Thanks for the input! I meant veg actually. But ya I just was semi interested in it because basically free fuel sounded great to me. But I guess it's not that great.
Yes it can be free fuel but keep in mind you have to spend a lot of time driving around collecting all the used oil, taking it home, cleaning it up (which takes forever) and then transferring it back into a tank in your truck.
You'll also need to find a place that's willing to give it to you. It's a hard thing to do because you want to find oil that's as clean as possible which means restaurants that change out the oil every night. Your average dive place will use the same oil as long as possible (like a week) and then change it out. The problem is after a week it's so filthy it's almost unusable and even then it's probably only 2-3 gallons.
The sooner a restaurant changes the oil out in their fryer, the fresher their food tastes so ideally you want to find a nice classy restaurant that changes it out each night. The catch is that most restaurants like that have contracts with major collecting companies that actually pay the restaurant for the oil.
I had addend up the cost of everything I spent on everything and then figure out how many miles I had to drive on pure veg before I started saving money. Each time I had mechanical issues and had to spend money to fix it it just made it longer until I was able to save money.
The biggest mechanical issue that will come up was is that the ports in your injectors are so fine that in the event you don't get every single particulate out of the dirty oil, you run the chance of clogging up the injectors.
Again to me it just wasn't worth it after all the time I spent dealing withdraw stuff.