Tuning turbo engines

"A lot of hot air."

What is a turbo. If you go back to your childhood you probably remember those windmills sold at the seaside. Imagine a windmill with 2 propellers back to back. As the wind blows the first propeller a shaft turns the second one and it will blow air in your direction. A turbo contains 2 impellers which are located in the exhaust flow and along the intake path.

The exhaust side rotates as the exhaust gases flow and this turns the impeller on the intake effectively sucking in fresh air. So the turbo essentially generates power from the waste exhaust gases. Although sticking a propeller in the exhaust flow will reduce the exhaust efficiency the power gains on offer more than make up for this. So who invented the the turbo? Aircraft running on fuel were altitude restricted due to the thin air and lack of oxygen this contains. By using a turbo the air could be forced into the engine and allowed the aircraft to run at higher altitudes or faster at lower altitudes. It was not long before someone saw the application in car engines and we started to see turbos arriving in popular cars. In recent times manufacturers have been forced to produce more economical cars. With a turbo you get more power per cc making an engine more efficient. It is the power gains that TorqueCars members are most interested in, although the economy is nice to have.The potential for turbo tuning power gains is massive. Most engines are over engineered for reliability and can take increases in power of 30-50%. Some engines can support even larger power gains. There is little surprise that in our 2 most tunable engines report, both are turbo driven. With the advent of modern engine computer control we get a method of maximising the power produced by the turbo. For example the exhaust gases are vented away from the turbo when certain levels of boost are reached. With a remap you can overcome this limitation. Fuel delivery also needs to matched to avoid running a lean mixture so the computer controls the timing and quantities of fuel delivery. Please review the articles on Remaps,BOVs, Boost controllers for more detailed information.Are there any drawbacks to turbo engines? Until the exhaust gases start to flow quickly enough there is little the turbo can do. This is manifest in what is referred to as lag where the engine seems lifeless until the turbo kicks in. The bigger the turbo the greater the lag problem. Also when you compress air you heat it up and as we all know hot air carries less oxygen than colder air. This is easily solved with an intercooler. No longer are we limited to a single turbo. Many cars now come equipped with Twin Turbos such as the GTO and Nissan 300zx. Big turbos are also on offer and this is the usual path an upgrader will take. We also see triple and quad turbo setups with boost controllers kicking in each turbo as exhaust flow increases for a steady power delivery.