Are these the kind of flames you are talking about?

http://www.shockwavejets.com/shockwave/SHOCKWAVE52.JPG
http://www.shockwavejets.com/shockwave/SHOCKWAVE6.JPG

http://www.shockwavejets.com/shockwave.cfm

Diesel fuel would not ignite but you could pump it in under high pressure and have it atomized from a nozzle and ignited by an electrode. This is simple and the same principle as an oil burner like the ones used in your furnace or in boilers
My diesel powered steam cleaner puts out a good flame.
Jim

 

yup thats what i want to dobut i jest wasent shure on how to go about dooing it

 

pipe propane straight into the exhaust then put the spark plg just past that

thats how you can do the flames

 

Ok but does there need to be a nozzle on the end of the pipe and I want to either have it on or be able to do short bursts how do I control the propane via a switch

 

Personally, I think it would be pretty sweet with a pair of stacks..