Can You Get 100 MPG in a Gas Guzzler?

TL;DR

A 660hp Mustang is pushed from 18 MPG to a momentary 99.6 MPG through driving habits, aeromods, and dangerous truck drafting.

Key Points

• 1.The baseline run yielded a surprising 18 MPG. A modified 660hp supercharged Mustang driven aggressively with wrong tire pressures, AC on, windows down, and sport mode still managed 18 MPG, showing how efficient modern cars are.
• 2.Driving habits alone boosted MPG by 33%. Correct tire pressure, windows up, AC off, and staying under 2,000 RPM raised the result from 18 to 24 MPG on the same 120-mile freeway route.
• 3.CFD analysis identified wheels and tail as the biggest drag sources. Superfast Matt's AirShaper simulation showed covering wheels and lowering the car dropped the drag coefficient from 0.314 to 0.242 — near Prius territory.
• 4.Aero modifications added 3 MPG, reaching 27.1 MPG. Skinnier drag tires with spoke covers, a front air dam, lowered suspension, and a large rear fairing were fabricated in one day based on Matt's wind tunnel data.
• 5.Drafting behind a U-Haul truck is the only way to approach 100 MPG. At 40 mph downhill directly behind the truck, the live MPG gauge hit 99.6 MPG by nearly eliminating frontal pressure drag.
• 6.100 MPG is technically achievable but practically useless. It required going 40 mph downhill, dangerously close to a rented U-Haul, negating any real-world fuel savings — so the answer is yes, but only under absurd conditions.