Need help with gas milage
 

hey guys, well, I've got a 78 and I'm looking to get better gas milage out of it. right now I'm getting between 11-12mpg. now I know that there are others out there getting 16-17mpg. my setup is stock right now.

My question is, what do I need to do to get better gas mileage?

Re: Need help with gas milage (I_want_a_C5)
 

need more info :thumbs:

Re: Need help with gas milage (I_want_a_C5)
 

what kind of more info. I know that the air filter needs to be replaced. I know getting a free-flow exhaust will help HP but will it do anything for milage? to be honest, I'm not extremely mechanically inclined especially when it comes to tuning, and such to maximize. so tell me what kind of info you need to help me and I'll try my best to provide it.

Re: Need help with gas milage (I_want_a_C5)
 

ok, you need to give us specs on the engine, carb, etc..

if you have a really big carb, you might consider going smaller..

how's your fuel pump?
spark plugs and wires?
what about fuel filter?

maybe you have really short gears.

any of those will help on gas

Re: Need help with gas milage (Corz)
 

:iagree: is it in (basic ) tune as far as you know ??? trans ? rear gear ?
speed you drive at highways ? all city ? Not try to be a azz need the info!
does it use oil ? (total miles on car) Believe me it's all pertenent (?spelling)\
you may drive "sporty" not thriftyalso, it is a VETTE :thumbs: :lolg:

Re: Need help with gas milage (comp)
 

like I said, I don't know all the specs and such, as far as I know, it's all stock except the engine was switched before I got it from the L-48 to the L-82.

as for speeds I drive, is usually about 45 averaged in city(75%) and about 75averaged on highway(25%)

Re: Need help with gas milage (comp)
 

btw - I'm usually closer to 10-11mpg when I start getting a bit of a lead foot.

Re: Need help with gas milage (I_want_a_C5)
 

OOOOH it deas make a difference :lolg: :lolg: :lolg: :lolg:

Re: Need help with gas milage (I_want_a_C5)
 

Coast More! :lol: :lol: :lol:


Seriously, best thing you can do w/o changing major parts is to do a complete tune up, make sure your tires are at the proper pressure, your wheels are aligned and most importantly step gently on the right pedal. :yesnod:

Anticipate stops, timing them to avoid having to fully stop thus saving fuel by not having to start from a dead stop. If you car is a standard trans, do lots of short shifting, getting into a higher gear as soon as possible. Basically follow all the "standard" driving items for improving fuel economy.

Of course that said this is a vette we are talking about. If you need to drive it like an economy car and your that concerned about a couple of mpg, perhaps you need to consider a different car.

Hope this helps. Good Luck!

:seeya

Re: Need help with gas milage (comp)
 

OK, I started at about 11 mpg in my 72. That was with a 350, TH400, 3.08, and Q-Jet.

Changes made affecting mpg
Performer manifold.
Edelbrock 600 cfm
K & N filter and Extreme filter lid.
1" 4 hole spacer
MSD 6A
Pertronix Ignitor
MSD wires
14 degrees initial and 36 at 2700 rpm.
Adjustable vacuum canister set just retarded of ping.
015 head gaskets for quench
FlowTech Jet Hot coated headers
2 1/2" exhaust with Dynomax Super Turbo's
Aluminum waterpump
Dewitts aluminum radiator and Spal fans
Cowl induction hood with the cowl open,
air conditioning system totally removed.
Derale deep tranny pan for trans cooling.
Minimum toe in wheel allignment.
Carb tuned using an Autometer A/F gauge.

Crusing at 2500 rpm, best ever mpg was 22. More commonly 19-20 mpg highway, 15-17 city.

Better milage can be expected by adding the new Edelbrock RPM 64 cc heads with the quench chamber, roller rockers, and an OD trans. The 200R trans goes in July 5th. :)

Good luck :cheers:

Re: Need help with gas milage (AlwaysWave)
 

thanks alwayswave, that's what I was looking for. I'll start looking at some of those items. Thanks.

Matt

Re: Need help with gas milage (I_want_a_C5)
 

A 200-4r trans has raised my highway mileage to about 28mpg (imperial gallons). Still dreadful around town, but I didn't buy a Corvette to kittyfoot around in the interests of fuel economy :) It seems an expensive way to improve economy, but with the cost of gas here being what it is, I reckon I've already saved 25% of the cost of getting it.
As well as a good tune up, better exhausts, etc, quite a lot of fuel is lost by cruising with the windows down, or top off (according to the manual for my DD). Also, an extra 5% of fuel is used if a roof rack is fitted :jester
Tyre pressures make a big difference. I'm running 35psi all round (255/60 15 BFG's).
:cheers:

Re: Need help with gas milage (UKPaul)
 

UKPaul, you're 100% right about the aerodynamics. Interestingly, I'm using the same tires you are. At 35 psi mine edge wear. Had to change the pressure to even out the wear patterns.