Subaru OTS Maps: High Wastegate, Low Wastegate, Normal Wastegate

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The COBB Tuning Accessport comes with Off The Shelf (OTS) maps designed to support any vehicle of a specific make and model throughout all climates and elevations.  For the Subaru platform, most vehicles have a wastegate option that can be chosen to better fit your car for its specific conditions.  Here we’ll define the differences in these wastegate options and explain how to make sure you’re using the right version OTS map for your vehicle.

If you’ve recently downloaded a map from the COBB website you may have noticed a dropdown menu presenting the High Wastegate (HWG), Normal Wastegate (NWG), and Low Wastegate (LWG) version of the OTS map you’ve chosen.  Each map has differences in wastegate duty cycle tables that allow a vehicle that may not be running target boost to run optimally.  You should start with the Normal Wastegate version of your OTS map.  Then, if you are overboosting or exceeding target boost, change to the Low Wastegate version. If you are underboosting or not reaching target boost, switch to the High Wastegate version.

The best way to determine if you are hitting target boost is to monitor the TD Boost Error parameter on the Accessport.  This parameter shown below is your target boost (including altitude and temperature compensations) minus your actual boost (negative values mean you are over the target by the amount while positive values mean you are under).  Ideally you want this value to be between 0 and 1.0 at wide open throttle (WOT), but –1.0 to 1.0 is acceptable assuming that you don’t have any significant knock corrections (The figure’s values below are not in this range so it is for illustration purposes only.  This is a vehicles idling since I wasn’t able to take a screen shot at WOT).  This figure is only relevant in determining over/underboosting issues at Wide Open Throttle through peak boost.  Overboosting is more likely to occur in higher gears and with colder outside temperatures so verify boost levels during these conditions if you commonly experience them.  Some vehicles have an acceptable variance of 1.5 PSI so be sure to check the map notes for more details.  These can be found by clicking the “notes available” link on any map or found in the support section of the COBB website.

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There are certain situations where these maps are not the solution to the boost targeting issues you may be experiencing.  For instance, if there are mechanical issues present causing underboost, the HWG map will not be of any benefit.  The most common mechanical issues that may prevent reaching target boost are boost leaks due to a loose coupler, an aged turbo, a clogged downpipe, a failing wastegate, or a torn vacuum hose.  The same goes for mechanical problems causing overboost and the LWG map.  The most common cause for a vehicle overboosting, especially any 08+ WRX/STI, is a catless downpipe.  These mechanical issues can not be solved with tuning alone.  They each need to be addressed by repairing, replacing, or further modifying parts.

A quick note for those of you that live at higher altitudes.  It is common for turbocharged cars at higher altitudes to run less boost pressure due to lower air pressure and air density.  Your turbocharger has to work harder to compress a less dense air mass compared to the same turbocharger at sea level.  This must be factored in when determining if your turbocharger is running the proper amount of boost pressure and not being pushed beyond its efficiency range.  For example, if you live in Denver at 5280 ft and are trying to run a peak boost pressure of 15 psi, your turbocharger has to work the equivalent of making ~17.5 psi at sea level. There are barometric compensations within the factory ECU that lower boost targets as you climb in altitude in an effort to keep the turbocharger in its optimal range. The COBB performance maps utilize these compensations and therefore, it is perfectly normal for the final boost target to be lower than what is listed for your map.

To learn more about the Accessport or to get answers to any questions you may have regarding COBB Tuning products, please call our Customer Support Team at 866-922-3059 or send us an email at support@cobbtuning.com.


COMMENTS
Todd Tucker on August 29, 2016 says:

I purchased the AP about a year ago and was getting boosts at around 19 PSI. I had the J pipe installed two weeks ago, and applied the Stage 2 normal WG map, and am getting boosts around 15-17 PSI. It doesn’t feel as quick off the line, but mid and high RPMS I can feel it. 0-60 is about the same, but my 1/4 mile is about .5 seconds faster. Should look into a different WG map? Thanks.

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Todd Tucker on August 29, 2016 says:

One additional note. I noticed on your website it talks about removing the restrictor pill, and not doing so will cause low boosts. There was no mention of that in the instructions. So, i need to know if I should have my mechanic do that, and they may solve my problem?

Thanks, Todd

Reply
    Marshall
    Marshall on August 30, 2016 says:

    Hey Todd,

    We do recommend removing the secondary restrictor pill in the factory boost control lines in order to achieve target boost using our Stage 2 OTS Maps. You can find more information on that near the bottom of the Map Notes Page. Look for the section labeled “Boost Control System Modification”.

