California is known for its sunny beaches, Hollywood lifestyle and terrible gas, especially in the winter when the percentage of ethanol increases. So when Sig Jamison, the owner of this '07 BMW 335i, was preparing to ship his car from the East Coast, he made a point to top off the tank with precious 93-octane. At the time, the 335i was running a custom turbo-back exhaust and Cobb 93-octane software which gave, according to Sig, "awesome performance."

As the 335i sucked down its last drop of 93 in California, he knew the party was over and planned to install the Cobb 91-octane program. Although he knew the lower octane would diminish performance, it was the scale of the loss that surprised him.

It wasn't just straight-line power that was down, but he found the BMW was more susceptible to heat soak, had different throttle response, poorer gas mileage and diminished overtaking performance.

Eventually, he removed the Cobb software entirely because he was uncomfortable with how much timing the motor was pulling under acceleration, and that the engine was retarding the ignition timing under full boost. So the 335i returned to stock, leaving Sig slightly bummed.

Fortunately, he moved to sunny SoCal for a new employment opportunity at Banks Engineering - specialists in diesel performance. His arrival couldn't have come at a better time as the engineers were in the process of finalizing development of its StraightShot water/methanol injection system. This would be the solution to restore and enhance the performance of his N54-powered 335i 3.0-liter twin-turbo.

Test Data

Dyno: Clayton Mustang MD-750
Temperature: 62-68°F
Humidity: 53-63%
Test Gear: third
Fuel: 91-octane
Modifications: custom 3" turbo-back exhaust with 6" high-flow cat

Test 1 Baseline

The baseline and all subsequent testing was performed on the same day, utilizing the same tank of 91-octane gas. All horsepower and torque figures have been automatically corrected by dyno software to compensate for environmental changes and were measured at the rear wheels in third gear. All temperature and timing readings were obtained using Cobb AccessPort Manager datalogging software.

Results

Peak Power 227hp at 5574rpm
Peak Torque 248 lb-ft at 2393rpm
27-99mph dyno accel 17.5sec
Range of timing retard 5000-6700rpm -1 to -7°
Intake manifold temp 5000-6600rpm 124-151°F
Peak boost pressure 8.75psi at 5545rpm
Timing at peak power cylinder #1 +5.25? at 5574rpm
Timing at peak torque cylinder #1 +7.875° at 2393rpm
Temperature 68°F
Humidity 53%

Test 2 Banks Engineering Straight Shot

Knowing our baseline numbers, we moved onto the meth injection kit installation. Although the Banks StraightShot meth kit was designed specifically for the N54 engine, it doesn't come with a bracket for the injection nozzle. Fortunately, Sig's 335i had the updated throttle body charge pipe without sound amplifier, which gave a perfect spot to locate the nozzle. So after removing the air box, removing the charge pipe was straightforward. This meant drilling and tapping the plastic for the nozzle took no time at all.

The most tedious part of the installation was running the tubing from the windshield washer bottle (used as the meth reservoir) in the front fender, back to the pump mounted in the trunk, and then up to the engine.

Fortunately, the harness was plug-n-play so required no cutting. The digital controller utilized the OEM boost sensor, so there was no need to run vacuum lines, so connecting everything was quick and easy.

For this installation, the controller's slim profile allowed the gauge to be easily mounted in the ashtray for easy adjustment and monitoring of boost and the pump duty cycle.

Using the Cobb AccessPort datalogger to glean data throughout the test, it showed a slight drop in boost pressure across the entire rev range. We also saw a dramatic reduction to intake temps, eliminating the timing retard, but increased cylinder one timing (the only cylinder we measured).

We did notice some power loss on the dyno below 2500rpm but were unable to fully investigate the problem. The Banks kit was still a prototype, so the calibrations and nozzle sizes weren't finalized. After our test, Banks engineers informed us they have subsequently swapped the #5 nozzle for a smaller #4.

System Configuration

  • #5 nozzle rated at 315cc/min at 100psi
  • System activated at 2psi, pump at 15% (boost setting 1)
  • Full operation at 15psi, pump at 100% (boost setting 2)

Parts

  • Banks Engineering StraightShot methanol injection system, #5 nozzle, Banks PowerBlend (50/50% meth and water)
  • Installation time: 2-3hr
  • MSRP: $798.89

    Parts

    • Banks Engineering StraightShot methanol injection system, #5 nozzle, Banks PowerBlend (50/50% meth and water)
    • Installation time: 2-3hr
    • MSRP: $798.89

      Pros

      • Plug-n-Play harness utilizes OEM MAP (boost) sensor to control meth delivery
      • 300psi high-pressure pump with integrated output pressure switch
      • 300psi-rated high-flow stainless steel solenoids with mounting brackets
      • Simple, compact controller nozzle featured large hex head, O-ring seal and holders with swiveling connections
      • System can be turned off

      Cons

      • Trunk-mounted pump combined with OE windshield washer bottle requires two fluid lines

      Results

      Peak power 236hp at 5597rpm
      Peak torque 258 lb-ft at 3129rpm
      27-99.8mph dyno accel 17sec
      Range of timing retard 5000-6700rpm
      Intake manifold temp 5000-6700rpm 90-91°F
      Peak boost pressure 7.75psi at 5101rpm
      Timing at peak power cylinder #1 +10.875° at 5597rpm
      Timing at peak torque cylinder #1 +12° at 3129rpm
      Max power gain 14hp at 5238rpm
      Max torque gain 15 lb-ft at 3129rpm
      Temperature 63°F
      Humidity 53%

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