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: http://forums.nasioc.com/forums/showthread.php?t=2639122
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.” (http://www.turbobygarrett.com/turbobygarrett/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:
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: http://www.turbobygarrett.com/turbobygarrett/pressure_ratio
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:
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
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 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.|
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 (220.127.116.11-5151 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 firstname.lastname@example.org if you have any questions.
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 18.104.22.168-5135 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.
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 www.cobbtuning.com or via phone at 866-922-3059.
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 is proud to announce the immediate availability of the 2004-2007 Subaru WRX and STI Sport Springs. The COBB 2004-2007 Subaru STI and WRX Sport Spring Kit is the best first step to a better handling and better looking car. The 1.25” drop front and 1” 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 2004-2007 WRX or STI. Click the link below for more pictures and information!
COBB is proud to announce the immediate availability of the 2004-2007 Subaru STI Anti-Sway Bar kit. The COBB 2004-2007 STI Anti-Sway Bar Kit is one of the most effective ways to improve handling without negatively affecting ride quality or NVH (noise, vibration, harshness). The perfectly balanced kit increases front bar stiffness to 880 lbs/in and rear bar stiffness is adjustable from 460 lbs/in, 560 lbs/in, or 690 lbs/in to resist body-roll, sharpen turn-in response, and reduce understeer. The CNC bent anti-sway bar kit includes rear mounting brackets and stiffer polyurethane bushings with bushing brackets for instant suspension response, and all are direct factory replacements to ensure perfect OEM-like fitment without compromising performance. The bushing brackets also include built-in grease fittings to make maintenance quick and simple.
This Anti-Sway Bar Kit is available for all 2004-2007 Subaru STI vehicles. Anti-Sway Bars are also available separately to help stage out the upgrade process. Click the links below for more pictures and information!
COBB 2004-2007 Subaru STI Anti-Sway Bar Kit
Part Number: 913250
COBB 2004-2007 Subaru STI Front Anti-Sway Bar Kit
Part Number: 913250F
COBB 2004-2007 Subaru STI Rear Anti-Sway Bar Kit
Part Number: 913250R
COBB is proud to announce the immediate availability of the 2002-2007 WRX Anti-Sway Bar Kit. The COBB 2002-2007 Subaru WRX Anti-Sway Bar Kit is one of the most effective ways to improve handling without negatively affecting ride quality or NVH. The perfectly balanced kit increases front bar stiffness to 880 lbs/in and rear bar stiffness is adjustable from 460 lbs/in, 560 lbs/in, or 690 lbs/in to resist body-roll, sharpen turn-in response, and reduce understeer. The CNC bent anti-sway bar kit includes rear mounting brackets and stiffer polyurethane bushings with bushing brackets for instant suspension response, and all are direct factory replacements to ensure perfect OEM-like fitment without compromising performance. The bushing brackets also include built-in grease fittings to make maintenance quick and simple.
This Anti-Sway Bar Kit is available for all 2002-2007 Subaru WRX vehicles. Anti-Sway Bars are also available separately to help stage out the upgrade process. Click the links below for more pictures and details!
COBB 02-07 Subaru WRX Anti-Sway Bar Kit
Part Number: 912250
COBB 02-07 Subaru WRX Front Anti-Sway Bar Kit
Part Number: 912250F
COBB 02-07 Subaru WRX Rear Anti-Sway Bar Kit
Part Number: 912250R