Pick--There are valid scientific explanations to support your point. I've forgotten way too much from my chemistry and thermodynamics days, but basically mixing hydrocarbons of lighter chain and greater volatility with the diesel can enhance it's combustion characteristics....up to a point and THAT is really the key. Past that point, things start to destruct within the engine. Especially if there's pre-detonation.
TINSTAAFL so I'd keep a close eye on your injectors, cylinder walls, pistons, etc for deleterious effects.
I respect Gale Banks' authority in the realm of high-performance engine modification. Here's what he had to say from an FAQ
on his website:
Is propane injection good for making power in a diesel?
Propane is a quick way to make horsepower, but we have not seen a system on the market that we are satisfied with. Most are somewhat crude in their design and use old carbureted forklift technology (forklifts are usually powered by propane.) During testing with one propane system, we experienced detonation on a diesel. While detonation is never good, detonation on a diesel is frightening! Be very careful about the promises that propane systems may offer.
Can propane be used on a non-turbocharged diesel?
The addition of propane to any diesel engine, whether turbocharged or normally-aspirated, introduces more fuel to engine, without additional airflow. Although it can be done, there is the constant danger of developing excessive exhaust gas temperatures, thus the possibility of engine damage.
It is for this very reason that Banks addresses airflow. Airflow is critical in the SAFE addition of fuel to a diesel engine, regardless of what that fuel is. For normally-aspirated diesels, the Sidewinder turbo is an excellent way to gain airflow and performance. Some people opt for the lower cost of a propane injection system as an inexpensive way to increase horsepower, but the real cost may be down the road when engine damage occurs.
Does Banks offer a propane injection system?
We've followed the interest in propane-injection systems for diesel engines, and tested several to see if they are a valid way of safely increasing horsepower. We uncovered a number of serious safety issues:
Propane injection is nothing more than a way to add more fuel to the diesel engine. Without additional airflow, that additional fuel delivery can produce excessive exhaust-gas temperatures that harm internal engine components.
When propane is injected into the intake tract, it actually displaces some air, further increasing the risk of excessive exhaust-gas temperatures.
Too much propane can cause detonation, which is very damaging to internal engine components.
Propane is commonly injected into the intake prior to the turbocharger. This means that propane is present in the pressurized intake air, introducing a volatile fuel in an air-stream that would not normally contain fuel of any sort. Turbo-diesel engines occasionally develop intake boost leaks, and when propane is present, a boost leak could result in the presence of propane in a heated under-hood environment. This is a great safety risk.
Before Banks ever sells a propane-injection system for diesels, these issues would have to be resolved in the course of our product development.