If someone were to pick up their brand-new 997 from the dealer, usually the last thing on that person's mind would be to modify it. But that's probably not the case with our readers. At european car, we're always on a quest to improve on what's already fantastic.

The 355bhp Porsche 997 is just that-fantastic. The 997 S, however, with its X51 package, is superb. With the touch of a button, the DME switches to a more aggressive ignition map and exhaust tone good for a total 380 bhp-a difference you can definitely feel.

We got our hands on a 997 S for testing but with its X51 package also featuring different cams, headers, and exhaust systems there's nothing to touch in these respective departments unless you're building a race car. After paying Porsche serious coin to upgrade to the S, why take the factory upgrades out?

On the software side, we contacted GIAC to see if the tuning could be further improved. Sadly, while they have software for the turbo and base 997 models, nothing is available for the S. GIAC reportedly attempted to improve the software previously with the X51 996 model, but didn't see any gains. It wasn't anything bad on GIAC's part, rather, it was simply evident the X51 software strained the engine enough on the allowable 91-octane that there wasn't any extra power to be had safely.

This left us tracking down an intake system. Fortunately, we found Evolution Motorsport, which had one readily available for us to test. Its intake is engineered using CAD/CAM 3D modeling, CNC machining, and computer-controlled airflow testing. It also features rotational and injection molded construction for a factory look and fit. Since the unit is reportedly used on several 997s running in the Grand-Am Cup GS Series, we felt it was good enough to test on our street car.

Peak wheel horsepower: 297 whp @ 6450 rpmPeak wheel torque: 256 lb-ft @ 4600 rpm

Vehicle Data
Transmission: Six-speed manualMileage: 12,750Testing octane: 91

Current modifications

Dyno Data
Dyno type: Dynojet 424x
Temperature: 60 degrees F
Location: Tuning Technologies in Colton, Calif.
Transmission test gear: Fourth

We were curious to do a separate test showing the difference in wheel horsepower between pressing the sport button to activate the extra 25 bhp versus leaving it off, but it wasn't until we already had the car strapped and running on the dyno that we realized pressing the X51 sport button would freak the car's DME on the dyno.

Even though the 997 S is rear-wheel drive, it needs an all-wheel-drive dyno that has the front and rear rollers connected to run simultaneous speeds or the computer puts the car into a limp mode. While Tuning Technologies' Dynojet is also for all-wheel-drive cars, the front rollers are spun separately by the front wheels. In order to properly test the X51 software you apparently need to use a Mustang or Dyno Dynamics dyno. This didn't stop us from being able to test the intake system.

We also noticed Porsche keeps this 3.8 liter running fairly rich up top for a non-turbo engine. Air-to-fuel ratios consistently dipped into the high 11s from 6400 rpm and on.

Evolution Motorsport's Intake System

Peak wheel horsepower: 300 whp @ 6500 rpm
Peak wheel torque: 258 lb-ft @ 4450-4700 rpm
Peak wheel horsepower gain: 17.3 whp @ 5550 rpm
Peak wheel torque gain: 16.4 lb-ft @ 5550 rpm


*Heat shielding properly seals when hood closes
*Uses OE ram-air ducting
*Washable and reusable cotton air filter
*Factory look
*Easy installation
*100 percent reversible
*Awesome intake roar past 5000 rpm


Intake pipe to MAF, heat-shielded airbox with snorkel to factory ram-air inlet, cotton conical air filter, hose clamps, silicone boots, hardware

Installation time
1 hour


Testing was done while monitoring oil, water, and inlet air temperatures to record gains as accurately as possible

Given that most cars benefit around 4 percent with an intake system in terms of peak power, we expected to see a larger gain up top, netting around 307 whp in the end, which, at 5700 rpm, the curve looked to be heading toward.

While the power increments there seemed to slow down suddenly, it's hard to believe that this was caused by running a freer-flowing intake system. Given the shape of the curve in that region, however, we can assume it's from a slight reduction in ignition timing from the DME on these last pulls. We've seen DMEs do this before (and a 1-2 degree retard will be evident on the curve), but without the ability to monitor ignition values that day we can only speculate. Still, in the low-end and midranges were some nice, steady improvements averaging around 5 lb-ft of torque. The dyno also confirmed a 0.1-second improvement in acceleration from 3500-7000 rpm in Third gear

What makes this upgrade even more worthwhile is the new engine song at high rpm that will have you dancing in your seat. Driving it around at part throttle and the car's cruising decibels are as docile as a 997s should be. Rev it past 5000 rpm and it roars in a matter that will make you want to leave your window rolled up for fear of getting sucked into the air duct. Henceforth, we can't determine if the intake system has helped our fuel mileage because we're always flooring on it. Special thanks to Tuning Technologies for its assistance and dyno use.

Evolution Motorsports Tuning Technologies
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