There are many glitched times on multiplayer boards. on the top and also below.
IMO the best overall wipeout hd pilot is still Wotan998, Yeldar is 2nd atm.
If you want to have a better view at how he races, you'll find many videos on this site, some of Yeldar, some of Pirahpac (only phantom class) and even some from me, maybe it can helps to judge how fast it's possible to be on various tracks with all difficulties (br, shortcuts...)
Show us a video of your racing skills and no doubts will remains !
i'm always interested to see someone new able to beat Yeldar, i thought i knew all the pilots able to do that !
A laptime of 17.99 is faster of 15 seconds (lol) than the rank 1 speedlap (33.46) = it's simply impossible without glitch, respawn or bug of timer.