    Marshall@COBB

    Reply
John Neidrich on April 13, 2017 says:

So one thing I have not seen answered is if TD Boost Error is always supposed to be within +/-1 or just at WOT. I am currently OTS Stage 1 on my 2010 LGT with an aftermarket Mach2 BPV being the only non OEM part. TD Boost Error is -6 to -8 at idle or when coasting but comes within 1 if I have my foot on the gas to maintain speed. Didn’t know if I need to go digging for a boost leak or need to get a custom tune due to the BPV which people are saying is closed under vacuum where the OEM valve is open under vacuum.

Reply
    Marshall
    Marshall on April 14, 2017 says:

    Hey John! TD Boost Error will definitely fluctuate a bit during partial throttle/cruising situations. That monitor is generally only used during WOT pulls. The values you are reporting sound normal to me.

    Marshall@COBB

    Reply
CJ Mandala on May 1, 2017 says:

I have a 2015 WRX with an aftermarket catback exhaust and stock intake running the Stage 1 93 octane map. I have only hit 15 psi two times and consistently hit between 11 and 13 psi. I live in New Jersey and am wondering if i should be producing more boost. I was told peak boost should be 19 psi. Should i be concerned that i am not hitting the peak boost of 19?

Reply
    Kyle
    Kyle on May 1, 2017 says:

    HI CJ,

    That would be very low. I’d recommend first making sure you are on the correct map. Then, go through the intake tract and vacuum lines in the boost control system to check for any air leaks. If you’re still having issues, give us a call at 866-922-3059 or email us at support@cobbtuning.com and we can help you troubleshoot.

    Kyle@COBB

    Reply
Trevor Wilson on May 20, 2017 says:

Hi, I just added a cobb intake and i also have a downpipe and I’m running stage 2 on my accessport. I was driving in fourth gear and my car cut out and my check engine light came on, does anyone have an idea whats going on?

Reply
    Kyle
    Kyle on May 22, 2017 says:

    Hi Trevor,

    I’m sorry you’re having issues. It’s tough to say exactly what the problem could be without any other information. If you give us a call at 866-922-3059 or email support@cobbtuning.com with some details (including what kind of car you have, exactly what modifications – which intake and downpipe – and the code being thrown) we can help you troubleshoot!

    Kyle@COBB

    Reply
adrian lopez on September 14, 2017 says:

Hello,
I was just wondering which map would be best fit for my 2017 Subaru STI. I’m currently using the Stage 1 ACN boost select map and I’m hitting about 14-15 psi boost. I’m in San Diego and the car is fully stock. I just don’t want to ruin my engine! lol thanks for your help. I’ve also tried the LWG map but still hitting same boost at around 13-15 psi.

Reply
    adrian lopez on September 14, 2017 says:

    I meant i’ve tried the HWG* map and it read those boosts.

    Reply
    Kyle
    Kyle on September 14, 2017 says:

    Hi Adrian,

    Is this at WOT? If so, that’s definitely low. Have you considered the Boost Error at WOT outlined in this article? If it’s on the high side, you likely have a boost leak. If that doesn’t help explain your issue send us a datalog to support@cobbtuning.com and we cna help you troublehsoot.

    Reply
Clay Stock on November 21, 2017 says:

Hello, I’ve got an 18 wrx and was running the 93 it’s stage 1 tune as my car is completely stock. In the summer I would hit 18 psi WOT but now that it’s winter time I Was only hitting 15-17 psi. I switched to the HWG stage 1 and am hitting about 17-18.x psi WOT. While monitoring the TD boost error it’s right about +/- 1.5 to 2. My question is if this tune is the one I should be running and or will this cause any issues for me in the future.

