Excellent Gas Mileage

lusterblade · #1 (**permalink**) 02-06-07, 11:52 AM

I was on the highway with quarter tank of gas (87 octane). 3 people were in the car. I reset the average mpg. Set the cruise to 71 and after 10 miles of driving the Average MPG was 29.0!!! Awesome. I wonder what I would get if it was 91/93 octane. Just thought i would let you guys know.

iametarq · #2 (**permalink**) 02-06-07, 12:14 PM

That is right on with my averages at 70mph as well! On a LONG road trip from Northern Michigan to Colorado two years ago I averaged 30-31mph at 75mph with just me in the car.

Raze · #3 (**permalink**) 02-06-07, 12:29 PM

My shorter gears won't let me get above 26MPG or so on a nice level grade @ 70 mph

but I don't care

mikeay · #4 (**permalink**) 02-06-07, 01:38 PM

raze...what do you mean "shorter gears"?

Raze · #5 (**permalink**) 02-06-07, 02:18 PM

DTS/STS/ETCs all have a higher final drive ratio, 3.73:1 vs 3.11:1 in the DHS/SLS/ESCs, but the real kicker is the power differences (mostly due to more aggressive cam grind) which provides for more power on the L37 vs the LD8 engine, i.e. the DTS/STS/ETCs while providing more power also have shorter gears to combat, thus negating any potential gains in the MPG department of the extra power/efficiencey. Kinda a double edged sword.

mikeay · #6 (**permalink**) 02-06-07, 02:22 PM

got it...thanks....

submariner409 · #7 (**permalink**) 02-06-07, 04:40 PM

Yep, that's right in line with my recent 1,600 mile Florida trip: 23.9 mpg, 87 octane, 2 people, luggage, 70 +/- interstate, mostly. My STS runs around 2,400 rpm at 70-something. What does a post-'98 SLS turn??? If it's a couple grand lower, there's the extra mileage. I believe the fourth gear in these vehicles is on the order of 0.7:1, or like an overdrive gear. The "fifth" speed comes from torque converter lockup.

**Ranger** · #8 (**permalink**) 02-06-07, 06:55 PM

Quote:

What does a post-'98 SLS turn???

1950 RPM @ 70 MPH