XM slalom video

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Mandrake
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Post by Mandrake »

Kowalski wrote:The impression I got from watching the video was that the driver seemed to be throwing the Granada about a lot more than he was the XM, some of that was because the car was sliding.
If you look in the windscreens you can see he's clearly turning the steering wheel less on the elan and the XM - probably due to higher geared steering. When the rear on the other one started sliding he wasn't able to turn the wheel fast enough to compensate and started to lose control.
The XM behaved like a front wheel drive car should, it was docile and understeered but the Granada was a bit more tail happy, being rear wheel drive it slid but could be caught and corrected and the driver didn't manage to spin it. If the Granada had traction control, it may have passed the test at the higher speed but since it didn't its an academic question.
I doubt if traction control would have done any good, I don't think any of the 3 cars were reaching their power-on over/understeer limits, I think the middle car was losing control due to poor damping control of the rear suspension which was allowing the rear end to flick over each time the car reversed direction, provoking a fish tale reaction.

Both the XM in Hydractive Hard mode and the Elan would have had MUCH stiffer damping than the other car. Also notice that when the XM corners the side going down goes down more than the opposite side comes up - the highly asymetric damping rates in the hard mode cause an overall drop in average height during cornering...(on purpose, to stop the rising edge from flicking up too high)

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Simon
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deian
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Post by deian »

i wonder what engine the granada had? they had a 2.8/2.9 24v V6 cosworth engine in the top end ones, nice car tho, would have been amazing to see a rear wheel drive xm, if they did such a beast i'd have one now instead of my xantia, i'm sure the granada is a longer car than the xm though.

i was talking engines because if the granada had the cosworth engine then the xm would have had the V6, plenty of torque lower down, where as the Elan's engine would have been smaller and therefore needed to be raced more hence more control around the slalom?
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Post by oscarloco »

What do you expect?

They are Citroens. 8)
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Post by Sturdybloke »

Thats deffo a 2.9i 12 valve version Granada as its 1990, but its not fitted with the Cosworth 24v power unit - that came a little later in the cars life. The Granada (when in saloon form) is slightly longer than the Xm but the Xm is a larger car inside as it dosent have or need a huge transmission tunnel as its FWD where as the Granny is RWD or 4x4.
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Post by SimonM »

Mandrake wrote:
ACTIVE8 wrote:Thanks for posting that clip Mandrake, well done it's an interesting bit of film. :D 8)

I completely agree with 406 V6, they should have also tested an Activa as well.
Bear in mind that the clip clearly says 1990 - before the Xantia even came out in 1993, let alone the Activa in 1995.

So it will be one of the very early Hydractive 1 XM's.

One of the reasons I thought it was interesting is because "everyone" will tell you that a big, heavy, long, front heavy front wheel drive car can't corner or handle well and will "understeer" yet in that video I see no more understeer than the elan.

(Check the elan going past the last cone, it is clearly starting to understeer and slide through the last bend even though its almost certainly rear wheel drive)

The XM is very neutral in that clip and has a slight bit of drift at the back as well as the front.

As for the other car (whatever it is) - clearly oversteering and showing why for anything other than "showoff" driving oversteer can be dangerous...he was doing pretty well keeping it from doing a complete 180.

Regards,
Simon
The Elan is front wheel drive and so will understeer.
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Post by deian »

4x4 too, oh yes, the sierra came in 2.8 4x4 too, 150bhp if i remeber correctly, not much for such a big engine, 4x4 would slow the car down a little and it would oversteer more as the back is powered more than the front... as the video shows.
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