4 Throttle Body Injection

Let talk Performance:

The 4 TBI setup is not about fuel economy….its about power.   Our Throttle bodies are bored to 1.25″ on the 2 and 4 TBI versions to provide maximum airflow, fuel delivery, and power.   We did not design this system for racing since crank triggers are not allowed, but if you want good pull with plenty of top-end… this is your system.  We program the ECMs for the middle of the road engine setups, but this kit will require a laptop to tune your engine further.  All of our kits are supplied with NBO2 sensors, but support the use of Wideband O2 sensors (purchased separately) and is highly recommended for advanced tuning and precise fuel control of these engines.  

The Direct linkage system for the 4 Throttle body kit which opens all 4 TBIs evenly using the standard dual Corvair Throttle linkage.  It does NOT use progressive acceleration as the injectors evenly distributing fuel through the 4 throttle bodies to give a better and smoother response.   All 4 injectors are working to avoid stutter at “tip-in” and proper adjustment and maintenance of the TPS/MAP are imperative for the proper operation of the 4x TBI kit.  

If you are interested in more power than a conventional setup, but want decent driving around mileage,  you may want to consider the Dual TBI kit with block off plates or install “thin plates” under the secondaries of the 4x kit to keep the quad look.  

Ignition:  This kit uses your Corvair modified distributor and a VAG logic coil for a dependable and simple EFI system.  We recommend mounting the Coil to the rear body support to promote better cooling and long life.  We do NOT provide spark plug wires for this kit as it uses standard Corvair plug wires.  If you plan to install Air Conditioning, the AC pulley will interfere with the Trigger wheel and will require you send your Harmonic Balancer to us for modification and a special type of trigger wheel.  You will modify your own distributor with the simple instructions provided here (future)

NarrowBand O2 Sensor:  The NBO2 sensor is included in your kit and in most cases will not need any modification unless your engine is outside the norms (Cams/Bored, etc).  Your engine is designed to run at 14.7:1 AFR except at idle and under heavy load (85% or higher MAP).  The NBO2 sensor will adjust the burn to 14.7:1 when off idle and not under heavy load up to 10%.  If your engine is running extremely lean/rich at idle or heavy load, an adjustment must be made. 

Wideband O2 Sensor:  WBO2 is NOT included in your kit, but is available as an option.  This will allow the engine to be tuned to a specific AFRs using a MAP/RPM table.  The WBO2 follows the table and adjust the fuel table to match the AFR so that it burns where programed.  You will need to contact tech support to set up your software and ECM to use the WBO2 sensor. It is advised to purchase Tunersudio software ($39) to open up the “Autotune” feature that will assist you in tuning your engine.  You can manually tune the engine, but it will take more time and fuel.

Dual O2 Sensors:  Our system supports dual Narrowband O2 (NBO2) or Wideband O2 (WBO2) sensors for dual exhaust.  To make use of 2 sensors,  you will need to install an additional O2 wire into the wiring harness and set up the software to read each sensor and adjust fuel on each bank (head).  This additional O2 Sensor wire will need to be special ordered and we will modify your software for you.   You can not mix WBO2 and NBO2 on the same engine. 

Spartan2 WBO2  https://www.14point7.com/products/spartan-lambda-controller-2

WB WBO2 (Low Cost) – https://www.wide-band.com/product-p/wb_d2n.htm

Innovate LC2 WBO2  – https://www.innovatemotorsports.com/products/lc2.php


Kit Contents

1 ea    Throttle body assembly w/Injector, and TPS

1 ea    Throttle body assembly w/Injector, ICS Actuator and Solenoid

2 ea    Throttle body assembly – Secondary

1 ea    Fuel Line Drivers Side Primary

1 ea    Fuel Line Drivers Side Secondary

1 ea    Fuel Line Drivers Side Main

1 ea    Fuel Line Pass Side Primary

1 ea    Fuel Line Pass Side Primary

1 ea    Fuel Line Pass Side Main

1 ea    Fuel Line “T” to Tunnel line

1 ea    Fuel Pressure Regulator/Filter

1 ea    Map Sensor, GM Type

1 ea    Narrow Band O2 Sensor

1 ea    Head/Engine Temp Sensor

1 ea    Fuel pump block-off with O-Ring

1 ea    Wiring Harness with Relays

1 ea    30 amp fuse assembly

1 ea    ECM Computer (pre-programmed and user adjustable)

1 ea    Smart Ignition Coil

1 ea    Smart Coil to Distributor Plug Wire

1 ea    36-1 Trigger Wheel w/bolts and spacers

1 ea    Trigger Sensor Bracket

1 ea    Trigger Pickup Sensor

1 ea     PVC Hose to Idle Control Vacuum Line

4 ea    *Carburetor cores required

Cores:   Send your cores (Early models are preferred) when you order to allow time for the modifications to these items and avoid delays.  Your cores must be in reasonably good shape and must have a fairly straight Bell Crank, a throttle plate and throttle shaft that are free.  Unusable bases have to be thrown away, wastes your shipping and another set of cores will be needed.  A core charge will be charged for each unusable core.





The 4 Throttle body Injection system can also be used on engines that have had the extra Carburetor pad added (Fitch type).    The Throttle body injection unit uses the standard Corvair gaskets, but will need insulators to ensure the proper height of the TBI.  

Ignition:  We only offer the single-type ignition for the Four TBI kit. 

Kit includes all items from the fuel pressure regulator to the engine. Fuel Pumps and return line are NOT included. ** – Usable cores are required. See Cores Page.