Drop in Fuel Mileage? I may have a solution.

Earlier this year a friend enlightened me to better gas means better fuel mileage. I'd been running what ever was cheapest for years in my cars, and watched my gas mileage drop a little bit year after year.

My Volvo use to get 29.25-29.50 miles per gallon before E10 was mandated in my area. I watched over the last eight or nine years my fuel mileage drop to mid 26's. I was blaming the mandated E10 for my drop in both the Volvo and the 5 mpg drop in the Prius.

Last year I started with the Volvo waiting until the tank was almost empty and tossed in a bottle of Techron and switched to Shell V-Power + Nitro gasoline exclusively. Any top tier gasoline should work if you don't have Shell in your neighborhood. The Techron was added to accelerate the cleaning during the first tank. I use the Shell because I have one of their stations near my home and the cost is the same as the other stations in the area.

After about 200 miles I noticed the engine has smoothed out dramatically but the fuel mileage hadn't moved off the mid 26's. I drove it around locally for a few weeks and had filled it up once. I decided on a Sunday last Sept to take a ride to see an automobile museum for something to do. I'm now filling the car up for the third time with Shell V-Power before the start of my trip.

I'm on my way to the Museum is when I noticed the numbers on my Scan Gauge where climbing past 27 mpg and continued up to just over 29 mpg. On the way back I saw the same fuel mileage numbers stay in low 29's. Took the car to Fl. in December, 1170 miles each way and the fuel mileage never dropped.

A few months ago I decided to do the cleaning process to the Prius with a bottle of Techron and switched over to Shell 87 exclusively. Being I rarely drive the car on the highway for any length of time, I never really saw the real gas mileage the car was capable of.

Today I was out this afternoon on a highway run for about three hours. Stock Prius, 70,250 miles, Defender tires 44F-42R, no grill blocks, no Hypermileing, cruise control set at 55 mph with the A/C running the whole time, air temperatures low eighties with Shell 87 in the tank.

My fuel mileage for the day, round trip at 55 mph with the A/C on the whole time came in at 61.3 mpg recorded by my calibrated Scan Gauge. I've seen during short runs at 65 mph mileage numbers in the 55-56 mpg range in past weeks. This is western Pennsylvania and we have hills around here.

You are not going to see a major change in the first tank or two. But after a few tanks you should see a jump in your fuel mileage as you eventually clean the gunk that has built up over the years. It took years to build up you're not cleaning the crud out of your fuel delivery system in a tank or two, give it a little time.

 

I only use 87 in the Prius. The Volvo has a 91 octane or better requirement thus the V-Power+Nitro.

I will tell you, I tried to lower the octane in the Volvo and filled it with 89 on a trip to save money. It was a fuel mileage disaster, like a 3 mpg drop. At the time it was getting mid 26's and when I filled with the 89 it dropped to 23 mpg. My point is use Top Tier with a higher detergent additive package and over the long term you'll save money with better fuel mileage.