Subaru WRX Forum banner

1 - 4 of 4 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
Hello I'm a first time WRX owner (2017-FA20) and was hoping one of the pros can give me a quick guideline for the different stage tunes and the mod journey i am about to embark on.

car has about 20,000kms on it, been running 94 octane from Petro-Can since I bought it


here is the plan so far based on my research, feel free to correct or suggest any changes.

PHASE 1 mods:
-MAP Air Intake Kit
-Cobbv3sub004 AP unit set to MAP OTS stage 1-93oct

PHASE 2 mods:
-Mishimoto 3" downpipe w/ Cat
-Invidia Gemini R400 Burnt Tips Catback
-MAP OTS Stage 2-93oct (should i be worried about running diff branded bolt-ons with a MAP tune?)

~~HKS SSQV BOV (this part I am having some serious doubts about, apparently the new FA20 has a MAF system which apparently a BOV is not good nor needed for??? im not sure what a MAF system is so any info on that would help)


is there any other engine mods I should be doing at this point

eventually i will be getting a front mount intercooler and upgraded turbo but these 2 phases should last me the first year,

any feedback or guidance is appreciated!

Cheers from Toronto
 

·
Registered
Joined
·
477 Posts
Yes, a blowoff valve is not good on a MAF car (that includes all WRX, unless specifically tuned using Speed Density).

To give you an understanding, it's quite simple. Your car measures how much air is going into the intake with a MAF sensor. It measures the volume of air. It then adds fuel based on that reading. When you have a blow-off valve, or hybrid blow-off valve, some of that air leaves the system... but your car still gives the same amount of fuel. That means when you let off the throttle and release some air, you will induce a rich condition which will result in mild things like driveability issues (hesitation when you let off the gas and tip back in)... exhaust afterfire (exhaust pops) or worse yet, if the spring is too weak, you will experience full-blown stalls when you press in the clutch. Most of these can be mediated by a very stiff spring, but not eliminated. It's generally a better idea to run a full recirculation valve (it functions the same, but releases the pressure back into the intake system and not atmosphere so you don't lose any air you already measured).

But... you don't actually need one until much higher power figures... unless you want a louder "pshhhssst" of course.


To answer your actual question:
COBB has notes for every map. I'll just copy and paste info from this page: https://cobbtuning.atlassian.net/wiki/spaces/PRS/pages/75071626/Map+Notes+for+VA+WRX+6MT

Stage1 - Otherwise stock vehicle with the following modifications*:
Intake Requirements: Stock airbox with stock air filter
Exhaust requirements: Stock exhaust or upgraded cat-back exhaust

Stage1+BigSF - Otherwise stock vehicle with the following modifications*:
Intake Requirements: COBB Tuning BigSF Intake and Airbox System (Part # 745100 for 2015-2017, Part #745110 for 2018)
Exhaust requirements: Stock exhaust or upgraded cat-back exhaust

Stage2 - Otherwise stock vehicle with the following modifications*:
Intake Requirements: Stock airbox with stock air filter
Exhaust requirements:
Upgraded J-pipe with high flow catalytic converter
Upgraded cat-back exhaust (stock exhaust acceptable)
Boost Control requirements: Deleted 2nd restrictor pill (between Tee and wastegate actuator). See additional information in "Boost Control System Modification" section below.

Stage2+BigSF - Otherwise stock vehicle with the following modifications*:
Intake Requirements: COBB Tuning BigSF Intake and Airbox System (Part # 745100 for 2015-2017, Part #745110 for 2018)
Exhaust requirements:
Upgraded J-pipe with high flow catalytic converter
Upgraded cat-back exhaust (stock exhaust acceptable)
Boost Control requirements: Deleted 2nd restrictor pill (between Tee and wastegate actuator).See additional information in "Boost Control System Modification" section below.

*The addition of any other hardware may make the vehicle perform poorly.
 

·
Registered
2019 WRX
Joined
·
8 Posts
Here's some good information about the differences between the stages. Basically, stage 1 is a tune, stage 2 is a downpipe, and with "+" it means you add an intake as well. There aren't really well defined "stages" past that or OTS tunes as far as I'm aware.
 
1 - 4 of 4 Posts
Top