COBB R&D Update : January 2015

We’ve been hard at work on some new products and features due out in early 2015!

Here’s a quick peak at some of the exciting upcoming releases from the Subaru and Ford Expert Groups!!

2015 WRX Tuning Results : 344 WTQ / 313 WHP

2015 WRX_George_18_blog

We have enjoyed seeing all of the 2015 WRX custom tune results being posted around the ‘net and decided to jump in with our own after a bit of playing around with our car on the Austin R&D dyno today. While this combo of parts isn’t likely to be an pre-configured OTS “StageX” package that is available from us, we try to do as much hard parts testing as we can to make sure we have a good understanding of the cars. It’s important for us to have knowledge over how the car will react to common aftermarket upgrades. No records or anything crazy but this thing is definitely one quick WRX now!

We bolted up all of the airflow mods we have on-hand for the car and decided to see what she could do. A bit more time to continue refining the tune would have likely yielded even larger results, but I quickly “chickened out” after realizing how close we were to 350 wtq. :eek:  It is likely that the connecting rods will prove to be the long-term weak spot for modified FA20DIT cars, so we decided to call it an afternoon with our engine still intact for now :cool:

Engine/Power Modifications on our WRX consist of the following: COBB Tuning Accessport V3, COBB Tuning Turboback Exhaust (Catted), COBB Tuning SF Intake/Airbox (Prototype), TurnInConcepts TGV Delete Housings, Upgraded Aftermarket TMIC.

2015 WRX Dyno Chart

Results vs stock vehicle: +77 wtq (28.8%) , +62 whp (24.6%) 

At this point this car is now making a tad more torque and horsepower than a Stage2+Intake 2015 STI on the very same dyno — very impressive for a 2.0L with diminutive factory turbo. We are slowly beginning to really like these cars now as the uncorking process continues :)

Long term, this testing helped us identify some other areas of the factory ECU where we should focus our future reverse engineering (table/logic discovery) in order to provide the precise control and ease of tunability that the COBB Protuner network demands, even as the power numbers get crazier and crazier as new mods become available over time. We can’t wait to keep pushing this platform and seeing what kind of amazing results you guys achieve over time!

Thank you for your support during the DIT craze!


The COBB Subaru Expert Group

2015 WRX Rev Hang

For 2015, Subaru introduced a completely overhauled WRX!  There are some awesome new changes, like direct injection,  and other changes many aren’t too thrilled about.  Subaru’s new “Rev Hang” logic seems to top the list of complaints.  Luckily though, COBB is hard at work coming up with a solution!

What is Rev Hang?

Typically, when you are in gear and revving high into the RPM range, pressing in the clutch would result in the RPMs quickly falling.  With Rev Hang, the RPM stays constant for a bit and slowly falls.

This isn’t necessarily a bad thing.  However, many car enthusiasts are purists and feel the only inputs the car should be considering, especially when it comes to throttle, come only from the driver.  We tend to agree!

Here’s a quick video of the Rev Hang “Fix” in action:


This does look subtle on video but if you own or have driven a 2015 WRX, you know how big a difference this will make!  Check out the latest v111 maps to try out the fix:  Stay tuned to our Website, Facebook Page, Twitter, Instagram, and Blog for the latest!

COBB at Subiefest 2014!

We’ll be heading out to Subiefest next weekend at Auto Club Speedway in Fontana, CA!

Make sure to come by the COBB booth to check out new products and enter in for your chance to win some awesome prizes!

COBB Socal will also be at Subiefest selling all of your favorite COBB parts!!

Subiefest 2014 Flyer 5 Version 3

2015 Subaru STI Development Update – COBB SF Intake Testing

So, you’ve probably seen some pretty cool early results from hardware swaps on the 2015 STI platform.  But, have you seen any actual data besides some basic dyno charts with really high smoothing?  Probably not. :) Lucky for you, we’re here to provide actual quantified data behind the madness.

