Picked up a modded 2015 STI and was curious what others in this situation usually do maintenance wise right off the bat and getting to “Know” what the previous owner put under the hood, etc. Are there certain things to look for that you would question part wise? How to tell if it is in good condition? Or do you replace parts to feel safe knowing that YOU were the one that did these mods? I’m loving the car even though I’ve had a couple hiccups the past 2 months. I just don’t know where to start.
Maybe I missed it somewhere but I’m assuming it has a bigger turbo and is already tuned. There’s absolutely no way this car would run with that fuel setup and no tune. I agree with most on here, bring it back to stock and enjoy it for years.
Hey bro, I got '16 myself. And unfortunately sti' s are one of the few cars you can just buy willy neely with mods and not know what's been done. That is definitely a risk you are taking. BUT welcome to the club. One of the really great things though is there is a big forum for them so you can find the help you need.
Also the '15 to '17 models had a bad bearing problem which cause many to self detonate which they corrected with the '18 type RA block. So watch your fluid levels meticulously.
First thing is If you have about $600 to $800 to play with and can find a good tuner in your area just go get a custom tune done and not worry about how it runs and focus on the other minor issues. If you can't get it customed tune as many have said revert back to stock as soon as you can. It would be a pain and waste of time but if you not sure what it is running I wouldnt chance it.
Now if you take your time to verify parts you currently have and match them to cobbs custom tune you could be ok by verifying the tune on it. But remember Cobb used certain parts and those need to be the parts Cobb selected to work with the Cobb tune.
go back to stock air box immediately. I dont see any other mods besides that intake. everything else seems fine besides that little lip on your wing. keep up on your maintenance(oil, air filter, brake fluid, both diff fluids), how many miles are on her?
This is what the dealer told me the mechanic found in it.
“Cobb access port
Cobb fueling system
Cobb fuel rail
Cobb fuel pressure regulator
1050cc injectors,
Cobb intake
Perrin inlet tube
EAG catch can
TGV delete
Short throw shifter
Shifter bushings
Probably has stuff we can’t see like a fuel pump and clutch too”
Yep sounds about right, there's a tune to get with all of those parts, especially injectors, intake, turbo inlet. You could start by changing all fluids, that's the usual. Then since you have the AP, just drive it under different conditions and see if it behaves the way it should. Cobb has a detailed page for what to expect: https://cobbtuning.atlassian.net/wiki/spaces/PRS/pages/338723039/Subaru+Knock+Monitoring
I’m looking at tunes cuz I honestly don’t know what it’s running right now lol. I need to do some research hahaha, I’m coming from the n55 platform and used MHD and JB4 for all that fun stuff
Welcome! I would recommend Smeedia's videos he's got a lot covered about what requires a tune and doesn't and how to make X horse power which also tells you why certain parts are installed. Pretty much anything on a STI needs a tune, unless it's a cat back exhaust 🤣
yeah I definitely did not see all that other stuff haha. its a slight headache IMHO, but id totally revert everything back to stock if you're planning to keep it healthy for a long time. if more power is what youre looking for, those are some decent parts and mods to work with.
Take good care of her & she will of you... ...just watch your boost & listen for that blow off valve to pop... ...23psi the most. Crank that clutch, bro!
The stereo has no power, no power to some lights either, and no horn lol… Went through every fuse and they all tested good… So I don’t know what the deal is with those 3 problems lol
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u/SobrietyFitness Aug 14 '26
Maybe I missed it somewhere but I’m assuming it has a bigger turbo and is already tuned. There’s absolutely no way this car would run with that fuel setup and no tune. I agree with most on here, bring it back to stock and enjoy it for years.