scoobyIrl

How hard is this on your car?!!
Looks like fun but I can't imagine it being any good for the diff!

YouTube - STi Burnout

Davey P

iTrader: (1)

I'm surprised the car lasted that long. There is no way I would try something like that in a 4WD car!

joey_turbo

iTrader: (26)

What is DCCD? I've heard it a few times, and kind of gathered its some kind of electronic diff control. Is that right?

MrRA

DCCD - Driver Controlled Centre Differential

Basically an electronic diff that can be manually overrided to send more torque to the rear, thus changing the driving attitude of the car.

The newage cars have A-DCCD (Auto DCCD). This is basically like the ACD (Active Centre Diff) in the Evo and automatically apportions torque front/rear in order to maintain traction through infomation fed from several different sensors in the car.

StudentScooby

Must have a brake line lock on that

joey_turbo

iTrader: (26)

Thanks for the explanation, MrRA.
I saw a thread on it earlier, seems like a lot of hassle to install, but good if you like all the toys.

scuba_doo

From what i've heard when the handbrake is on , the center diff declutch's same as evo's so would be totally rear wheel drive only if the handbrake was just on enought to bring the handbrake light on and declutch the center diff (2005 model sti) thought when the dccd is in manual ,it was split between 50/50 to about 39/61 .

MrRA

Pre MY05 cars were 35:65 front/rear split, MY06 cars were revised with the addition of a steering input sensor to provide additional info for the DCCD, torque split also changed to 41:59 front/rear.

DanTheMan

Is the post MY05 DCCD the same as the old STi TypeR DCCD ?

ru'

Doesn't bringing the handbrake light on make it totally front wheel drive? The last thing you'd want when doing a handbrake turn is all the drive going to the (locked) rear wheels? Or is the idea that you also depress the clutch?

(I don't have dccd etc., so I'm just guessing here)

Hol

iTrader: (1)

On a Type R, the DCCD is 'disabled' when the handbrake is on.

Basically, all it does is get an electronic signal from the handbrake ON light that turns off the DCCD electrics and opens the diff to its 35:65 open position.

On a newage car, this does not work, when the AUTO button is on. Otherwise the same.

MrRA

The most it can achieve is 50:50 front/rear or 0:100 front/rear in momentary bursts.

Hol

iTrader: (1)

If fully open is 30/70-ish, - then there is no mathematical way you could get 0/100.

The front wheels will always get a minimum 30% of the total drive. To a maximum of approximately 50/50 dependent on how the electro magnet is set in the centre. Eg half way 40/60.

Johns thread is where most people go to get the full operating lowdown: https://www.scoobynet.com/drivetrain...light=felstead

Gav

I've got DCCD-A on my JDM 03 STi. Could someone list for me what each light means? Nathan who i bought it off explained it to me when i bought it but i've forgotten and i'm scared to take it off Auto

ru'

I'm guessing:

https://www.scoobynet.com/drivetrain...light=felstead

Hol

iTrader: (1)

Gav,
I leave mine on auto to be honest. Uness it is snowing, or I am in a field.

With the auto turned off. it behaves exactly as in Johns explanantion in the above link.

powerman1

FUN you need to get out a bit more..seems pointless to me..watch me i can make my tyres smoke and you have never seen it before

Gav

Alright Hol, how's my cars twin(ish) coming on???

I dont play with it and leave it in Auto constantly (i love the feeling when you can feel the car adjusting itself mid corner) but i'd just be interested to know! I've read the John Felstead thread many times but still dont understand what this means :-

Lock - 100% (does this mean locked at 50/50 drive)
Orange (triangle) - 85% (85% front wheel drive, 15% rear wheel)
Orange (triangle) - 65% (as above but 65/35)
Orange (triangle) - 35% (as above again but 35/65)
Green (whats different to orange??) - 15%???? (15% front wheel drive?)
Green (no triangle) - 0% but does this mean that the A of the DCCD will not cut in and is essentially a rear wheel drive car????

Any help anybody????

Gav..

Granby

iTrader: (5)

Do you think he might of had one of these fitted Neetronics or a RWD conversion

Normski

The point is, it's an open diff when the bottom green light is on (or when the handbrake is pulled) so the end with the least traction gets the most torque.

Think of a normal fwd car, this has an open diff between the two wheels. If you get stuck in mud you will see only one wheel spinning, that is the one with the least traction. It's the same with a DCCD only it's the centre diff.

Hol

iTrader: (1)

Thats actually my point (from a different perspective). [so get your own ] as it relates to the displacement from the centre diff. As the gearing of the front and rear diffs themselves will never allow less than 30% to go to the front.

The statement I was asking about was the one below, suggesting that the fronts could receive absolutely no drive???:


BTW, Ive had DCCD for six years So I do know exactly how it works.

Normski

One end can receive no drive as can be seen in the video above. It's an open diff, that's what they do in certain circumstances. The gearing you mention only applies when all wheels have full grip.

MrRA

I was talking in realtion to A-DCCD, not DCCD

GravelBen

The percentage figure is referring to static torque (ie rotating force) distribution, 0/100 or 100/0 is possible but only when the diff is fully locked. A fully locked centre diff does not mean locked to 50/50 torque split, it means the front and rear axles have to turn at the same rate. So if for example the rear end is on tarmac and the front end on ice, with diff locked both axles will be turning at the same rate, but the front wheels will have no traction and will be doing no work, so 100% of the torque is being delivered through the rear axle until the front gets some traction.

When set to fully open the front and rear axles can turn at different rates while maintaining the mechanical torque split (which is 64r/36f for Type R/RA, or 50/50 for regular 4wd Subarus which have an open centre diff all the time). They have to be able to turn at different rates to go round corners on sealed roads without scrubbing and understeer, as the front and rear of the car take slightly different paths through the corner. This is especially noticable at low speed, try turning around in a car park with the diff locked

The thread linked to before: https://www.scoobynet.com/drivetrain...light=felstead explains it all better than me.

Hol

iTrader: (1)

Yup thanks Ben,

I think we have a lot of people confused between Drive and Torque.

I think I was first to post the link.

https://www.scoobynet.com/drivetrain...nslation.html?