Snake oil mods?

[Rich Z]

I'm sure we have all looked through lots of catalogs selling performance enhancements for our Corvettes, and some things sound logical and others, well, they just have me scratching my head wondering how in the world such a thing could POSSIBLY enhance performance.

Just leafing through a catalog here on my desk....

• Performance hood seal
• Throttle body Velocity stack
• Throttle body bypass tube
• 160 degree thermostat
• Pro Blend Engine Oil Additive
• Hi-Performance Throttle Body Air Duct

I'm sure there are others....

Ok, maybe they DO increase horsepower and I just don't understand the physics behind it. But seriously, if such gains could be had by such modest mods, why wouldn't GM have done so on the assembly floor?

Some mods are just contradictory. On one hand I have heard that the Hi-Performance Throttle Body Air Duct will increase performance by reducing turbulence in the throttle body. Then on another hand, I heard about some sort of "tornado" doodad that goes INTO the duct and increases horsepower by INCREASING turbulence....

Yeah, I know, caveat emptor, but sheesh, isn't there some sort of truth in advertising law (or at least "ethic") about promoting this stuff?

[Mekanic]

The TB Bypass is the only one proven to pick up anything at all, I think 5HP is the average.

My favorite one is the "Performance Throttle Position Switch" It makes the engine think its at 100% throttle, when your at 80%... which does nothing but drain some money from your wallet, since I'm not so broken down that I can't push the throttle to 100% on my own.

[ClockworkC5]

ive always wondered about the velocity stack thing. it restricts the airflow. dont see how thats better, but obviously someone has bought it.