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Old 10-15-2018, 04:19 PM   #1
Drixtunes
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Default 2019 WRX Peak Boost change overnight ?

Hey guys, newbie to the NASIOC community, but have always lurked in the shadows figured it was time I JOINED! so what’s up everyone!!

- recently just got a 19’ base WRX it has 400 miles on it currently.
- I’m aware of the break in period but still like to get on it a little here and there.. max peak boost of (21-22.3 psi)

- recently I swapped out my Halogens for HID’s & the C lights for LED’s..
(Took out the air box) when I put everything back together and went to start the car, I had check engine lights and traction control off, PANIC MODE lol.. I idiotically forgot to plug the MAF sensor back in :/ ...
(Didn’t drive car, I shut it off and went to double check my work, plugged the MAF back in & pulled the battery to reset ECU)
Once I started it back up, Everything was perfectly fine, all check engine lights etc .. gone.

However now my peak boost will never surpass 18.5 psi .. even at WOT (2nd, 3rd pull)
I am in NY and the weather has gotten a bit more “Fall -ish” (50-60 degrees)
But it seems when I go WOT, the car doesn’t have the same torque band.. doesn’t feel like it did prior to this whole MAF sensor thing..

Any one have any insight ?!?!?
Thanks !!
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Old 10-15-2018, 04:23 PM   #2
rtv900
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my experience is when ECU's are reset, or reflashed the car takes a few days and handful of WOT pulls to work it's way back up to it's peaks.
I think it's designed that way as a safety feature to make sure nothing is wrong so it starts off a tad more conservative and re-learns those peaks again.
Plus, when it's colder it will, and should reduce peak boost too. So if you are comparing from a day it was 85 just a week or two ago and now it's 50 in the mornings, that will make a difference, however you should not feel less power if it reducing boost due to colder temps.

I'd give it a few days and keep doing some WOT's with whatever octane you use regularly to let it re-learn those peaks
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Old 10-15-2018, 04:31 PM   #3
Drixtunes
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Originally Posted by rtv900 View Post
my experience is when ECU's are reset, or reflashed the car takes a few days and handful of WOT pulls to work it's way back up to it's peaks.
I think it's designed that way as a safety feature to make sure nothing is wrong so it starts off a tad more conservative and re-learns those peaks again.
Plus, when it's colder it will, and should reduce peak boost too. So if you are comparing from a day it was 85 just a week or two ago and now it's 50 in the mornings, that will make a difference, however you should not feel less power if it reducing boost due to colder temps.

I'd give it a few days and keep doing some WOT's with whatever octane you use regularly to let it re-learn those peaks

Awesome, ok I will keep an eye on it.. might just be in my head since I’m seeing less on the peak boost ***129335;***127995;****9794;***65039;.

Thanks for the response man!
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Old 10-15-2018, 04:32 PM   #4
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Boost target for your car is 15.9lbs. The tune on the 2015+ DITs make it so there are brief periods of over boost during almost any normal WOT run, it's very brief spikes and it's not sustained for very long at all- just because this run hit 18 and then other run hit 23 doesn't mean one was faster than the other. It's a symptom of the stock tune. As long as your are hitting 16lbs you are hitting target boost.

The reason why the spikes have been less pronounced (18.5 vs 23 PSI) lately is because its colder out. Another symptom of the stock tune is it ties your wastegate duty cycle to your intake temp. Lower temp = lower maximum duty cycle (duty cycle = how much your wastegate opens), high duty cycle = more boost. When the intake temp falls below a certain threshold your WGDC is reduced, which means the car makes less boost. This is done because cold air has more oxygen than hot air, so when it's cold out you can make the same power with less boost.

Tl;dr Its tied to temperature, wait until it warms up and your boost will come back.
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Old 10-15-2018, 04:36 PM   #5
Drixtunes
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Originally Posted by GlarryHoodDIT View Post
Boost target for your car is 15.9lbs. The tune on the 2015+ DITs make it so there are brief periods of over boost during almost any normal WOT run, it's very brief spikes and it's not sustained for very long at all- just because this run hit 18 and then other run hit 23 doesn't mean one was faster than the other. It's a symptom of the stock tune. As long as your are hitting 16lbs you are hitting target boost.

The reason why the spikes have been less pronounced (18.5 vs 23 PSI) lately is because its colder out. Another symptom of the stock tune is it ties your wastegate duty cycle to your intake temp. Lower temp = lower maximum duty cycle (duty cycle = how much your wastegate opens), high duty cycle = more boost. When the intake temp falls below a certain threshold your WGDC is reduced, which means the car makes less boost. This is done because cold air has more oxygen than hot air, so when it's cold out you can make the same power with less boost.

