Blindly bought a modded 2018 STI

Yoitscode

New member
If I post pics on here are you guys able to tell me what stage my car is ? I just bought a 2018 sti and wanna make sure my investment was worth it. Don’t know a whole bunch about these cars but it has afermarket Intake, exhaust, Cobb tuning stage 3 I believe..? It came with accessport and there’s so many stage 3 options how do I know which map is best for my car ?? So many questions so I’ll post some pics here soon. Car has 16k miles. Also took around block for first time and got an engine light first was “system too rich” now that’s randomly gone and got engine light for sensors open codes or something... losing sleep over this ! Lol
 

Yoitscode

New member
 

Alin

On a quest of STi erudition!
@Yoitscode , welcome to IGOTASTI!!! You're going to absolutely love it here!!

Post some pictures of the engine bay and interior. We can't help if we don't have a list of actual modifications or visuals.

In reality, you shouldn't have purchased it blindly. Also, I wouldn't recommend driving it without knowing if it's properly tuned, and it appears that it is not at the moment.
 

Yoitscode

New member
 

Batmobile_Engage

Eats rice, drinks V8.
Staff member
Sorry for blowing up but another question why don’t I have a top mount intercooler ?
You have a Front Mount Intercooler. Not sure, but judging from the charge pipes, it might be a Perrin FMIC.

As for tuning, I would highly recommend finding a protuner that has an all-wheel drive dyno and works with Cobb Accessport.
Go to: https://www.cobbtuning.com/dealers
...and "Narrow By Dealer Type" to PROTUNER and see who is available in your area.

They can run a baseline, figure out the specifics to your tune and make any changes that might be needed. You definitely do not want to blow up your engine by assuming that the previous owner had everything done properly.
 

Batmobile_Engage

Eats rice, drinks V8.
Staff member
Also, while @Alin is right that driving it with a tuning problem is risky, it might be the only reasonable way to get it to a protuner. So if you must drive it, make sure you are very lite on the gas pedal, so that the turbocharger is not producing much boost. Producing a lot of boost with a poorly tuned engine is generally where you start blowing things up.
 

Grinder34

Track Monkey
Would love to hear a bit more of the backstory. Was this through a middle man, or can you reach out to the original owner? Does he have a mod list, receipts, maintenance history, tuner name? Any/all of that would be SUPER helpful.

To answer your specific questions about the stage 3 tunes on there, they're all slightly different. So the ACN91 is for places with "bad" gas that only goes to 91 octane (A - alaska, C - California, N- Nevada, 91 - 91 Octane). Then theres a wastegate setting HWG vs LWG, A Valet mode (probably limits RPM, boost, etc...)
 
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