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1999 White Diamond ETC
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Discussion Starter #1

The EPA fuel economy test consists of two driving routines, or schedules, performed in the laboratory.​
City: Represents urban driving, in which a vehicle is started with the engine cold and driven in stop-and-go rush hour traffic. The driving cycle for the test includes idling, and the vehicle averages about 20 mph.​
Highway: Represents a mixture of rural and Interstate highway driving with a warmed-up engine, typical of longer trips in free-flowing traffic. Average test speed is about 48 mph and includes no intermediate stops or idling.
The city schedule represents low-speed driving in stop-and-go
traffic and considerable idling.

The highway schedule simulates non-metropolitan driving at higher speeds, with no stops and negligible idling.

Test Schedule Characteristics Driving Schedule Attributes
Test Schedule
City
Highway
Trip Type
Low speeds in stop-and-go urban traffic
Free-flow traffic at highway speeds​
Simulated Distance
11 miles
10 miles​
Time
31 minutes
12.5 minutes​
Average Speed
20 mph
48 mph​
Top Speed
56 mph
60 mph​
Stops
23
None​
Idling time
18% of time
None​
Engine Temp. at Startup*
Cold
Warm​
Lab temperature
68-86 ºF​
Vehicle air conditioning
Off​
* A vehicle's engine doesn't reach maximum fuel efficiency until it is warm.

Source: http://www.fueleconomy.gov/feg/fe_test_schedules.shtml
 

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1999 White Diamond ETC
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2,538 Posts
Discussion Starter #2
On my most recent road trip, I averaged 68 MPH and got 27.2 MPG. 4+ hours of I-35, pulling over twice. Not bad! :)
 

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2003 STS w/BoseNav, 1993 Deville, 1985 Deville
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Ah, no wonder the STS got 27MPG highway EPA. They never go over 60MPH. Now, only if I can find a highway where I can go that slow and not get run over......

Mtflight, thanks a zillion for posting that information. Very helpful.
 

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2010 Black Cherry CTS AWD
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263 Posts
The last road trip I took to Boston, I averaged 29 to a little over 30 MPH and if I can remember right, I averaged about 75-80 MPH.
 

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1999 White Diamond ETC
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2,538 Posts
Discussion Starter #5
MACTICULOUS said:
The last road trip I took to Boston, I averaged 29 to a little over 30 MPH and if I can remember right, I averaged about 75-80 MPH.
I think the SLS and other Caddies using the LD8 engine (@275 horses), have a different final gear ratio, allowing for less RPMs at higher speeds than say the L37 rated @ 300 hp). Lower RPMs = better fuel economy. Please correct me if I'm wrong.

The pro to the L37 is you are closer to the higher power band--so you can accelerate more agressively on the highway and what have you...
 

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1999 White Diamond ETC
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2,538 Posts
Discussion Starter #6
thu said:
Ah, no wonder the STS got 27MPG highway EPA. They never go over 60MPH. Now, only if I can find a highway where I can go that slow and not get run over......

Mtflight, thanks a zillion for posting that information. Very helpful.
Then again, thu, you're used to flying!
 

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2003 STS w/BoseNav, 1993 Deville, 1985 Deville
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1,089 Posts
mtflight said:
Then again, thu, you're used to flying!
That's right, mtflight! Now, only if the STS came with a Prop Pitch control. :)

I opened it up yesterday. It was awesome. It wanted to go faster....
 
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