NotesDyno numbers reveal that from 2000 rpm to 3400 rpm, we see an immediate increase in both horsepower and torque as 7 hp and 8 lb-ft of torque was delivered over our baseline run. The power gains continue as midrange power at 3500 rpm and beyond increases to 23 hp and 35 lb-ft of torque. Both horsepower and torque are once again recoded with gains of 25 hp and 20 lb-ft of torque from 5500 to redline. It should be noted that all test and tuning was accomplished on California's wonderfully shitty 91 octane pump gas.
Dyno 3:a'pexi gt spec exhaustPeakhp 292.0 / Peaktq 267.9
Horsepower Gain* 1500 to 3500 HP range: -1 to 3 * 3500 to 5500 HP range: 5 to 10 * 5500 to redline HP range: 6 to 13
Torque Gain* 1500 to 3500 TQ range: 0 to 4* 3500 to 5500 TQ range: 6 to 9* 5500 to redline TQ range: 10 to 7
ProsConstructed using a fully polished and lightweight stainless steel design, the A'PEXi GT Spec exhaust system was designed for performance using a 95mm, or 3.74 inches, with a 4.5-inch tip with removable silencer-one of the largest in production for the EVO.
ConsWhen it comes to installing an exhaust system, we recommend you take the time to properly align the flanges and gaskets on each section to ensure a free-flowing system. We've come across many EVO owners who claim their exhausts end up touching the driveshaft, when in fact improper installation was the problem.
PartsExhaust, piping, exhaust flange, nuts and bolts, stickers, instructions
Tools12- 14- and 17mm socket, 12-, 14- and 17mm open end, ratchet, extension, crescent wrench and WD-40
Installation time45 minutes
NotesWith the new GT Spec exhaust in place and proper tuning applied, the EVO responded with an increase of 7.9 hp and 5.9 lb-ft of torque over our previous run. The gains in both torque and horsepower remained consistent from 2000 rpm to redline with the largest gains of 10 hp and 8 lb-ft of torque at 7000 rpm. We noticed both horsepower and torque to be more responsive with the new exhaust as power was achieved quicker from 3300 rpm as it maintained its gains till redline.
Dyno 4:hks evc vi boostcontrollerPEAKHP 299.7 / PEAKTQ 270.5Horsepower Gain* 1500 to 3500 HP range: 0 to 4* 3500 to 5500 HP range: 4 to 25* 5500 to redline HP range: 0 to 15
Torque Gain* 1500 to 3500 TQ range: 0 to 0* 3500 to 5500 TQ range: 10 to 15* 5500 to redline TQ range: 10 to 5
ProsThe HKS EVC VI is the newest boost controller in a long series of EVC's (5th generation) sold throughout their 20-year anniversary. HKS states their newest EVC has improved boost stability for maintaining pressure at high rpms, offering increased top end power. Another highly regarded feature is a new mapping feature, which allows boost pressure to be precisely tuned for throttle and rpm (over vehicle speed). Another slick feature we found likeable on the EVC is the ability to monitor up to two additional engine parameters such as boost pressure, throttle position, engine rpm or vehicle speed. With so many boost controllers on the market today, it's nice to know HKS doesn't stray away from continuing to develop a sleek, un-gaudy looking boost controller that has the newest functions that's sure to benefit your vehicle.