Reply
    Adam Hill
    Adam Hill on November 21, 2017 says:

    Hi Clay,

    Boost behavior can be a big can of worms with Subaru’s, but we should be able to help without too much confusion. The short answer is that those values and boost behaviors actually sound relatively normal depending on a few variables. The first thing to understand is that the FA20 WRX’s do specifically target a certain boost value and it pretty much always wants to hit target when at full throttle (full throttle is important, partial throttle behavior will skew your boost error values enough to make that monitor irrelevant), but a variance of +/-1.5 when at peak boost is considered normal. Also, the car does adjust the target based on sensor feedback and a few other variables, temps and elevation are both significant inputs. It is common for these cars to reduce boost targets when ambient temperatures drop, basically, the colder temps make the system more efficient, so it may intentionally target a couple psi less, but still makes the same power. The cars actually do this from the factory at an even more drastic amount without our tune. At the end of the day, anytime you are concerned about peak boost, you should always start with a pressurized smoke test, even on a new car, you’d be surprised at the number of new cars we see with loose or broken fittings/clamps. If everything seems perfect, then feel free to send over a datalog or two to support#cobbtuning.com so we can review them and give some more feedback. – Adam@COBB

    Reply
joseph guyotte on March 27, 2018 says:

I have a 2018 wrx recently i have been hearing a rattling from the engine bay I braught the car to subaru for warrenty but i forgot to take the stage 1 tune off they said that the tune caused something to go wrong in the wast gate is this even possible or is this on subarus end they want me to pay $250 just to find out. my car doesnt have spikes in boost or loss of boost at all it just rattles like crazy in boost anyone have any ideas??

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Manny Mora on April 24, 2018 says:

2012 stock wrx, Just flashed stage 1 ACN 91. Only hitting 13 psi boost. TD Boost error numbers are 3+

Reply
    Adam Hill
    Adam Hill on April 25, 2018 says:

    Hi Manny,

    Please record a couple short WOT datalogs in 3rd gear and send them to support@cobbtuning.com. Let them know the exact setup of your car and we’ll see if we can give you some feedback on the boost behavior.
    Adam@COBB

    Reply
Martin Pereyra on July 19, 2018 says:

Hello I have 16 sti that is just recently not hitting target boost in any of the si drive modes most I reach is 8.25 and td boost error reaches 9.0 at wot. I recently installed the accessport with a perrin aos together and was reaching target boost when I first installed them but now it won’t reach target boost. Is it possible that I could have a boost leak somewhere in the aos? From the way I installed it only place i can think of a leak is from the line off the intake manifold under the throttle body?

Reply
    Marshall
    Marshall on July 20, 2018 says:

    Hey Martin, a large boost leak seems most likely. Are you seeing a Check Engine Light as well? If so, any codes associated to it may point you towards a potential issue.

    Marshall@COBB

    Reply
      Martin Pereyra on July 20, 2018 says:

      I did scan the car with the accessport but no active or pending codes. Can I get a boost leak thru the aos?

      Reply
        Adam Hill
        Adam Hill on August 6, 2018 says:

        Martin,

        You can’t necessarily get a boost leak directly through the AOS but an incorrect install could indirectly affect something that would impact boost behavior. So I would double check thing install.
        Adam@COBB

        Reply
BENJI BROZOVICH on August 5, 2018 says:

i have a 2018 sti 1100 miles just installed the stage 1 maperformance tune with cobb tuner that is supposed to hit a peak boost of 20 to 23 and it won’t even break 10.5 but if i got back to stock tune I’m running 16 to 17 psi boost any ideas why i lose boost with a tune and gain when i go stock??

Reply
    Kyle
    Kyle on August 6, 2018 says:

    Hi Benji,

    That is weird. Are you running it in I-mode? Maybe try running it in S or S# and it will have a different target. Maybe it’s the wrong map file? Also make sure you have the correct modifications installed (or not installed). If you contact MAP directly, they may have better troubleshooting tips for their map.

    Reply
Steven Jones on August 15, 2018 says:

Thanks for the article. (2016 STi 3rd Gear S# pulls)
When I ran the Normal WG map I was seeing boost errors between 1 and 2 with max boost of 18.1 psi.
After flashing the High WG map I was seeing boost errors between 0 and 1 with max boost of 19.2 psi

Reply
    Kyle
    Kyle on August 16, 2018 says:

    Hi Steven,

    What map are you running?

    Reply
Joshua Tiller on August 16, 2018 says:

Good evening, I appreciate the article.
I have a 2017 STI with a Stage 1 93 oct. HWG map installed. I am at 750 ft elevation and on a 90 Degree F evening at Wide Open Throttle (in S#) I am hitting a peak boost of 16.3 psi. I am a bit confused as the map states that I should be hitting a peak of 18, but the TD Boost Error gauge shows a value very close to zero at WOT. Is this conflicting Information, or is it within acceptable variables? Thank you!

