Re: Using the Exhaust as a veg oil warmer?
i don't think the proposed exhaust heating system would warm things up any faster than a coolant based heater. And the advantage of the coolant based heating system is that it won't overheat your veggie oil. Depending on where the copper tubing is located on the exhaust, it could be several hundred degrees, especially while climbing a mountain in the summer. The exhaust system midway to the back of the bus probably takes longer to heat up than the engine coolant.
Quis custodiet ipsos custodes (who will watch the watchmen?)