Hey everyone,
After a long journey, I'm finally putting thoughts down on the cold air intake, headers all the way back exhaust, and aftermarket tune on my 2014 BRZ.
As promised, a playlist comparing the mods before and after the header+tune is below along with my dynos. I tried to replicate the conditions exactly for the comparison clips.
I don't apologize for my lack of video editing skills.
The car:
2014 BRZ purchased Dec 2013
+ Perrin CAI (front bumper cover removal)
+ FT86 SpeedFactory Catted UEL header (horray, pre-orders)
+ Perrin Overpipe
+ Berk Catted Front Pipe
+ Perrin Resonated 2.5" Exhaust
Current mileage: 52xx
Current power: 195hp/150tq dynojet, 179hp/136tq mustang dyno
Goal:
#1 - Unlock the BOXER rumble
#2 - Reduce/eliminate the torque dip
#3 - Avoid aftermarket tuning
Method:
#1 - Gentle by the book break-in for 500mi followed by raising RPM limit by 500rpm for every additional 100 miles until redline is achieved.
#2 - Complete break-in over a two week period.
#3 - Baseline dyno.
#4 - Install CAI, overpipe, catted front pipe, and exhaust.
#5 - Revised dyno.
#6 - Install catted UEL header.
#7 - Revised dyno.
#8 - Tuning, if required.
Results:
==> Success! But tuning was required.
Overview:
The stock BRZ is lawmower quiet. Neutered. It's designed to produce efficient power while reducing any (perceived) unwanted noise in the cabin or bystanders. It does this extremely well.
I wanted that RUMBLE and was prepared to mod in order to achieve it. Without it, the twins lose that character that soundtrack many enthusiasts crave.
After a baseline dyno and successful break-in, I acquired the aftermarket parts minus the header.
The BRZ runs extremely rich from the factory under power. Breathing mods increase this further.
These modifications by themselves without the header provide a great sounding car with very little highway drone. It sounds much more like what we expect from the FA20, but still lacks that deep down growl.
The revised dyno shows I actually lost a small amount of power after driving with the mods and no tune. -7hp/-5tq at the wheel.
Based on my understanding of closed loop operation, a battery reset will achieve the same thing as shutting off the ignition. Short term trims adjust on the fly to operating conditions constantly. To reset long term fuel trims, an ECU reset or clearing these values with a computer is needed.
Since fuel trims became richer, the ECU has already adjusted the fuel tables for the increased flow. This was not unexpected, but still a disappointment because it means I needed to chip or tune.
The FT86 SpeedFactory header was pre-ordered and installed 6~7 weeks ago from today and tuned by Evasive using ECUTek. The Mustang dyno is below and remember, this is with cats. I have or had the strongest catted NA in the Evasive computer.
The header improved the sound and raised the overall volume by 3-4dB under full throttle and marginally on cruise/part throttle. It now has some rumble especially in the 1,500-4,000rpm range.
The torque dip was almost completely eliminated, it may be that with fine tuning and more break-in, it will be completely flat. Driving, it's not even noticeable.
Throttle response feels improved on the initial tip-in and there's less clutch judder rolling about at parking lot speeds.
When the dealership starts it up to pull in to the back for servicing, the BOXER snarl and rumble was more noticeable OUTSIDE the car. It sounds great.
It doesn't wail or rasp anywhere through the rev range.
It has a pleasant hum, not an intrusive drone on the highway. And no stink.
When you do the Mustang obligatory 10% adjustment to equate to Dynojet, I'm right around 225hp/172tq crank and 195hp/150tq to the wheels.
That's a 15% increase over stock power levels at the final cost of parts and labor at $3700.
I can live with that. And live with the sound.
For those looking to save money, you can get the listed mods and tune without the header.
The improvement in sound from the header happens primarily on part throttle, which ends up being where you spend most of your time. That's why it was a must have for me.
5 video playlist, volume boosted 3dB to more closely match actual volume.
Hero3+ Silver with Fat Gekko dual suction mount. Resolution was lowered to 480p for small files while retaining the sound for easy, low bandwidth streaming.
#1 - Short pull, no header
#2 - Short pull, with header
#3 - Freeway merge, no header
#4 - Freeway merge, with header
#5 - Cruise up hill and deaccel
#6 - Exterior exhaust revs
#7 - Exterior drive-bys
http://www.youtube.com/playlist?list...3hqEgws7VYUv3Q
Now, onto the dyno charts and AFR.
#1 - Baseline dyno, corrected dynojet
#2 - AFR, blue line stock, red line with mods, black line hot pull
#3 - Mustang dyno
