08 STS fuel economy better than expected

**Bonsvoeux** · 12-12-08 07:23 PM

I have a 2008 STS V6 with direct injection and am getting outstanding fuel economy: 17.5 in town, and 29.5 on the freeway at 70 MPH on 87 octane. And the power is so much better than my 05 STS V6.

Anybody else seeing these good numbers?

**rb92gt** · 12-13-08 08:08 AM

For its size/weight, the STS is not bad with fuel consumption regardless of V6 or V8. I do not believe anyone else is actually getting 29 mpg hwy though. The electronic avg mpg calculator is a bit generous with hwy mileage.

The next time you fill up your tank, zero your trip odometer. Then use 3/4 tank of fuel and refill. Divide your miles by the gallons refilled (obviously). I did this and consistently get 3 mpg less hwy than the car says. City is actually very close (0.5 mpg less actual).

Overall, who cares, who wants to be seen in a Prius.

**marathonman89** · 12-13-08 10:01 AM

2008 V6 DI

I constantly get 24 MPG highway at 75-80 MPH.

18 MPG around town.

Both with AC on.

**pjbizjak** · 12-13-08 11:52 AM

Shoulda had a V-8! I get 18+ mpg all around city and 23+ highway.

**MARKVIII** · 12-13-08 12:58 PM

i have '05 v8 and get 20.5 combined with 40k miles on it.

**bigTYME** · 12-18-08 02:51 PM

Yea same here. I am averaging 22 mpg in my '08 STS DI and thats also on 87 Octane. They are more efficient than they look. The six speed is great. I took a 400 mile trip about 6 months ago and I averaged about 27.5 mpg. Mine is a RWD though. On the '08 CTS DI AWD I am doing about 19.6 mpg.

**EChas3** · 12-22-08 10:40 PM

My wife and I took a driving vacation in October in her 2007 RWD V8 and got 25MPG on 87 Octane when cruising at 80MPH (except for the left lane road-blocking slowpokes). I saw a bit higher from the DIC but a bit of braking and resuming does have a cost. The 2008 V6 is supposed to be better but since it produces similar HP & Torque numbers it may not be significantly different.

Anybody seeing 10% better on 93 Octane?

**justgreat** · 12-23-08 09:31 AM

direct injection was originally developed as a fuel saving solution not for greater hp numbers. mitsubishi tried it back in the 80's but couldn't get their di engine to pass federal certification for use in this country.

the v6 with rwd has a 3.42 rear end, so the hiway mileage suffers somewhat over the v8 which has the 2.73 r/e as the base ratio.

the 6 speed might help on the hiway, IF they dropped the rpm for top gear; the 5 speed turns 2050 at 60 mph....

jackg
06 sts6

i get 16-17 mpg on strictly around town driving...