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NASCAR Rules and Performance Gains via Creative Engineering

3:00
20:26
440.6K views

At 3:00 in

UP CLOSE: Ernie Irvan's 1991 Daytona 500 Winning Intake Manifold & Cylinder Heads (Larry McClure)

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What happens here

The discussion moves to how these extensive modifications were a response to NASCAR rules, particularly the "restrictor plate" era. Teams engaged in highly secretive practices to gain an advantage. The concept of the restrictor plate, designed to limit horsepower by restricting air into the carburetor, is explained. Teams developed methods to "bleed air" or optimize airflow around these plates. An example given is the use of clear plastic washers ("hooter tubes") underneath the restrictor plate to create an "air wall" that would make the carburetor ask for more fuel, thus increasing horsepower by 40-50 HP.

Goal: Understand the strategic and often clandestine engineering used by NASCAR teams to circumvent regulations for performance

Tools and materials

  • Clear Plastic Washers — Creating an air wall under the restrictor plate to optimize carburetor signal

What they say

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cylinders with ridges and little holes and what is all that to distribute air better after the plate did they make you put on there yeah what kind of power gains would this contraption make over an intake that didn't have any of that oh probably see all the 30. 30 horsepower yeah so if you didn't have this figured out you were screwed in this little the center chamber here is like completely blocked off from why is how does that work now that I don't you'd have to ask somebody that you know really worked on these things you know and Larry might know I don't know you know a lot of us weren't allowed back in the engine room when all this was going on because it was top secret you weren't even allowed back there yeah but you didn't ask you didn't you wouldn't walk up go run what does this right here do

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