It’s been a few years but I had occasion to ride a 600cc 2-stroke with an aftermarket turbocharger a while back and, man, was it impressive.
I believe the stock engine at that time made about 110-hp and with the turbo it jumped up to about 150. That was more power than the big-inch, naturally aspirated sleds were making at that time and it felt like the boosted twin was literally trying to tear itself out of the engine bay.
Throttle response was good – with some lag – but the sled felt like it had gained about 300ccs of displacement. The increase in torque was the most evident – the sled easily lofted its skis, transferring its weight rearward and the studded track dug in like a drag racer. Pretty impressive, and my impression was that the 2-stroke responded to turbocharging way better than a 4-stroke.
We’re wondering, with the increasing use of turbocharging in the 4-stroke off-road SxS market, if more snowmobile OEMs besides Arctic Cat will be offering turbos in the near future?
The reason we’re raising the question about 2-stroke turbocharging is because it makes such a huge difference and can be added with little modification to the 2-stroke engine.
Think of a 160-hp 800 twin boosted to 200-ponies. Even with sophisticated fuel management systems like Cleanfire, slot injection and E-TEC, a turbo could be made to work and it would avoid the need for OEMs to increase 2-stroke engine displacement.
Yes, there seems to be a resistance to building 2-strokes any larger than 800ccs and the cost to re-certify a new engine could really be prohibitive, not to mention the sheer risk of warranty problems from a super-lean 900, 1000cc or larger mill.
Sometimes we’re so close to the business, we miss the obvious. A turbocharged 2-stroke would be a huge coup for whoever offered one. In limited numbers, we think the market would get on board in a flash.