okay first off my car is an 05 sti with an ss protune on ecutek..okay my question is..i have a custom exhaust setup right now because i wanted my car quiet..but now i dont want it quiet anymore..but right now i have an invidia catless dp and an hks hi power axle back setup with the stock center section with 1 factory resonator still there..if i was to finish my exaust and delete that stock resonator would i need to have my car retuned??or would it be ok like that?? scott chime in because i know you know the answer
I'm not scott siegel to be sure.... But probably not unless you're currently on stock ECU. Resonators don't provide all that much backpressure, so you won't run into to stuff like boost creep if you take that one out.
i wouldnt think you would need a re tune but i know you can probably pick up some power because there was a thread a while back of someone running three inch but had the 2.5 inch resonator on the system and by changing that they made better power... more cause of the flow restriction from size but ever bit helps!
Any change that makes a hp difference "MAY" need tuning for. This means almost anything that is worth installing might need to be tuned for... So either don't make a change after tuning because it won't do anything, or plan on possibly needing a tune for it. Probably the only things that don't need tuning for are a filter change or going to one step colder plugs. Almost anything else that actually makes a difference, probably should be tuned for. If you pick up power by changing exhausts, you will probably overboost... then again, if you have an AP2, I probably gave you a Low Waste Gate map that might be perfect... Siegel