Test 1: Cobb Tuning Accessport
Since the Cobb Stage-1 ACN91 map accommodated either a stock or aftermarket exhaust, we installed the ARK Design exhaust next. The stainless steel ARK Design Superflow Dual Exit exhaust installed quickly and easily, taking a mere 30-45 minutes to install, once the factory exhaust cooled down enough to be handled. A little spritz of WD40 or any other spray lubricant on the exhaust hangers and the bolts holding the exhaust together helps to expedite the disassembly and removal of the stock system. The exhaust includes all the necessary hardware for installation, including new gaskets, nuts and bolts. The only factory hardware you’ll reuse is the two 17mm bolts that mate the catalytic converter to the exhaust.
249.91 WHP @ 6,000 RPM
270.52 lb-ft @4,250 RPM
22.59 psi @3,300 RPM
The Cobb Tuning Accessport can flash the factory ECU with any of the different tuning maps that can be downloaded from the Cobb Tuning website. The Stage-1 ACN91 map yielded an extra 7.21 peak horsepower and an incremental gain of 9.9 horsepower and 11 lb-ft torque.
Test 2: ARK Design Superflow Dual Exit Exhaust
The benefits of the massive 3.5-inch stainless-steel piping became immediately apparent, as the reduction in exhaust backpressure resulted in substantial gains on the dyno. With 25.75-psi boost pressure, peak power and torque increased by 31.07 horsepower and 27.3 lb-ft, respectively. This shows the effect that exhaust restriction has on this particular vehicle, and how it bottlenecks output and boost pressure. The increase of 3-psi of boost accounts for roughly 20 whp of the power increase, while the remaining 11 horsepower gain can be attributed to the reduction in backpressure. The greatest incremental increase in torque of 34.62 lb-ft occurred at 3,200 RPM. When compared to the stock exhaust for sound, the lack of a presilencer didn’t seem to have a dramatic effect on the exhaust note, as noise levels measured 75 dB at idle, 88 dB at 3,000 RPM, 87dB at 4,000 RPM and 89 dB at 5,000 RPM. Although noticeably louder than stock at 3,000 and 4,000 RPMs, the exhaust was only 3 dB louder than stock at 5,000 RPM.
280.93 WHP @ 6,300 RPM
297.93 lb-ft @3,400 RPM
27.3 psi @3,100 RPM
The ARK Design Superflow exhaust, in conjunction with the Cobb Tuning Stage-1 ACN91 map, reduced back pressure while increasing boost pressure by 3psi. The result is an impressive peak gain of 31 whp and 27 lb-ft of torque.
Test 3: AEM Induction Cold Air Intake System
Moving on to the engine bay, the intake was the next item to be upgraded. This installation took about 75 minutes to complete. Once the factory equipment had been removed, installation of the AEM Cold Air Intake proved straightforward. Fitment was spot on as a direct replacement for the factory unit. The factory air duct forces cool air into the AEM Induction plastic air box. Within the air box, the Dryflow cone filter channels filtered ambient air through an aluminum tube with MAF sensor on its way to the rubber inlet hose connected to the compressor inlet. The new rubber inlet hose has vacuum ports and retains stock placement of the factory bypass valve. The use of rubber and plastics helps in resisting heat soak while maintaining a low-key appearance. Not that avoiding detection would be an issue for this intake, which has a C.A.R.B. exemption order assigned to it, making it street legal even in California.
284.95 WHP @ 6,400 RPM
312.80 lb-ft @3,200 RPM
27.5 psi @3,000 RPM
The AEM Induction Cold Air Intake not only helped the EVO X realize incremental gains on the order of 29.64 horsepower and 28.27 lb-ft torque at 5,300 RPM, it also has C.A.R.B. approval for street use.
Before firing the engine, we loaded the Cobb Stage 1+SF ACN91 map to the ECU. This map was refined with a cold air intake taken into consideration, making this tune the proper calibration to pair with the AEM Cold Air Intake system. This intake not only o ered a less restricted flow of incoming air compared to stock, it also reduced intake air temperatures by approximately ten degrees Fahrenheit. Utilizing the gauge mode of the Accessport, we observed a drop in intake air temperatures to between 80-84°F, compared to 90-95°F with the stock intake. Peak horsepower increased to 284.95, while peak torque jumped up by 14.96 lb-ft to 312.80 lb-ft . Peak boost pressure increased again, this time to 27.50 psi, gaining 1.75 psi compared to the previous stage with the exhaust. Although peak horsepower only increased by 3.97, that figure doesn’t tell the whole story, as the greatest incremental gains of 29.64 horsepower and 28.27 lb- ft torque occurred at 5,300 RPM. That’s an improvement of eleven percent in both horsepower and torque.
The Bottom Line
Investing less than three labor hours into the installation, the EVO X MR realized a total increase of 42.26 horsepower and 41.75 lb- of torque compared to its stock baseline. The greatest incremental horsepower gain of 44.82 took place at 5,300 RPM, while the greatest torque gain of 58.86 lb- occurred at 3,200 RPM. This leaves quite a bit of room for improvement, as we’re just scraping the surface of the available upgrades for the EVO X. Upcoming improvements include a downpipe, intercooler, throttle body, flex fuel conversion, fuel system upgrades, a larger turbocharger and camsha fts. We’re aiming for approximately 400 horsepower while staying within the torque capacity of the TC-SST transmission. Stay tuned
| HP Level | HP Increase | % Increase | Total | |
|---|---|---|---|---|
| BASELINE | 242.69 WHP | – | – | – |
| Test 1: Cobb AccessPort + Stage 1 Map | 249.91 WHP | +7.22 | 2.9% | 7.22 |
| Test 2:ARK Design Exhaust | 280.98 WHP | +31.07 | 12.4% | +38.29 |
| Test 3: AEM Intake + Stage 1 + SF Map | 284.95 WHP | +3.97 | 1.4% | +42.26 |
| * * * * * | ||||
| FINAL POWER | 284.95 | – | 17.4% | 42.26 |
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Parts List
| Cobb Tuning AccessPort V3 (AP3-MIT-002) | $500.00 |
| ARK Design Superflow Exhaust (02-F2035M-01) | $995.00 |
| AEM Induction Cold Air Intake System (21-678C) | $440.28.00 |
| MSRP Total | $1,936.28 |
| DSPORT Street Price: | $1,569.74-1,644.49 |
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