Just drill/tap the main pipe after the boost sensor, before the throttlebody. Use lock-tight to keep it from moving/backing out (red). Face the open side of the injector towards the intercooler away from the throttle body ( help atomize/break up the mixture ).
And no. You don't need a tune at all. Could you gain more power with it when getting a custom tune? Sure. But that means a couple things...
#1 car NEEDS/requires meth injection to run WOT.
#2 if the injection system has a failure, you could have a big failure.
#3 more money/time.
If you put the injector after the intercooler, but BEFORE the boost sensor, then that sensor will see the colder intake temps, and increase timing/power. That maybe a better idea actually. But its sort of "yet to be seen" on this car. Other wise, the charge temp will actually be much cooler than what the ECU thinks.
Unless you have reliable, easy accessible 100% meth, just use windshield washer fluid with the highest content of meth you can find.
In my personal experience ( years on my srt4 ), 100% water keeps it from knocking the best, but made me run a smaller nozzle. 100% meth let me run the biggest nozzle which lead to the best results for me because the stock srt4 turbo could only atomize so much liquid. The greater volume of liquid made a bigger difference. Issue is... 100% meth isn't around every street corner. You could use E85 which is damn close to the samething if that's in your area.
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