Throttle body air foil value ?

Any opinions or actual knowledge regarding the air foils that go on the throttle body inlet ? I see a lot of marketing, but it seems to me GM would have included them if there was any real performance value.

Thanks,

Tom

You are correct. They do zero, zip, ziltch, nada.

They make money for someone

Quote :

GM would have included them if there was any real performance value.

Not necessarily. They were marketed as a solution to insufficient air flow in what can be an undersized or restrictive throttle body, particularly as other mods are made to the engine to increase intake and exhaust capacity. There a number of solutions to restriction in the throttle body, the easiest being bigger ports. Aftermarket throttle bodies often have airfoils built in. But then you have to deal with all intake and exhaust restriction points in the system to achieve a substantial benefit.

There is more internet chatter on this than perhaps most other topics. There are few actual tests with data published. Some who reflexively bash the airfoils gleefully spend $300 on air intake plumbing and "high throughput" filters, cold-air intakes, yadda yadda to increase air flow with about the same modest/nil effect on a stock engine. The difference is everyone can see the extra plastic when the hood it up. The air foil is hidden, so no ooh and ahh factor either.


Opinions may differ, but results from the test below suggest a very modest improvement for about $50 and 10 minutes of time when installed on a stock LT1.


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Like any other modification, You may or may not get an increase in performance. If the throttle body supplies enough air that the engine can not use it all, it will make no difference. If the turbulence caused by the protruding parts limits the airflow to less than the engine can use, it will increase performance a little but may still not provide enough flow to satisfy the appetite of the engine.

Replacing the throttle body with a larger one will accomplish the same thing, and probably for about the same money. As long as the airflow is enough to satisfy the demand of the engine, more modifications to the throttle plate will not make any further improvement.

Before making modifications, you need to know what the engine wants, and modify accordingly. For example 500 HP needs about 850 CFM. If you can flow 1000 CFM, the extra 150 CFM is irrelevant. If you have a carburetor and you use too large of unit, it can negatively affect the power of the engine.

""There is more internet chatter on this than perhaps most other topics.""

Try doing a search for "best oil filter to use" to get REAL chatter.

Wait... you need to change them????

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Installed one on my '96 and also replaced the totally-collapsed rubber gasket under the plastic cover on the upper throttle-body. The airfoil did nothing, but SURE looks cool when the intake elbow is removed...and that's what counts.