Direct injection/port injection explained?

[regnak]

I can't speak to FI tuning as I've never touched it.

But, to address your question about running as much DI as you can, Doug, for the most part, yes you should. As Andrew mentioned, there's the charge cooling aspect to DI. But charge cooling isn't just dependent upon how much fuel is being injected via direct injection but also when the fuel is injected. When tuning a specific condition and a fixed amount of fuel, maybe you change the pfi/di ratio from stock to allow more fuel on the port side to allow for good mixing and then slightly retard the DI timing so the fuel mass from the DI side cools the cylinder (air inside gets denser -> more air can come in -> higher volumetric efficiency -> more power).

Andrew and Mike also touched on how charge cooling allows for operation at high compression ratio. By cooling the charge air and cylinder, you're directly affecting where the onset of knock will be in relationship to spark timing (cooler cylinder temps mean lower chance of fuel igniting on its own).

[mike the snake]

I'm really hoping my tuner has a good grasp of all this, because my car's going in for the turbo kit and WMI install and tuning next week! LOL

He's a very accomplished tuner, so i have high hopes.

[pro_turbo]

Ive tried to copy the map from stock rom to my Motec m150 ,
Result is car is run and react more agresively..
More middle range pedal to torque feel compared to just using di up to 4000rpm up.
The stock package map from motec are just using DI 100% up to in 4000 rpm they use 10%on 70kpa up
Then on the 100kpa up they use 20% max
This has been a good map for years if we run turbo or even na.
Easier to tune
But i just done the tune today with the combined fuel injector from the low rpm.
Let see where it will take me.

[FlyingJett]

Hello guys ;-)
I know that it is necropost, but is it worth to set port injection to be 0 in hot mode for NA?
Could it somehow damage engine?