Hey everyone, I'm new to the evo scene, I did some searching but didn't really find what I was looking for. I am getting ready to install a 3" turbo back exhaust and a cone filter replacement. I am just wondering if a tune would be absolutely necessary? From my experience with other vehicles, American brand mostly, if u put a cia intake and exhaust, the factory o2 sensor and computer could adjust accordingly. Is this the same with evo's? Sorry if I sound stupid.

 

most likely yes i would get it retuned.. the afr is going to go much leaner, but its hard to say what afr you will end up at without actually logging the afr with a wideband.

the evo uses a narrowband o2, the maf will adjust to the mods you add, but the stock o2 will not do anything to correct open loop full throttle AFR. the actual fuel maps need changed for that.

 

where to start, this was just the first page
https://www.evolutionm.net/forums/ec...t-my-tune.html
https://www.evolutionm.net/forums/ev...y-exhaust.html
https://www.evolutionm.net/forums/ev...need-tune.html
https://www.evolutionm.net/forums/ge...-can-hurt.html

 

Throwing parts on is great but without tuning you wont see the actual gains from it.

 

Thanks for the help and the links, think I got what I need. Much appreciated!

 

I am not the expert here but this is the best way for me to explain it. You have a o2 sensor or two and you have a Mas air flow sensor. Both sensor detect changes on the intake and exhaust part and both sensors send signals to to the ECU to adjust the fuel trim bases on what they read. When things are changed from the factory then the ECU has a fail safe mode that protects the engine by throwing a rich AFR(Air to Fuel ratio).

A rich AFR means less power and worse gas mileage. You can fine tune the car with a tune and readjust the AFR for maximum power. my .2c'

Carlos