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MG MGF Technical - Hydragas question
| Cars that have used Hydragas (with varying degrees of success):Allegro, Metros A and K, Princess, later Maxis. And the F, of course. Somehow I've got the notion that the spheres used on the Princess were different from the ones used on the smaller cars. Or am I getting my hydrolastic confused with my hydragas again? |
| JH Gillson |
| According to the paperwork that comes with the Hydragas pump, these are the cars with Hydragas and Hydralastic suspension and thier front wheel trim heights... Hydragas MGF (368mm) Metro 1980 - 1990 (12 7/8") Metro 1990 onwards (341mm) Ambassador (14 1/2") Allegro to car no. 226629 (14 3/4") Allegro car no. 226629 onwards (14 1/2") Maxi (14 1/8") Hydralastic Mini up to Dec 1965 (13") Mini from Dec 1965 (12 5/8") Mini Clubman (13 1/2") Princess (14 1/2") Princess Mk1 (13 5/8") Austin/Morris/Wolseley 1800/2200 (14 7/8") Austin, Morris, Wolseley, Riley (13 5/8") MkII 1100 & 1300 with arch rear spring (14") MG Normal Air (i assume this is the 1100 / 1300) (13 5/8") 1300 GT (13 5/8") --------------------- OK, the above is a complete list that the Hydragas pump is compatible with and not necessarily a complete list of cars with Hydragas / Hydralastic suspension (i seem to recall the Marina also having Hydralastic suspension - not sure though). Going back to your question the Princess definitely has Hydralastic spheres whilst the later cars had Hydragas spheres. I don't think the size of the car was the reason for the difference, rather the Hydralastic set up was replaced by the Hydragas system and (with the exception of the Ambassador, which was the last incarnation of the Princess and therefore a 'throwback' IIRC) only the smaller cars within the Rover stable were fitted with this type of suspension. HTH SF |
| Scarlet Fever |
| Mate, you are the greatest :) Many Thanks !! Just copied and added to the hydra thingies site. http://www.mgfcar.de/pump |
| Dieter Koennecke |
| Marina definitely did not have Hyda anything suspension. Torsion bar the the front, cart springs in the back Cheers Patrick |
| Patrick Beet |
| Mate, Marina, ... the Austin ? Please explain. http://www.angelfire.com/mo/convertible/images/aussi.jpg |
| Dieter Koennecke |
| Patrick wrote... >> Marina definitely did not have Hyda anything suspension. Torsion bar the the front, cart springs in the back << OK, don't know where i got that idea from, just for some reason it popped into my mind when i was typing it up. I assume the Ital had a similar set up to the Marina (virtually identical car IIRC). -------------- Dieter wrote... >> Mate, Marina, ... the Austin ? Please explain. << Hmmm, could be complicated this Dieter and i am sure to make a few errors, but as i understand it BMC was a large corporation in the 1950s/60s/70s which eventually became BMH, then Leyland, then Austin Rover, then Rover and now MG-Rover. Under the earlier names it aquired most fo the independant car manufacturers including Austin, Riley, Wolseley, Triumph, MG, Rover, Morris etc. It was the trend at the time (and if you look at the VW, Ford and Fiat group nowadays) to spin off a number of vehicles from a common floorpan and badge them as different marques. An example of this is the MG 1100 and 1300 small saloons. These originally wore Morris badges, then it was badge engineered to form an Austin version, a Vanden Plas version, a Riley version and a Wolseley version as well as the MG branded models. OK, so what we have then are several standard cars, each with thier own spin off variants under different marques. The MG midget / Austin Healey Sprite is another example, as are the MG Magnettes which was also offered in the guise of the Wolseley 4/44. OK, potted history lesson over before i make any (more) errors and get rudely corrected by people on this board who actually have first hand experience of these cars! ;-) OK, so we have established that there were several marques of basically the same car (differing trim levels, badging and engine specs, but otherwise the same vehicle). Unfortunately the list on the Hydragas paperwork is a little vague in some cases and i basically copied down word for word what was there as in some cases i could not identify the car from the name. The ones i am unsure about are: Austin, Morris, Wolseley, Riley (13 5/8") MG Normal Air (13 5/8") 1300 GT (13 5/8") The Austin, Morris, Wolseley, Riley (13 5/8") i have no idea about, this is a list of Marques with no model identification so AFAIC they could apply to any car! The MG Normal Air (13 5/8"), again i am a bit stumped over, i assume it is a variant of the 1100 and 1300 but am not sure. At first i thought it was the MG Farina Magnette Mk IV, but according to my reference material this car had 'Front: Coil and wishbone with anti roll bar / Rear: Half elliptic with stabiliser' suspension, so again i am stumped. 