Reply
    Kyle
    Kyle on August 17, 2018 says:

    Hi Joshua,

    That is a little short of the target range but could be expected in high heat. I bet you’ll see better numbers when the air gets cooler and more dense. More boost does not always mean more power. If you feel like there is an issue, send us a datalog to support@cobbtuning.com we can help you troubleshoot!

    Kyle@COBB

    Reply
ason figueroa on August 29, 2018 says:

Hey man.
I have a 2007 Wrx with a Stage 2 91 OCT HWG Map. It has an Invidia Catback exhaust, Tomei downpipe and a Typhoon K&N Cold Air intake system and no bov. I changed it from NWG to HWG just now to see if it would fix my boost problem but still no avail. My boost max ranges from 12.5-13.5 and I know thats way off. No check engine light but I am reading code P0128 – Coolant Temperature Below Thermostat Regulating Temperature. Any help?

Reply
    Kyle
    Kyle on August 30, 2018 says:

    HI Ason,

    I’d first recommend using the stock intake. The variance in the intake may be causing issues with the MAF readings which could explain the boost conditions. Beyond that, check for boost leaks, ideally with a smoke tester.

    Kyle@COBB

    Reply
christian farinato on October 13, 2018 says:

hey, i have a 2018 sti with 8k miles just pulled the trigger on buying a cobb intake and AP, super eager to install it but for the life of me i cant figure out whats wrong. I uploaded the stage 1+ 93oct tune and in either [i] [S] or [S#] im peaking at 8.5 psi ive tried boost select and high wastegate option and im getting the same readings.. any ideas?

Reply
    Kyle
    Kyle on October 15, 2018 says:

    Hi Christian,

    Make sure you’re not using the Valet map. If that’s not the issue, and you’re looking at the correct monitor, there is likely a boost leak. In that case, go through all of the connections and make sure everything is tight. A smoke test would be ideal in revealing the leak.

    Kyle@COBB

    Reply
Jeremy Foor on February 28, 2019 says:

I am curious if i am reading the TD Boost Error gauge correctly. In 3rd gear WOT my Target Boost gauge read 17.47, my Boost gauge read 16.20, and TD Boost Error reads -12.53/14.09. Is this normal operating range? Thanks for the help.

Reply
    Kyle
    Kyle on February 28, 2019 says:

    Hi Jeremy,

    The min and max aren’t really relevant for TD boost error. The boost numbers are within normal ranges.

    Kyle@COBB

    Reply
Jeremy Foor on February 28, 2019 says:

Sorry I forgot to include that this is my 2018 WRX 2.0, running stage 1 NWG. I have not installed the bg sf intake yet.

Reply
vitor nogueira on April 13, 2019 says:

was just wondering i have the stage 1 91 oct tune map on 2017 wrx normal waste gate but was wondering if i could run it on the high waste gate on everything stock only have a bov and a custom exhaust

Reply
    Adam Hill
    Adam Hill on April 15, 2019 says:

    Hi Vitor,

    Running low vs normal vs high wastegate maps doesn’t really have anything to do with modifications. Those tunes are specifically made for adjusting boost control to varied atmospheric conditions, especially regarding altitude. So if you are not at a high elevation, there is typically no reason for run the High Wastegate map. Your ideal peak boost should always be the same for each stage map regardless of the wastegate variation.

    Adam@COBB

    Reply
bryan dalisay on May 16, 2019 says:

I have a 2002 subaru wrx with stage 2 COBB map tune pulling 12-15psi boost then i installed my 3 port booscontroller and tune it with stage2+EBCS ACN91 high normal wastegate and making me pull only 6.0psi boost should i tune it with stage2+EBCS ACN91 lowwastegate ?

Reply
    Adam Hill
    Adam Hill on May 17, 2019 says:

    Hi Bryan,

    I wouldn’t worry about the difference between the normal or low wastegate maps. The difference is not big enough to make boost that low. I would triple check to make sure the EBCS lines are hooked up correctly. That’s the problem 90% of the time. Also, triple check for any boost leaks. Keep in mind that 6 psi is slightly below the minimum spring pressure of the wastegate, so even if the boost controller was set up to make as little boost as possible full time, it should still make around 8spi at WOT in 3rd gear. If you can’t find anything, please record a datalog and email support@cobbtuning.com

    Adam@COBB

    Reply
John McClure on July 4, 2019 says:

I have a 2018 STI w/cat back SPT Exhaust and the previous owner installed a K&N drop in filter. Just tuned with Stage 1 93 Octane normal wastegate maps and the car has transformed. I haven’t data logged yet or reviewed the TD boost errors values yet, but my god. What a transformation!!

