Anyone do a CNG conversion on a 5vz-fe? Or any other small engine?

[Jetboy]

I've been tossing around the idea of converting my 4runner to cng. I see some universal kits around but they all look kinda hokey. I'd like a high quality tunable injection system if that's possible. I also would like to keep it completely DOT/epa approved. I haven't seen any systems built specifically for the 5vz-fe. Anyone done an at home conversion? How's it work?

Utah has a good CNG network of dealers, and it would be a fun project.


Also, If you've done a conversion, do you have heat problems? I've heard that combustion temps are slightly higher, but don't know if that's true. If it worked well I'd love to swap one into my landcruiser with a turbo. It'd probably be cheaper to run than biodiesel and more environmentally friendly.