WPI Northstar Throttle Body Conversion Kit

3800 Performance is now taking pre-orders for the WPI Northstar Throttle Body Conversion Kit, with the expectation of first orders shipping to customers by 7/19/04.

The stock throttle body used on the L67 supercharged engines have a 69mm inside diameter outlet. The stock throttle body used on the Cadillac Northstar V8 engine has a 75mm inside diameter outlet. This 6mm increase in size dramatically increase throttle response and provides solid horsepower gains with customers running a 3.0" or smaller supercharger pulley, and moreso for those with an aftermarket cam or cam/heads package.

WPI created this conversion kit to match up perfectly to their WPI Xtreme SC or Xtreme IC SC, which have 75.5mm bored inlets. But for those customers running a stock or WPI Competition Supercharger, which have 72mm inlets, WPI has a solution for you as well. WPI offers 2 different adapter plate designs: one adapter plate mates the Northstar 75mm outlet to the stock 72mm SC inlet by tapering the bore for a nice smooth airflow transition, while the second adapter plate mates the Northstar 75mm outlet to the 75.5mm WPI Xtreme SC inlet with a straight-through bore.

The WPI Northstar Throttle Body Conversion Kit uses a Corvette LS6 Mass Air Flow (MAF) sensor that will need to be tuned in with either custom PCM work, a TechEdge ICCU, or a TechEdge Mini-AFC 2.0. WPI provides the option below to purchase the TechEdge Mini-AFC 2.0. You MUST have access to a diagnostic scanning tool (such as AutoTap) to monitor your front O2 sensor and LTFT (Long Term Fuel Trim) parameters so that you can adjust the fuel settings for your car. Not doing so could have an adverse affect on your engine and other components which WPI and 3800 Performance will not be liable for.

The WPI Northstar Throttle Body Conversion Kit comes COMPLETE with the following components:

From the very start of WPI's R&D for creating an upgrade throttle body kit for the L67, the goal was to not only provide a high-performance solution, but also to not alter the configuration of the linkage and wiring. That is why WPI found the Northstar TB to be the perfect choice, as it is already designed for a front wheel drive car and therefore, the linkage is on the proper side of the TB as well as the IAC sensor. And there are no worries of the customer having to splice into your engine wiring harness or having their linkage cables caught up in the engine wiring harness. Also the stock PCV system in NOT blocked with this kit; there are passages in the custom adapter plate so there is no need for a valve cover breather to allow unmetered air into the engine.

Due to the many different air intake configurations on the market, WPI is not able to include any adaptations for the MAF sensor to your air intake solution. It will be the customer's responsibility to solve this, although 3800 Performance and WPI can help assist with finding/figuring out what you will need. We are currently researching an add-on fenderwell solution that will be able to be added on to the Northstar Kit.

- For those customers without an EGR system enabled on their vehicle and are currently using a block-off plate on the lower intake manifold, you will need to let WPI know. For these customers, WPI will include, for free, a custom block-off plate for your lower intake manifold, as others will not work with this kit. If you have an intercooler installed though, then this will not a problem.

- As an incentive for our customers to purchase WPI products that we stand behind and use ourselves, any customers that purchase the WPI Northstar Kit with the tapered adapter plate for their stock or WPI Competition SC, they will be able to upgrade for free, to the straight-bore 75mm adapter plate if they purchase a WPI Xtreme SC in the future. Customers can contact 3800 Performance prior to purchasing the WPI Xtreme or Xtreme IC SC, and we can ship the straight-bore adapter in your shipment (a core charge will be placed on the adapter plate) so that your vehicle can be upgraded at the same time. You can then ship back your SC housing core and tapered adapter plate back to receive both core charges.

For any questions you may have related to the WPI Northstar Conversion Kit, please email WPI@3800performance.com to get all the specific details answered.