Thursday, June 23, 2011

Ford 4.6 V8 Mustang Crown Vic Ported/Halfshafted throttle bodies

When porting these throttle bodies we use a variety of techniques to increase airflow through your engine economically. When you look at a stock unmodified throttle body there are several issues to deal with when you start looking at airflow. The oem design is made to cheaply produce not necessarily maximize performance. The biggest flow improvements come from what is known as Half Shafting the throttle body. This is where the top part of the throttle shaft which holds the throttle plate is removed to allow more airflow. I go one step further and Quarter Shaft the throttle plate by removing about 1/4 of the remaining side of the shaft. This picture shows in red how much of the shaft has been taken out of the airflow path:







This is a good start to improving flow however if you use the stock screws to reattach the throttle plate to the shaft you have another object sitting out in the way of flow. To prevent this issue I use beveled screws and countersink them into the throttle plate. I also remove the end of the screw protruding from the back of the shaft so there is no turbulence or reduced flow from these jutting out into the path of airflow.




To compliment these modifications I also make sure to smooth the airflow transition from the throttle inlet as well as the transition to the intake manifold. The less turbulence produced in these transitions the more air will flow through. Do Not use throttle body spacers that claim to improve performance by introducing turbulence or swirl by the throttle body. The only time turbulence improves performance is when it is about to enter the combustion chamber or when fuel is flowing through that part of the intake. Neither is the case with your throttle body, the fuel is injected into the lower intake as close to the heads as possible and the air will have to straighten as it goes through the individual runners negating any swirl effect that could possibly help.


The throttle plate on most throttle bodies doesn't open to be totally perpendicular to the airflow, as such the plate is creating another restriction by being at an angle. It can be surprising how much of an angle these come stock with. I remove just enough of the throttle stop to allow you to fully open your throttle.

Finally I finish off the throttle bodies with a ceramic black high temp paint for a clean look that wont clash with any under hood color combination.  

I offer these throttle bodies for 99$ + refundable core charge Currently I can get good used cores for these engines for about 40$ however this charge is subject to market price/availability. Core charge is refunded upon receipt of a usable core.

1 comment:

  1. I have a 98 mustang 4.6 fully stock. I would like to increase the horse power without going into the engine. In my research I have found that a cold air kit, 24 lbs. injector kit, 80mm flow meter will help. I am considering your polish and porting up grades of the throttle body. What else do you need to know to maximize the power to the up grades i'm considering.

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