31.4 MPG on my 2009 RL

[wtxhl]

I took a trip to VA from NJ this weekend and I averaged 31.4 MPG (one way) in my new RL. That is much better than the 28 MPG that is on the window sticker. I am very impressed. So impressed in fact that I am reconsidering the mods I had in mind. It has plenty of power the way it is and why mess with 31.4 MPG? It has the best of both worlds the way it is (performance and MPG).

[SR819]

I went from Colonial Heights VA to Hampstead NC and averaged 30.6 round trip in my 08' RL 5-speed

[BSRL]

In the past I've had similar readings off the DIC but the best advice is to figure your mileage the old fashion way, resetting it when you fill up then when you fill up again divide your mileage from your last fill up by the amount of gas you just put in your car.

The DIC doesn't always read that accurately, especially when you reset it often.

But that is great mileage none-the-less. I often try to get up over 30mpg on the DIC by driving real conservatively, staying on the highway, etc but sooner or later I can't take it any longer and just punch it.

[Ruthie]

I average 22.5 - 23.5 with daily driving (lots of starts/stops). Best I've seen out of it was 28-29 on the trip to KY a few weeks ago.

[G8TR]

Drove from Tampa to Tail of the Dragon in June. Drove the area for 3 days and then back home. Over the whole 5 days I averaged 30.9.

[MaverickFlash]

My 5 speed RL has averaged 32.1 on the DIC. Through mileage/gallons at fillup i have been averaging 31.7. This is a mix of [mostly] highway and city. Although sometimes it dips below that if you know what i mean.

[Bogie]

Originally Posted by wtxhl

I took a trip to VA from NJ this weekend and I averaged 31.4 MPG (one way) in my new RL. That is much better than the 28 MPG that is on the window sticker. I am very impressed. So impressed in fact that I am reconsidering the mods I had in mind. It has plenty of power the way it is and why mess with 31.4 MPG? It has the best of both worlds the way it is (performance and MPG).

The 28 mpg is based on a hwy "average" that includes...well...an average of hwy driving conditions. If you can get the car into a steady state driving condition and keep it there, you should get 30+ mpg or better. In fact, I would not be surprised to see 35 mpg or better on some flat roads over long distances. A two liter engine with forced induction in a steady state condition should be very fuel efficient.

[turbo53]

Originally Posted by Bogie

In fact, I would not be surprised to see 35 mpg or better on some flat roads over long distances. A two liter engine with forced induction in a steady state condition should be very fuel efficient.

That's almost exactly what I got a few months ago. I drove from from Fairfax County out to Winchester VA, Route 66 all the way. I had my cruise control at 62 (in a 65 zone...everyone was blowing past me). 200 miles round trip and I had about 36 MPG. And this was computed the old-fashioned way, dividing the mileage by the number of gallons to fill up.

[Roadie Rob]

Never trust your DIC (especially if tuned). After my Hahn kit, I was avg 36-38 MPG but doing it the old fashioned way (fill & divide) yielded only 27-28 at my best. Something with the tune messed up my DIC. It always seemed larger than I believed and sadly, reality proved it was smaller when doing the hard math.

My new RL - easily in the 30's while breaking her in. Now that I am at 670 miles with my K&N tray filter and Magnaflow exhaust, I can only average low 20's for some reason???

Ironically, I also get to my destination about 3-10 minutes faster than before.

Must be the add-on's.

[fershy]

Originally Posted by Roadie Rob

Never trust your DIC (especially if tuned). After my Hahn kit, I was avg 36-38 MPG but doing it the old fashioned way (fill & divide) yielded only 27-28 at my best. Something with the tune messed up my DIC. It always seemed larger than I believed and sadly, reality proved it was smaller when doing the hard math.

My new RL - easily in the 30's while breaking her in. Now that I am at 670 miles with my K&N tray filter and Magnaflow exhaust, I can only average low 20's for some reason???

Ironically, I also get to my destination about 3-10 minutes faster than before.

Must be the add-on's.

My DIC is suggesting that I am getting 19.3 mpg and that is highway driving! I only have 2200 miles so maybe I am not broken in yet I don't know?I can only dream of 30mpg that everyone seems to report. Maybe we should start a thread to see who is getting the worst mileage?
fershy

[uranium-238]

Well, I've been getting 25 mpg with a lead foot, (26.5 on the DIC) and about 27-28 if I don't launch from redlights.

[CountryGirl]

Originally Posted by turbo53

That's almost exactly what I got a few months ago. I drove from from Fairfax County out to Winchester VA, Route 66 all the way. I had my cruise control at 62 (in a 65 zone...everyone was blowing past me). 200 miles round trip and I had about 36 MPG. And this was computed the old-fashioned way, dividing the mileage by the number of gallons to fill up.

You were able to drive I-66 all the way from Fairfax at 62 mph? How did you do that? Was it the middle of the night?

[08BlueSky]

23 on back roads to work (25-35 mph)
33 on the highway (65 mph)
33 on back roads to Shanksville (30-55 mph)
(actual - not DIC, though DIC was not far off)

5-speed, Pittsburgh

[turbo53]

Originally Posted by CountryGirl

You were able to drive I-66 all the way from Fairfax at 62 mph? How did you do that? Was it the middle of the night?

Memorial Day weekend. Traffic was amazingly light. Especially once I got past Centreville.

[Rustyknight]

2008 RL, 18k miles, tire pressure checked monthly (set to 32 hot, average cold pressure measurements of 28 per dic), oil changes per dic, 93 octane amaco ultimate

Daily driving about half (city/rural) and half (interstate) average of upper 60's to lower 70's on interstate, mpg average measured, not per dic runs between 32 and 33.5 since about 5k miles (was lower in the 30 - 32 range for first 5k miles)

[jgeorge]

The DIC in my 08RL consistently runs 2MPG higher than I actually get. I'm rabid about calculating mileage (it's a personal quirk, one of many).

Over the last 10 tanks of gas the DIC says I've averaged 26.9MPG and actual math says I've averaged 25.0.

On long highway drives I can keep the DIC saying about 30MPG and realistically get 28-29.


Joe

[BurningIsLove]

my DIC reads 33-34mpg at 65mph. My rolling average for pure highway (about 5 tanks worth of data) is about 32mpg as I frequently look down and find myself at 70mph. So my DIC is reasonably accurate within 5% most times.

Country road usage (LOTS of ups & downs in this area) w/ minimal traffic lights and stop signs, averaging 40-45mph is nearly 40mpg. Generally shifting in between 4th-5th gear depending on hill grades and conditions.

[Wolfheart]

I average about 21.4 MPG, that should tell you about my driving style, my foot is so heavy I leave imprints in blacktops on hot days. However, this car does get better mileage than my SUV, RV or my Caddy and about equal with my Talon. All 4 of my motorcycles get better gas mileage, but not by much my hand is heavy too. LOL

[BurningIsLove]

Score! Just took my longest biz trip so far in my 2008 RL. It's about 230 miles from my house to the client site, and including two very quick pit stops for coffee, I got a lovely 35.4MPG which included two quick stop&go traffic jams (less than 5 minutes each). Average speed, having reset the DIC when I left, was 67MPH.

Very excited about that vs the 21.0 MPG I was getting in my Explorer.

[bob]

My best is 30.0 and thats cruising about 70-75mph.

[mikecronis]

32.5 to 33.5 but mostly standard cruising at 80mph. Strange the sticker only says 28mpg highway. GM always underestimates.

[uranium-238]

Are these the numbers off the DIC, or were these calculated the "old-fashioned" way? I've found the gas mileage numbers on the DIC to be high by 2 mpg pretty consistently.