2008 Scion xB RS 5 - Power Pages

Notes:
The '08 xB uses two catalytic converters and two O2 sensors to monitor engine vitals. The primary catalyst is welded to the OE header, so replacing it with one that brings power gains means removing the first catalyst altogether. Since doing so will throw off the proportions of O2 read by both cats, Strup includes a trick CEL Eliminator kit that fits between the second O2 sensor and catalyst to cure the problem. Driving with the CEL won't hurt performance or damage the vehicle, but it's annoying to deal with ... and you won't be alerted to any engine problems that may occur for other reasons down the road.

Dyno 4
Strup Performance 4-1 Header
Peak HP: 140.9 / Peak TQ: 139.8

Horsepower Gain
* 4,000 to 5,500 HP range: -0.5 to 4.8
* 5,500 to redline HP range: 0.7 to 6.9

Torque Gain
* 4,000 to 5,500 TQ range: -0.6 to 2.0
* 5,500 to redline TQ range: 0.3 to 6.2

Conclusion:
After improving output by over 16 whp and 18 lb-ft of torque at points throughout our xB's powerband, we consider this installment of Power Pages a complete success. Eliminating the restriction of the stock airbox and piping brought instant power, as did eliminating the car's primary catalytic converter. The TRD muffler helped out a little, but served to bring out the 2AZ-FE's deep tone in a subtle, mature manner. Most impressive is that these gains were realized with one of the car's catalytic converters still inline, and half of its stock exhaust bolted up. Imagine what power could be found by adding a racing exhaust and a little tuning ... some forced-induction ... maybe building the block...