YH Fuel Injection Throttle Body for Turbocharged Corvair Engines



The Black Hawk Engineering YH EFI Throttle Body replaces the Carter YH carburetor used on turbocharged Corvair engines.  The throttle body bolts on to the turbocharger compressor housing with socket head cap screws and uses the original air filter. No head modifications are required.  The throttle body has a 1.83" bore to fit the F flow (180 HP) turbocharger inlet bore. The Performance Trends “Engine Analyzer” simulation software predicts that the throttle body will flow 256 CFM versus 128 CFM for the original YH carburetor.  With the boost limited to 12 PSI for longevity, Engine Analyzer predicts 193 HP net versus the 148 net HP of the stock "180 HP" system. 

I have had a turbo throttle body with MegaSquirt I EFI system running on my car for about a year. It starts instantly and runs much smoother than with the YH carburetor. There is a significant increase in available power and an increase in fuel economy.

This part layout is for the previous version but the current version parts are similar.

The extra performance and fuel economy are very nice, but the most amazing thing to me is that the engine starts every time (no flooding or vapor lock). I have a 95 HP engine with a 180 turbo in a 1964 Monza coupe. I was getting 13 to 16 MPG with that somewhat mismatched collection of parts. Once I started making metering rods, I was able to improve to 19.5 MPG. I have not made a great effort to improve fuel economy with the fuel injection, but I have averaged 21 MPG so far despite using the increased performance.


This installation uses a MegaSquirt control computer to control 2 pairs of injectors. The first pair is used for cruise and both pairs are used for boost. See www.msefi.com/ for details about the control computer. Other controllers like Simple Digital Systems, www.sdsefi.com/, could also be used.

I'm working on a solenoid fast idle control system and a smaller throttle body for 150 turbos. I will convert to a MegaSquirt II controller soon for ignition and IAC control.

Powder coating is available in various colors

The latest version with 6 injectors will be available in early 2010.

A complete system with a wide band oxygen sensor can be assembled for less than $3,000 plus shipping.

Here is a list of Suggested Vendors and Prices

Here is the detailed Installation Procedure.

Here is a list of estimated times for each phase of the installation: Installation Times. Your times may vary depending on what tools you have available and your skill using them.

While I can provide a set of tuning files as a starting point, you really have to consider tuning a do-it-yourself project. The good news is that it is easy. For MegaSquirt I, data from a wide band oxygen sensor is collected on a laptop computer while driving, evaluated and the tuning table entries are adjusted with a software program. With MegaSquirt II and MicroSquirt, the adjustments can be made automatically within the MegaSquirt controller.

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Last Update:  December 4, 2009 9:40 AM
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