Diravi

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ayden
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Diravi

Post by ayden »

Call me thick but what does "Diravi" do on the models of citroen that have them ? i saw a diravi controller on ebay for a CX and just wondered whats it for ?
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Post by tomsheppard »

It is speed sensitive power steering. It will only work on a CX or an SM, (although some early XMs may have had it IIRC), is diabolically strange to drive for the first few weeks then quite wonderful. One of the few positive reasons for buying a CX.
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Post by Stinkwheel »

Mostly answered by Tom above but i will add a couple of points.

Yes its a fully powered steering system, It has virtually no mechanical link between steering wheel and rack, only very basic emergncy use linkage.

Its finger light at very low speed and builds up to a stiffer maximum at high speed due to a clever box that tells the steering what speed you are doing (its all linked into the speedo drive)

It will self centre at all speeds, so you turn the wheels and let go of steering and they will return to the ahead position, this happens at all speeds, in a CX never let go of the steering wheel totally to let it feed back out of a turn, you will end up going straight on, most people only make the mistake once. Once you are used to the system you dont even think about it, I've driven CX's after a break of months or years and been at home straight away.

I love this steering system, it gives very relaxed but perfectly precise control, some people complain of lack of feedback, to them i say, rubbish.

Its fitted on 99% of remaining CX's only very early 2 litre and 2.2 cars had the option of non fitment, and these were in like 1975 an 76. It was also fitted to some XM's, but only european mainland V6's.

Drive one once if nothing else, just to say you have.
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
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Post by 406 V6 »

One cool feature of the Diravi: being fully powered, as was refered above, you can get a wheel on a ditch and the wheels will remain at the same position like it was still on the road, as there is no feedback to the steering.
It's something i wish the C6 had...
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Post by andmcit »

O GOD I LOVE DIRAVI!! It MAKES the CX a SPECIAL car rather than just a nice car...

Right, be kind to me if I confuse everyone with the following explanation - this is as far as I understand it!! No doubt I'll stand corrected on parts or all of the follwing!! :lol:

In my expereince with loads of CX's it's a VERY reliable system, so doesn't need any "fixing" to break it!! :D

The actual controller on ebay for a fiver is only a part of the system. It's effectively a steering column that has a system of valving that opens and closes according to the steering inputs/angles from the driver. This valving controls the rack's movement and there IS a physical connection from the steering wheel to the rack. IT'S PURPOSE THOUGH is a cam affect that KEEPS THE STEERING STRAIGHT at dead centre [effectively FULL self centring steering].

There's a complete high pressure artificial 'feel' to the weighting of the "power steering" VARIABLE according to the car's speed that's controlled by another element of the system - the steering governor - this varies the assistance that's supplied to the rack. The 'counter acting' effect of the governor to the FULL assistance available is controlled by a physical drive from a speedometer splitter out of the gearbox.

You feel the job this actually does if there's a problem with the speedo drive!! The car effectively runs in a FULLY ASSISTED power steering state that's finger light at ALL speeds. FUN on a GTi TURBO as you do really 'think' every little nuance of the car at high speeds.

The final ace in the hand is the steering lock to lock of two and a half turns on the Cx and an even MORE sporting two on the SM!! The Xm DIRAVI only made it onto LHD V6's and was attached to a 'woolier' three and a half turn rack to make it more Ford driver friendly... :wink:

A good pal is engineering himself a fitment of DIRAVI to his RHD XM 24v V6 as/when he finishes buliding his house - not long now!!

After trying a proper DIRAVI car ANYTHING else will feel tame!!

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Post by fastandfurryous »

My understanding of the DIRAVI system is that there is NOT a mechanical connection between the column and the rack, except a very sloppy emergency coupling that can only be felt when the system is un-powered.

The cam arrangement operates directly on the steering column, and it is this cam, operated by variable hydraulic pressure, that stiffens the steering at speed.

The rack effectively follows the command of the steering column, whatever that may be. There is no feedback, and there is no possibility of the steering wheel being tugged from your hand if you hit something large.

DIRAVI is bizzare to drive to begin with, but once you understand how it works, and why it is so amazingly safe, then you love it. After all, you can have massive failure of a front tyre, and still retain control of the car. Parking takes a little while to get used to though, as the system still self-centres even when the car is parked. You will almost never see a CX parked with it's wheels anything other than straight-ahead.

Oh, and of course, a CX is completely unaffected by sidewinds, or air-wash from a large vehicle.

Strikes me that it would be a bloody good thing to fit to a landrover. Having nearly broken various fingers over the years from off-road steering-wheel spin fron hitting objects!

"DIRAVI" is to steering what "citroen fully powered hydraulics" are to brakes. None of this power ASSISTED malarkey... this is FULLY POWERED
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Post by Stinkwheel »

I agree with your last comment mate :-)

As for the feel thing again though, people say you can never be quite sure what a CX is doing due to the fact that Diravi gives you no direct feedback, i say 'rubbish' the CX feels so good everywhere that the whole car gives you the feedback.

I also like the way a CX understeers when puched hard, and even breaks the back away, although always comes back with a little lift off.

