You guys aren't even trying hard. Near my house, there's an exit ramp that covers two off-ramps. If I pop it in neutral, I can coast for a 1/4m.

My instant goes up to 99MPG....slackers.

 

MPG who cares? When it is real good the fun factor has to almost be in negative numbers..sigh.. I only care there is enough fuel in the tank to get me to either where I need to go or the next gas station along the way with some margin of safety getting there.
Dave

 

Here is my best, 25 MPG on the hi-way 75 MPH ---12 MPG driving around town

 

If that's what you are claiming as AVERAGE mpg you might want to have the computer checked or try a manual calculation.

There is no f**king way a C5 Corvette averages 40 mpg. Period.


I say that as someone who has had my *** in the driver's seat of one daily for the last 7 years.


My 96 averages about 9 mpg.

 

100 mile commute across the wide, (mostly) flat, boring Sacramento valley, from on ramp to off ramp, and back, 28, 29 mpg with a 96 LT4, six speed. lot depends on traffic and being able to hold a steady ( legal 65 mph) speed, (1700 rpm).

 

I guess you guys didn't have the patience to watch the entire video from start to finish. That is on a bridge using the long, flat section as a mileage test. I also did a steady state (65 mph +/- 1 mph) run down 101 from Belmont to my job in Santa Clara and AVERAGED 36.6 for that run.

There is also this:

http://forums.corvetteforum.com/1577610806-post1.html

The LS engines get MUCH better mileage than the C4's do. I put 28K on mine in 13 months and it did very well the whole time. If you drive it like you stole it anything will suck down gad like there's a hole in the tank.

While I agree that the DIC numbers seem high, why is it that everyone trusts all the other information from the DIC but everyone screams BS when it comes to mileage? Even if it was 10% high, that's still GREAT mileage for a car with that kind of performance.

 

It's simple really... claiming 40 MPG average from a C5 IS BS.

C5s get great mileage for what they are. I don't think many will argue that, but they don't average anywhere close to 40. Again, I say this as someone who has driven C5s daily for the last 7 years. Do the math. It isn't hard. Figure out how much gas you put in the car and figure out how many miles you went. It takes about 10 seconds to calculate when you fill up.

 

Because its hard to argue with "facts".

Do your mileage test the way I stated above, and post the results.
Fill your tank up, and drive until almost empty. Then fill again, recording the gallons used and miles traveled.
Divide the total miles traveld by the gallons of fuel used.

Anything other, and you won't be getting real world numbers.
The "Instant" reading is completely useless. Because in the next instant (like going up the other side of the hill you were going down), that reading would drop down into the single digits or low teens.

The "Average" reading is pretty accurate, as long as you don't reset it for a few tanks of fuel.
If you reset it, and only take a short trip on flat interstate, then it also won't be a true reading. It will only be an average of those few miles you traveled.

Reset it, and then go through several tanks of fuel without reseting it and see what the average reading is.
The longer intervals you go between resets, the more accurate it will be.

Bottom line, it will cost you "X" amount of dollars in fuel costs to drive your car for a year.
You shouldn't be too concerned what it costs you to drive down a level interstate for a few miles.

 

C5 fuel mileage on the DIC is pretty notoriously inaccurate for some reason...

My Z06 is a good 15% low usually, even after 5,000+ mile sample sizes. My friend's C5 reads just the opposite and is usually 15% high.

Go figure.

 

In addition, I would suggest that one calibrate their odometer beforehand. Like any of the gauges on the car, the odometer can be off which will affect the manual calculation of gas mileage.

 

My 94 averaged less than 5.5 at Laguna Seca this last Monday, it was probably that steep hill

 

anyone know the mpg for a 1984 corvette? mines not running at the moment so i cant find out myself.

- I just found 13 city and 20 highway http://www.fueleconomy.gov/feg/bymod...Corvette.shtml

does that sound right to anyone who knows from experience?

