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Fow restrictions result in pressrue drops. The turbo has to work harder to overcome this and produces more heat and even more heat as the operation conditions so dictated make the turbo less efficient as well. So a lower restriction IC means a more efficient heat exchanger to deal with less heat. When a turbo has to work harder to over come restictive pressure drops, the wastegate directs more exhaust flow thru the turbine which increases exhaust back pressure and reduced shaft HP.
So with a small restrictive IC, you get a hotter less dense charge air and lower HP potential, and the turbine back pressure robs shaft HP from the engine. At 15PSI of boost, the exaust back pressure in a typical undersized OEM turbo application is probably around 30 PSI. The turbine energy is not free.
You want to reduce all pressure drops. modied air box, K&N 33-2663, turbo compressor discharge silencer, rework throttle body, Sports exhaust and the final stage would be the Viggen IC.
There are otehr issues that bear on the end result of thes changes, such as where the boost control point is. For a MBC connected upstream of the IC core, high RPMS leads to a drop in pressure in the manfold, and drooping torque. ECU controlled boost has a control point at the monifold, so the turbo works harder to compensate for the IC pressure drop. A MBC tapped after the IC core is better than from the compressor housing!!!
Knock is most often post igniton and very rarely pre-igniton. Hot charge air makes knocking more likely. Combustion deposits become hot spots and are a primary risk factor. Techron Concentrate is fairly effective at removing suck deposits. A weak injector can also cause a lean cylinder and the Techron will help keep injector spray patterns good and reduce cylinder to cylinder richness variations. Hi octane fule is also required.
posted by 209.172.20...
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