NASCAR Nationwide: Tapered Spacer vs. Restrictor Plate

[Don]

A NASCAR Nationwide Series official has mentioned that in the July 2010 Daytona Race, the restrictor plate will be replaced with a " tapered spacer ", specifically for the Nationwide series which might/will include the new race car design.

Anyone have any details, the impact on top speed and the typical restrictor plate grouping of race cars with limited passing ?

[Don]

From the link below which has additional detail:

" A tapered spacer is different from a restrictor plate. A restrictor plate is thin, while a tapered spacer (shown below) is about an inch thick. Tapered spacers have four tubes running through the spacer. Each tube has a hole at the top and a smaller-sized hole at the bottom (which is why they are called ‘tapered’).

" Tapered spacers have been used in all Nationwide cars since the beginning of this season. The large end of the spacer mates with the carburetor and the narrow end points toward the intake manifold. The tapered spacer gradually narrows the path through which the air must travel to reach the engine. Try breathing through a scuba tube and then pinching the tube down. A smaller hole decreases the flow, which decreases how much air/fuel mixture is getting into the engine and thus how much horsepower the engine can generate. "

http://www.stockcarscience.com/blog/...tapered_spacer

[Ron61]

Basically a more expensive version of a restrictor plate. It still lowers power and makes it almost impossible to pass without a lot of luck.

Ron

[DAVID GAGNARD]

Tapered spacers work great as they are designed to do....I run one on my race car, only difference is it's inverted.....Small hole on top tapered to a larger hole on the bottom....It sits under the carb on a single plane Victor Jr. intake and on the dyno was good for 16 hp and about the same torque................

David