In this article I’ll talk about the conditions I drove in to obtain 391 miles per on a full tank, to get 31.56 MPG. This is great for a Scion tC with 241k miles on the odometer!
How to calculate MPG
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Fill up your tank
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Reset the trip counter on your odometer
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Drive as far as you can
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Fill up the tank, log the total gallons used
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Calculate [miles driven] divided by [gallons filled] = MPG
In this trip: 391 miles driven divided by 12.385 gallons used = 31.56 MPG!
The 2005-2010 Scion tC has a 14.5 gallon tank, I could have easily got over 400 miles, but that’s pushing it!
Video
Almost perfect conditions for driving
I just finished some “major” maintenance @ 241k miles before attempting this road trip. I thought this would be the perfect time to see how far I could take a tank. Here are some key points:
- Sustained driving (aka, minimal stops and acceleration)
- Brand new ignition coils and spark plugs, fresh oil change
- Kept my speed mostly under 75, ideally I would keep it under 70
- Trying to plan my trip where my pass through LA would have the least amount of traffic (stop and go)
Full details of the trip
Trip: San Diego to Discovery Bay, going northbound on Interstate 5. Time of day approx 12:30pm to 8:30pm.
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2006 Scion tC, 241k, Original Engine, Original Trans
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Stock intake, stock exhaust
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Fresh Oil change Valvoline Restore & Protect, 5w/30
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Bottle of Chevron Techron fuel system cleaner
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87 Octane 7/11 gas
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17×7 OEM wheels, 32PSI all around
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AC ON the entire trip, it’s too hot to not have it on
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65-75 MPH, 1 stop.
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NOTABLE: I have a brand new Catalytic Converter and NEW O2 sensors replaced December 2024
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NOTABLE: I’m running the Quantum VVTi Solenoid
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NOTABLE: I’m running the NST lighter crank pulley
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NOTABLE: I get better MPG on my stock 17×7 setup than my 18×8.5 setup.
Is over 400 miles on a tank possible?
Yes! The most I’ve done is 407 miles! I drove into the gas station on fumes! I didn’t really log any of the details at the time, it was mostly similar conditions. I’ve heard of stories of other users getting 32 and 33 MPG driving over 400 miles on a tank. It’s doable. I have filled up over 13.5 gallons before, but it gets really scary driving on that last gallon, car will sputter and almost hesitate on uneven surfaces. Driving on bare empty is really pushing it and it’s bad for your fuel system
Other things to consider for next attempt
– Drive at night, cooler outside temps, and I can turn my AC OFF for the trip
– Almost guaranteed straight through LA with no stop and go
– Keep it at 70 MPH or under
– Drafting off big rigs. I’ve heard EV drivers do this. I’m not a fan of driving behind big rigs just to save gas. Big trucks kick up too much debris (rock chips on windshield).
Links to notable Maintenance and mods
– Oil Change: Valvoline Restore and Protect
– NST light weight pulley set installed