1300 GT is also a mystery to me, there was an Austin 1275 GT which may fit the bill (the MG 1300 actually had a 1275cc engine, but became known as the 1300 so there is a presidence here), but again i am unsure. Being born in 1971 sometimes can have it's disadvantages! :-) Anyway, not sure how much help this will be, but i can bring my copy of 'The MG Collection' (a book) with me on the Treffen if you want to borrow it, has loads of information on the post war MGs including mechanical specifications, potted history of each model and some details of the other variants. Let me know if you are interested mate. SF |
| Scarlet Fever |
| Oh one other thing Dieter, The " marks represent inches!!!!! ;-) Obviously some of the cars on the list were pre-metric measurements so the ride heights are measured in inches as opposed to millimeters. Strange that we learn centimeters at school over here but never use them in the real world! Everyone else in the EU uses centimeters, we UK people though measure everything in metres or millimetres - we just HAVE to be different don't we!!!!!!! ;-) SF |
| Scarlet Fever |
| And one more thing whilst i think about it! Some of the cars had measurements for the rear wheel heights and also pressure readings (i assume imperial lbs/sq ft). I can give you this information as well if you want Dieter (will probably need to put it on an Excel table and Email you the info - if you can get my ISP unblocked!) :-) SF |
| Scarlet Fever |
| Cheers ! >OK, potted history lesson over before i make any (more) errors and get rudely corrected by people on this board who actually have first hand experience of these cars! ;-) This is a live BBS. All can be true, all can be wrong. No worries. Nobody is perfect but ... now who volunteers ?? :) Mate, got the half cupboard full with MG history books. No reason to see more currently. If I retire and get my 'real' mgtf then we speak again. >we just HAVE to be different don't we!!!!!!! ;-) Of course, WE have to :)) Cheers Dieter |
| Dieter Koennecke |
| Having trouble finding pictures on the web of these cars, but have found an Austin Princess: >> http://atsearch.autotrader.co.uk/WWW/CARS_popup.asp?modelexact=1&make=AUSTIN&min_pr=&postcode=cm6+3qs&source=0&model=PRINCESS&max_pr=&sort=3&miles=1500&max_records=50&search.x=20&search.y=8&start=1&distance=137&adcategory=CARS&channel=CARS&id=200231042943089 << SF |
| Scarlet Fever |
| Scarlet The Germans actually use inches BUT they call it the 'Zoll' and when I was working in Germany a couple of years back doing some DIY for the mother-in-law I discovered that plumbing is referred to in 'Zolls' so:- 'Halbzoll' is 'half inch' - 'Dreiveitelzoll' is 'threequarters inch' etc. Dieter - sorry if the spelling is not correct:-) Ted |
| Ted Newman |
| And here's a Morris Marina: >> http://atsearch.autotrader.co.uk/WWW/CARS_popup.asp?modelexact=1&make=MORRIS&min_pr=0&postcode=cm6+3qs&source=0&model=ANY&max_pr=0&sort=3&miles=1500&max_records=50&search.x=30&search.y=14&start=1&distance=148&adcategory=CARS&channel=CARS&id=200231042967944 << A Morris 1100 (Morris version of the MG 1100): >> http://atsearch.autotrader.co.uk/WWW/CARS_popup.asp?modelexact=1&make=MORRIS&min_pr=0&postcode=cm6+3qs&source=0&model=ANY&max_pr=0&sort=3&miles=1500&max_records=50&search.x=30&search.y=14&start=6&distance=57&adcategory=CARS&channel=CARS&id=200231042979272 << SF |
| Scarlet Fever |
| Back to the header. From what I see there are three versions of the Hydra... or Hydro... out. One pre 1973, the hydrolastic units with rubber and fluid only. 1964 ? Then the hydragas with rubber damper valve and between 1995 and 2001 we have the MGF specific hydragas unit with metal damper valve inside. http://www.ukcar.com/features/tech/suspension/Springs.htm (MGF missing there) http://austin1800.homestead.com/Page16.html |
| Dieter Koennecke |
| LOL... 25.4 to convert inch or Zoll is always in my mind as former mechanic. Mind you on the german spelling of the fold-stick to measure the 'meter'. Nobody names it 'Meterstock' or Metermass' but we all say 'Zollstock'. http://people.freenet.de/Zollstock/www.zoll-anim.GIF http://people.freenet.de/Zollstock/site03.htm |
