Propane isn't popular in the horsepower junky crowd. Diesels work very differently than gasoline powered cars. Propane on my truck would raise the cylinder pressure and EGT's through the roof, probably enough to blow a head gasket or break a rod. A totally dry nitrous system would basically finish the combustion cycle with all the excess fuel I have and LOWER my EGT's substantially. The more air you have the cooler the EGT's are. The EGT's would do the same thing if I had a bigger turbo and ran more boost. I don't want the lag of a larger turbo. Right now I can foot brake 5psi and still launch hard enough to go low 1.8 sixty foots with my Garrett GTP38R ball bearing turbo. Typically I see 37-39psi when it gets into overdrive. That turbo comes with a wastegated 1.0 A/R housing and several others are available. Sitting on the shelf is a non-wastegated 1.15 housing that should pick up 20+RWHP just because of the reduced drive pressure. The extra 20+RWHP will come with a little extra lag, but nothing too bad.
As soon as someone talks about a performance diesel, the first thing that pops into their mind is a Cummins. I have one of those sitting in the garage too. Right now I'm just enjoying the shock value of having a Powerstroke that runs with most street cars. If this thing hauls with 440RWHP, imagine what my 800RWHP Cummins is going to do...
