EA81 Gas Sipper

[3eyedwagon]

I just picked up an 86 GL Hatch Hi/Lo, and I was looking for any and all tips on getting every single last mile per gallon out of it.

 

The car is bone stock, with the Hitachi, and I intend to keep it that way. I'm not going to do a weber or anything (for awhile), as it has plenty of power to turn the stock size tires. I drive along ways nearly every day, and a little better gas mileage would be a big plus for me.

 

I'm going to start with the obvious. A good quality part tune-up, check the timing. Some carb clean, etc. Tire PSI, and whatnot. I know all the obvious little stuff, but there has to be some good tricks for these to get a little boost.

 

If anyone has any little tips on squeezing every last MPG out of one of the EA81s, give me a hand. I can get every last bit out of a small block Chevy, but don't know all the little tricks for the flat 4s.

 

THANKS IN ADVANCE!

[Ginger48]

Advance your timing until it pings under load at full throttle at low RPM's, then back it off about 2 degrees.

 

Inflate your tires to 40 PSI but only if you don't live on a rocky dirt road. Rocks are very hard on tires that are over inflated. Many websites advocate inflating as high as 50-55 psi but I personally don't recommend it.

 

Rejet your carburetor -10% to -20% on the primaries (total jet area)

Watch your spark plug color when rejetting. Don't let the color get any lighter than a very light tan or off white. You don't want a melt down by going too lean.

 

Drill out the primary air bleed to 0.002" larger than stock.

 

Purchase and install a brass float. They are available from Advance Auto Parts.

 

Drive like there's an egg between your foot and the gas pedal.

 

Keep your highway speed under 60mph.

 

If you do the above and your engine is in good condition, you'll see 40+ mpg highway.

[[HTi]Johnson]

I recommend using techron additive or chevron fuel...it added 3 mpg to my car.

[Ginger48]

One more item.....run narrow tires like 165/80R13. Narrow tires have less rolling resistance than wide tires.

[hatchsub]

Replace both fuel filters. Also check/clean/replace your PCV valve. Sounds like you got everything else covered. Im assuming your tuneup will include an airfilter?

[3eyedwagon]

Thanks for the help guys!

[Uberoo]

if you can why not adjust the suspension down so the car sits lowers and presents less of a target?

[backwoodsboy]

Try a little do-it-yourself water injection (there are plans on the 'net everywhere)

 

Ive done it to quite a few of my rides. If done right, you can run your engine a little leaner, and advance your timing a little more.

[ferox]

It doesn't make a huge difference on these cars, but if you are trying to eek out every bit of MPG you can install a fuel pressure regulator. The one on my '81 hatch is set at 2.5 psi. It's been on there so long I can't remember the performance difference. Since the pump on your car is in the back (mines under the hood), it will probably make less of a difference as far as smoothing fuel pulsations, which aren't huge in these cars to begin with. I think it's just generally recommended for carbed cars anyway, and it's an easy install. The cheapies aren't so cheap anymore, so I would go with a Redline or something that has a rheostat type dial vs. the set increments, so you can dial it in precisely.

[robm]

Tire pressures. When these cars were built, tires carried their load at 32 or 35 PSI. Now, the same size carries the same load at 44psi! Don't ask me why, but that is what the sidewalls say. My most recent set of tires say 51 psi!

 

To me, that means if I put 28 PSI, in those tires, they will be underinflated.

 

More to the point, if you put 40 psi in a 44 psi tire, it will probably be just about right.

 

Any tire techs out there to bear me out on this?

 

Rob.

[hatchsub]

I never run the maximum pressure that it says on the tire. I usually go a few below like you said. My car is running 40 on all wheels cause it feels about right. If the tire gets warmer as well the pressure expands so thats my reasoning behind not filling it all the way.