An Impreza with DCCD or without what is better for fast safe road driving?
 

Posted this over on the Type R _RA forum earlier.
I am very interested in peoples views on all this.

As a ROAD car. I have always gone for the non DCCD imprezas. Why? because I recon it is safer on a country road when giving it full beans with hazzards around like nice big trees. Power down a straight-Brake - Get the car balanced - feed the power down through the bend - reach the limits of grip - mild PROGRESSIVE understeer (which I have induced) - straighten the wheel a touch feather the throttle get a spot of grip back into the front tyres - and off we go hurled out of the bend.
So what I am saying is that as a default I like the car to understeer under power in a progressive way and not power oversteer on the road. I only like oversteer on the road when I induce it - trail lifting or braking.

If I was using the car for the track or for hill climbing then DCCD would be a must. Power oversteer all the way :) Besides that it is more fun.

Its just I always found that I could get more out a non DCCD WRX in a safe manner on the road. Only driven a DCCD car twice. So regular owners who know the cars better may feel a DCCD car is more controlable.

Would the DCCD fans to tell me why they like it so much :) - and how they use it in what situations and when it has an advantage over a car with out it. Are there others that prefer the non DCCD cars for the reasons I just gave?

When I buy my bext classic scoob - I am debating whether to go for a DCCD car or not????

Trying to open up a bit of a debate here
Cheers
Steve

PS I drive alot in the alpine region - often in very harsh conditions in the winter. What do you recon to a DCCD car in these types of environment.
RWD - really can struggle in this environment.

On a classic - DCCD=no ABS. That would make me choose the non-DCCD car.

Fair point.

I am not one for ABS. Prefer where to know where my brakes will lock up. So I take it from what you are saying that all DCCD cars come without ABS.

Err no, read Johns post again..!;)

DCCD = NO ABS..!

Doh!
Kind of read that wrong didn´t I LOL :)
Think some editing is due ;)

TBH i wouldn't be driving anywhere near the limit on normal roads, and can't feel the benefit of DCCD on normal road driving. With it in open postion it can still understeer. It depends at what point you 'boot' it I suppose, it can be provoked into oversteer, but I'm not a good enough driver to be confident to think I could control it on normal roads.

Hey i just went out in a type R with dccd, the owner didnt really know what it done and what %.

Can anybody tell me where its at the top is it open closed? at the bottom opened/close i am reffering to the gauge on the dash.

Also what are the % splits?

Thanks

D

John Felstead did the definative post on this a few years back
Has any one got the link for mozzaITA?
As that answers all your questions.

please do that would help.

Cheers

I have an Sti V3 and road/hillclimbed the car with no dccd (and abs) for 3 years. Seemed great to me.

I installed dccd, removed abs and used a Type R trans with tight plated rear diff etc again for road/hillclimb.

The only time I can say ythe dccd is 'noticable' is on the track and you DO need to get the setting right.
JohnF IS THE EXPERT, and he 'tuned' mine using a test track (a real one, not a public road).
Traction is better and heavy braking is good...don't miss the abs at all.

On the road I drive fully open.

Graham.

ps: I don't blast it on the road so I may well be missing something, just too dangerous and I only have 380 bhp on a very good day....
I race on full racing slicks.

I like the hairy chested approach, the newage UK sti's with suretrack diffs and no DCCD. Just keep the power on!

So Graham has the car now moved from one that power understeers to one that power oversteers and is that power oversteer nice and progressive. Has the DCCD made it a quicker car for your hillclimbs?

I do blast it on the road - every now and then. One - I do a lot of driving in Germany. Two - It just a case of picking your moment if you come across the right conditions. Looking at the road surface, visability, limit point and potential hazards. There are some good empty roads in Europe with sets of open bends.

How is it indicated being full open? Leds top or bottom?

Why did Subaru Japan make a decision to add DCCD to Impreza's?

Do you think they make these decisions without extensive, prolonged, and in depth research which costs millions of pounds?

Why do you think they decided to fit DCCD to ROAD Impreza's?

Its in the 'open' position when at the bottom and green, then gradually pushes torque split towards the front, until diff lock, top position. From what I've read, it constantly senses and alters the torque split rather than being fixed at each setting.

I've had this discussion with felstead before. From an average drivers point of view DCCD is a waste of time, and can in fact be quite dangerous. I can wring a lot more out of driving on the roads in a much safer manner in a non dccd car.

If you're a very good driver then dccd is the way to go. A lot of people kid themselves that they are good drivers simply because they sit in a performance car.

Dccd splits are 64% rear and 36% front IIRC.

Steve #12:

The Sti has been dialed out of understeer by the suspension (hard work to do) so is very neutral especially now with racing slicks, but the dccd does make for a faster time.
With the same engine output etc my times are much better (even as I age!)

A badly set dccd on road or track can be a dangerous affair unless your wits are about you.
hard braking with the dccd tight (towards locked) will have the rear all over the place in a dramatic manner.

Get it right and it is curiously 'hidden' as it works to get the best from the chassis.

The wheel position is NOT linear in its effect on the transmission. Halfway from fully open (all green) to fully locked/switched (full red) is infact about 80% locked!

When I installed mine I did not bother with the dash lights and used the notches on the wheel and a sprung detent where you can count the clicks from fully open. I run mine 8 clicks from the open. 10 is hairy.
There are about 20 clicks on the wheel just to scale things.

This is much more accurate than the 6 position lights on the dash as I only set the dccd on a hillclimb run.

Scoobynutta:

I totally agree with you.
Squeezing the best from an Impreza is very hard, especially in competition, and dccd on a road car driven gently (a relative term) is pretty pointless.
Sells cars? or assumes Impreza drivers will actually find the best setting and really use the car hard where conditions are sensible?

