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Yesterday on a trip to Houston (about 150 miles), I decided I would test the SRT gas mileage at different speeds, that I might actually drive with the cruise control set, when I am on long trips. The results were interesting to say the least.

Here are the basics,

Road is pretty flat between Victoria and Houston.
I ran each test for 5 minutes at the given speed.
Running Toyo Proxes 4, 275/40/20 on all 4 wheels, at 34 psi.
no other mods, bone stock.
2 people in vehicle along with about 150 lbs. of tools in the trunk.
block was heat soaked since I didn't start the test until after about 20 minutes of driving... so as to simulate real world conditions. Outside temp at the time was 77 F.

Speed MPG RPM

74 MPH 19.2 2550
73 MPH 19.2 2500
72 MPH 19.7 2400
71 MPH 19.9 2300
70 MPH 20.4 2250
69 MPH 20.8 2175
68 MPH 22.3 2150
67 MPH 23.6 2075

I decided I wanted to repeat the test on the way home last night but traffic wouldn't let me hold a constant speed in the 70's.... I guess lots of people driving to Mexico for cinco de mayo. Anyway, I set the cruise at 67 on the way home and still had a hard time even going that fast. After about 60 miles at 67 miles per hour, I had averaged 23.8 MPG.

After I had reached the test speed and maintained that speed for at least 30 seconds, I reset the calculator on the Evic so that any averaging in the computer between tests would be eliminated. The RPM listed is an estimate and not taken from the easter egg menu which would possibly give a more accurate value of RPM for speed, but I listed the RPM to demonstrate that the terrain was flat and no stress on the engine.

Has anyone else experimented with finding the best cruising speed for the SRT.... granted I KNOW these things were built to cruise above the take off speed of a Cessna. But with gas at 3.50 /Gal and taking long trips on the company car. I want to save a little money to be able to pay myself.

I must say i did not expect a difference of almost 23% in mileage between 74 mph and 67 mph.
 

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Those numbers are totally accurate. I run from the Phoenix area to Las Vegas often. The roads are slight twistie up and down hill...but also a lot of flat straights.

I calculate my mileage both with pen and paper and the EVIC. The EVIC is dead on everytime.

If I run about 85 miles per hour most of the trip I get about 19.8 to 20.0. If run 65 most of the trip I get 23.8 miles per gallon. I also get real bored and cranky going that slow.

Another thing I have noticed, if there is any type of headwind forget all the mileage in the world with these cars. It drops like two to three miles per gallon.

Nice write-up.
 

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I'd agree that it's fairly accurate. My only experiments with the MSRT8 have been long road trips between here and Chicago and sometimes beyond to MN. When I can cover some 370 miles nominally at highway speeds (typically 60-65 mph) with only brief slow downs for an occasional small town stoplight or change of highways, etc., the MSRT8 easily averages 22+ mpg EVIC and/or Calc'd. I've no doubt on a long stretch of flat interstate at 65 mph it would be somewhere above 23 mpg.
 

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Those numbers are totally accurate.
I also get real bored and cranky going that slow.
Nice write-up.
That says it all. Who can go 65 in these cars? I do a 69 mile sprint to my in laws in about an hour.

Fuel mileage= POOR!
 

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I get about 20 MPG at 70-75..tough to go much slower than that:biggrin:

Eric
 
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