Many people were initially disappointed that our first release only included Stage1 maps.  This was because we prefer to *thoroughly* test parts to find out what each modification will do so that we can be sure our Staged Package offerings have a definitive gain for your investment.  For example, here is a NASIOC thread showing some of the testing we did to compare power output when a downpipe is added to a 2015 STI:

For intakes, we decided that looking at only power wasn’t good enough.  An age-old claim in Subaru world is that the factory airbox is not restrictive with the stock turbo, and we wanted to see it for ourselves.  We put this to the test by measuring turbo inlet vacuum generated on the stock airbox and with a COBB Tuning SF Intake system fitted to the car.  Garrett refers to vacuum in the turbo inlet as “depression”:  “Any restriction (caused by the air filter or restrictive ducting) will result in a “depression,” or pressure loss, upstream of the compressor that needs to be accounted for when determining pressure ratio.” (

By comparing the depression created by the factory intake against an upgraded intake, we can actually “see” if we have removed a restriction or not.  If the depression is the same, well, all we’ve done is added a noise-maker to the car :)

To complete this test, we first gathered boost and depression data on the stock airbox using a stock-hardware 2015 STI (tuning only), first on wastegate boost pressures only, then at ~17.5psi peak via our Stage1 93 OTS map in “S#” mode.  Next, we gathered the same data on the COBB SF Intake, with no calibration changes other than for the different MAF curve required.

What did we find?  Results!  The stock airbox creates depression levels of a bit over 1psi on wastegate boost at redline, and well over 2psi on the Stage1 boost levels!  What does this mean?  Here in Austin, where the elevation is ~800 ft, the barometer was ~14.21psi for the testing day.  With the stock airbox at redline, the turbo was only being fed with approximately 12psi of pressure due to the depression.  For comparison, this would be the same as running the car at 5500 ft of elevation if there were no depression!

Here is the boost and depression (intake pressure) data for wastegate and for 17.5psi, shown in gauge pressure relative to ambient atmosphere:

Boost and Intake Pressure – Wastegate Spring Only


Boost and Intake Pressure – 17.5psi Setting

As you can see, thanks to the reduction in depression with the upgraded intake, boost is a bit higher on the wastegate.  At 17.5psi, we can see that spool has improved and high RPM boost is held out better on the same WGDC settings.  In each case, the depression created by the COBB SF Intake system is roughly half of the factory airbox.  What does this mean?  Simply put, we’ve reduced restriction in the turbo’s inlet path, as shown by the reduction in depression.

I also decided to take this data one step further, which is to calculate the turbocharger’s effective pressure ratio for each case.  One caveat is that we’re looking at post-IC pressures, not pre-IC, but because the intercooler has not changed at all between tests, it shouldn’t skew the results too greatly.

Here is the pressure ratio for each scenario (again, baro in Austin was ~14.21psi on testing day), calculated using Garrett’s methodology here:

Pressure Ratio Comparison – Wastegate Spring Only


Pressure Ratio Comparison – 17.5psi

On wastegate boost pressures, we can see that there isn’t too drastic of a difference — perhaps a tenth of a point at very most.  However, at 17.5psi, we can see the COBB SF Intake really start to separate itself: pressure ratio is decreased by about two full tenths across the board after spool.  What does this mean?  The turbocharger compressor is now operating more efficiently, at least in terms of the demanded pressure output (boost) again the amount of pressure available at the input.

So, at the end of the day, here’s what power looks like between the two.  COBB SF Intake are the solid lines, stock airbox are the dashed lines:

Stage 1 vs Stage 1+SF Intake Dyno Comparison

Long story short?  On the 2015 STI, even in otherwise-stock configuration, the COBB SF Intake system (and others that have the same or better airflow capabilities) help the turbo breathe easier and in turn, make the same boost more efficiently or more boost at the same efficiency when compared to the stock airbox.