| Dieter Koennecke |
| Hi Guys, Andy just told me about this thread... >> The Austin, Morris, Wolseley, Riley (13 5/8") i have no idea about, this is a list of Marques with no model identification so AFAIC they could apply to any car! The MG Normal Air (13 5/8"), again i am a bit stumped over, i assume it is a variant of the 1100 and 1300 but am not sure. At first i thought it was the MG Farina Magnette Mk IV, but according to my reference material this car had 'Front: Coil and wishbone with anti roll bar / Rear: Half elliptic with stabiliser' suspension, so again i am stumped. 1300 GT is also a mystery to me, there was an Austin 1275 GT which may fit the bill (the MG 1300 actually had a 1275cc engine, but became known as the 1300 so there is a presidence here), but again i am unsure. << Being a sad follower of BMC and its decendents, I think I can help with some of the above... The references to Austin/Morris/Riley/Wolseley could refer either to the 1100/1300 variants or the Mini spin offs. The Riley 1100/1300 variant was called the 'Kestrel', but I can't, off the top of my head, recall what the Wolseley was called? The Mini Riley and Wolseley versions were called the Elf and Hornet. Basically a Mini with a boot grafted on the back and a wood interior. Like my Mk1 '67 Mini, they had Hydralastic suspension. So unfortunately, the list is confusing, and incomplete. No idea what the "MG normal air" thing refers to??? Regarding the Farinas (of which the Magnettes were based), these were thoroughly conventional machines - coil and cart springs as you say Andy. The 1275 GT is a Mini Clubman variant - brought in when Leyland decided it couldn't be bothered to pay John Cooper royalities to use his name on hot Minis. This car used rubber cone suspension that more contemporary Mini fare. Not to be confused with the 1300 GT (that favourite 1100 shell again) - equipped with hydralastic. Did they mention the Austin Princess 1300 Andy? Confused? Makes the Volkswagen/Audi/Seat/Skoda/Bentley/Lamborgini/Bugatti conglomerate seem logical doesn't it? ;o) |
| Rob Bell |
| SF - I, too, was born in 1971. The year they axed the Mini Cooper S and introduced the Marina. I've always thought that made me some kind of criminal. Don't know why but I have an unnatural fascination with Dr Moulton's fluid suspensions. And this is the story of these suspensions so far as I understand it, and I'm no engineer. Hydrolastic and Hydragas (hereafter to be referred to as Hydralasticgas) have both been misunderstood by the press and public and underdeveloped by BMC/BMH/BLMC/BL/ARG/RG/MGR (hereafter to referred to as BLARMGMC which the company should have been known as all along.) It was LJK Setright that put me straight about the potential brilliance of Hydralasticgas. In a "Car" magazine test of the MG Maestro 2.0 EFi (very complimentary actually, which is unusual for Setright) he said that "a car of this breeding really should have the Moulton suspension." Prior to that I'd swallowed the press line that Hydralasticgas was a bit mad. After all, if Setright liked Hydralasticgas there must be something in it. Then Mrs Thatcher appointed Graham (later Sir Graham) Day as the head man at BLARMGMC. And his mission was to privatise BLARMGMC at all costs and ASAP. And the first thing he did was cancel R6. Which was a brand new, conventionally-sprung K-series engined Metro replacement. A bad move really. Another might have been, like the Issigonis 9X, Rover P8 and Truimph Lynx; anyone got a time machine? Like I say a bad move - but not for Hydralasticgas. Instead of R6 we'd get R6X, a made-over Metro with a K series engine. BLARMGMC looked at a conventional suspension for R6X and then fate intervened. Dr Moulton was always hacked off with the A-series Metro's version of Hydralasticgas: the car did without interconnection which was the whole point of the system. So Dr M converted his Metro to Hydralasticgas as he had always envisioned it. That meant subframes and anti-dive front suspension geometry. Dr M also has a Hydragas equipped Mini. "Car" magazine wrote a very complimentary piece about the modded Metro. BLARMGMC got to hear about it, and saw that it was good. And it would be cheaper to reconfigure the Metro's Hydralasticgas to the Moulton specification than to reenginer the car for steel suspension. R6X was launched in 1990. "Car" proclaimed it to be the world's best riding and handling small car (eclipsing the Peugeot 205), and "What Car" made it their "Car of the Year" (yes, really.) And Hydralasticgas