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Throttle Body – Explained

Hello everyone and welcome in this video we’re going to be talking about throttle bodies so what is a throttle body well this right here is a throttle body and basically it’s located between your air intake filter and piping and your intake manifold and acts as a valve restricting the amount of air that can go into the engine so this is a mechanical throttle body so when you press on the gas pedal what you’re doing is you’re actually opening up this valve and allowing for more air to pass into the intake manifold and then into the engine so by allowing more air to go into the engine you inject more fuel and you create more power and the revs increase and so on so why might you want an aftermarket throttle body well on stock engines the stock throttle body is typically going to be a good size to not create much restriction as far as how much power it’s going to make but if you do have a modified engine then your throttle body can become basically a restriction if it’s too small and restricting the amount of air that goes through so by getting a larger one you can pass more air through it and thus create more horsepower so that’s why you may choose to use an aftermarket throttle body so let’s take a look at some of the features on this throttle body and what they’re there for so the first thing we’ll be looking at is the mechanism which actually opens the butterfly valve so what we’ve got here is this is where your cable your throttle cable is going to route and be connected up top here and so as you press down on the gas pedal which is connected to the throttle cable you’ll be turning this and then opening up the butterfly valve to allow airflow on the side we have where the throttle position Center mounts and so as this valve opens you can see it will rotate and it will change the throttle position sensor and it will know how open the throttle is so up on top we have the manifold absolute pressure sensor the map sensor mounting which mounts right here and then you can see this hole here which comes down and then feeds behind throttle plate here so it’s sensing the pressure behind the throttle plate so as you allow for more airflow and it will read a higher pressure and the engine will know to inject more fuel now on the left side here we have this throttle body stop screw and basically what this is doing is preventing this spring from rotating the throttle body anymore and this basically just creates the stop for where this should stop rotating in order to fully close the throttle so this doesn’t need to be adjusted it should be left basically where it is and that’s why you can see that there’s a paint pen mark on it indicating that it’s in the initial position now on the inside of the front you’ll notice this port here and that’s for the IAC valve which is controlling the amount of air the engine gets at idle so you’ve got this bypass here and then your IAC valve which we mounted back here can regulate the amount of air going to the engine at idle so on cold starts it can allow for more air and allow the engine to warm up faster now up on top here we have the idle adjustment screw and so this can be screwed in to this port here and allow for more or less airflow that’s always going to be able to pass the throttle body to adjust your idle speed with the engine so basically there’s a little port in here and as you screw that in you can see the port the idle air control port has another hole inside of it and that’s a little difficult to see but there’s a hole right there and that feeds up to this hole and then can come out as you can see here behind the throttle plate so as you put this screw in you’re going to be blocking off that port right there and then minimizing the amount of air that can come through here so you can adjust it simply by screwing it in more or less and that will adjust the amount of air that can pass around the throttle plate now on the bottom of the throttle body you’ll notice these connections here to connect up hoses and these are actually for coolant lines so that you can connect up coolant lines to this and basically what happens is if you’re in like sub-freezing temperatures and you’ve got air coming through here and you might have some condensation build-up or something like that on the throttle body that could freeze this valve closed and so by having these coolant lines pass through they make sure to keep that a bit warmer and thus prevent this from freezing and you may be thinking wow if you’re heating up the throttle body you’re going to be heating up your intake charge and I mean that’s true to some extent but it’s honestly quite minimal the amount of heat passing through here is pretty small and basically you’re just putting it enough so that things won’t freeze up but at the same time you know the surface area is relatively small and the amount of heat passing through it is pretty small so you’re not actually going to be heating up your intake charge significantly and then on top of the throttle body you can see this vacuum line and the little hole there which it’s the – and this is for emissions control basically you know some vehicles may or may not be using this feature of it so thank you for watching if you have any questions or comments feel free to leave them below

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