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MG MGF Technical - Pumping up he suspension

I have built myself a pump for pumping up the Hydrolastic suspension of my F.
I was encouraged by the experiences pf others I have read on the BB who have done the same, and gained a few hints from them in the process.
The question I am asking, can someone tell me the likely pressure I will encounter in the car as I am concerned about my fittings.
Eric Hayes

400psi Eric - at 'normal' ride height - so I guess you'd nrrd to engineer for a pressure of 5-600?
Rob Bell

Thanks Rob,
Dear o Dear, I did not think it would be that high.
I was thinking in the order of 250psi
12 years ago I restored an G MG 1100 and pumped it up with a pump I had built to test Model loco boilers.
I just connected it up and started pumping - and viola up she went
I was going ro use the same setup on the F much perfected, but I do not think I could obtain these pressures.
This is probably why a friend of mine took his car to a Mini specialist and the hoses from the unit burst and covered his car with Hydro lastic fluid.
I should have asked you experts over there before I started on the project - put it down to brain fade.
tjanks - back to t eh drawing board

Eric Hayes

Hi Eric,
no need to spend time at the drawingboard :O)
Look at Dieters Tech Site and see how others have made it work. Low costs involved,only a re-built hydraulic jack and some parts from truck tyres..

BR, Carl.
Carl Blom

all you need
http://www.mgfcar.de/pump/index.htm

Regards
Dieter
Dieter K.

Thanks, Why I went the way I did with the pump is that I had most of the equipment
What I can not ynderstand is that the car weighs 2400 lbs - in round terms - that is 600 pound per couner . The difference in weight between front and rear is taken care of with the Hydrolastic units being of different specidication,probably diameter.
Now if the effective area of the Hydro.unit is 3 Square inches i.e. 2" in diameter, that produces a force of over 600 lbs at 200 psi
I know that the units are no where near as big as the old 1100 or 1800 units but they have got to be larger than 2" in diam
If they are 3" in diam the result is a lift force of 700 lbs at 100 psi
This was the theary I ws working on.
Why do they need 400 to 500 psi
We have had no experience out here with cars later than the last Mini in the 70's. The Alegros, Momtegos etc never came here.
Eric Hayes

Hi Eric,
somewhere in Internet space is a very good description of the system. (Please give the URL Dieter !) Donīt forget that there is also high pressure nitrogen involved in one separate chamber inside the sphere. Here is the reason for the surprisingly high pressure needed. But even with the simple home-built "pumps" several of us on this BBS has put together the adjustments of ride height is a simple task. Just a bit messy when releasing the valve connection ... ;O) / Carl.
Carl Blom

I think you mean this from Dr. Geoff Rideout ?
http://www.mgfcar.de/hydragas/ehydragas.htm
btw, the former Canadian student *developed* well. I got several pdf files with more research reports on my HD. :)

Will you visit the Munich electronica fair this year again ? (option to handout a CD)

Eric, typical pressures for the MGF is between 360 and 400 psi. They modified the ally pistons and lower diaphragma cover.

http://www.mgfcar.de/hydragas/compare.htm

More about Metro
http://www.dpr-racing.co.uk/tech_hydrolastic.htm

HTH
Dieter
Dieter K.

Most probably going to the fair (one day trip, flight from Copenhagen),will let you know times etc. asap. / Carl.
Carl Blom

This thread was discussed between 17/09/2004 and 19/09/2004

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