How to use the MAP DCCD Center Differential Controller

Added: 2026-06-03

[00:00:00]Folks, welcome back to Flat Iron Tuning.

[00:00:01]I'm sitting here in Nigel's race car because we're going to talk about the MAP DCCD controller. We've got a lot of questions since our flurry of DCCD videos have come out lately. So, we're going to go into how the box the MAP DCCD box actually works.

[00:00:14]How do you connect a computer to it? And then we're also going to talk about how the maps work and then how you can start changing the maps as well. Before I dive into that, just want to say make sure you like, subscribe, hit that hype button if you see it. It helps us out a ton. All right, let's start with the basics. The MAP DCCD controller box, how does the box actually work? So, we're going to start with the basic functions of the box. There are two buttons and then there is this knob, this dial.

[00:00:38]All right, the dial only works when you are in manual mode. How do you change the modes? All right, when you push one of these two buttons, either one, the first thing it does is it shows you the map that you're in. So, Nigel's DCCD controller is in map number three.

[00:00:52]So, when you after you push a button the first time, if you want to change the map, then you push the button again. And basically the two buttons, it's just a left or a right and so that's what moves the selector. All right, so we're going to push it once. We're going to bring the map all the way back over here to the M.

[00:01:06]That's the manual mode. Now, when it stops flashing, all right, now we're in the manual mode. This is where the dial works. If I turn this dial, you can see the the light move. That means that more current is going to the center diff or if I turn it back, less current is going to the center diff because I am in manual mode and that does not change. So, the current going to the center diff is just fixed wherever you put the dial.

[00:01:27]Now, you go to one next to the right, that is the A, that is the auto mode. That uses the accelerometers in the box and that just basically changes the lock of the center diff based on whatever those accelerometers are seeing.

[00:01:40]Um worth noting here is that when you're not changing the maps, this light on the face of the DCCD controller, that's telling you how much current is going uh to the diff or not. How basically how open it is if the light's all the way to the green on the left and how locked it is is it's going into the orange all the way on the right. And if you've seen the video like where we we put the the diff in various different modes and you see the light moving, that's just the indicator of what it's doing.

[00:02:05]Then, if you want to change any of the modes, you push the button again, you go into these 1 2 3 or 4 maps. So, this is the four stored maps, the pre-built maps uh that are loaded on the controller and you can select from them uh which whichever one you want. But, to see what maps are loaded on the controller and to change them, that's where you connect the computer. So, let's get to that next. So, now we have the SB cable and this is just ours, but MapDCCD controller comes with one. But, connected from the controller to the PC, power is on. I have the MapDCCD controller software loaded on my computer. And there's a button here uh top kind of center that says connect, so I'm going to hit that button to connect.

[00:02:49]I am now connected to the DCCD controller. So, when you see these map 1 2 3 and 4 at the top of the screen here, that is those are the four maps that are on the controller as it sits.

[00:03:00]So, here we see map number one is tarmac one, map number two is tarmac three, map number three is tarmac three, and map number four is tarmac tarmac four.

[00:03:08]That is how MapDCCD ships these from the factory.

[00:03:12]Now, what if you want to change the map?

[00:03:14]Well, let's say we want to put in map four, we want to put the wet mode or wet map from MapDCCD. So, we go to map four, we select the file, load map four from file, and you're going to have uh base maps that that come in this software in miles per hour. And so, we're going to select that. All right, so wet we have down here at the bottom, so I'm going to open this up.

[00:03:40]So, now in map four is the wet map. So, there's map notes that see it's wet, and you can see that the the the settings have changed. So, we're going to we're going to get into more details here in a second about what like how all this works. but now that I've changed this, if I go to upload maps, you're going to see it transferring the maps to the controller.

[00:04:01]Now that's done, if you wanted to be 100% sure, you could disconnect then and then reconnect to it.

