Old Tech: Whatever Happened To It?

Propane, Vegetable Oil, And Stacked Boxes?

Jason SandsJul 1, 2013
While compiling our old-iron issue, we got to talking about how much the industry had changed in the past few years. Open up an issue of Diesel Power in 2006, and you’d likely run across an article about propane, using vegetable oil as a fuel, or running stacked boxes (or “chips”). If we looked hard enough, there’s probably an issue with articles on all three. Yet now, in 2013, almost nobody talks about any of them. So the question then, is what happened?
Propane Injection
Propane injection was used on diesels in the early years of diesel truck performance because it gave a nice, 50 to 80hp kick and could be used as a supplementary fuel to boost range and economy. In many states, propane was much cheaper than diesel fuel, so using it (especially while towing) meant a substantial savings. We’ve seen trucks running empty get 40 mpg while on the ’pane, so it’s clear that it works. We’ve also ridden in a mostly stock 7.3L Ford that definitely felt faster with the propane system kicked on. So what happened? Why isn’t propane injection common anymore?
Photo 2/11   |   Although propane is consumed in the process of injection, it does make for a crazy mpg increase. Jeff Dean achieved 38 mpg in Diesel Power Challenge 2008, and a couple of years later Matt Handwork upped the bar even more with a 45.5-mpg reading. While both competitors were injecting CNG instead of propane, the theory remains the same.
For one, propane is a fuel, so it makes a diesel engine susceptible to pre-ignition or detonation. This means that in super-high- performance applications, propane can actually be detrimental to performance, as pre-ignition in a diesel is very, very bad—and normally results in broken parts. Also, although fuel economy is increased while using propane, the propane itself is consumed, too, adding to the price. When propane was $1.00 a gallon, it wasn’t a big deal, but the cost has almost doubled in the last 10 years, negating the cost advantage of using propane. There’s also the inherent task of finding a place to mount a bottle, filling it and, of course, re-filling it every time it runs out. Bottom line is, with the advancements in tuning, rise in propane costs, and rise in diesel truck prices (people aren’t very willing to risk injecting extra fuel into the intake of their brand-new $60,000 diesel), propane has gone by the wayside.
Photo 3/11   |   Tadd Layton had propane injection on his 6.0L Ford in Diesel Power Challenge 2006, and he was able to make 709 rwhp with nitrous, which ended up being the power-adder of choice for virtually all racers.
“Veggie” Oil
“Hey man, you runnin’ veggie oil in your diesel?” We used to get this question all the time. Then, less and less. Now, almost never. There has been no bigger rise and fall than the buzz around people running vegetable oil in their diesels. Part of the reason it became so popular was there were restaurants that were literally willing to give it away, which people saw as free fuel. Even at sled pulls or dyno competitions, there was always the occasional diesel that smelled like popcorn when the pedal was put to it.
Photo 4/11   |   Back in the June ’07 issue, we profiled EcoCab, a Northern California-based cab company that ran a fleet of old Mercedes cars off vegetable oil. With relatively mild weather, the owner said the Benzes were very reliable and just needed the occasional filter change.
Unfortunately, running vegetable oil did have its drawbacks, mainly because vegetable oil isn’t a fuel that has to pass any sort of tests for lubricity, gelling, or a number of other factors. Just because a diesel would run on it, didn’t mean it didn’t cause problems. As the years went on, fried injection pumps (no pun intended), burned injectors, and gummed-up fuel systems became more and more of a problem for people running the greasy stuff, and often a steep repair bill would offset the cost they had saved by running vegetable oil in the first place. Also, because vegetable oil isn’t taxed as an over-the-road fuel, some people got sued by states or local governments for running it, as vegetable oil isn’t taxed as a fuel. Finally, many of the vegetable oil suppliers found outlets for their vegetable oil in the form of fuel companies, which would buy the raw vegetable oil and mix it with other fuels and chemicals to create biodiesel, a much more refined and diesel-specific fuel.
Photo 5/11   |   The downside of running vegetable oil is that at least part of your garage has to look like this. Not straining the gunk out of the grease usually means a clogged fuel filter and a stranded vehicle.
Stacked Boxes
A few years ago, a lot of people measured horsepower in how many boxes were stacked together on one diesel engine. Stacking boxes on every make and model became the norm—sometimes even two or three devices, along with propane or nitrous would be used on the same truck. These trucks would either run really hard, barely run at all, or explode. Still, after a while, many folks started to sort through combinations that actually worked. Stacks such as the Smarty/TST or PPE/MP8 seemed to make Dodges come alive, and Duramaxes and Fords were jumping on the bandwagon as well. With all the hubbub in the early days, one might expect to see three or four boxes on each diesel truck by now.
Photo 6/11   |   In December 2006, we took the stacked-boxes approach to a poor 6.0L Ford that had no idea what was coming.
Well, that didn’t happen. Much like cameras, computers, and phones have all merged into one in the past few years, so have programmers. While there are a few who still live and die by old-school stacks, myriad different tuners have led to enthusiasts stacking boxes less and less. Also, one could also get into trouble with stacked boxes. Using one box to add timing and then another to add timing would make it feel great—probably right up to the point where it blew up. Many people would inadvertently run 40 degrees of timing or more, max out their rail pressure, or fuel way harder than they needed to simply because they didn’t know any better. After a few blown engines, people relaxed and started trying to actually learn what sort of fuel duration, timing numbers, and airflow characteristics their engines needed rather than throwing multiple boxes at them. EFILive was also a game-changer, as it allowed the end user to see rail pressure, timing, and fuel curves, and tailor them to a specific vehicle. With that type of power, the stacking-boxes approach became virtually obsolete on certain makes and models.
Old Tech = Better Tech?
So the question remains: Was this old tech actually better than the new fangled fads? At this point, we’d have to say no. While all three of these approaches of increasing diesel performance are tried and true, technology marches on, and the future holds more choices, a better-informed enthusiast, and a more comprehensive approach to diesel performance.
The 2.8-inch-Inducer-Turbo Class
Probably one of the hottest classes in any type of diesel motorsport was a sled pulling class that had a rule of a 2.8-inch maximum-diameter turbocharger inducer. If you went to a pull a few years ago, the 2.8-inch-inducer Class would be one of the most competitive classes out of any of the categories. Turbo rules were also loose and fast, and many competitors were getting wheels as large as 3.6 inches chopped down to 2.8 inches to compete. While the 2.8 Class was fun to watch, the emergence of hotter and hotter 2.6 trucks, and drivetrain breakage meant that most pulling classes eventually dropped the 2.8 Class, and competitors had to enter either the 2.6 Class or the 3.0 Class. While we’re OK with propane injection, veggie oil, and stacked boxes falling by the wayside, the 2.8 Class was one thing we were sorry to see go.
Photo 10/11
Hot Rod Mercedes Diesels…
Back in 2006, the words Myna Diesel were floating around the office, and videos of a 400hp Mercedes were floating around YouTube. With inline engines and stout construction, Mercedes diesels had already made a name for themselves with vegetable oil, but we thought performance might be a possibility also. In a few words, nope, it wasn’t. Parts were too hard to get, and nobody really wants to be seen driving an ’80s Mercedes anymore. As cool as the idea of a 400hp commuter was, newer BMWs and Mercedes vehicles are a much more logical choice.
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