 

Cant wait to get my first Corvette .(2012-13 GS convertible 3LT).My Cobra gets11 mpg if I have fun ,or 13 to14 if I don't .I always have fun .625HP

 

Dont feel bad think my 383 with a 6 spd combined may still be in the single digits


Funny how people get 5+ more mpg than the GM did guess they forgot to test them.

 

At a constant 55mph with the top off I got 27.5 mpg.

At a constant 55mph with the top off I got 35.2 mpg!

Coming back from mountain carving, I got an average of 31.5mpg with about a quarter of it at 70+mph, another quarter at 60-65mph, and the rest at 50-55mph I got 31.4mpg

 

I have gotten #'s like that to on my gauge, But in reality it was more like 22 mpg. The gauge does not show actual mpg.

 

The guage isn't always accurate, I agree. But I have actually gotten over 30mpg by dividing gallons by miles on the tank.

 

If we are going apples to apples here,

my 57 chevy truck has an 89 corvette 350 with a carburetor on it currently. The carb is a Holley economaster. I have an MSD distributor, al-7 box, set at 9 degrees advanced.
The cam is a 350 ramjet roller cam, same as in the HT383.
The rest of the engine is stock with a std. bore and moly rings.
Running a 92 firebird serpentine belt system with power steering and hydroboost and the stock 92 firebird alternator with reverse rotation water pump, electric fan.
My tires are 27 inches tall, with a 3.42 rear axle ratio. The truck weighs 3700 lbs without me in it. (add 160 for me)
my trans is a 4+3 out of an 85 corvette.
I put 7 gallons in it and I can go 200 miles. 200 divided by 7= 28.57 mpg
at 75, the tach is at 1750.
This is do-able for your truck.
When I put the TPI on it, I will expect to see another 3 mpg.

My last engine was a 327, and the engine had to work harder to get the truck moving and keep it moving. I now get about 9-10 mpg more than the 327.

 

I purchased my '84 (auto) new. 12-14 MPG was the range for around town driving, and 18-20 on the highway, assuming 70-80mph on cruise.

The variance was due to traffic conditions, time of year, and a/c usage.

After being brought out of storage (for the past 15yrs) the mileage range seems to be the same. I have driven it about 500 miles in the past 6 weeks. All calculations were done by miles driven divided by gallons consumed. Enjoy your ride!

PS. I also can get some astronomical mpg numbers on the DIC by accelerating to 100mph+, sticking her in neutral, and coasting down a big, long hill!

 

I haven't seen the 40, but the others might be about right.

I have had pretty good luck with highway mileage on my Vettes. In central Illinois the roads are pretty flat and that helps.

In my '94 6M I would get about 31 on the highway and my mix of driving still averaged about 28. I was commuting about 100 miles per day and most of it was highway and interstate so biased to the highway economy.

My C5's get a couple mpg better than my '94 on the highway. I frequently average about 33 highway.

I have a slightly modified '99 6M also. It has a FAST intake, Vararam, LG longtube headers and X-pipe with a B&B catback, and a tune. I was using it to run for some parts this summer and decided to make a "mileage" run. I went to a town south of here and back (Clinton), then to a town northwest of here and back (Peoria). I put the cruise on at speed limits (55 on the highway & 65 on the interstate) There was some road construction for a few miles (maybe 10 miles) that I slowed to about 50. The average on the DIC was 37.7 mpg for that 175 mile trip. I ran into town (Bloomington) and filled up later in the day. The total for the day came out at 36.1 mpg calculated by the miles divided by the gallons on over 200 miles.

That was higher mpg than normal for me since I was driving slower and not using much throttle while trying for best mileage. I agree the DIC on my C5's is usually optimistic by about 1.5-2 mpg, but even real fill up calculations showed it was great.

So I don't think that mcm95403's mileage numbers are way off. In certain conditions I think they could be pretty close. Mine did some remarkable numbers too.