308 Owners - what type of mileage do you get from a tank of gas...

Discussion in '308/328' started by Wayne 962, Dec 4, 2003.

  1. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    I'm trying to figure out where all my fuel is going. Looks like either my gas gauge is off (haven't measured at the pump yet), or I'm getting about 6 mpg around town, which is pretty bad.

    What is everyone else getting? I tried searching the archives, but I couldn't find anything on it (old and new site)


    P.S. VB3 Topics only search is not working...
  2. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    A carb 308 around town will get around 10 mpg sometimes 11 or 12 but mainly 10 around town. Since you are getting 6 mpg there is something wrong. Look for fuel leaks, check your float settings, leaking needle valves, etc.
  3. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    Hmm, it could be 10 mpg, I haven't done a detailed measurement. For some reason, I thought it would have been a bit better. After all, the engine should use only as much fuel as it needs, and if I'm not driving it hard, it should get comparable results to a 911 3.0 with carbs?

    I'll do a fill again in a couple of days to see where we're at. What is expected on the highways?

  4. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    I don't know. All of my friends that have carb 308s don't really do any better than 10 around town. Some say they do but I don't think so. A QV on the other hand will do better than 10 mpg. To be honest gas mileage isn't a very big deal to me on my 308.
  5. ferrarifixer

    ferrarifixer F1 Veteran

    Jul 22, 2003
    Full Name:
    Phil Hughes
    Carb car...6mpg on track, 12mpg city, up to 25mpg touring.

    QV +25%, 328 +20%

    Got 27mpg from fibreglass / sprint pack (genuine 255BHP) engined car while touring Italy. Same car did 7-8mpg on track and lapped faster than 328 around Brands Hatch.

    6mpg in city would indicate very poor fuel quality/octane, or horrendous tune problem...or leak!

    My 512BB carb gives about 5 track, 10 city and 20 touring.
  6. Wayne 962

    Wayne 962 Formula Junior

    Nov 27, 2003
    The thing reaks of fuel about 10 minutes after I shut it off - I haven't quite figured out why? Any thoughts? Fuel leaking from the bowls into the head? It typically starts right up with no problems right after...

  7. tigermilk

    tigermilk Formula Junior

    Jul 12, 2001
    Houston, TX
    Full Name:
    James P. Smith
    I figure it costs me $5-6 each time I commute to work, which is about 45 miles roundtrip. At $1.50/gallon for premium, that's upwards of 4 gallons, so 11-13.5 mpg. There are 6 stop signs and around 13 stoplights. Time to make a 22.5 mile trip is around 30 minutes, so it's biased towards highway miles.

    Oh, and my car smells of gas afterwards, especially if parked in the garage (wife complains and always gets afraid since we have a gas water heater out there). Figured it's just the pool of gas in the bowls in the carbs.
  8. funshipone

    funshipone Formula Junior

    Jan 2, 2002
    Harrison Twp. Mi. US
    Full Name:
    John Bicsak
    Never checked, but maybe I will just for heck.
  9. Sean F.

    Sean F. F1 Rookie

    Feb 4, 2003
    Full Name:
    Sean F
    The smell of gas indicates that the fume recovery system on your carb'd car is probably not connected correctly. Do you see that charcoal canister in the back? Look in the owners manual, their is a nice drawing of the system. You won't be able to see much w/o removing the air cleaner cover over the carbs.

    Smell the passenger side air scoop. I'll bet it reeks of gas fumes. A lot of people disconnected the fume recovery system and simply dumped the lines into the air cleaner cover.

    I get ~10mpg around town. The last few times I've filled up, it took 12 gallons and the trip OD said 125 miles. On the trip home from NJ after I bought the car, 1100 miles, I got ~17mpg going 80MPH most of the way.

    TigerMilk, I'll bet you have the same issue as me, disconnected fume recover system. With a water heater in the garage, you are in VERY REAL danger of starting a fire, unless your heater is elevated 18" or more. Gas fumes are heavier than air and will collect near the ground, right where your pilot light on the heater is. Your wife is correct to be concerned.
  10. Zigno

    Zigno Karting

    19 mpg freeway with some stop and go in 90+ degrees last summer on a 175 mile trip. 1978 308 GTS. Barely half as good trundling around town.
  11. BigAl

    BigAl F1 Veteran

    Mar 17, 2002
    Full Name:
    GSgt Hartman
    I get around 12 in town, can't remember highway.
  12. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Two Time F1 World Champ
    Rossa Subscribed Owner

    May 4, 2001
    Birmingham, AL
    Full Name:
    I can run a tank of gas down to the little orange light in one nice weekend. If I fill up not too long after it comes on I can only put in around 13 gallons. That means it is warning me with 4 or 5 gal left. usually I am around 180-210 miles before the light appears, depending on how much was highway driving. (84 308)
  13. Tennlee

    Tennlee Formula Junior

    Feb 10, 2002
    Great Smoky Mountains
    I get about 10 mpg in my '79 308. I don't really care about the mileage, since it don't collect miles like a daily driver. It is a shame that I have to visit the gas station so often, though. Better than the 6mpg I get in my factory five cobra though!
  14. tigermilk

    tigermilk Formula Junior

    Jul 12, 2001
    Houston, TX
    Full Name:
    James P. Smith
    Sean, thanks for the comment. The water heater is elevated and probably 20 feet away or more from the rear of the car. I typically leave it outside for a few hours before pulling it in.

  15. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    The best I ever got was 17mpg on the open road 70-80mph. I normally get 240 -260 miles on a tank and fill it to the top of the tank. 77 308
  16. Mike C

    Mike C F1 Veteran
    Owner Lifetime Rossa

    Aug 3, 2002
    Southeast USA
    Full Name:
    Mike Charness
    My 308QV gets 10-11 in town, and around 20mpg on highway trips.

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