lowering suspension?

exminiman · Post by **exminiman** » 24 Jun 2008, 14:23

Having read a few articles on driving economically (at £1.30 a litre for diesel who hasnt????) I have taken off the spare wheel and cage, cleared the boot and took out the rear seats complete as its only used by me 99% of the time, Reduced cruising speed from 70-75 to 55-58mph and I`m slip streaming hgv`s, saiitng in the clean air behind them. Does any one know if its possible/feasable to file/drill/cut another "slot" in the suspension lever "gate" next to the handbrake so it`ll ride a tad lower on nice flat motorways. Ther is a standard higher setting already marked which i assume is for heavy loads/towing.....will this adversly affect brakes/p steering? Or am i, as i suspect, coving old ground and being a numpty? Oh, almost forgot. 1.9td xantia estate. almost forgot, its my first post!

jgra1 · Post by **jgra1** » 24 Jun 2008, 15:01

hi exminiman

I may get shot down for this response

I think the answer is no..

the select really only lets you have full up, full down, or normal.. I have never found a use for the intermediate postion.. on all my xantas it seems to be full stiffness etc..

One test to disprove waht I have said, would be to get someone to hold lever half way between low and normal and see if the car sits at half its normal height etc.. I dont think it will.. the roll bar will be trying to get the suspension to rise...constantly, and be forced back down by the lever position..

the normal ride height is only govenered by the position of the roll bar link clamps, front and back...

You could try and set them both up to decrease the ride height perminently when on 'normal' setting ? i.e. get the car 2-3 inches lower all the time...

safety first

John

jgra1 · Post by **jgra1** » 24 Jun 2008, 15:11

I must admit once or twice I have thought of putting on LOW on a motorway

I can imagine the reality

exminiman · Post by **exminiman** » 24 Jun 2008, 15:57

so i was being a numpty then?lo

JohnD · Post by **JohnD** » 24 Jun 2008, 16:02

I don't think it's advisable. When the C5 is put in any position other than 'normal', an advisory speed limit is shown on the central panel. Whatever level the suspension is in, once you reach 25mph, the level automatically reverts to normal height.

jgra1 · Post by **jgra1** » 24 Jun 2008, 16:25

no exminiman i wouldn't say you were..

i may be wrong anyway

I wonder how much difference it would make, in theory... lowering by 5-10cms... to economy

Hi John the xantia has no such overiding systems.. its all mechanical....

edit..
doesn't a new Citroen have a higher-speed suspension lowering button/mode?

exminiman · Post by **exminiman** » 24 Jun 2008, 16:42

while i`m on, i had it on the lowest and highest setting the other day, just to show my son, and it took ages(4 mins!) to go from lowest setting to normal again.....spheres?

Post by **CitroJim** » 24 Jun 2008, 18:57

Welcome Exminiman

Not a silly question at all. The C5, I believe, does have a fast cruise lowering and it brings it down about 15mm when going over about 65mph.

The Xantia though, is designed to ride at one height and the function of the height correctors is as hinted in the name, to correct the height due to load changes. If you change it too much, you'll run into ride quality issues.

However, nothing is gained without experimentation so why not try say, a 15mm lowering by doing it properly and adjusting the ride height via the anti-roll bar clamps. It'll be interesting to know the result although i cannot imagine fuel economy will be much enhanced. An Xantia is pretty good aerodynamically anyway.

If you do adjust the ride height via this method, the operation MUST be carried out on a ramp or over a pit. It is next to impossible otherwise and extremely DANGEROUS to go playing around with height correctors unless the vehicle is fully supported and every precaution is taken to avoid injury if it should suddenly collapse to low. These cars can and have killed through crushing. Take care.

John, if you set to LOW on a motorway, you'll find the ride awful

as you'll have no travel at all, just like if you try to drive in HIGH..

Xaccers · Post by **Xaccers** » 24 Jun 2008, 21:20

With my '95 Xantia hatchback I managed 816 miles on a single tank without any modifications to the car.
Just drove at 55mph (give or take), rolled down hills, accellerated slowly, and slipstreamed lorries etc.
That's about 55mpg.

f00lzz · Post by **f00lzz** » 24 Jun 2008, 22:04

Just to clarify something on ride height.. My V6, obviously Hydractive 2 self lowers at speed.. I believe controlled by various sensors.. So not purely mechanically controlled.

DickieG · Post by **DickieG** » 24 Jun 2008, 22:48

f00lzz wrote:Just to clarify something on ride height.. My V6, obviously Hydractive 2 self lowers at speed.. I believe controlled by various sensors.. So not purely mechanically controlled.

E'rr that not correct as height control is purely mechanical, the electric's on Hydractive 2 merely stiffen the ride dependant either on the manner the car is being driven or the condition of the road surface, indeed even on an Activa the same applies other than its ability to also correct roll. I believe you need to go to a later version such as Hydractive 3+ for 'lowering at speed'.

I'm not too sure about all this 'streamling lorries' yes save a few quid on fuel but the front of your car now needs a respray to account for all the debris being thrown up

then as for the question of vision beyond the lorry,,,,,,,,,,,,maybe more than a respray may be needed, I think I'll look for other ways to save money personally

Xaccers · Post by **Xaccers** » 24 Jun 2008, 23:17

DickieG wrote: I'm not too sure about all this 'streamling lorries' yes save a few quid on fuel but the front of your car now needs a respray to account for all the debris being thrown up then as for the question of vision beyond the lorry,,,,,,,,,,,,maybe more than a respray may be needed, I think I'll look for other ways to save money personally

Yep, it's not the safest of things to do, and the police take a dim view of it.

andmcit · Post by **andmcit** » 24 Jun 2008, 23:29

Surely in optimum aerodynamic working conditions you're NOT
significantly reducing the frontal area of the car so NOT reducing drag
whether you're at maximum or minimum height ANYWAY and you'd
have to have fancy F1 speed/body design and budget to get any kind
of downforce/ground effect etc etc which have nothing to do with fuel
economy.

Anyhow, our totally rubbish roads in the UK are so awful the ride of a Xantia
is working hard just to get ANY comfort before you start deliberately
reducing the suspension travel.

Like Richard, I'd say leave it alone!!

You've got it right; stripping down weight to further your range is the only
really viable option after tuning the efficiency of the engine to run to it's
optimum first. After that's cost you a good few quid you could have bought
a fair bit of fuel!!

Franky, to save on the cost of using a car, the answer is simple - don't!!

And take off the roofrack first!

Andrew

Ross_K · Post by **Ross_K** » 25 Jun 2008, 00:57

As regards slipstreaming trucks and coaches:
http://www.autobloggreen.com/2007/10/28 ... rove-mile/

Mythbusters did an episode about Big Rig myths that included a look at the drafting myth? Does anyone really consider drafting a myth? Anyway, they found drafting increases your miles per gallon up to 39 percent at 10 feet distance away from a big rig. At two feet apart however, they found miles per gallon actually went down.

I still don't fancy hanging ten feet off the back of a truck doing 55-60mph to save a bit of petrol money though...

handyman · Post by **handyman** » 26 Jun 2008, 06:33

Hi Exminiman, what happens when you get a puncture?

No spare wheel.

Have you thought about stripping out all the interior and the glass to lighten the car?

Personally, I would go the route of drill and hole cutter to lighten the bodywork. There must be a "hole" lot of metal you could remove which would not weaken the structural integrity of the car.

What about a remote clamping device, fitted to the front of the car, allowing you to hook onto the rear under-run bar of any passing truck? Will get you the ultimate tailgating position. You might be lucky and get a truck going the same way as you!

Handyman