From a diesel perspective, anything that isn’t turbocharged is a waste of time from a tuning point of view. Similarly, anything that isn’t using electronically managed direct injection is a pointless tuning proposal so we are somewhat limited to modern Turbo Diesels.
Get rid of those two ointment bound flies and things get more interesting
Twin scroll turbosWe look at the advantages of twin scroll turbos, discuss how they work and how to set them up. People have used twin turbos in the past to address many of the problems you hit with a single turbo and the twin scroll turbo offers a neat drop in upgrade and provides many advantages.
Blow off valves, dump valves and screamer pipes
Blow off valves and dump valves.
When the throttle is closed (when you lift off the accelerator) in a turbo driven engine there is a build up of pressure as forced air is still coming from the turbo. Lifting off the throttle is a lot like putting a plug in the sink – the flow through is stopped and water would just build up and overflow the sink.
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.














