Dccd Svx

[TomsSVX]

Looks like I finally found a DCCD controller that I can deal with. since there is no such thing as automatic mode for any other car than DCCD compatible cars, I have siad bleh to trying to adapt a stock controller. After some issues with hooking up all 4 tires lately I have ultimately decided to get an aftermarket controller. Neetronics makes one but it is pretty costy. So, once I can caugh up the $500 it will cost to buy it, I will be the first dccd SVX out there

Tom

[dynomatt]

Race ya! I'm going down this path too.

M

[sperry]

Originally Posted by TomsSVX

Looks like I finally found a DCCD controller that I can deal with. since there is no such thing as automatic mode for any other car than DCCD compatible cars, I have siad bleh to trying to adapt a stock controller. After some issues with hooking up all 4 tires lately I have ultimately decided to get an aftermarket controller. Neetronics makes one but it is pretty costy. So, once I can caugh up the $500 it will cost to buy it, I will be the first dccd SVX out there

Tom

I've got one of those in my 6MT converted WRX. It's pretty slick, and it makes a *huge* difference, but I wouldn't consider it as "smart" as the Auto mode in the Subaru DCCD. Andy mentioned something about a new version w/ G sensors, but that's probably a while out yet.

It looks like the latest version adds some cool features like the launch mode, etc. My unit doesn't have that, but it was still a *massive* upgrade from nothing.

On my unit, you can set the unit up for three basic modes: acceleration, braking, and normal. Normal mode uses the whatever setting the knob is at, so it's on the fly driver-adjustable. Acceleration override locks the DCCD at a pre-set duty cycle when the throttle exceeds a user-set limit (i.e. lock the center diff up when accelerating hard out of a corner). Similarly, the brake override does the same when the brake pedal is being pushed.

For time trials, I run a 20% normal rate, 45% acceleration, and 35% braking. I haven't played with it all that much, but I've found with those settings, the car seems to stabilize under braking and fight throttle-on oversteer when exiting corners, yet can still rotate well when turning. Of course my suspension setup has a lot to do with this as well, but before the DCCD controller, the car was loose-in, and loose-out, and "okay" mid-corner... so basically the controller allows me to run the suspension loose without making the car uncontrollable.

Anyway, since converting a OEM DCCD controller is near impossible (even in my WRX, since it meant retro-fitting the car with an STi ABS system, it would be even harder in an SVX) the Neetronics is a damn good substitute... especially if you see gravel in the car, since it's apparently much better than the OEM unit on loose surfaces.

I'd definitely recommend it... even at $500, it's a "deal".

[TomsSVX]

well I have basically already made up my mind to get it... Just need to figure how I will afford this, my wilwoods and the rest of my engine build, and thats not to mention my suspension and tires...

Tom

[jman050]

I remember the guys on Nasioc talking about the DCCD in the sti. What exactly does it do and can you explain how it works? Is it an option or do all sti come with it?

[TomsSVX]

Sti's come with the dccd controllers as long as the transmission comes with a Driver Controled Center Differential

Tom

[sperry]

Originally Posted by jman050

I remember the guys on Nasioc talking about the DCCD in the sti. What exactly does it do and can you explain how it works? Is it an option or do all sti come with it?

All the US STi's come with it... it was optional on some of the earlier JDM/Euro models IIRC.

Basically, the center diff in the tranny is electronically controlled with regards to the amount of slip is needed before the diff "locks". The torque split is fixed at 35f/65r by the mechanical nature of the differential, but the allowed slip percentage is electronically controlled.

So, when the diff is manually set to 0% lock, it basically means the rear wheels can spin freely at a speed much faster than the front wheels. While at 100% lock, the rear wheels are not allowed to spin at all faster than the fronts. At settings in between, the rears are allows to slip for some amount before the electronics begin locking the fronts and rears together.

In "auto" mode, the DCCD computer uses a variety of sensors (G sensors, yaw sensors, steering sensors, etc) to decide how much to lock the center diff. So under braking and acceleration there's more lock to help increase traction and stability, but when turning there's less lock to allow the car to rotate.

Something like the Neetronics controller allows the user to specifically program the locking parameters for certain scenarios, but doesn't provide an adaptable locking schedule based on the dynamics of the car.

[jman050]

Originally Posted by sperry

All the US STi's come with it... it was optional on some of the earlier JDM/Euro models IIRC.

Basically, the center diff in the tranny is electronically controlled with regards to the amount of slip is needed before the diff "locks". The torque split is fixed at 35f/65r by the mechanical nature of the differential, but the allowed slip percentage is electronically controlled.

So, when the diff is manually set to 0% lock, it basically means the rear wheels can spin freely at a speed much faster than the front wheels. While at 100% lock, the rear wheels are not allowed to spin at all faster than the fronts. At settings in between, the rears are allows to slip for some amount before the electronics begin locking the fronts and rears together.

In "auto" mode, the DCCD computer uses a variety of sensors (G sensors, yaw sensors, steering sensors, etc) to decide how much to lock the center diff. So under braking and acceleration there's more lock to help increase traction and stability, but when turning there's less lock to allow the car to rotate.

Something like the Neetronics controller allows the user to specifically program the locking parameters for certain scenarios, but doesn't provide an adaptable locking schedule based on the dynamics of the car.

so is an sti wasnt equipt with a DCCD would the front diff just be controlled by a mechanical limited slip?

What setting do most guys use for launching if they were drag racing?

[sperry]

Originally Posted by jman050

so is an sti wasnt equipt with a DCCD would the front diff just be controlled by a mechanical limited slip?

What setting do most guys use for launching if they were drag racing?

I believe the JDM 6MTs without DCCDs are 50/50 torque split and work functionally identical to the WRX 5MTs. But I don't remember for sure.

As far as drag racing... I've never done it, so I don't know what's the best DCCD setting. My guess is you'll want quite a bit lock to minimize wheel spin. However, I've noticed that Auto mode on the OEM DCCD pretty much whoops any manual setting except for running on ice/snow/gravel where lots of lock is desirable.

[Tim]

Not to make you depressed again... but what are you going to do once the beast is complete and there's nothing else to mod?

[TomsSVX]

SHUT UP!!!! That is never gonna happen!!!...eh maybe I will sell it and start all over again...again

Tom