Under bonnet temperatures are one of the biggest performance killers around.
Quite simply, you want your engine to be sucking in cold air as this carries more oxygen and will allow you to burn more fuel.
The exhaust system is one of the contributors to under bonnet temperatures. You can therefore lag the exhaust to help prevent this heat soak into the engine bay.
Principles of porting an engine and big valve conversions
The inlet and outlet ports on the engine block are usually larger than those of the manifolds that connect to them.
This allows for scope in the manufacturing process to allow for mismatched alignment.
Generally the engine ports are larger in the upstream flow direction avoiding turbulance but power gains can be made by matching these up.
Limited slip diffs, which LSD is best for handling.
Slip diffs "Time for something DIFFrent" Every car has a slip diff but with a few tweaks you can totally […]
Particulate filters and FAP Performance gains.
The particulate filter is a stand alone unit. It is located upstream of the cat in the exhaust system and its purpose is to remove soot particles from the gas stream. The cat the proceeds to do its usual job of converting CO to CO2 and is in no way dependent or relied upon by the particulate filter.
In diesels the cats are two way devices and run in unregulated mode (ie. no O2 sensor like a petrol car).














