The phrase "mph dash" refers to the speed at which something is moving. 'mph' stands for "miles per hour," which is a unit used to measure speed. So, a "mph dash" implies a quick or fast movement. Full definition
The car can finish the 0 - 60 mph dash in five seconds. (thesupercars.org)
The car can do a 0 - 60 mph dash in 3.2 seconds. (thesupercars.org)
With Sport + enabled to sharpen things up, the large wagon is more than quick enough with a 0 — 60 mph dash of slightly over 5 - seconds and can take the car up to 129 mph before the speed limiter kicks in. (carbuzz.com)