I wouldn't go by a description tho. Think about the physics behind it. 1. Neither TBS increases the volume of air, just the velocity. 2. Spinning the air through a velocity stack (cause thats basically what it is just a smaller one) will increase the velocity of air at lower rpms. The downside is that the higher the rpms get, the less the spinning air benefits the engine as it becomes as much of a bottle neck as a benefit. Its not really getting much more air at high rpms as it would if it wasn't there. Think about it, the throttle bore needs as much "room" as possible to pull air into the engine at high rpms. The air hits the "screw" of the TBS and the path of the air changes from straight forward to a spinning motion while moving forward which decreases the energy of the air by just moving forward, but the air in return is now being funneled into the engine. It balances itself out so to speak at high rpms. 3. The smooth bore will increase the velocity over the entire rpm range, but it does not have the funnel effect so it does not "ram" the air into the engine at low rpms as much as the torque curve TBS will. As the rpms increase the TBS consistantly helps the air flow into the engine in the same way a velocity stack does, but it does not bottleneck the air as much as the torque curve TBS would at high rpms (if at all). [The velocity stack theory being that it gives the air more chance to speed up before it is dispersed though the intake while "evening out" the flow of air.] 4. My theory is that both produce the same gains, but the torque curve is mostly at the lower - to mid rpms while the smooth bore would be more consistant across the board with not as much of gain right off of idle and more on higher rpms. 5. Am I blowing smoke up your asses? No, I put way too much thought into this as I've had a TBS on three vehicles now. First one was my Nissan where I went from smooth to torque curve, then I had a torque curve on my 91' GMC and a smooth bore on my 99' Silverado. Does that mean I'm 100% right, no but I damn sure think Im close! Ha ha.

 

The velocity stack is probably the item I could have done without. It is just a funnel with the idea of a smoother flow than the irregular surface of the throttle body. I should have used the money to by a spacer.

 

Where is the velocity stack on your truck? Right in front of the TB?

 

yes

 

It is shaped like a slightly warped funnel with 2 large openings. There is a lip that fits around the filter side of the TB to keep it from being sucked into the blade. The intake tube slides over it and holds it in place.

 

Jcbst12 - OK, so this brings up an idea I had a few months ago. What if you were to move the throttle body valve as close to the air filter as possible, that way the air would have plenty of time to smoothe out and increase speed before it hit the cylinders? It would have 2 times as much tube to travel past the TB. Any ideas on this? Someone able to give it a try? I just don't have time, just ideas.

 

i would think the throttle response would be greatly affected

 

Throttle response may be better, but what about power? I have instant throttle response now after the reprogram.

 

i don't think it would be better, there would be a delay from the time the throttle blades opened and then the air traveled through the tubing to the intake

 

Do you think the delay would be longer than normal? I would expect a slight but barely noticeable delay, then possibly more power due to smoother flow, especially after the gain I saw after just adding the TBS.