Hyundai is the brand of your DVD+R DL disc?
Good luck, you’ll be lucky to get those to burn (often the MID, or mediacode, is faked) - the only brand worth using for DL (8.5 gig) discs is Verbatim.
But anyhow. If the disc is rated for 2.4x, then burn it at that speed and see how you go with ImgBurn
Edit: Rats, Maineman beat me to it this time