Thanks for reading along! Hopefully you found this data interesting and helpful. We plan to keep providing results like this as we dig in further on the 2015 STI and WRX, so stay tuned :)


The COBB Subaru Expert Group

Suspension – Yes, you should probably upgrade that too!

We can all sometimes get a little caught up in making power…and that’s great!  But what good is all of that power if you cant put it to the ground?

Check out our latest video for a little insight into what suspension modifications you can make to improve Contact, Comfort, and Control of your car.

Then, head on over to our website to check out what suspension parts we offer for your specific vehicle!

COBB Releases – January 2013

COBB is proud to announce performance and suspension part releases for January, 2013!

COBB BMW 1-Series Springs – The best first step to a better handling AND looking car! Click for more pictures and details. COBB BMW 1 & 3-Series Anti-Sway Bars – This perfectly balanced kit reduces body roll, sharpens turn-in response, and reduces understeer. Click for more pictures and details.
COBB BMW 3-Series Spring Kit – An easy way to enhance your stance and improve handling! Click for more pictures and details. COBB Ford Focus ST and MS3 Rear Motor Mount – Improve traction and reduce wheel hop while minimizing NVH with a unique bushing design. Click for more pictures and details.
COBB Nissan GT-R Sport Spring Kit – Improve handling and appearance while reducing coil slap. Click for more pictures and details. COBB Nissan GT-R Anti-Sway Bar Kit – The easiest way to minimize body roll, increase turn-in response, and balance your body rotation. Click for more pictures and details.
COBB Subaru 08+ Anti-Sway Bar Kit – The perfectly balanced kit reduces body roll and improves turn-in response! Click for more pictures and details. COBB Mitsubishi Evo X Oval Tip Exhaust – A long time favorite is back! Click for more pictures and details.

2013 Subaru WRX Stage 2 Firmware and Map Updates

COBB has just released new map and firmware updates for all AP-SUB-003 AccessPORTs that fixes a map issue for the 2013 WRX, STI, and Forester XT that can cause the vehicle to show a P0605 ROM Error with Stage 2 mapping. To prevent this from happening or to resolve a current issue, first you will just need to uninstall the AccessPORT from the vehicle using the Uninstall option from the main menu. Then, update the AccessPORT to the latest firmware ( or greater) using AP Manager. Finally, do a full Reflash map change with the newest maps on the AccessPORT or downloaded from the Maps section of our website. You can verify your current firmware by going to AccessPORT, then About and you can verify your current map version by going to Tune, then Show current Map, then Reflash Map.

For the 2013 STI, use Stage 2 map version v321 or greater. For the 2013 WRX, use Stage 2 stock intake map version v301 or greater or Stage 2+SF/AEM map version v312 or greater. For the 2013 Forester XT, use Stage 2 map version v311 or greater.

If you are unfamiliar with updating the firmware on your AccessPORT, please follow this link for Step-By-Step Firmware Update Instructions. Please feel free to call us at 866-922-3059 or email if you have any questions.

2013 Subaru STI, WRX and FXT AccessPORT Support Available Now!

COBB is excited to announce immediate support for the 2013 Subaru STI, WRX and Forester XT models! Owners of the latest high-performance Subarus can now attain the same level of power and control with the AccessPORT as enjoyed by previous model year owners. Our AccessTUNER software has also been updated to allow custom tuning of the 2013 STI, WRX and FXT by both professional tuners and DIY tuners alike. Read on for more details about the work COBB Tuning is doing to make sure the AccessPORT is the most comprehensive tuning solution for Subaru performance enthusiasts.

2013 Subaru STI, WRX and FXT AccessPORT

2013 Subaru STI, WRX and FXT AccessPORTs are available for purchase now and come preloaded with performance-enhancing Stage1 and Stage2 maps to get new users up and running quickly with the push of a button. The AccessPORT also comes preloaded with our unique Non-Performance maps for fuel economy, valet parking and anti-theft to help protect your wallet and your investment.

