Gel-Cel and the electricity required to top it off is a fraction of the fuel cost!

Good luck with your project and remember to take pictures of your work often!

Yes, that is something that I am very interested in doing. I have thought of a two battery setup (not sure what capacity I will need) with a built in plug on the car to do the charging when I get home.

there is a guy on here "metroMPG" that is getting unbelieveable mileage. he has also done some radical modifications to his car to get there. I think the wildest was a transmission swap but he got really good gains from doing it. this may be the secret to getting the gas mileage that you are talking about.

my first car was a '93 geo metro with 3cyl 5spd and power nothing (maybe breaks) I dogged the crap out of that car. when I got rid of it in '99 I was still getting 46mpg.

that guy metroMPG has a web site www.metroMPG.com he also talks about a car that got 75 or so mpg he has a pic or a link to a pic where the guy actually cut a metro in half long ways and reduced the drag on the car. it is weird looking but it got great mileage.

being a long time metro fan, I thought it was kind of cool. I had two, a '93 and a '97 they were both good on gas and both hatchbacks.

I don't know how feasible it would be, but how about converting the older xfi to fuel injection with a megasquirt? That'll keep you entertained for a while, eh? :)

That would be nice, but I think that is WAY over my head. I could probably handle the megasquirt part, but machining the engine to handle the FIs is something that I couldn't do. It would be interesting to see the results.

Why not use throttle body injection then?

An adapter to put a tbi on a carb manifold could be made from a piece of aluminum plate with a saber saw and a drill press if you are careful and take your time..

As long as you aren't worried about pollution a tbi might even get better mileage than a more injection system.

You have my attention. I was thinking of putting TBI on my 1980 Buick LeSabre V6, just because it would be easy. Now I have another good reason.

It seems to me that a tbi might actually have better air/fuel mixing than a more sophisticated (the word I left out above) injection system because there would be more time for the fuel to vaporize between the injector and the combustion chamber..

If you made sure the intake manifold was heated that would help too.. I've read on another forum that preheating the gasoline before the injector helps a bit. Vapor lock is not a problem in injected engines.

Considering you have a small, lightweight car with a low drag coefficient you may want to start with your miata (or another one). A lot of the stuff that makes a car fast on the track, can net you good MPG (low weight, lowered suspension). Detuning the engine and a few aero tricks[1] to further improve it's CD would likely net impressive results.

[1]A teardrop shaped hardtop springs immediately to mind.