EDIT: Oh smeg there was a second page.... Ignore me
Tyre size & presures, gear ratio (which on your dads road car will almost certainly be geared for cruising & fuel economy), aerodynamics - all of these things are a factor in quarter mile times ... plus the age of the driver of course, you young sprogs have reactions like gnats compared to us old sloaths... There's more to Drag racing than taking the windscreen wipers off your car to get your bgp/tonne up. How well does your running gear roll, is there a warp in the chassis, how much rubber is making contact with the ground... etc etc. Oh, compound of the tyre, tyre temperature... Gear shift latency, tracking & suspension geometry...
(I'm stopping here because i'm bored of thinking up the many factors involved)
Come back with a mathematical model explaining why the XRT is wrong, and we'll show you the parts that aren't in LFS... which is basically just the aerodynamics and a few very minor things (has Scawen put drive shaft flex in yet?)
It may not be perfect to the tenth decimal place, but i'll say this much for LFS: It aint bad you know
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