QCVette

Wow these are great cars.

I had to run to get some parts today and decided to make it a mileage run since the parts were in stock in two other cities. I just behaved a little and set the cruise just over the speed limits (slower than normal). I ran about 175 miles with a little over half interstate and most of the rest on a 2 lane highway. I made 3 stops for parts and 1 stop for lunch. All of them were pretty close to the highway.

When I got home the DIC showed an average of 37.7 mpg. That was a little optimistic though, but when I topped off the tank and figured it, it was still about 36.1 mpg.

It amazes me that these cars can run so good and still get mpg that rivals a lot of economy cars.

Vetteman Jack

I don't think I've seen one get 36+ mpg, but with the 6 speed it's not uncommon to get 30+ mpg from the car. It sure is nice that GM decided to make the C5 an economy car.

robert miller

But the next time you go with this route, Fill the car up mark the miles when you get back from your trip fill back up and do the math to it. Robert

jsbzoh6

If its straight and steady I've seen an accurate 35mpg going 70MPH. I'm sure there's room to get 37+ under the greatest circumstances.

The fact I posted that in regards to a 350+HP 5.7L V8 sports car is truly incredible.

Brackneyc

Wow, the mileage these things get keeps climbing. Impressive. Even Detroit never claimed 36mpg.

Edmonds only claims 28 with a manual trans.

TC_1961

I just did a road trip and best I got was 27 with a 6m....I have a hard time believing 37.

Brackneyc

That is about what I got. I wish I could get 700 miles out of a single tank.

QCVette

That is what I did. That is why I said the 37.7 was optimistic and when I filled it up I calculated 36.1 mpg.

After I filled up, the range on the DIC showed 697 miles. I'm not expecting that much though, and I don't usually drive that "tame".


It is a 6m with a Vararam, FAST intake, LG lontube pro's, Catless X pipe, B&B Route 66 mufflers, and a tune. Other than that it is stock.

pleadingbark

I was doing 33.8 with mine the other day with an intake and front tires at 36psi and rear at 40. I bet if I pushed them to 40/42 I'd get 35.

Evil-Twin

Me too! and especially in the summer... now if you are talking extremely flat terrain and close to sea level like in New Jersey , in the winter where air is much more dense, 33 MPG is attainable..Never saw anything close to 37 in Michigan when we were developing this car and trying to breach the guzzler tax.

scott1094

Welcome back E.T.. You left the forum just as I arrived. I hope you will again give us the privilege of your vast knowledge on these wonderful automobiles.

Scott

Na4now

My car, running 75-80mph (6 speed w/ 3.42's) gets right around 24-26mpg (hand calculated), ....and although Im nowhere near stock, the engine just has a mild cam/fast 102/headers, ect.

Im hoping that once I have it dyno tuned, the mileage will improve a bit. If I could get 28mpg highway, Id be so stoked.

......Power to hang with 600cc sport bikes, and economy like a Civic. Cant go wrong with that!

dreww

Who can crusie at 70mph in 6th and not bog down?
I rarely hang in 6th unless 80mph or higher.

Dunno if its due to mods or z51 gearing.

ksvette74

I beleive the z51 is just suspinsion, nothing more (could be wrong on that) as far as gearing goes, the guy that is cruising at 70 in 6th sounds like he has switched his rear end out. This would cause the rpm's to be a bit higher, thus preventing it from bogging. usually that type of switch will decrease mileage, but under that circumstance could increase it for that speed, as well as increase the over all acceleration.

DeeGee

I reset my average mileage as I set off yesterday. I ran a 25 mile leg at about 50 mph. All gentle driving on flat roads with only one overtake and gentle throttle in easy flowing traffic. The absolute best I got was 26 mph.

A4 with 3.15 rear end.

There's absolutely no way I could ever get 36 and with gas at $8+ a gallon I wish I could.

Greg MFn Z

I have a LS1 powered C4 with the ZF 6sp and at 70 MPG I'm cruising at 1400 RPMs

DeeGee

Now 70 mpg at 1400 revs would be a record

c5chines

With the known fuel gauge problems I wouldn't trust the dic's calculations at all. I can fill up and show low fuel a block down the road and stay that way until the POS starts working about 1/2 tank.

RetiredSFC 97

I believe it. If your trip is mostly flat terain like randy's was and half of it is on 2 lane roads with a lower speed limit and mostly all highway I don't doubt it.

This is my DIC readout from the Power tour this year. A lot of interstate driving and 2 lane roads with some spirited driving mixed in.

I haven't done a calculation yet but from just glancing at my receipts and mileage I wrote down I would say it's pretty close if not exact.

RetiredSFC 97

I drive in 6th all the time and pass other cars and don't bog down. But if I want to really get with it I go to 5th or sometimes even 4th.

But mostly I stay in 6th. But if you're in hilly terrain I can see not hanging in 6th.