my official mpg test.

[Roboskittle]

We are talking about strictly highway miles right? I just don't see myself ever getting mileage like that unless it was on a cross country trip.

Mine was mixed driving but the majority of it was highway.

[Oren09]

If you're using premium you might as well bump up the timing; might get better mileage that way too.

How do you do that? I don't have any experience with ignition systems.

[batstiva]

For some reason, MPG seems to go down when you put a turboed B6 in place of the stock motor.

Odd. That statement almost seems to defy logic.

Under real world conditions (read me driving whatever speed I happen to be going:-D) My 89 carby 4 speed seems to average somewhere between 42 and 45 mpgs. Meant to chart mileage to OSX, but too lazy to actually write down mileage at fill ups.

[Evil D]

Ok so someone tell me what i'm doing wrong...i've just done a full tune up...what more can i do? If there are people getting 40+mpg with the same car as me (the above post being my car exactly... an '89 4 speed carby) then why am i getting 30ish at best?

[neanderpaul]

I've seen several carbys that got around 30. Every single one was really quick for a stock festiva.

[Pu241]

If there are people getting 40+mpg with the same car as me (the above post being my car exactly... an '89 4 speed carby) then why am i getting 30ish at best?

Timing correct?
Long idling (going nowhere)?
Wheel squealing starts from stop signs and stoplights.
High speed driving style?
Carry excessive useless weight in the car?
Low tire pressure?
Lots of short drives?

Larger than OEM tires makes ODO read short of actual miles, thus calculations of MPG are low.

How many tanks of fuel is this 30ish figure based on?

[batstiva]

^^ In all honesty, mine is not stock carby. Mine is sans all of the vac lines/sensors/all that emissions stuff. Don't know if that should help or hurt my fuel economy, but I'm guessing it helps. My 88 carby only averaged between 35-38. So I'm guess not having all that stuff hooked up must help.

[econoaddict]

I drive 90-100 miles a day, 5 days a week, almost all freeway.

My 88 B3 5 spd would get an easy 45+mpg regularly, no special driving- just go with the flow. Stick at 55-60mph and get 55+mpg.
The B3 died and I put a B6 in its place, carbed and now can't get past 31mpg no matter what I try.

I picked up a 91L B3 injected (of course) 5 spd and so far I have managed a best of 57mpg.

Honestly if I can see 40-45mpg I am a very happy camper.

[DriverOne]

I've also been experimenting with Premium gas. I know the higher octane won't really help the fuel mileage, but at the Exxon station here, the Premium doesn't contain ethanol. I seem to have gained a bit of mileage, but nothing significant. I'm about to switch back to regular (10% ethanol) and see if the mileage drops.

Gas logs: http://www.fuelly.com/driver/oren09/festiva

You've entered into the long-time dispute! I personally have found that both my cars get much higher (close to 30% higher) fuel mileage using non-eth gas, if it is truly non-eth. I've run across a few pumps that said non-eth, but they were also pumps that pumped ethanol so you never quite get 100%, and so it's almost pointless to buy there. My Saturn kept showing codes on the dash, and the Check Engine Soon light. I took it to the local muffler shop 'cause I figured since everything else was in great shape, my O2 sensors or cats were bad. Neither. What the shop told me was that many cars can't handle the ethanol-laced gas and to search for and run solely non-eth gas. He pointed me to Lindsay Oil Co. in Seneca, where I've been filling up, and I found a non-eth station a little closer to home, so I have two good options. Bottom line: No codes. No problems. More HP, more fuel mileage. Enough that what used to take half a tank (Clemson to Greenville, 65 mile round trip) now takes a little over a quarter tank (10 gal).

I've seen several carbys that got around 30. Every single one was really quick for a stock festiva.

Mine's carbed, gets 37.6 mpg, and will SCOOT. B3, baby!

[bhazard]

Another mid-39's tank for my b6t.

[Evil D]

Timing correct?
Long idling (going nowhere)?
Wheel squealing starts from stop signs and stoplights.
High speed driving style?
Carry excessive useless weight in the car?
Low tire pressure?
Lots of short drives?

Larger than OEM tires makes ODO read short of actual miles, thus calculations of MPG are low.

How many tanks of fuel is this 30ish figure based on?

Well i definitely don't beat on it...my other toy is a 420hp '85 Mustang so there's not much of a speed fix driving this car lol. I do have probably 75lbs of tools in the trunk. Tire pressure is spot on. I do drive mostly 7-8 mile trips to and from work though. I've ran out 3 tanks so far...32 on the first and then switched to 13s and got 28 and 29 (of course being a little off due to tire size).

^^ In all honesty, mine is not stock carby. Mine is sans all of the vac lines/sensors/all that emissions stuff. Don't know if that should help or hurt my fuel economy, but I'm guessing it helps. My 88 carby only averaged between 35-38. So I'm guess not having all that stuff hooked up must help.

Whaaaait a sec...i was under the impression that all those hoses and emissions junk couldn't be removed?? If i can ditch all that crap plugged into my carb...i'd be super happy. I have no echeck and my philosophy is less equals more so the more i can get rid of the less there is to go wrong. Where can i find info on removing all that stuff?

[TominMO]

I drive 90-100 miles a day, 5 days a week, almost all freeway.

My 88 B3 5 spd would get an easy 45+mpg regularly, no special driving- just go with the flow. Stick at 55-60mph and get 55+mpg.
The B3 died and I put a B6 in its place, carbed and now can't get past 31mpg no matter what I try.

I picked up a 91L B3 injected (of course) 5 spd and so far I have managed a best of 57mpg.

Honestly if I can see 40-45mpg I am a very happy camper.

Carbed B6? So you put the B3 carby manifold on the B6? Try switching to a Weber or Holley/Weber. You should get more power and more mileage too.

[econoaddict]

Carbed B6? So you put the B3 carby manifold on the B6? Try switching to a Weber or Holley/Weber. You should get more power and more mileage too.

Would love to try a weber but before this swap was started money was tight and then the swap ended up costing about $400 more than planned for so now its beyond tight.

I know a weber would be a huge differemce in power, mileage and runability.
The B6 being FI has NO provision for the egr valve so all the egr/feedback stuff is now just along for the ride plugging holes.

[ghosthunter242]

my yaris went from 39.7 mpg average down to 31-33mpg once the ethanol e10 was mandated here. there is only one place i know of and it is in springfield oregon that sells straight non corn gas and it is 80 cents more. but, it is for exemptt vehicles. my charger is exempt but the festy is nowhere close. the charger runs so much better on non e10 gas. the yaris hates it too. i have found (cue boos) that the shell with nitrogen(a joke?) premium got me in the 35 to 37 again in the yaris. i am hoping i can find a non corn based station on the dumball rally. we're leaving portland-ish oregon and going to ....orofino idaho, then to bozeman, then to jackson hole.
any suggestions of gas or food?
thanks!!
mark

[bhazard]

Try running 40 psi in the tires (or whatever the max sidewall is) instead of what the door sticker says... and coast coast COAST. The more you use your brakes the more momentum you waste.