I spent a 4 hour session on a track with Felly and he utterly transformed my car's chassis, and that included the dccd setting which I had in totally the wrong place ie 16 of 21 clicks.
The car was a bitch at that, but now......:D

Do not understimate the effect the right or wrong dccd settings can have on a fast drive.

fully locked or close can have a huge influence on understeer, the greatest way to slow a car down!

Food for thought I hope.

Felly is truly a chassis mapper, a joy to work with on the car.

Graham.

ps: If you want to see a well set dccd and chassis look ar Rob's hillclimber in projects. The in-car vids say it all.
Mind you, he is half my age and with 80 bhp more, so that is the only reason he is faster of course!

DCCD-A 4 teh win.... in my opinion... grab nuts, point, and squirt and let the car sort the rest out! :D

Great post Graham.
Thats exactly the kind of insight I was after - from someone that has experienced both
Cheers
Steve :)

Each to his own...But

So for ROAD driving as a rule non DCCD.

As DCCD gives you an edge on the limits. Limits you often wont come across on the road.

DCCD can give you edge and as has to be set up correctly as part of the whole chassis package. Time,thought and money has to be put into this. If done correctly this makes the car better for track and hillclimb times. And can have the added benefit for the road.

I take it that people are driving around with DCCD cars as road cars - which although they have the potential to be quicker and safer in actual fact in the real world are slower as they are too much of a handfull on the limits (as they havent been set up properly). A non DCCD car properly set up is very predictable on the limits.

As I say each to their own. But I think that sums things up.

My next ROAD car will be non DCCD then - with much of the understeer dialed out.

If I ever drove an impreza competitively then I would buy one with DCCD and spend time and money getting it set up right.
( I would love to hillclimb - perhaps one day :( )

Anyone got that JF DCCD thread?

Steve

DCCD-A :thumb:

This seems to be the most sensible route Steve. I am a competent driver, but I've never been on a track or pushed my cars to their full potential. I struggled with the standard dccd set up on the typeR and 22b I had.

Indeed, the first time I took my sti5typeR out I very nearly spun it on a wet roundabout and had the back out very easily. This is after having 2 years driving experience in a wrx.

However, if you're quite a good driver of rear wheel drive sports cars and you intend to do some track work, then do not dismiss dccd equiped cars.

Everyone that's experienced dccd will have an opinion on the systems worth. the only surefire way you'd know if it suited you was to test drive a car in the conditions you'd expect to be driving in.

Im not sure if this is the kind of info you are after but last night on my way home i came to a nice quiet empty dual carrage way so thought id give it some beans, as i came to the round about saw i was clear i gave it some going round it, and im sure my back end twitched like it was a rear wheel drive car, i did not like it! this was with the DCCD set to fully open (All the way down)
I think im gonna have it set to fully locked (All the way up) from now on

Driving fully locked will make the ride pretty awful IMHO. You'll hop and skip in cornering and it's probably not too good for the car either.

Just to add my 2p's worth...

As has been alluded to previously - if you have experience of rear wheel drive cars prior to having a type R/RA then you'll get a lot more out of it. I run mine fully open most of the time unless it's particularly wet/slippery and/or I'm not in the mood for a good crack. Power-on oversteer has been a big grin factor for me (I've had RWD Escort road/rally cars for pretty all of the last 20 years or so).

I would say though, that a DCCD Scooby demands care and respect and it's worth noting that you need to be very carefull about where you are in the power band when considering sliding the back. From experience it can be a bit hairy if you've set the car up in a slide before the turbo comes on boost properly - otherwise if it hits boost after you've broken traction on the back you have the same effect as planting the throttle on a atmo car - right when you should be feathering it... I've also found the odd effect that the four wheel drive then transfers more power to the front with the effect of pulling you out the slide like a FWD car... just very quickly - it's rather un-nerving.

Would this be the one ..


https://www.scoobynet.com/drivetrain...anslation.html

I have mine set to Auto for 90% of the time but I have played with the control a little after reading the guide written by johnfelstead.

Nearly all of my previous cars have been rear wheel drive so over time I have learn't how to drive these car's (with the RX7 Efini being my favourite and most fun) - as anyone knows with these types of car's, once the back kicks out intentionally or not, you need to feed in the power to let the car straighten itself out or you end up facing the wrong direction or worse (I did this allot in the early days).

I had a go at tweaking the DCCD on my car and managed to induce some rear wheel drive type action however as people mentioned above, it was on the limit and I did spin the car several times however I have found a setting that works for me (mimicing rear wheeld drive cars) but to be honest, I will probably leave the control on auto for the majority of the time as I simply do not have access to the types of road conditions the car and the DCCD control demands.

It's good fun and if you have the time and space to tweak the car, then its worth having but I think for the average road driver its not really of any use except for being on auto (If I am correct, I think the intention for the auto version was to ease the dreaded understeer).

Have to say, what a pleasent 'conversation' on this subject!

Experimentation is the order of the day.
When Felly got round to my dccd after all the damper/camber settings we tried near to open and then about 50% of the 'wheel'.
I was now used to driving the track consistantly, so managed to get good relative impressions of the car to the dccd changes we made.

It really is amazing how much of a difference a few 'clicks' made to the attitude of the car, especially at full throttle and off the pedal changes so typical of a hill climb (or a fast country road run?).

Take care of the setting and you will gain a lot.

My dccd adjuster:
http://i9.tinypic.com/520nrc5.jpg

There's a neat trick to get "click" adjustment... :)

Nice one.

Hey im just about to buy a type R, im really scared now reading this!! lol, i Did have a nissan 200 before, had a few 'hairy' moments with that, i guess ill have to set this DCCD up according to my style.