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Subaru WRX STI DCCD Explained

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Subaru WRX STI DCCD Explained

Postby Megaman » Sun Apr 13, 2008 10:02 am

Everyone,

Here is my summary of how the DCCD works after trying various settings over the past couple of weeks.

When you first start the car the DCCD system will be in full auto mode which shows on the dash with the word Auto lit up in orange. For most drivers this is the best setting to leave the differential on day to day.

You can set the DCCD to manual by pushing the relevant button which then also enables a christmas tree of lights on the dash and allows you to use the rolling wheel. You now have the ability to move the rolly wheel up and down to lock and free up the differential. I will explain these settings now.

Setting 1
If you move the wheel all the way backwards you will notice on the dash that the orange "Auto" has gone out and that a green light at the bottom of the dash lights up. This indicates that the DCCD is in free mode and that most of the power is pushed to the rear wheels.

The car will tend to oversteer and the back end will start to come out when you push the car. Be careful when using this setting as when the back end does start to come round you need to be prepared to put in opposite lock to correct this. I expect this is good for some fun on the track but can be a bit dangerous for road use if you are not expecting the back end to start stepping out unpredictably.

Setting 2
Moving the wheel up you will notice that the green light will go out and that another green light above it will show on the dash. With this setting less power is sent to the rear wheels and this will give a good balanced drive. The car will handle and feel like a normal RWD car with the back still edging out when pushed to the limit. It will be far easier to control the rear end stepping out as it is more predictable when it is going to happen.

Setting 3
Move the wheel up slowly again and you will see the green light will go out and the first of orange lights will light up. More power is pushed to the front of the car creating a more or less 4WD all the time drive. The DCCD will start to lock up more when applying power instead of allowing the rear wheels to slip and lose traction. This is one of the best and safest settings to use for wet weather driving as the back end should never step out and it is very difficult to make the car do anything that you cannot predict.

Setting 4 & Fully Locked
When you move the wheel further up there is another orange light and then eventually the top locked mode. The car shifts more power to the front and in locked mode is a true 50/50 split of the power. This
setting is only really recommended for snow or when stuck in a field etc.

Warning
When driving slowly, parking and reversing, it is best to use the AUTO DCCD setting or in the fully FREE setting (bottom green light). If you leave it in fully locked mode then the DCCD will be put under a lot of stress, will probably clunk and make funny noises and is generally not recommended. The car can also crab when you try to park up which is "interesting".

Summary

Setting 1 (Bottom Green - Diff Free)
Most power to rear wheels, back end can be unpredictable.

Setting 2 (2nd Green)
Drives like a RWD car, safer and more predictable.

Setting 3 (Orange)
Drives like a 4WD car, safe wet weather driving.

Setting 4 to Locked (Top Orange Lock)
Locks the diff, 50/50 power split use in snow/mud when stuck, not good on the road.

Final Note
I recommend testing these settings in a controlled environment where you have room to make mistakes and not on some tight and twisty country roads where one mistake could write off your pride and joy. We all like trying out new settings and driving quickly, but do it safely please.

Cheers

Mega
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Postby WR 1mposter » Sun Apr 13, 2008 11:51 am

Good info for new owners of the WR1, important info regarding slow manovering when using the dccd, it really does scare the crap out of youthe first time you experiment. Great post Megatron :lol:






Also for us older enviromental retards who have slept and leave it in autopilot :lol: :lol:
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Postby Megaman » Sun Apr 13, 2008 12:04 pm

Well i thought i might as well post my findings in easy to understand speak as it will benefit new and current owners. I have trawled numerous sites explaining technically in detail what a diff is how it works and so on but nothing really tells you what settings in real life driving is used for what. This guide is my feelings on it which hopefully ties up to the technical explanations online. I havent tried any of this on a track so things may well behave differently i.e. fully open diff might be really really oversteery but hopefully the guide ive posted helps driving on the roads and covers the basics.

cheers

Mega

:D
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Postby Gee Wr1 » Sun Apr 13, 2008 2:23 pm

WR 1mpostor (aka number 1 moderator) wrote:Also for us older enviromental retards who have slept and leave it in autopilot :lol: :lol:


Can't believe you've not used it & left in auto for nearly 4 years Martin!

Good write up Mega prob the best beginers guide to using DCCD i've read.

I wouldn't be as affraid of using it fully open as it's not anywhere as upredictable & tail happy as you make out, this is the position i use 99% of the time rain & dry with no worries at all. Yeah it will step out but more so if you provoke it than it just snapping out from losing traction. In fully open you still have 33% going to the front wheels so there is still more than enough grip. You probable read a lot of DCCD stuff about classics when you were doing your reading about, fully open on a classic is what you call tailhappy! It's more like a full rear wheel car in a classic, having driven Jacqui's TypeR quite a few times i feel i have a good comparison.
I only ever venture up to the 1st orange light if there is a lot of standing water on the road.
As for auto thats best switched of as soon as you start the car, don't like this mode at all! In auto i find the front end really snatchy going over lumps & bumps in the road & had a couple of hairy moments mid corner where the front end suddenly snatches the car to the inside of the corner! Prefer not to have a computer deciding things for me. Oh & that annoying orange light in the dash when in auto to lol.
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Postby Megaman » Sun Apr 13, 2008 5:38 pm

thanks for your feedback - i was trying out the dccd controls in the wet and definately noticed the back would start to edge out when the dccd was in fully open mode when applying full power out of a corner after apexing it. Like you said it wasnt completely out of control and you do have to push the car to get these effects but i wasnt expecting it so thought best to warn other newbies like me to it.

Id rather know what the car does on the absolute limits so you at least have a chance of catching and correcting it should you start to drive outside the cars limits of grip.

cheers

Mega
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Postby Micktype WR1 » Sun Apr 13, 2008 6:10 pm

A great read Megatron Man. Mucho appreciato !
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Postby WR 1mposter » Sun Apr 13, 2008 6:12 pm

Gee Wr1 wrote:
WR 1mpostor (aka number 1 moderator) wrote:Also for us older enviromental retards who have slept and leave it in autopilot :lol: :lol:


Can't believe you've not used it & left in auto for nearly 4 years Martin!



TBH Gee we dont have the roads that yourself has in and around the highlands of Scotland, a good stretch of road here normally attracts a tractor or two, sunday drivers, plus the lack of anything to do other than harass motorist devon&cornwall constabulary :roll:

Also the novelty has worn off, I've slept since yesterday and being senile forgot about it :lol:
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Postby WR1 Bro » Sun Apr 13, 2008 6:29 pm

Great read Megaboy
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Postby GregK » Fri Apr 18, 2008 10:17 am

Excellent post Megaman!

I tend to drive with diff fully open, probably 99.9999% of the time.....

Cheers

Greg :)
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