What Is a Turbocharger and How Do They Work?

What Is a Turbocharger?

A boosted engine or a turbo charged engine is one that uses the exhaust gasses normally expelled into the air back into the engine through forced turbines to produce more horsepower. Once again, Arctic Cat was the company to lead the way by being the first to stick a turbo on one of its sleds when they released the T660 four-stroke engine in 2004. Now there are more brands selling sleds with the option of a turbo charger and many companies selling the turbocharger kits. 

Before we continue here, I should note that Precision Boats in Idaho Falls has a turbocharger kit made by Boondocker, the Auto Sidekick, that has a major sale price right now. It fits any 2018-2019 Arctic Cat Ascenders. If you're in the market for a turbocharger for your snowmobile, give Tollen or Tim a call at (208) 529-0520 and he will tell you the current sale price. 

I digress...

How Do Turbochargers Work?

Turbochargers make horsepower by pressurizing the intake manifold, squeezing and forcing air into the engine thus increasing the air and fuel mixture, which allows the engine to pump more air and make more power. In essence, it's simply taking the air expelled through the exhaust system and pumping it back directly into the cylinders. 

The History

In 1905, A Swiss engineer named Alfred Buchi was the first to patent a supercharger driven by exhaust gases. Buchi graduated from Federal Polytechnic Institute (ETH) in Zürich and his father was a chief executive at a Swiss industrial engineering and manufacturing firm. Buchi was well set up to be a leader in the industry. It was his fascination with the challenge of improving combustion engine efficiency relating to exhaust heat loss that led to what we now call the turbocharger. He recognized the exhaust process as energy wasted.

It wasn't until a couple decades later that his theory and invention finally got a practical application. The German Ministry of Transport requested from Buchi the construction of the "Preussen" and "Hansestadt Danzig" passenger liners in 1923. Both ships featured twin ten-cylinder diesel engines with output boosted from 1750 to 2500 horsepower by turbochargers designed by Büchi and built under his supervision.

Today we recognize his 1905 patent as the "birth of the turbo charging era", but it was really his success with the passenger liners that dropped jaws and got attention when he combined his technology with a diesel engine and increased its efficiency by over 40%. Now people were listening. 

Only a few years later into the 1930s did car manufacturers start taking a page from his book and started adding turbochargers to racecar engines. 

Alfred Büchi died October 27, 1959.

Turbo System Layout

A turbocharger system consists of a turbo mounted to a flange on the exhaust pipe or manifold, an air intake tube and a tube that feeds the compressed air back into the engine. However, there is much more that goes into a properly setup turbo system than just a turbo:

Turbocharger: The correct turbo in any application will feature low system restriction, low charge temperature; low RPM boost threshold and low exhaust manifold pressure. This is to keep the temperature down.

Fuel System: A turbocharger essentially increases the size of an engine because it forces more air into the cylinder and, since an engine’s fuel system is sized to match the engine, the system must be modified to work as if it’s feeding a larger engine. On a fuel-injected snowmobile this is often done with an aftermarket fuel controller such as those made by Boondocker or DynoJet.

Boost Control: Boost pressure is typically controlled with a wastegate, which is set to release excess pressure at a specific pressure point. Uncontrolled boost can damage an engine, so the wastegate typically uses a spring-loaded valve to release excess pressure. Some systems also use a blow-off valve, which releases excess pressure that builds up in the charge tube after the throttle is closed.

Intercooler: Some turbo systems use an intercooler that is similar to a car’s radiator only it flows air instead of coolant. When air is compressed it heats up so it’s the intercooler’s job to cool the intake charge. The cooled intake charge results in a denser air/fuel charge and more power!

Should I Turbocharge My Engine?

You won't notice a turbocharger at low speeds and low throttle, but when you do reach a speed that the turbo engages, you will feel the steady increase in power that while smooth, is still a very noticeable difference in speed and power. Because of how a turbo works, it will actually make your exhaust system quieter. 

If you're looking for a small change in power (30-40% increase) then a turbocharger is a great option for you. But if you're looking for 100% improvement and increased power...then a turbo charger is still a great option! That's the beauty of this design is that you have control over how much of a boost you're looking for. It's all about how much air is compressed into the cylinders. 

With more and more environmental regulations, we are going to notice smaller engines being created by the bigger companies. Make any small engine act like it's a huge engine by adding on a turbocharger to your Arctic Cat snowmobiles and sleds. 

Are you ready for more power? Want to see what this is all about? Give us a call or stop by and we'll show you your options.