Tl;dr Its tied to temperature, wait until it warms up and your boost will come back.
Thanks man, so my only question with this, is my good friend has a 2016 WRX same base model & he lives in my town, checked with him today & his peak boost is 22 still..
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Old 10-15-2018, 04:58 PM   #6
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It's impossible to tell based on that little info... If he was sitting in traffic and his intake was heat soaked then its not going to reduce WGDC nearly as much... There are other factors than intake temp for WGDC, that's just one of the biggest.
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Old 10-15-2018, 05:21 PM   #7
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My WRX before Cobb Stage1 would peak 22.1psi. After Stage1-plus, 19.2psi so I can see why the op is worried.
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Old 10-15-2018, 06:17 PM   #8
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It's impossible to tell based on that little info... If he was sitting in traffic and his intake was heat soaked then its not going to reduce WGDC nearly as much... There are other factors than intake temp for WGDC, that's just one of the biggest.


He had just gotten off work, car warmed up no traffic, did a WOT, 2nd to 3rd..with me on the phone while he did it loll .... his car has 11,000 miles on it. Bone Stock.
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Old 10-16-2018, 06:41 AM   #9
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Originally Posted by Drixtunes View Post
He had just gotten off work, car warmed up no traffic, did a WOT, 2nd to 3rd..with me on the phone while he did it loll .... his car has 11,000 miles on it. Bone Stock.
you have to make it clear though that you want him to tell you what peak the car is HOLDING, not just spiking to and then backing off.

Mine spikes to almost 19 but it never holds 19 for any actual amount of time.
It can hold 17.5.

You have to do it in a high gear otherwise there's no time for a steady state figure.
In my car 2nd and 3rd have way too much power to see what you are holding, the gear just whips through so fast you can't see crap.
Do it in 4-6
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Old 10-16-2018, 07:05 AM   #10
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Break the car in before you start WOT it. There is a reason the Manufacturer has a procedure. Then beat your brand new STI. Must have $$$$ ready for motor failure.
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Old 10-16-2018, 07:21 AM   #11
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STI and WRX hold different boost levels.

My STI held boost around 15.5psi stock, 17.5+ after stage1.
WRX held 22.1psi stock, 19.2 after stage1 plus.
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Old 10-16-2018, 10:32 AM   #12
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Quote:
Originally Posted by oichan View Post
STI and WRX hold different boost levels.

My STI held boost around 15.5psi stock, 17.5+ after stage1.
WRX held 22.1psi stock, 19.2 after stage1 plus.
So your stock WRX holds 22.1 PSI throughout the RPM's...


HMM.......
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Old 10-16-2018, 10:42 AM   #13
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So your stock WRX holds 22.1 PSI throughout the RPM's...


HMM.......
Yeah, that is what the peak showed on the screen. Once I flashed to Cobb Stage1-plus, it went down to 19.2 but more power!
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Old 10-16-2018, 11:38 AM   #14
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you have to make it clear though that you want him to tell you what peak the car is HOLDING, not just spiking to and then backing off.

Mine spikes to almost 19 but it never holds 19 for any actual amount of time.
It can hold 17.5.

You have to do it in a high gear otherwise there's no time for a steady state figure.
In my car 2nd and 3rd have way too much power to see what you are holding, the gear just whips through so fast you can't see crap.
Do it in 4-6


So, just to be clear. . I’m talking peak boost. His peak read 22, just like mine did right before the whole MAF sensor debacle...

Now mine will peak at 18/19 max ... we both did identical pulls 2nd to 3rd.. I’m not trying to beat on my car here at all.. but it’s noticeably different now. .
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Old 10-16-2018, 12:06 PM   #15
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Yeah, that is what the peak showed on the screen. Once I flashed to Cobb Stage1-plus, it went down to 19.2 but more power!
You dont seem to be grasping the difference between holding peak boost and briefly boost spiking. The OEM tune has a boost target of 15.9lbs, it is in no way sustaining 22lbs throughout the range, your car would knock like crazy and lunch itself in a month.

OP, of the car truly feels a lot different then take it in to a shop. Just because you're hitting target boost doesn't mean there isn't still a leak or something wrong somewhere else.
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Old 10-16-2018, 12:21 PM   #16
rtv900
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Originally Posted by Drixtunes View Post
So, just to be clear. . I’m talking peak boost. His peak read 22, just like mine did right before the whole MAF sensor debacle...

Now mine will peak at 18/19 max ... we both did identical pulls 2nd to 3rd.. I’m not trying to beat on my car here at all.. but it’s noticeably different now. .
we are not talking the same thing.
The screen will show you the peak that it spikes to, that's it, just the spike highest number.
That is NOT the boost your car is actually running at. Any turbo will rapidly increase boost and then the boost control system has to take over as quickly as possible and bleed off exhaust to pull it back down and manage it.
If it weren't for this system a turbo would simply boost out of control and shred the motor.