was further refined for the 1996 MGF which we all forget was greeted with a hero's welcome for its uncanny poise, huge grip, and general niceness. Hydralasticgas was highly regarded when it first apperared on the ADO16 "1100" in 1962; like the R6X 30 years or so later it was reckoned to be the world's best riding/handling small car. Also Setright speaks very highly of the ADO16, and it's not like him to like any car other than a Bristol or a Honda.) As an aside Soichiro Honda owned an 1100... And Hydralasticgas was more or less well received on the 1800/Maxi. The 3-litre used a self-levelling iteration of the system. Mini enthusiasts do not like it, however - the Mini was Hydralasticgas-equipped from 1964 to 1968 (although some Minis, notably the Cooper 'S' continued to use it after 1968.) Hydralasticgas was an attempt to square the circle: it was a attempt to endow a short wheelbase car with a big car ride by moderating the short wheelbase car's tendency to pitch. In the Mini, Hydralasticgas actually exacerbated the little car's tendency to pitch especially under acceleration and braking. The BLARMGMC Competition Department found a partial cure for this by fitting auxiliary front dampers. Same goes for the 1800, Maxi. But, what of the Allegro? Simply put, it was botched. Bean-counters and outside interference put paid to the Aggro. The bean counters deleted the costly front subframe. As for the outside interference Dr Moulton gave an interview to "Car." He wasn't specific, but the journo (Richard Bremner) read between the lines: apparently, Rover's Spen King did not like the cost and complication of Hydralasticgas, he favoured conventional long travel suspensions (as per the Range Rover, TR7, SD1.) Indeed, King eventually got his way with the Maestro and Montego. Without a front subframe anti-dive front suspension geometry could not be employed without incurring horrendous road noise. Without anti-dive the Allegro was doomed to the bouncy, pitchy ride for which it became infamous. This is my understanding of Hydralasticgas. As I say, I'm no engineer. But it seems to me that the real merits of the system only became apparent when it was too late. And that means that every Hydralasticgas equipped car out there has enormous potential. All that's needed is a little development. The problem with most Hydralasticgas equipped cars (other than leakage) is their tendency to pitch under acceleration and braking. In steady state conditions the system does exacly what it says on the tin. The BLARMGMC Competitions Department developed a front damper conversion for the Mini/1800/Maxi which, according to hearsay improved the behaviour of the cars no end. I wonder why such a conversion wasn't developed for the Allegro and Princess? Was it for the want of a couple of dampers that the Allegro became so derided? I have a feeling that with appropriate development and modern tyres you could turn any one of these Hydralasticgas cars into something that in ride/handling terms would whup the ass of 98% of moderns. |
| JH Gillson |
| Guys, you will find most of the definitive information on Keith Adams' new site - http://dialspace.dial.pipex.com/town/way/yuw18/austin-rover/index.htm he is very thorough and there are lots of piccies too....saves worrying about the memory ;-) |
| David |
| Blimey, JH! Anyway, I've got a question: Those MGF lowering knuckles: are they Allegro-compatible? I have a hilarious (and cheap) Q-car in mind. |
| Xerxes McLeish |
| >Those MGF lowering knuckles: are they Allegro-compatible? Nope, only from principals but they are different design. (upper shaft with lower cone and roll surface) MGF bits look like this. http://www.mgfcar.de/lowering/index.htm BTW. I've seen a picture of the upper swivel long bearing recently at the miniparts advert site. That one seams to look equal to the MGF. The bearing only, not the arm. JH, now after having tried the new MGTF I'm with you regarding Moulton honours. The hydragas interconnection simulates a larger axle distance which definately improves the pitch behavior at the old MGF. Do you know about the site @ http://www.mgfcar.de/hydragas/ehydragas.htm , I got some more documents of the american student and his later studies, but still need to upload. Dieter |
| Dieter Koennecke |
| The other problem with any interlinked suspension of this type is that when you have a four seater and put people in the back, the front rises! NOT very clever and impossible to rectify. Of course, this does not affect the F Incidentally, has anyone put an "F" engine into a Metro? As the F uses Metro sub-frames, this would appear an easy job? |
