Why not Hydragas?

[PerS]

I hope to find your opinion on an issue that keeps coming up here at the forum on a regular basis.
It seems to be the majorities opinion that hydragas is something that should be ditched, as soon as the right opportunity arrives.
WHY???
The only car I´ve had with full hydragas (hydrolastic really) was on a Mini many years ago.
I am not an engineer so maybe that´s why I don´t understand this opinion(that hydragas is bad).
In my opinion the most successful sports car of yesterday was(is) the Lotus Elan, with a suspension setup with coil and dampers.
The basis for this success was that the suspension had a long enough "travel", to cope with hard coils and soft dampers.
If you want to compare the extremes why not test an Elan versus a Morgan!
I therefore believe since the Midas have short suspension travel you have to solve the suspension issue with something else.
And "voila", that something else could be hydragas!
I have had my two front hydragas containers rebuilt with a valve, to be able to adjust the gas pressure.
Not yet mounted, but I hope to resume a nice front suspension character, once done.

Please give me your experience or opinion.

Per

[Jin]

The first and only car I've driven or owned with hydragas is my current cortez, and it's actually ok, it handles great gives a comfortable ride and true to form they are compact units even if the rear end is soft as cheese and is in desperate need for rear shocks
However, for me anyway as an engineer it just dosent seem right somehow, don't get me wrong the geezer who designed it was monumentally clever, way more so than I'll ever be, but there's an inherent weird uncertainty of driving around in a car supported on essentially water balloons, you can't quite see them internally, the ratios are all working against them mechanically in tearms of leverage and to solve issues such as lowering and uprating isn't as simple as conventional coil springs, that's where the uncertainty comes from, for me anyway, and with uncertanty come the desire to change, as soon as I get time I too will be fitting coilovers on mine

[Hans Efde]

The problem with hydragas I think is:
1) springing and damping in 1 unit. I prefer that to be separated for maximum efficiency/performance. A hydragas will always be a compromise.
2) age, the older they get the less effective they work. Mine was quite harsh, the small springs I have now give a much better ride quality. Possibly you sorted it by being able to put air in them with the added schroeded valves.
3) ride height. It changes with cold/warm. Bring a cold car to an MOT and they adjust the lights because they shine too low. Once the car is warmed up, so is the hydragas and the nose of the car is 1 cm higher. Ofcourse this is only a problem with the Gold having just hydragas at the front. Hydragas at all wheels wouldn't have this problem. Now the headlights need to turned down again. I had it every year with my convertible. That's sorted now with the springs.

[benofbrum]

Justin, your Cortez had new rear units installed in Autumn 2009 after one of the rusty originals sprung a leak and lost all the fluid while on holiday in France. The air (nitrogen?) pressure in them is therefore as it should be. As they lose air pressure, it has the same effect as making a spring shorter and stiffer. When a settled system is pumped up. it is fluid which is added, not air, thus making the suspension firmer.
Coaches and lorries have used air suspension for many years to improve ride quality.

[Hans Efde]

When a settled system is pumped up. it is fluid which is added, not air, thus making the suspension firmer.

That's the problem with the hydragas units. You can only have them served for fluid, not gas. After 20 years of age these things are boneshaking harsh. The addition of the schroeder valve is a very good mod for anyone staying with hydragas because I don't think there are many new ones around.

[kelvink]

I think if you speak with Alistair he can tell you a lot about Hydragas units and how to get the best out of them for the Midas. He can recharge them with both fluid and gas.

There's a lot of things said about hydragas mainly because people don't understand them and make the wrong assumptions about the units. A bit like the K Series engine really.

[PerS]

The problem with the spheres losing the nitrogen can be dealt with. With a shroeder valve as Alistair also recommends, or Citroen valves.
I was looking at Mgf sites when I came across a guy who renovated spheres using Citroen C5 valves. He ran a Mgf and several Citroens, so he was familiar
with the problem at hand.
The problems with the expensive and not very successful "coil over kit" that was presented to Mgf owners have not been resolved. I ask why.
The Mgf run the Metro front sub frame at both ends, so we share the platform.
Of course I have read about the convertion many of you have done, using various coil over components. The greatest drawback seems to be having to weld a "hat" over the new coil over, in order to keep it in place. Big work and at a cost.
I had hoped to hear from someone with experience of Metro Cup cars, since I believe they had to use the original set up, with spheres.
As for the rear my Midas Gold use coil over dampers, they´ve seen better days. I`m thinking of mounting Öhlin(Ohlin) dampers as on the Lotus 2Eleven as they
can be adjusted so much more.

[Geoff Butcher]

Hmm, Ohlins 2-way adjustables appear to be £650 each...I was recently speaking to Leda about rear dampers for my Mk3. They are clearly a cut above the usual types of aftermarket dampers, but I was somewhat taken aback by the price of £325 + VAT each. Suddenly they seem almost reasonable

[PerS]

Well, I haven´t checked prices yet, only talked to a friend of mine who just bought a 2Eleven.
I´ve read so often that the ordinary aftermarket coil overs seldom delivers adequate performance, problem with choosing coil to use and not enough options on the damping.
Ohlins, I´ve heard are long lasting, serviceable and can easily be made to fit any type of car. Well it sounds promising anyway.

Per

[Jin]

Justin, your Cortez had new rear units installed in Autumn 2009 after one of the rusty originals sprung a leak and lost all the fluid while on holiday in France. The air (nitrogen?) pressure in them is therefore as it should be. .

i know mate, thats why im a bit puzzled regarding the bouncyness of the rear end, any longer than 10 mins behind the wheel and i feel sea sick