Terrible MPG
Thread Starter
Intermediate
Joined: Dec 2011
Posts: 27
Likes: 0
Terrible MPG
I just got a new engine in my 76 and it is a 355ci. It has a lot of horses but the gas mileage is seriously terrible. Like my 20-25 mile round trip from home to work sucks up 1/4 tank......This cant be for real right? If so i guess thats the price you pay for driving a classic. I love my car but that thing drinks gas like we breathe air!
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
if you're idling the whole way or driving like Bondurant it may make sense... otherwise you've got an issue you need to chase.
Could be lots of things:
1. worn bearings
2. transmission issues
3. faulty ignition components
4. carb tune
etc.
If it's an auto with low gearing and no O/D I wouldn't be surprised to see 11-13 MPG on a city commute. This however only takes 2 gallons and shouldn't cause a 1/4 tank drop, more like an 1/8 at best.
Could be lots of things:
1. worn bearings
2. transmission issues
3. faulty ignition components
4. carb tune
etc.
If it's an auto with low gearing and no O/D I wouldn't be surprised to see 11-13 MPG on a city commute. This however only takes 2 gallons and shouldn't cause a 1/4 tank drop, more like an 1/8 at best.
Thread Starter
Intermediate
Joined: Dec 2011
Posts: 27
Likes: 0
I think it stays around 3000-3500 rpms. But i just feels like leaking gas....which i know i most definitly not, but i was just seeing if there was a tweak or part or something i could buy/modify to help a little bit in the gas devouring department
Drifting
Joined: May 2006
Posts: 1,902
Likes: 0
From: midlothian texas
typical white person
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
15mpg should still be consuming a lot less fuel than the OP is seeing.
Hogwild is right on the OD trans. A good carburetor tune is worth a lot of MPG too. There's really no reason to run richer than stoich @ cruise.
Hogwild is right on the OD trans. A good carburetor tune is worth a lot of MPG too. There's really no reason to run richer than stoich @ cruise.
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Thread Starter
Intermediate
Joined: Dec 2011
Posts: 27
Likes: 0
i drove it like an *** at first of course, but i have been driving very conservatively for the past week and it just suck that gas like crazy. My friend came out when it was running and goes "whew that thing smells like it is running rich" i dont know if thats the issue or if that is something that i can fix myself.
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
Changed out the carb to a Summit 600 cfm,annular boosters one piece design.Cost was 239.00,ez to tune runs great no more fuel percolation,19-20mpg on the hiway running a 6spd OD trans.Before the swap I tried to rebuild the existing carb.Had similar issues as you are having now.Poor mpg,rich smelling exhaust,car would run ok but use a lot of fuel.Here's the writeup.http://forums.corvetteforum.com/c3-t...or-review.html
Demon has released a new street carb,looks like an modern Qjet
[IMG]
[/IMG]
If the Demon was out when I was looking for a new carb, I would've tried it.However the Summit carb is a great buy at almost 100.00 less!
Demon has released a new street carb,looks like an modern Qjet
[IMG]
[/IMG]If the Demon was out when I was looking for a new carb, I would've tried it.However the Summit carb is a great buy at almost 100.00 less!
Racer
Joined: Mar 2009
Posts: 394
Likes: 1
From: Everywhere US
If you're smelling fuel, you're probably running way rich ..... may be able to jet it down .... or you may have too much carb ...... what';s on it ????
whats your location ???
whats your location ???
Last edited by LastC3AZ; Sep 28, 2012 at 01:59 PM.