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What do I next with my '18 STI?

2K views 7 replies 5 participants last post by  VA STI 
#1 ·
I bought the car used with a Cobb SF/Invidia Catted DP/N1 Dual already installed - There was sadly no Accessport in the vehicle.

I have since had a few people with a fair amount of knowledge drive the car and all agree that it HAS to have been tuned to run as well as it does and to never throw a CEL.

My concern is obviously the fuel system with the Intake/Downpipe setup - But things like an AOS, TMIC, Headers, etc. are also important.

Suggest on a 'next step'?
 
#2 ·
First step, buy an Accessport.

My opinion on the rest:

AOS is useless for a street car. The factory PCV system is fine, and if your blowby is bad enough its causing oil to get into the intake then you have other issues that need addressing. If you're tracking the car, then I think an AOS is a good "investment".

No need for a TMIC with stock turbo, as the factory TMIC is really good. Especially on the 15+ STis. It can easily hold up to 400 whp. but if you HAVE to upgrade, ETS would be my choice.

Fuel system is not needed unless you are running out of injector. Log your IDC when you get an AP before you spend a lot of money on fueling upgrades. if you aren't routinely hitting above 95% I wouldn't even worry about it.

The only header upgrade you should consider is an ELH, like Killer-B or Invidia. Aftermarket UELH are pointless, and be advised that if you swap headers you will lose the rumble but gain power and keep the engine running healthy.

Considering getting a 3 port BCS, like Cobb or Grimmspeed. Its a worth upgrade
 
#7 ·
First step, buy an Accessport.

My opinion on the rest:

AOS is useless for a street car. The factory PCV system is fine, and if your blowby is bad enough its causing oil to get into the intake then you have other issues that need addressing. If you're tracking the car, then I think an AOS is a good "investment".

...
Would the occasional autocross or track day (1-2 times a year) warrant an AOS? Or are you referring to more heavy use? (i.e. less daily/fun car and more legit track car)
 
#3 ·
You almost certainly have an Accessport tune but the hardware is AWOL. TMIC is fine for well over 400whp. AOS is a good idea on just about any Subaru. ELH are good for ~20hp/tq on stg2/3ish cars. 3 port doesn't really do anything with a stock turbo but if you're getting a tune and want one better to tune once.
 
#4 ·
Would it be possible with an AP to see if I have a tune? Or discern with one if the car already has bigger injectors/pump.

And to that end - If it does not have injectors/pump are those things with Pressure Regulator/Sensor enough to balance out the fuel system? Or do I need the entire 'Kit'?

Cobb FPS/FPR
1050IDX
AEM Pump
IAG AOS
Cobb BCS
Getadomtune Cylinder 4 Mod
Tomei ELH
Protune

This is my plan loosely.
 
#5 · (Edited)
The AccessPort during install will warn you that an AP is already installed and if you continue the original AP will be wiped out. Opensource will be locked out by the AP install.

You just need to look at the injectors and pump to know. There's no tuning required for the pump.

This is what you need for the fuel system:
ID1050s
AEM320 Pump
COBB FPR

The rails are cool looking but not required.

upgrading the BCS can give you more linear control but it isn't required with a stock turbo.

Happy to help you with parts and tuning!

Josh
 
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