92SilverSHO

iTrader: (3)

around 12mpg city without getting on it and around 28-30 on highway.

Blackboosted2

LS1 RX7 - Mid high 20's in town and 35 highway. This was when it was a stock LS1. Cammed and bolt on later in it's life it was lower 20's and 29/30 highway.

Vette - 19-20 City 30-31 highway

WS6TransAm01

iTrader: (13)

With 508HP and 4.56 gears on a 275 50 17 M&H DR I am getting 25mph on the highway and around 18-20 city.

Xtreme57

iTrader: (6)

Not to call BS on anyone here, but I'm kind of curious how some of you are calculating your Mpg?

Pocket

iTrader: (22)

Same way you should

Fill tank up 100%, reset trip meter

Drive and refill tank 100%

Divide trip mileage by gallons at last refill

City/highway designation is whatever you were driving on the most with that tank: I.E. if you took a long trip and drove almost entirely highway speeds then you can assume thats a pretty accurate calculation for highway mileage

lazylongboarder

iTrader: (2)

It's ironic but kinda common to see a Ls in the high 20's low 30's!!! I love this motor!!! I went from 16 mpg freeway with the 3.6 (not a typo) Porsche motor to 30+ with over double the RWHP!!! WOOO!!!

I cheat though, not to many street LS cars are under 2600 lbs

DANOZ28

iTrader: (1)

i've posted this challenge before with no takers, fill up, post your milage. then drive around whatever and refill at the same station, same pump and post your milage plus # gallons to fill. LET US DO THE MATH! i dont believe anyone with a V8 gets over 29! PROVE IT! thank you in advance. my hwy best is 25 with an A4, average after the tune is 20.5mpg. i have 2:73s i'm not calling anyone a liar, i just think you failed math class.

LS1Andrew

I get 19/20 City and 30+ Highway.

It's rare that I drive 100% Highway, but I almost always get over 30.
I drove across the country with my car LOADED DOWN, including the passener seat and every foot well, with luggage (I was moving at the time... wheels, tires). I still got 28+.

Every trip to the gas station, I divide the number of miles since the last time by the number of gallons. The next time I use all of a tank on the highway, I'll take a few pictures.

lazylongboarder

iTrader: (2)

I was in a 427 C5 (granted it had little 243's) with 583 whp...35.5 mpg from San Francisco to SLC. It's not uncommon. These are the best motors ever. Lightweight, efficient, HUGE aftermarket, reliable, unlimited HP potential...what more could you want?

lazylongboarder

iTrader: (2)

BTW, check my sig, i'm a conversion guy, i can't find a drawback to the swap...like i said in my earlier post, i was getting little more than 15-16 on the freeway with a well tuned BIG 3.6 horizontally opposed flat 6, i lost over 100 lbs going from the 6 to the v8.

It's not the # of cylinders that makes the motor inefficient, it's the tune/gearing/auto...

Also, the Porsche motor was rebuilt and only had 5k miles. 5,000 miles

javierb14

Just topped off the other day, it took 14.284 gal....previous fill was at 87,257 miles this fill was at 87,526...18.83mpg. Stock '00 SS w/ls1 intake and DIY P&P TB. Could easily get over 20mpg if i drove it easier haha

Xtreme57

iTrader: (6)

Some of the highway stuff I believe. I think that 30+ highway is not an easy task, but in some instances I will buy it. However I think what's harder to attain is mid to high 20s in town. Even bone stock that's a tough task for a 6spd.

csmc711

iTrader: (4)

Well, there are a few claims that have really great gas mileage. Not sure if they are true or not but would like to hear if there is anything that compares in 2014, and, please feel free to be a little more descriptive.

Sadly, I dropped the interest when I lost my 2001 Camaro, but, I am back looking to see whats going on.

dudesqueak

When I had only an SLP ram air/lid and was grandma-ing it on the highway I TOUCHED 28 mpg with an extra 200 lbs in my car. Now that I have TSP LTHs and an ORY with a tune as well, I can't keep my foot off of the pedal! 13 around base, 17 mixture of city/hwy, 25 hwy. 2000 M6 stock gears, 275/40zr18s on back, 17s on front. 93 octane from Shell.

csmc711

iTrader: (4)

Thanks for the detailed input.

Now I need you to go grandma it on the highway and let me know what you get. Good luck with that, ha ha!

thunderstruck507

iTrader: (18)

Highest I've gotten was 21mpg highway on flat roads. On the roads I'm normally on it's dead nuts 19.5mpg and never varies more than .5 from that.

In town is around 12mpg in summer if I behave. It drops ******* quick if my foot gets heavy or winter because it needs to warm up longer.

LS1-450

iTrader: (33)

33 MPG (highway) on way to Hot Rod Power Tour in 2011. We were EFI @ the time (5.7L). A/F ratio for highway driving was leaned out to 16.5:1 in order to get good gas mileage. Car weighed 2670# with driver.

BTW, the # after 2670 is a pound sign, as it has always been. Don't know what this hash tag bullsh!t's all about. Next they'll be calling a turd a diamond & then engaged chick's 'll be wearing turd's on their finger.

svede1212

iTrader: (3)

The 2004 GTO is the only LS in the country to get an Australian computer with the lean cruise function (although it is turned off stock). When I was stockish and had it enabled I could get in the 30s highway. Now that I'm a 383 I was getting low 20s although when driving it last month for tuning before I stored it I didn't go for economy. My lean cruise is not turned on yet and that gives me another 10%+ bump.

bane89

iTrader: (3)

Same here w/full bolt ons, cam, and 4.10s. Car is a m6 and has 173k

csmc711

iTrader: (4)

Okay, looks like all I did was stir up another hornets nest as this stuff is squirrley as hell and all over the boards. Oh well, keep the info coming, I will get something out of this one way or another....heh.


Did you have a on demand tuner that you adjusted as you went or was that something you did on a dyno/the side line before going?

Yea, **** keeps changing for no good reason and kills me, almost litterally! Putting computer information on "the cloud"? Since when is it now a "cloud"? Same god damn internet its always been since day 1. I could go on with a multitude of things, but, have fun this weekend and take plenty of "selfies". Jesus Christ!!




I think i would have to have a little powwow with your car. Unless I was making close to 6 figures, I would not be a liking to that mileage, lol.