This is a dangerous thread, Im supposed to be selling my prestige you know, now i want to keep it again :-)
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
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Post by andmcit »

You're absolutely spot on - the two fingers of the yoke on the column never actually touch one another BUT when the hydraulic assistance goes they can be turned against one another and transfer the steering input down the rack.

Preaching to the converted - we've formed our own little cliqué of the DIRAVI appreciation society here!! Bet you'll never find Volvo drivers waxing lyrical about their steering systems!! :wink:

Drive DIRAVI today BEFORE 'they' make old and interesting car ownership illegal...

Andrew
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Post by Peter.N. »

I think all cars should have it! When I had my first CX it felt a little strange for the first few miles but once you are used to it you never want to drive a 'normal' car again. After 10 years of CXs I eventually succombed to the XM, its got a heater that works and you dont have to change the head gasket every 6 months (diesel) but as for comparitive handling its rubbish.
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Post by Stinkwheel »

Peter,

Im afraid i find XM's totally boring - I dont know why.

I think to be honest you were unlucky with your CX diesel head gaskets as I've known of severerly high mileage ones that didnt cause that amount of problems.

As to CX's in general................
This is something I've been told the whole time I've had/been involved with CX's that they are un reliable money pits. OK so some things can be expensive but i mainly do it myself and they are no more expensive than any other car, also I have never had an unreliable one and have never been left stranded by one.

I drove home a distance of approx 300 miles from scotland in a 22TRS that had a leaking water pipe (the metal one that runs below the Crank pully) and also managed to rip the exhaust off and deflate a tyre by hitting a brick half way home. By topping up the water and whacking the spare on after coming to a controlled and easy stop after a high speed front wheel incident it still drove me home happily. This really endeared that car to me so a week later i totally re-piped her, service, cam belt, tyres, hydra flush, new spheres etc a month later it was written off by a lady in a nissan sunny on her mobile phone, bum.
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
freek
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Post by freek »

Hi,
As an owner of a CX I agree that the diravi system has advantages: cruising on the highway al well as driving in inner cities is very comfortable: turning at low speed is very easy and at high speeds the car is very stable. But: it also has a very important disadvantage. In the 70's and 80's a judgement of the safety on slippery and icy roads was part of road tests. These tests were conducted by a very famous race and rally driver, Rob Slotemaker, who also owned a anti-skidschool. He found that the CX was in fact a very dangerous car on slippery and icy roads. The diravi system prevents to turn the steering wheel back very quickly, and therefore it is very hard (or impossible) to get the car in control again. His judgement: he had never driven a car before who was so hard to handle! I hope I will never experience this myself...
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Post by Stinkwheel »

I've driven a Gti Turbo 1 on snowy and icy roads, they seem as easy to control as anything else up to my ability level but i can see what you are saying, someone with high skill levels could probably be better in a direct steered car.

My answer is slow down in snowy/icy conditions, in fact no, my answer is drive a 2CV in icy snowy conditions, light, narrow tall tyres etc perfect :-)
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
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Post by andmcit »

Hi Freek - I've never had the occasion to actually catch the steering out - in fact it saved my LHD Belgian GTi 2.4 on a british road many years ago from being rearranged on a roundabout!!

A big van was driving wide right round the outside of the roundabout and was about to catch the left hand side of the vehicle as I was exiting the roundabout - I noticed a BIG bumper about to strike me being on that side and was able to 'think' the car around the impending disaster and accelerate out of trouble!

The same couldn't be said on a more recent occasion where a HGV Spanish 40 tonner decided I was in his way whilst I was driving a RHD GTi 2.5! Let's say I'm a very untrusting driver on any roundabout these days... :(

The answer IF there is a flaw in the system is simple - if it's icy on the road you SHOULDN'T be driving such a masterpiece of styling and engineering anyway!!

- that's what Xm/Xantia/Bx's are for!! :wink:

Andrew
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Post by Stinkwheel »

Blimey,

you have got bad dont you :-)

Whats the CX count up to these days ?
"Rust Never Sleeps" said Neil Young. Did he own old citroens?
1998 Xantia TD exclusive auto estate +3 x BX's +77' ami 8 break + 73' dyane 6 + '83 2CV6 + 94' XM 2.1 sx auto + 89' XM2.0i
+ '85' GSA + '97 XM 2.0 16v + '81 Visa super E
andmcit
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Location: Swansea - South Wales
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Post by andmcit »

Cx lost count actually!! :wink:

There's three turbos on ebay at the moment that I'm trying to ignore. Not easy as the BEST CX is in my humble opinion a metal bumpered turbo1 - THE BEST seats in the business too!

Don't fancy leaky sunroofs though...

DIRAVI is the WHOLE reason I love these Soooo much!

Know what you mean about 2CV's in the snow too - a parchment/salmony coloured Special with ami 135 tyres made a total nonsence of EVERY other car in my village on a seemingly 'impassable' incline in some bad snow a while back...

Loved that car - foolishly swapped it for the GTi that was later rearranged by said Spanish 40tonner. Mind the Cx was a beaut - totally gutted when it's rear nearside was pushed in and the offside struck a conveniently located lampost thus knackering both rear 3/4's in one go - the bodywork was pushed into the centre line of the rear tyres... :cry:

I'm repenting now with a 1960 ripple bonnet that's starting to get collected together though someone kiefed the bonnet :(

Andrew
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