[00:04:06]Uh but then basically again, now what you're seeing 1 2 3 4, and then four is now the wet map. That is I've now uploaded the wet map onto the DCC controller. The best way to disconnect, I think, is to exit. That exits the program, and now you can turn off the PC, turn off the DCC controller, and those maps are now stored on the controller. So, let's take a look at what these actual what these uh basically blocks of functionality are actually talking about, and you can start to look and see what the difference is between these maps. Let's head inside. This video is brought to you by the MAP DCC controller, and MAP DCC makes the DCC controller and these two vehicle speed signal processors, the VSSP and VSSP advanced. Keep all these in stock at flanders tuning.com. We've also got uh some good guides as far as how to install and wire the MAP DCC controller, and now a video on how the MAP DCC controller works. And uh we've got all the information you need to get this installed in your car and get it working exactly the way that you want it to. So, with all that being said, let's get back to the video. All right. So, now I'm a little bit more comfortable, but we can now walk through these different maps. And so, I've got on my computer set up just like we have on Nigel's car.

[00:05:11]Map one is tarmac one, two is tarmac two, three is tarmac three, and then four is the wet map. So, let's talk about these four different blocks and what is going on with them. So, at the top of the the MAP DCC screen, what we're going to see is the throttle map, then to the right of that, the the throttle modifier, then below that is a little line that says braking maps, and then to the right of that is the braking modifier, and then there's the left foot braking map, which is the bottom line on the screen. All right.

[00:05:40]So, let's talk about how this works. So, the throttle map, basically as you're applying throttle, which we have the throttle position sensor, is the uh x-axis, basically from no throttle to 100% throttle. So, no throttle to 100% throttle, then you go across, and then it's looking at engine RPM. So, what RPM is the engine at? That is That is the Sorry, the y-axis is throttle, x-axis is RPM.

[00:06:05]So, basically, as you're full throttle and the engine RPM increases, then you can see what happens to the lock.

[00:06:11]Um and we're we're in the wet map here, and so basically 100% throttle, as you go over basically once the engine is at 3,000 RPMs, you're 90% lock, and then you're 99% lock, effectively full lock at 3,500 RPMs, and then that's just what happens. Now, if you back off the throttle and you go to say 50% at 3,500 RPMs, now you only have 83% lock of the center diff. If the engine slows down, uh then the lock opens up. If the engine RPM goes up, then the lock increases, but if you come off the throttle, then that's where you go basically up the y-axis, and so at 3,500 RPMs, if you come off the throttle, then that also is what unlocks the center diff.

[00:06:53]So, basically, like with that in mind, that's what is That's what the throttle map is doing. It's basically just the more throttle you go and the more RPM that you have, the more lock that you're getting in the case of this map. Um worth looking here at the different maps. So, map one, you can see how that behavior is. It's not as aggressive as the wet map. Map two is the same amount of lock. Map three is still the same amount of lock, and then again, with the wet map, you can see that it is more aggressive in terms of lock.

[00:07:21]Now, let's go and look at the throttle modifier.

[00:07:25]So, this is looking at vehicle speed in the x-axis, and then the y-axis, this is lateral acceleration.

[00:07:34]So, the again, there's an internal G sensor to the map DCCD box, and so this is the default is set to the lateral acceleration. So, if the car is turning.

[00:07:42]So, if the if the DCCD sensor uh uh reads that the car is turning, you have the the Gs here in the Y axis, 0 to 1 G.

[00:07:52]And there's a check box here that enables this.

[00:07:54]But then there's also a drop down here.

[00:07:56]We can actually select different options for this. So, we have a longitudinal accelerometer. So, is the car accelerating or not? This would be like for a drag input and then you can add in uh like the Subaru sensors um a 0 to 5 V sensor. Like if you wanted to add an external something that that you wanted to to use to control it, you can add it here. Uh but the default again is the lateral accelera accelerometer. So, we'll we'll just talk about how that works going forward. So, basically, let's say that you're going 40 mph and let's say you're at 100% throttle and 3,500 RPM. So, with our first map here, we would know that we'd be at 99% lock.

