Our BG professional technicians changed the oil and performed the fifth checkup this year. The results are below.

Performance

Performance has not changed in the past 5,000 miles. The fuel economy is also holding at about 18-20 mpg.

Borescope Analysis

You can see in the videos below that the deposits continue to get thicker on port walls and valve stems and are forming to point of sticking out away from the port walls (Note the first photo of the Cylinder 1 valve seat area at bottom of the port).

Oil Analysis

Our tests are still showing fuel dilution in engine oil but not quite as much as the last couple of check ups. This might have been due to a shorter drain interval.

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Performance

One test driver’s comment on the car’s throttle response was “sluggish” as compared to its first miles on the road. “Sluggish” for a car with a twin turbo could only be noticed as a momentary hesitation to the average driver.

The on-board fuel economy calculator shows a greater mpg loss, motoring away at only 18 mpg. That’s a total loss of six miles per gallon in the first year on the road!

Borescope Analysis

See how the deposits continue to grow on the intake valves and ports in the photos and videos below.

Oil Analysis

Fuel dilution is still present at the same level as the last checkup.

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Performance

Several BG test drivers noticed a slight lag in immediate acceleration response. With two turbochargers, overall acceleration decrease is difficult to detect.

The on-board fuel economy calculator shows a recent, dramatic decrease in mpg from 24 to 20.5 mpg. With the mpg drop, we’re now refueling 66.5 miles sooner (a loss of almost 3 gallons per tank)!

Borescope analysis

In the progression of photos and videos from the first checkup to the third, deposits continue to thicken on intake valves and ports. The borescope video below shows deposits caked heaviest further down the intake port near the intake valve. This is especially detrimental to overall driveability because of the decrease in air movement efficiency through the intake port and in to the combustion chamber.

Oil analysis

In addition to growing deposits, our data indicated that fuel dilution is still present, but not as significant as the 10,000-mile checkup.

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Watch the video below and notice the caked deposits as the borescope works its way down the cylinder toward the combustion chamber.

In the photo of an open intake valve in Cylinder #2, notice the deposit formation on the exposed valve stem compared to the part that pulled back into the valve guide when the intake valve is closed.

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The BG Fuel Test Car cruised through training in Miami, Florida.

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Check out where the BG Fuel Test Car has been in the first 5,000 miles!

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