quad throttle

how much does quad throttle add to hp? how can u tell how powerful they are is it by how big or something?

what is a quad throttle?

The short answer is, they won't add anything unless your current throttle body is a point of restriction for your motors aspiration. Even if your current throttle body were a restriction, a quad throttle set up is overkill, it would probably be just fine to get a single larger bore throttle body. There aren't many people that actually need a quad throttle set up.

Even a Twin thottle body is heaps!

Agreed.

yeah other mods would improve wateva car ur driving.(exaust,induction,ci,computers)

That depends on what you means by four throttles?

The placement and size of the throttles can affect the performance more that one might think. The throttles should also not be too small nor too large.

Also, several thottles have been used instead of a single larger one, as a large single one can make the car difficult to drive. Today many throttles are controlled by the ECU so that doesn't matter that much.

Most high power engines are using a single throttle per cylinder placed on each runner.

Good point, the driveability issue is worth bringing up. For instance, the throttle bore on 1st gen. MTX Dodge Neons was tapered in the middle in order to improve driveability. So the bore was actually a smaller diameter in the middle. But to make a generalization, a quad throttle set up is not necessary on the vast majority of road cars.