Direct Injection vs. Port Injection

[Mike Giblin]

I think I understand the advantage of direct injection, injecting into the hotter compressed charge increases charge cooling and permits higher compression ratio. If correct, why also port inject? All flavors are out there.
Mike

 

[Roger Reid]

Direct injection only has no fuel flowing around the valve stem. Fuel flow around the valve stem minimizes carbon build up on the stem. Pre 2016 Audi R8's had this problem. Also tuners have been able to get higher horsepower from (Audi R8) post 2016 dual injector design. Emmissions can also be

 

[Shane]

I second what Roger said. A lot of manufacturers switched from port to direct injection, only to find out a few years later that their engines were suffering huge carbon deposits on the intake valves resulting in various engine driveability issues.....so most manufactures have now gone to the port/direct injection combo to keep the intake valves cleaner.