Hello everyone and welcome In this video we're going to be talking about rev matching and what is rev matching? Now in my video review of the Nissan 370z Nismo someone was asking "Hey could you do a video explaining rev matching? and it was a highly upvoted comment so I thought "Hey what better vehicle to do it in then the vehicle in that review." and also this vehicle comes with downshift rev matching so it's a great way to demonstrate the feature. So, the first thing you need to understand in order to understand rev matching, is gearing. and so, what happens is when you're in first gear you have a lot of torque because of the short gearing but you can't reach a high speed. So you can reach maybe 30mph very quickly but you can't exceed maybe 30mph. It's going to differ for every vehicle. Now once you go into second gear, you lose a little bit of torque but you increase the top speed of that gear. So taller gears have less torque and higher top speeds, shorter gears have more torque and lower top speeds. Ok. So now what we realise from that is, at any given speed of your vehicle let's say you're travelling at 40mph when you're in fourth gear your engine is going to be at 1 rpm, When you're in third gear, your engine's going to be at a higher rpm, and when you're in second gear your engine's going to be at an even higher rpm. So for any given vehicle speed, any transmission gear will put your engine at a different rpm. Ok great. So now the thing we need to understand is why is rev matching important? So what we have here is the connection between your engine and the transmission So this is the clutch disc and you can see it's splined internally, So this will be splined to the transmission and whatever gear you're in, is what's going to rotate this. So if you're in first gear, this is going to rotate very quickly. At lower speeds if you're in sixth gear, let's say, this'll rotate slower this is splined to the transmission so it's always going to be rotating with the wheels, unless you have it in neutral. Now here we have the pressure plate and so this is bolted up to the fly wheel and so this is always rotating at whatever the engine speed is. So whatever the engine speed; is your pressure plate is rotating at. and that is the contacting surface which sandwiches the clutch disc between itself and the flywheel. So remember, this is always rotating with the transmission, this is rotating with the engine. Ok so now a little demo. Let's say we're in fourth gear and we want to put it in second gear. So both of these are currently engaged together so they're both rotating at the same speed, We're in fourth gear and the clutch is engaged, and so we want to go down into second gear. So, we disengage the clutch - we pull that away - and then we put it into second gear. So now this is rotating much faster than the engine is, So what you want to do is you blip the throttle and you bring this up to the speed that this clutch disc is rotating at and then you mash them together and you have a very smooth transition. So why is it important that you match the speed between the engine and the transmission before connecting them? Well really there's two reasons. The first reason is that you're going to have less wear and so if your clutch speed and your engine speed match up, when you mash those together there's no difference in speed and thus you're not going to have any wear on your clutch. That's a great thing to have. The other benefit, and this is probably the most important benefit for downshift rev matching, Is that you're not going to upset the balance of the car. So in racing, if you're coming into a corner hard and you're in fourth gear and let's say you need to make your way down to second gear, when you pop that into second gear, if you don't rev match and then you let out the clutch, what's going to happen is it's going to send that braking torque from the engine to those driven wheels and so you're going to upset the balance of the car and you know, you could lose the corner. So what you want to make sure is that you a really smooth transition into that gear So that you don't upset the balance of the car and you can maintain that corner and you know you're not having any influence on the dynamics of the vehicle through the clutch which you don't want, you want to have it all through the steering wheel, through your throttle application, through your brake application, not through the clutch. So that's downshift rev matching. Hope you guys enjoyed the video, thanks for watching. If you have any questions or comments feel free to leave those below.