Reply
Joel Dean on July 7, 2019 says:

My 2017 WRX USDM MT after installing a Big SF Intake and a Comp RS Catback exhaust is pushing boost 20 22.5 after install 93 octane Big SF 1+. This is too high…. correct? Please advise….

Joel

Reply
    Kyle
    Kyle on July 8, 2019 says:

    Hi Joel,

    The peak boost is 20.5. Anything beyond that would be too high. If you’re seeing this in 5th or 6th gear, you should downshift. If you send a datalog to support@cobbtuning.com we can help you troubleshoot.

    Kyle@COBB

    Reply
Tito Lopez on August 30, 2019 says:

2011 stir running stage 2+ 93 boost select, on sport I hit peak boost between 15-16.6psi which is normal but in S# I hit peak boost at 16.8psi instead of around 19psi, I have 2 datalog pulls of 3rd and 4th gear pulls for both S and S# with the td boost error. ill send the catalogs but was just wondering why I can’t hit peak boost in S#

Reply
    Marshall
    Marshall on September 3, 2019 says:

    Hey Tito,

    It looks like you have a ticket with Andrew in CSR. He should be able to get you squared away!

    Marshall@COBB

    Reply
Alain Hungerford on March 8, 2020 says:

Well, hate to jump in on this one as it seems like the question has been answered a bajillion times, but I can’t seem to wrap my head around how TD Boost Error readings work.

I’m currently running the Stage 1+ SF ACN91 HWG map with the SF short ram intake and a Factionfab Axelback exhaust (I was hitting around 13.5/14.5lbs of boost with the normal WG map), and consistently hit 15-16lbs of boost with the HWG. Car feels great and pulls hard, doesn’t have any crazy learning corrections.

I realized I should probably check the TD Boost Error to see if I’m having any boost creep, and after doing a quick pull in 2nd gear hit 15lbs of boost at WOT, and my TD Boost Error was reading around -.5-+1.5, with min/max values of -18/+21. I have absolutely no idea how to interpret this, but the numbers seem odd.

What do you guys think?

Appreciate your superb customer support, as always!

Reply
    Kyle
    Kyle on March 9, 2020 says:

    Hi Alain,

    Those numbers are acceptable. As mentioned in the article, the value is only relevant at WOT. This makes the min/max values irrelevant.

    Kyle@COBB

    Reply
Sergio Said Lopez Juarez on March 11, 2021 says:

Hi Guys,

I have a wrx wagon 02, I have the AP v3, aftermarket air filter, up and down pipe, 3″ catless pipe through the muffler, EBC, aftermarket wastegate, a legacy b4 motor block, I download the stage2+ebc+lwg+93 octane map I’m having overboost at 2 gear at WOT I hit some minutes ago 21 psi and I dont event wanna try 3rd and 4th, the map target boost it’s 17psi, any advice on how to lower the boost?

Reply
    Marshall
    Marshall on March 12, 2021 says:

    Hey there! The modifications you’ve listed are not supported by any of our Off The Shelf Maps. Utilizing a catless exhaust is not only harmful to the environment, it can also cause the boost creep issues you are experiencing. We recommend changing the mechanical configuration to match what the map supports.

    Marshall@COBB

    Reply
      Sergio Said Lopez Juarez on March 12, 2021 says:

      Thanks Marshall.

      Reply
Jason Neiderer on March 27, 2021 says:

I recently went through the classes to become a basic Cobb tuner, in order to tune my own car, bc the person tuning my car was having such a tough time.
I actually have a JDM Powered Ej20Y 5MT Baja Turbo.
I have a million questions, but lets keep it to one for now, I have a EBCS, all new vacuum lines, so no restricters, and my WGDC high is set to 30, and the boost target is set to 19psi, and it goes straight to 17 and holds perfectly, but no matter what I do, I can’t get it over 19psi originally, and now over 17-18psi. I just upgraded the BOV with a GFB and everything stayed the same. Am I doing something wrong?

Reply
    Marshall
    Marshall on March 29, 2021 says:

    Hey Jason, do you know what the spring pressure of the actuator is? It sounds like you may be running into the mechanical limit of the wastegate spring. That would be my recommended first place to start if everything seems to check out calibration-wise.

    Marshall@COBB

    Reply