Here’s another look at the wear. You can see why the belt was forced off of the other pulleys.
I ran inside and grabbed the Hyundai idler pulleys. That engine has four idlers, but three of them were identical. By some miracle, the Hyundai pulleys were identical in diameter and offset to the Mitsubishi parts. Even the bolt thread was the same albeit the Korean non-JIC standard bolt head was a 15mm. As an added bonus, the idler pulley was made of STEEL which guarantees an exponentially longer lifespan. Tyler installed the upper Hyundai idler and I installed the lower. We put the belt back on, plugged the injectors back in, and fired it up. The belt stayed exactly where it should have of course.
The idler pulley on the right is the one you want. There are three of these idlers on the Hyundai 4B, oh sorry, Theta II. It looks like the one on the left might even work, but I didn’t bother trying. The Hyundai part number is 25287-2C000 and you can pick them up for $49.48 each at Dealer Direct Parts.
Its been about 800 miles since the Hyundai idler pulleys were installed and there have been no issues with the Hyundai idler pulleys so far. I think they’re a winner.
While this MR was raced across China in the Gumball back in 2008 and had a pretty damn hard life for the first 20,000 miles, the car only had 49,800 miles on the clock when this belt fiasco occured. While this car’s average RPM is probably a bit higher than yours, this issue will very likely occur on your EVO X eventually. And now you know what to replace those shitastic plastic idlers with. If you’re smart, you’ll even get some of these idlers now and change them out to the steel Hyundai parts as preventative maintenance. It would suck if you lost a belt on the way to Vegas, overheated the engine, ruined your trip, pissed off your girl and had a $1000 towing bill now wouldn’t it?