<Table> <Tr> <Td> </Td> <Td> This article does not cite any sources . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2008) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article does not cite any sources . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (June 2008) (Learn how and when to remove this template message) </Td> </Tr> <P> A throttle body spacer is usually a 1 - inch (25 mm) thick piece of metal that is bolted to the outlet of the throttle body upstream of air flow into the manifold . By changing the airflow, this after - market add - on does claim to be a performance enhancing accessory that can increase an engine's horse power, torque and fuel economy . It functions by swirling or directing the air flow to maximize air volume to the manifold . There is much debate about the veracity of the manufacturers claims for these devices . The general consensus is that it works well on some engine configurations, and not at all, or adversely on others . In 2009 the BBK Performance R&D Department performed extensive dyno testing of off the shelf throttle body spacers from other manufacturers . The intention was to determine whether or not throttle body spacers were a viable product that BBK could manufacture that would provide notable results for their customers . The tests were performed on Ford 4.6 L 3 - V, GM LS, and Mopar HEMI V8 applications using a Dynojet 248C dynamometer . The tests consisted of a baseline dyno run, cool down period, and a repeat test after the spacers were installed . None of the spacers produced any additional horsepower or torque when tested . The only notable change was a loss of 4 horsepower to the tires on the Mopar application with the spacer installed . An additional test was run after removing the spacer, resulting in a return of the lost horsepower . Proving that some spacers can actually rob power from an engine . After seeing the results, it was clear that throttle body spacers were simply gimmicks and provided no real performance value . BBK scrapped all plans to manufacture throttle body spacers . </P> <Table> <Tr> <Td> </Td> <Td> This article about an automotive part or component is a stub . You can help Wikipedia by expanding it . <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table>

What is the purpose of throttle body spacer