[00:08:35]But uh if the car is turning, now we're subtracting uh let's see. Let's say we're doing turning hard, 1 G. Now, we're going to subtract 25 from that or 25, you know, points. So, instead of 99, now we're at 74.

[00:08:52]So, that's that's basically how this works is you have the initial map uh initial lock is determined by the throttle position and the RPM.

[00:09:00]Then you're modifying that depending on if the car is turning and how hard and how fast the car is going. So, that's how these these maps work. So, you look at the initial behavior and then the modifier.

[00:09:11]Um and then again, you can go back and look at 1 2 uh 3 uh term of 1 2 3 and look at what the differences are because, you know, for instance, map 1, there's no unlocking. Uh map 2, there's minimal unlocking. Map 3, there's a little bit or actually it's the same unlocking, but now we have braking modifiers.

[00:09:28]Uh so, that's that's how you can look at these maps and tell what the difference is. Now, let's look at the braking uh modifier behavior. Um we'll look at Yeah, we'll start here with with tarmac one. All right, so with map DCC control, the brake input is basically the brake switch. It's an on-off. So, if you're if you're braking, it's going to switch from the throttle position to brake. Um, the left foot braking function, this is where, you know, if you're applying throttle and brake at the same time, and you click on the left foot braking modifier, then it will go to the left foot braking modifier. Cuz sometimes, like in a rally car for instance, you want to use your left foot on the brake to control the slide a little bit. So, then that would be your your brake modifier versus just like normal driving where you come off the throttle, go on to the brake, then you're going to switch from the throttle to the brake modifier. And the brake modifier is, again, it's one input, it are you on the brakes or not, and it's very simple, and it's just adding lock based on vehicle speed. So, if the car is stopped, there's no modifier. If you're going 15 mph, you get 10 per- or 10 points of lock. 30 mph, it's 20 points of lock if you're on the brakes, and so on.

[00:10:36]Now, we look at the tarmac two map compared to the tarmac one, tarmac one, there's no modifier if you're on the brakes and the car is turning, tarmac two, there is. So, if the car is turning, so you have the lateral accelerometer giving a reading and the vehicle speed, um, this one is easier to picture because, you know, again, like say at 60 mph, you'd have 80 points of lock. But at 60 mph, if you're turning with 1G on the brake, then you have 35 points removed from that. So, instead of 80, you're getting 45 points of lock.

[00:11:06]So, 45% lockup if the car is turning.

[00:11:09]So, basically, as you're turning, it's starting to unlock the center diff uh, even if you're on the brakes. So, the car starts to loosen up, and you can see the different braking behavior maps. So, the tarmac three is more aggressive in how it unlocks the center diff if you're turning it on the brakes. Uh, compared to tarmac two, tarmac four is more aggressive still. And then the wet map, well, it's just going to lock up if you're on the brakes, but there's no modifier if you're cornering. So, that's that's the difference and that's how you can start to kind of look at these maps and see what the differences are. And just a a quick footnote here at the end, if you want to change some of these values, like if I'm you know, going 40 miles an hour 1 and 1/2 G's in in tarmac 2, but I want I want to remove 50% of the lock, you can just put that into the cell and then you can you know, you can start entering values and that's how you can change the behaviors. So, that's what these maps how these maps work and that's how you can kind of start to you know, you drive with the car with the different maps on, you can start to feel the differences, then you can look at the map settings and start to see what the different values are which are kind of contributing to that difference in behavior and then you can go in there and start adding values, you can change things that way and that's how you can start building custom maps which now now you know how you can go and load them on the DCCD. So, in a nutshell, that is how the map DCCD works, that's how the maps work and that's how you connect your computer to the map DCCD controller.

[00:12:33]>> [music] >> And of course, this is available at Flatirons Tuning if you need it. We try and keep these things in stock and >> [music] >> and we really do like this diff controller. So, thanks very much for your support as always and until next time, >> [music] >> stay tuned to Flatirons Tuning.

[00:12:55]>> [music] [music]