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I just want to do a COBB Stage 1 tune to 1) Get rid of the annoying stumble, and 2) Protect my car from the (obviously) sub-par factory tune - that's it - nothing crazy, not even bolt-on parts. Sad, sad days.
Sadly the 2019 STI probably has one of the better OEM tunes performance-wise compared to previous years. Although I've heard mixed reviews about the safety of the OEM tune..

The video below talks about the OEM tune being more aggressive on the 18 STI. I believe this held true for the '18 Type RA & '19 STI as well. They mention the OEM tune leaning out in higher RPMs (above 5,400rpm) and pulling timing. Cobb's map runs a bit richer to avoid this.
2018 STI Baseline and Cobb Stage 1 Data on the Dyno - YouTube

I also found the information below from Cobb regarding the OEM tune's aggressive timing:
COBB Tuning – Subaru WRX STI Type RA Accessport and Parts
The Type RA is loaded with a much more aggressive tune than we are used to seeing from Subaru. In fact, on ACN91 octane fuel the car was seeing enough knock to shut off the boost control system completely. Using higher quality fuel (93 Octane) we did see much more consistent power out of the Type RA however it is still leaning fairly hard on the knock detection system – with hits of 4 degrees seen relatively consistently. With that said, our internal calibration team was still able to find a bit of power, specifically in the mid-range, which can be realized in our Stage 1 Off The Shelf Maps. By using a different tuning strategy, we were also able to mitigate the concerning levels of knock. This makes for noticeable gains and peace of mind, especially for those using ACN91 fuel.

The factory calibration essentially starts with higher base timing values and the knock system rarely allows it to fully take advantage of dynamic advance. Our calibrations will start at a slightly lower base value with a higher allowance of dynamic advance. It’s not necessarily disastrous for longevity as the knock correction system is indeed doing its job. Our approach is to not lean on that system as hard as the factory calibration does.
The consensus seems to be that the OEM tune may encounter some knock and pull timing on 91 octane. Both sources claim that the OEM tune is still safe as the knock correction system is functioning as designed. The Cobb stage 1 tune claims to rely on the knock correction system a bit less while also increasing mid-range power.

How lucky I am to live in California where 91 is the only option unless I go the flex fuel route..
 

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Discussion Starter #42
Welp, looks like you already know what you're doing. Fill your boots. We'll talk again when it happens.
Not trying to be hard headed or create any friction with you. I'm just saying there is a reason why Subaru settled and extended their warranty for bearing failures. Some people want to keep their cars healthy without losing the value of the warranty.

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They're in the "will not void" section along with a catback & tmic:



The following vehicle conditions or modifications...shall not... exclude the Settlement Class Vehicle from receiving a repair under the terms of the Extended Warranty.

a. Installation of aftermarket Cat-Back exhaust installed after (or downstream of) the factory catalytic converter;

b. Installation of atmospheric blow-off valve;

c. Installation of aftermarket cold-air intake; and/or

d. Installation of aftermarket top-mounted intercooler.


So what I am understanding is they are ok with these mods?!


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So what I am understanding is they are ok with these mods?!
I wouldn't that Subaru is okay with these mods for general warranty purposes.. but rather it's been determined that they can't exclude you from "Extended Warranty Repair" for the Class Action Settlement Agreement. Maybe they had a harder time proving that these were damaging. I can see this being as problematic since Subaru offered the SPT intake as an "aftermarket" option. The BOV still puzzles me. The TMIC and catback make sense.

http://www.enginebearings.settlementclass.com/assets/pdf/Settlement_Agreement_Signed.pdf

I'm sure Subaru could still find a way to deny a general warranty repair for having them :lol:
 

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Sadly the 2019 STI probably has one of the better OEM tunes performance-wise compared to previous years. Although I've heard mixed reviews about the safety of the OEM tune..

The video below talks about the OEM tune being more aggressive on the 18 STI. I believe this held true for the '18 Type RA & '19 STI as well. They mention the OEM tune leaning out in higher RPMs (above 5,400rpm) and pulling timing. Cobb's map runs a bit richer to avoid this.
2018 STI Baseline and Cobb Stage 1 Data on the Dyno - YouTube

I also found the information below from Cobb regarding the OEM tune's aggressive timing:


The consensus seems to be that the OEM tune may encounter some knock and pull timing on 91 octane. Both sources claim that the OEM tune is still safe as the knock correction system is functioning as designed. The Cobb stage 1 tune claims to rely on the knock correction system a bit less while also increasing mid-range power.

How lucky I am to live in California where 91 is the only option unless I go the flex fuel route..
Thanks again for the information, STINick. I can tell you my 2004 never had these issues - but that was by all accounts almost a different car ;-). Just FYI, I run 93 Octane in NJ, and it still stumbles around that 4-5K mark, if you accelerate with any authority. Since COBB runs a little richer, I'm assuming that "leaning out" at higher RPMs was Subaru's way of getting the best mileage they could out of this "variant" of the EJ.
 

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Thanks again for the information, STINick. I can tell you my 2004 never had these issues - but that was by all accounts almost a different car ;-). Just FYI, I run 93 Octane in NJ, and it still stumbles around that 4-5K mark, if you accelerate with any authority. Since COBB runs a little richer, I'm assuming that "leaning out" at higher RPMs was Subaru's way of getting the best mileage they could out of this "variant" of the EJ.
Subaru certainly gets a bad rap for their OEM tunes. I'm not saying that there isn't any validity to it, but we have to keep in mind that OEM tunes have to balance power, reliability, emissions, fuel economy, variation in fuel octane (91 vs 93), climate, elevation, etc. It's impressive that they still meet the necessary regulations considering the EJ has remained relatively unchanged over the last 15+ years.

Pro-tuners primarily focus on increasing power for your specific conditions.. and the good ones go about it in a safe manner :) They have no emissions or fuel economy regulations that they have to meet.
 

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What are my19 peak boost #'s? In sport# with only a Cobb titanium cat-back at sea level I have hit 19.5.








https://imgur.com/KE2UX4x
 

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They can send the ecu of to get read thoroughly, but it'd have to be for a good reason, An expensive warranty claim could do it.

Can they see past peak boost levels easily? That'd be an easy give away.



I only ask because of this. Purchased my car off the showroom floor in February 2019.
 

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I only ask because of this. Purchased my car off the showroom floor in February 2019.
19.5 psi is pretty high for the stock tune even if that's just the peak boost. I recommend resetting it like enoxard recommended and check if you consistently see #s that high. If so, you may want to take it to the dealership and have them take a look. Then you at least have it on record if there's ever a problem down the road.
 

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My pcm has never been flashed and battery hasn't gone dead. That's what it shows for 1-2. 3-6 is 12-14psi.
 
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