Our pre-loaded Off-The-Shelf maps for the 2013 STI include a number of large and small refinements thanks to additional calibration tables now defined within AccessTUNER Pro and Race. The most significant mapping change is the introduction of “Triple Boost Select”, which now allows for independent boost targeting/control in “I”, “S” and “S#” SI-Drive Modes. Factory logic that previously caused an automatic transition from “I” to “S” mode during aggressive driving has been identified and eliminated. Throttle response in “I” and “S” modes has been refined to provide better take-off and low-speed drivability behaviors, a frequent complaint area for stock 2008-2013 STI owners. The AccessPORT for 2013 STI puts more control and flexibility into the driver’s hands than ever before!

The 2013 Subaru STI, WRX and FXT AccessPORTs come equipped with all of the same features released on previous versions, including Launch Control, Flat Foot Shift, Speed Density support, Real-Time Tuning, Performance Measurement, DTC Scanning/Clearing, and Live Data and Datalogging of over 100 ECU monitors. A full list of AP-SUB-003 enhancements is available in the AP-SUB-003 AccessPORT Firmware Release Notes. All late-model (V2 and V2b) Subaru AccessPORTs (Part Number: AP-SUB-003) can be updated for free to support 2013 vehicles with a simple firmware upgrade to version or later.

AccessTUNER Tuning Software

The AccessTUNER Race and AccessTUNER Pro tuning software packages have been carefully updated to fully support the 2013 Subaru STI, WRX and FXT for USDM markets. 2013 owners can bring their cars to a professional tuner for a custom tune to maximize power output. Experienced self-tuners can download a free copy of AccessTUNER Race and make modifications to their own calibrations. All software users have access to our extensive database of Off-The-Shelf maps, which serve as excellent starting points for your custom tunes. Existing AccessTUNER users can update their existing software to the latest version following these Step-By-Step Software Update Instructions. New AccessTUNER Race users can acquire their copy of the software by filling out the AccessTUNER Race Request Form.

Additionally, this release includes AccessTUNER Pro-only support for many recent Japanese Domestic Market (JDM) turbocharged Subaru vehicles, which are supported by the AccessPORT in their native market via collaboration with Prova. Any currently-licensed member of our Subaru professional tuning network may perform a custom tune on these vehicles; only Prova-supplied AccessPORTs are compatible with these vehicles. This release also includes minor bug fixes and usability improvements.

Step-By-Step Guides

Follow this Step-By-Step AccessPORT Firmware Update Guide to quickly and easily update the firmware on your AccessPORT.

Follow this Step-By-Step AccessTUNER Software Update Guide to update your software to the latest release.

Follow this Step-By-Step AccessPORT Map Download and Transfer Guide to download maps, transfer them to your AccessPORT and flash them to your ECU.

To learn more about the AccessPORT for the 2013 Subaru STI, WRX and FXT, or to get answers to any questions you may have regarding COBB Tuning products, please contact our Customer Support Team using our Live Chat feature at or via phone at 866-922-3059.

COBB 2008+ Subaru WRX and STI Sport Springs

COBB is proud to announce the immediate availability of the 2008+ Subaru WRX and STI Sport Springs. The COBB 2008+ Subaru STI and WRX Sport Spring Kit is the best first step to a better handling and better looking car. The 7/8” drop front and 7/8” drop rear lowers the car’s center of gravity to improve cornering speed and response while also minimizing wheel gap for a sportier look. This aggressive stance reduces squat and wheel hop under hard acceleration. Custom spring rates provide the sport feel without being unnecessarily harsh or bouncy. Road course tested and real world approved, the COBB Tuning Sport Spring Kit is the best direct replacement spring available for your 2008+ WRX or STI.

Road course tested and real world approved, the COBB Tuning Sport Spring Kit is the best direct replacement spring available for your 2008+ WRX or STI. Click the link below for more pictures and information!

COBB 2008+ Subaru WRX and STI Sport Springs