Category: metrompg.com

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Snapshot: effect of tire pressure on rolling resistance

metrompg.com series | Highlighted on Fuelcons

In this further post published on metrompg.com, the impact of tire pressure on rolling resistance was assessed using two different vehicles: a 1998 Pontiac Firefly (Geo Metro) and a 1999 Toyota Camry. The experiments were conducted on a paved slope with flat run-out. The methodology involved inflating the tires to different pressures (20 PSI [1.38 bar] to 60 PSI [4.14 bar]) and then letting the cars coast down the slope with engine off, transmission in neutral, and brakes released. Distances to marked “stop points” were measured using a distance measuring wheel (some kind of).

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Reflections on side mirrors: testing drag vs. MPG

metrompg.com series | Highlighted on Fuelcons

This experiment, which was published on metrompg.com, aimed to explore the influence of side mirrors on a vehicle’s drag and fuel efficiency. The motivation behind this study stemmed from the adoption of video cameras instead of conventional side mirrors in high-efficiency concept cars, leading to a desire to ascertain whether such alterations yielded tangible advantages. The investigation was carried out using a “Blackfly,” essentially a black Pontiac Firefly, wherein the stock non-folding driver’s side mirror was replaced with a folding mirror from a 1993 Suzuki Swift 3-door, featuring an aerodynamically optimized hinge.

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Testing grille blocking & wheel skirts: +5.7% improvement

metrompg.com series | Highlighted on Fuelcons

This further experiment published on metrompg.com delves into a DIY aerodynamics experiment conducted on a Pontiac Firefly (like the Geo Metro a variation of the Suzuki Cultus), aimed at enhancing its fuel efficiency. The author drew inspiration from Phil Knox, who achieved an impressive 28% increase in highway mileage by implementing aerodynamic modifications on his 1994 Toyota T-100 pickup.

The two modifications put to the test were a grille block and rear wheel skirts, both crafted from readily available materials.

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Mini-experiment: the wrath of roof racks

metrompg.com series | Highlighted on Fuelcons

Between 2005 and 2009, Darin, the host of metrompg.com, shared some of his experiments on his vehicle’s fuel consumption on…metrompg.com!

Each individual post includes an introduction, a description of the conducted experiments and their results, as well as a discussion. Although the data is somewhat older, it still holds relevance, at least in terms of conventional vehicle fuel consumption.

Fuelcons plans to feature these experiments in a “metrompg.com series,” starting with this study on the adverse impact of a roof rack on fuel consumption.

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