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GM - Mass Air Modifier

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JMS Chip & Performance is revolutionizing mass air fuel injection systems with the Mass Air Modifier for GM 2008-2014 vehicles including; Corvette, Camaro, and CTS-V. This simple and easy to use in-line MAF tuning device is designed to accurately scale and filter the mass air signal on most new mass air equipped cars, trucks and SUV's. This product also allows you to install and tune an LS3 mass air flow sensor on LS1 or LS2 vehicles using plug and play adaptors.


Noisy mass air meter signals caused by aftermarket modifications have long been a source of frustration for GM ECU tuners. The JMS Mass Air Modifier is the only product that can filter the mass air signal, while also scaling the signal up or down. Cold air kits, camshafts, and the architecture of your air inlet on a turbo or supercharging system are just a few examples of what can cause turbulent airflow and a noisy mass air signal.


Why go "MAF-LESS" when you can use the JMS Mass Air Modifier to filter the MAF signal and clean up the "noisy" signal area that is causing your drivability issue. The JMS Mass Air Modifier features a simple switch that allows you to choose how the signal is filtered at idle, or filter at a variety of target signal ranges under acceleration. Use the rotary switch to choose between 16 built-in levels of filtering based on how or where the signal needs to be cleaned. Tuners will benefit greatly from this innovative concept, now they can quickly change the mass air signal in real-time on the dyno, and see instant results via basic OBD-II data logging. You can also choose to filter the signal based on the MAF frequency, or you can filter based on another input from a 0-5 volt sensor. With seven unique filter ranges you can fine tune the filter to your problem area.


Scaling the mass air meter allows you to add or remove fuel by shifting the MAF signal up or down. Tuners can use this feature to raise or lower the curve for improved performance, fine-tune the signal at the track, or tune for various size fuel injectors and mass air inlets. Another added benefit is the ability to correct lean or rich fuel codes caused by basic aftermarket upgrades such as a cold air kits, and you can correct the issue without a laptop or OBD-II programmer while maintaining a warranty-friendly status at the local dealership. To help support advanced tuning features, JMS offers a simple spreadsheet that provides mass air flow values for use with aftermarket custom tuning software, along with thorough instruction manuals and video how-to guides. If you own a "boosted or high horsepower" LS1 or LS2 vehicle, the JMS Mass Air Modifier can be used to install and scale the LS3 MAF sensor down below the 12,500Hz limit on the factory ECU.


The JMS Mass Air Modifier features advanced electronics housed in an aluminum case, a complete OEM-grade plug and play wiring harness using shielded cable, with additional cables for 0-5 volt signal input and optional on-board enable/disable switch. Specific wiring harnesses have been designed around common GM factory MAF systems ranging from 1997-2014. The device operating voltage range is 9.5-20 volts DC, and it is compatible with 12 or 16 volt DC power systems. The complete system is designed to be used with any factory GM mass air meter regardless of inlet size, will support a wide range of fuel injectors, and is offered for:

  • 1997-2004 LS1 Engine utilizing the LS3 MAF sensor (p/n 4001-GM4)
  • 2005-2007 LS2 Engine utilizing the LS3 MAF sensor (p/n 4001-GM3)
  • 2008-2014 LS3 Engine (p/n 4001-GM1)
  • 2008-2014 LC8, LMF, LU3, L20 or L99 (p/n 4001-GM2)