November 12, 2008
Propane Powered Sled
No… it’s not what you think!
As mentioned in ‘Belly Mon, Going Up’, my old friend Randy Swenson is up to his old tricks again.
I learned a long time ago to take his madness seriously, like when he announced he was going to build up his ‘Project 101′ RX-1 Turbo based on an early pre-pro unit, kicking off the whole Yamaha 4-stroke turbo thing in the process.
This summers project may not be quite as ‘impactful’ but it certainly is a head turner. The latest creation features a turbo-charged, propane power system bolted up to his Nytro MTX, offering him two major advantages. The first addresses the octane requirements of any +15lb boost engine. To make the big power, reliably, either a heavy blend of, or 100% race fuel is required. At $4.50 a litre it doesn’t take a mathematician to figure out the sting to giggle factor. Propane on the other hand is cheaper than regular gas and has an effective octane rating equivalent to a 120 RO.
The system Randy used is engineered specifically for 4-stroke snowmobiles (Yamaha) and has been three years plus in development. Val Simmons (of Simmons Flexi-Ski) and Brad Story (Team Thunderstruck) have both been very instrumental in the design and manufacturing of the Simmons Propane Systems turbo kit. Strangely enough one of the biggest hurdles in getting the kit to market has been found in the fuel cells which have been a long time in the government approval and certification process. The cells run in pairs and come in 4, 5, 6, 7 and 8 gal options. Randy is using two 7 gallon tanks which will yield about 160 km (100 miles) per fuel load in mountain condition. ed: This could be significantly more on our eastern trails.
He can add fuel at any service station that sells auto propane but for convenience, Randy has installed a 270 litre tank in his truck.
So what’s the big deal beyond the fuel cost savings? I believe what really hooked Randy, after riding Brad’s propane sled (in his words) was the ‘incredible throttle response‘ and ‘crispness’ of the engine. Our current FI system requires elaborate e-prom mapping to cover every conceivable fuel requirement with complex logarithms to meter the demands. With the addition of a turbo, this mapping has to be altered and its not unusual to experience some burble or hesitation at times.
The propane system removes the stock injectors and all the electronics that control them. The propane is delivered by a new ‘load based’ injection system that reacts directly to manifold pressure and according to Randy, he has never ridden a ‘cleaner’ responding sled… ever. Speaking of clean, he mentioned that the oil comes out of the engine looking almost as clear as the day it was installed, perhaps another benefit in the long term.
I asked him what kind of power he expected to make and at what level of durability. How about 300++ reliable horsepower at upwards to 26 lbs of boost. The engine internals are all stock except for a head shim to reduce the compression and some beefier studs to hold it all together, limiting deck distortion under full steam. As incredible as it seems, our engines have proven able to build this kind of power reliably over the long run, during several seasons of high boost and high mileage. Our engineers 
still smile when I bring the point to bare even though they won’t agree to the engine duty cycle probabilities as defined by our own internal standards. Randy is more than doubling the output of his Nytro MTX using the stock parts, so how long do you figure your new Nytro or Venture GT is going to hang together? 
Well that really only leaves one question in my mind: how much will all this cost for parts and time? How about 11,000 USD! Yeah I know… but consider this, the kit contains the turbo and all its components, the propane system complete, assorted body parts and professional installation. The latter is not an option at this time, you must have the work performed by Simmons Propane Systems. Considering the current cost of a gasoline turbo system (installed) and some of the additional magic like nitrous, to ensure crisp response plotted against the cost of race fuel, propane systems may well prove to be a bargain for the high-mark riders.
With around fifty of these monsters on the snow and more in the wings, I am considering the feasibility of having our accessory guys develop an optional ‘GYPA’ titanium grill for the tunnel deck. Can you imagine the ‘kabobs’ Randy could cook-up with 14 gallons of propane at 7000 feet! This would kick the crap out of buddies ‘Hotdogger’ nestled around the expansion chambers of his beloved, pine-cone-challenged, 2-smoke. And yet another good reason to go 4-stroke!
cheers cr
All I can say is WOW!!! Hard to believe how far we’ve come since the 1960′s one lungers. even a matter of 10 years ago it was hard to believe that there would be a viable 4 stroke performance snowmobile, and here we sit with propane injected turbocharged sleds. Unbelievable. The question that begs to be asked is “Where do we go from here?”
That’s an easy one Ben… we go for broke (one way or the other) lol cheers cr
November 12th, 2008 at 10:53 amHoly crap. That sled looks insane.
And just think of the Ptarmigan feast you could grill up in the back country
cr
November 13th, 2008 at 11:23 amCould there be a propane powered yamaha sled in my future?? maybe…
November 16th, 2008 at 2:18 pmABSOLUTELY AWESOME SLED!
There’s no doubt that when it comes to creativity and off the wall Technology the name “YAMAHA” Always seems to be in there somewhere. I could sure go for a Little Test Ride on that Bad Boy!
November 22nd, 2008 at 4:52 pm