Bottom line, forget that number on the screen and don't even look at it.
Look at the real time boost number that shows what the car is holding. In my car that's the one on the left, not sure if they've changed it.
You have to do a pull in a high gear so it has a chance to get steady and hold a number.
The left number is what the car actually runs at.
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Old 10-16-2018, 12:24 PM   #17
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we are not talking the same thing.

The screen will show you the peak that it spikes to, that's it, just the spike highest number.

That is NOT the boost your car is actually running at. Any turbo will rapidly increase boost and then the boost control system has to take over as quickly as possible and bleed off exhaust to pull it back down and manage it.

If it weren't for this system a turbo would simply boost out of control and shred the motor.



Bottom line, forget that number on the screen and don't even look at it.

Look at the real time boost number that shows what the car is holding. In my car that's the one on the left, not sure if they've changed it.

You have to do a pull in a high gear so it has a chance to get steady and hold a number.

The left number is what the car actually runs at.

I found this on YouTube. This is VERY Similar yo what I am experiencing .

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Old 10-16-2018, 02:33 PM   #18
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Originally Posted by Drixtunes View Post
I found this on YouTube. This is VERY Similar yo what I am experiencing .

https://youtu.be/se9ulMQrM48
Looks normal to me. Especially considering the driver isn't fully flooring it. Boost will spike quickly to 20 or so, then hold at 17-18 for the rest of the pull.
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Old 10-16-2018, 03:42 PM   #19
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Looks normal to me. Especially considering the driver isn't fully flooring it. Boost will spike quickly to 20 or so, then hold at 17-18 for the rest of the pull.
+1
normal
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Old 10-16-2018, 04:11 PM   #20
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I found this on YouTube. This is VERY Similar yo what I am experiencing .
ok, number 1, that's why I keep saying if you don't do it in a high gear it is friggin impossible to tell where the vehicle is running steady state.
That dude was a classic case. He'd just floor it, spike the boost, the control system would back it down for one second before he was off the gas going to shift, super hard to tell where it leveled off.

But agreed with the last two comments, that is TOTALLY normal for a turbo car. Every one will spike beyond it's target and then immediately pull back.
There is less than nothing to gain from a higher 'spike' than another guy has, it does nothing for performance.
If your car is running at your target then you are good to go.

So again, I'm not sure you are even confident what you are really running at steady state, the spike is totally meaningless.
You need to do this in 5th gear dude where you have a long stretch ahead of you so you can floor it and see where it runs steady.
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Old 10-16-2018, 05:42 PM   #21
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Looks normal to me. Especially considering the driver isn't fully flooring it. Boost will spike quickly to 20 or so, then hold at 17-18 for the rest of the pull.
This. The car is never going to hit full boost at 50% throttle. And we no idea where he's starting the pull in the rev range. Also, shout out to driving with one hand while filming with the other hand and purposefully getting on the car like a lunatic.

I feel like this is why more turbo'd cars don't have boost gauges... Hell, half the people on the road have an inability to read a speedometer let alone understand boost pressure...
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Old 10-16-2018, 07:15 PM   #22
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Originally Posted by GlarryHoodDIT View Post
You dont seem to be grasping the difference between holding peak boost and briefly boost spiking. The OEM tune has a boost target of 15.9lbs, it is in no way sustaining 22lbs throughout the range, your car would knock like crazy and lunch itself in a month.
No kidding, I was just simply stating what my WRX's screen showed as 'peak' acknowledging what the OP was saying he saw on his car and his friend's.

It would be silly to assume I am a newb with Subaru's (or turbo cars in general) nor this forum. I just forgot the email I used and its password nearly 2 decades ago when I had the 02 WRX new.
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Old 10-16-2018, 07:23 PM   #23
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No kidding, I was just simply stating what my WRX's screen showed as 'peak' acknowledging what the OP was saying he saw on his car and his friend's.

It would be silly to assume I am a newb with Subaru's (or turbo cars in general) nor this forum. I just forgot the email I used and its password nearly 2 decades ago when I had the 02 WRX new.
lol.

You - "WRX held 22.1psi stock, 19.2 after stage1 plus."
Vlad - So your car holds 22psi throughout the rev range?
You - Yes, it shows peak boost as 22.
Me/rtv - Peak boost is not the same as sustaining boost throughout the rev range.
You - I know 'cause I'm not a n00b.

Can't make this stuff up.

Last edited by GlarryHoodDIT; 10-16-2018 at 07:29 PM.
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Old 10-16-2018, 07:40 PM   #24
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Originally Posted by GlarryHoodDIT View Post
lol.

You - "WRX held 22.1psi stock, 19.2 after stage1 plus."
Vlad - So your car holds 22psi throughout the rev range?
You - Yes, it shows peak boost as 22.
Me/rtv - Peak boost is not the same as sustaining boost throughout the rev range.
You - I know 'cause I'm not a n00b.

Can't make this stuff up.
Hope you have a nice evening and a brighter tomorrow. GL
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Old 10-16-2018, 07:45 PM   #25
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Danke schoen
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