DCCD, best use of?
 

I have just bought myself a classic STI RA with the dccd. I have had loads of subaru's before but none with the dccd. I am looking for advice as how to best use this both on road and track.

I know it transfers power from front to rear bias but thats about it.

Cheers.

https://www.scoobynet.com/technical-...anslation.html

Enjoy :)

Excellent, thanks m8.

Mine never left open Diff, road or track, rain or shine.

Good to know. Take it the further into the green = more fun?

Yup, rolled all the way back in "O"....beware tho, open diff has bitten more than a few people in the ass...

Is open in the orange ?

No, orange is locked green is open.

leave it in the green open position, and if the DCCD breaks you'll be glad it's stuck in this position ;)

it will make no difference at all on road use. on the track it will make the rear looser on tight fast corners, i suppose it will give more over steer if that possible in an impreza

Get yourself an auto controller from DCCD-PRO and bang it in auto, best thing I ever bought.

Under steer is a thing of the past now.

You mean you can add 'Auto' function to a manual only DCCD?:confused: How does that work? Does it come with a host of other sensors like yaw sensor, steering angle sensor etc like in the newage?

Was there a lot of difference ?

It locks the centre diff to full 50/50 torque split when accelerating in a straight line, so feels like it has more pull, and as soon as you hit a bend, puts it back Open to 65/35. Best of both worlds really.

My view on DCCD:

I use the DCCDpro.com controller. I chose it for its low price and after several e-mails (great service), I was convinced that the technology would fit my needs. Following is a quick summary for my use of DCCD, followed by some technical descriptions we can argue on. Note that All cars will react somewhat different, but since its adjustable, this should give a basic idea for most. I have a rather track based suspension, **** rear lsd, good front 1 way LSD, 380NM on the wheels.


AUTO MODES:

Open: This is ****. Pros: Good for uncontrolled powersliding. Cons: If you lift a wheel, like I do alle the time, youre at standstill with wheelspin. Makes the car rather unstable.

15%: Wet: 25%. The daily driver and fun setting. Pros: Allows big powerslides out of corners. To little lockup to affect everyday driving, but enough to help traction. Cons: You can still spin your wheels easy, and though its fun, wheelspin out of corners dont really help on your lap times.

35%: Wet: 50%. For lap times. Pros: Weak enough to balance the car out of corners by power-oversteering. Strong enough to go close to or flat out mid corner. Cons: You will feel the diff in daily driving and parking lots. Can lead to some mid turn oversteer.

60-80%: Snow settings. Pros: Fun on low traction if you need the diff to open in turns. Great traction on any surface. Cons: WOT WILL give understeer on tarmac, even wet. Easy to balance on snow though.


MANUAL SETTINGS:
generally this is only used in very low traction situations.

0: Still ****.

25%: For the drifter. Keep the throttle in, or youll spin in a split second.

50-60%: My prefered snow setting in manual. Gives great control, a good balance between good braking and understeer.

100%: You can conquer any hill. From standstill.

How does it work:

No need to explain the controller without first explaining the mechanical parts.

DCCD is really just a 2 way clutch differential. The difference is that you decide the force of the clutches with a thumbwheel and electronics, insted of materials, spring pressures and shims.

Now to torque split. As far as I know, all DCCD tranny`s are blessed with 65% rear wheel torque, giving a more RWD character of the vehicle. Now, just so its said, even though DCCD will have an effect on the torque split, this is just a bi-product, and its a very dynamic figure. In real life, you never get 50/50, and really, people would be better of not thinking to much about it.

The primary function of the DCCD is the same as any other LSD. To reduce the speed difference of to axles, in this case front and rear. So like in any other LSD, increasing the DCCD output with the thumbwheel, makes the centerdiff work against the rolling differences of its to axles. Torque split, defined by the gearset, remains 65/35 in either DCCD setting.

The fun begins when either axle spins faster then the other, ie cornering or wheelspin. Just like in any other LSD, the DCCD now fights the speed difference of the axles. I hate the whole torque split BS, below Ill try to illustrate why you should stop thinking about torque split, and start thinking traction.

Lets say the rear axle lose traction when you flat out out of a low speed corner on wet tarmac. In "OPEN", or "0", all power is now on the rear wheels, except the small amount of torque the rear wheel can put to the ground, lets say 5%. You now have 5/95% split. Acceleration will suffer, just like any other RWD car.

In the same situation, with DCCD on, the force going to the front wheels will increase as DCCD output increase. In 25% you could have as much as 25/75 split. You still spin the rear wheels, but you get a fair bit of acceleration. Increase it to 60%, and you may not spin at all. This does not mean you got 50/50 split though, and it saved your day. It just means that the rear axle got a" third wheel" to brake traction at before it could spin. So perhaps the dynamic split was 65/35, but that doesnt matter. What REALLY happend, is that the center LSD allowed the power that was about to make the rear wheels slip transfer to the front, perhaps only for half a second or so.




So why not install a clutch type LSD, except the adjustability? Well, that is the most genious with the DCCD, and in this case the DCCDpro.com controller.

When you enter a corner, a G sensor sense the cornering forces. The output is quickly reduced, and if you let go of the throttle it can actually open the centerdiff completely. This dramaticly reduces understeer, and gives a much sharper turn in.

When you start accelerating, G sensors sense both turning forces, acceleration forces and a wire to your TPS sense your throttle input and increase DCCD output based on the sensor inputs.

This allows the use of a very strong centerdiff, without the cons of a traditional LSD system.






Sorry for the overkill lecture, but Im bored in an hotelroom, waiting for the company to call me out on a job. Hopefully this will give you a pointer on DCCD use though. Remember these are my experiences on my car. Your car will be different, so dont just slam it in fun mode and expect that you can do a controlled 600feet powerslide.