| T Green |
| Yep Rover, they put in the 1.4 K into the later cars- as the engine is the same block, with a modified head and drilled out internally, I guess you might want to put a bulge in the bonnet, but everything else should be a straight swap- why dont you go and have a look at the "Modified Metro Montego Maestro" board |
| Will Munns |
| >>The other problem with any interlinked suspension of this type is that when you have a four seater and put people in the back, the front rises! NOT very clever and impossible to rectify.<< Not entirely correct - that's what the self leveling suspension system is used for (see the Austin 3 litre). Besides, this effects conventionally sprung cars too, although not quite to the hilarious, aircraft blinding extent that it effected the heavily laden hydralastically-sprung 1100 estate... ;o) >>Incidentally, has anyone put an "F" engine into a Metro? As the F uses Metro sub-frames, this would appear an easy job?<< Quite a few of these knocking about - seen them sprinting too - very very quick cars. Been reading as much as possible about the Moulton Dunlop hydragas system recently. As JHG says, this is a real missed opportunity. Hydragas would appear to be dead - and as usual, we only get to see how good it was AFTER its gone :o( One of the things that gets me is that Hydragas would have been an excellent base for a fully active syspension system: not only could ride height be readily trimmed, but also damper AND spring rates altered, on the fly, by the simple expedient of altering the valving apperature in the hydragas sphere itself... |
| Rob Bell |
| Didn't the Austin 3 litre use a separate unit that pumps itself up to a set level, similar to that used on the Range Rover of the same period? I seem to remember it failed all the time. Certainly I remember seeing Astin 3 litre cars driving around with the body at about 30 degrees to the road! I think it is that basic flaw in interlinked systems that has seen their demise. The only way round it is to use separately monitored units on each wheel (as Citroen do) but this just works out expensive. The F1 experience of computer contrlled suspension shows it does work - but it is very expensive. |
| T Green |
| It does give you a clearer understanding as to why the company that brought you the revolutionary Mini and 1100s died. The philosophy seemed to be "lets stop innovating and copy everyone else. But just to ensure we fail lets make our copies are all as bad as the Allegro" I thought I read somewhere that Pininfarina designed the 1100 and had designed a replacement. Lord Stokes rejected the design and gave us the Allegro. Pininfarina then sold the design to Citroen who called it the BX! Clever move from Lord Stokes but then, no doubt, he was a generous contributor to the then labour government! Cheers Patrick |
| Patrick Beet |
| >>I thought I read somewhere that Pininfarina designed the 1100 and had designed a replacement. Lord Stokes rejected the design and gave us the Allegro. Pininfarina then sold the design to Citroen who called it the BX!<< With the benefit of hindight, it's clear that Stokes was an incompetent idiot. I believe cost was the reason for not taking the attractive design that Pininfarina prepared. And indeed, the Citroen DS does look suspiciously similar... Actually, I think that Renault have recently taken it up as well... cue the new Renault Languna! ;o) >>Didn't the Austin 3 litre use a separate unit that pumps itself up to a set level ... I seem to remember it failed all the time. << Yup, that's right. Shame the self leveling hydraulics were unreliable, otherwise the system (if not the plug ugly car) would have been much more of a success. |
| Rob Bell |
| >, it's clear that Stokes was an incompetent idiot< I have to disagree with you there Rob, Stokes was a very successful boss of Leyland Vehicles - one of the largest HGV manufacturers of the time - he just was not a car man, and if any one was incompetent it was the Idiot that thought a lorry maker would know about cars. Ted |
| Ted Newman |
| Bring back Leonard Lord... everything is forgiven! Ted, point taken. ;o) |
| Rob Bell |
| Yes ted, but the point of a manager is to make sure that you ENABLE the people who DO know to get on with it. If you don't do that, you're no good! |
| T Green |
| OK T.Green Point taken I am no good! Ted |
| Ted Newman |
| Or as was pointed out many years ago - 'the most competent person can be promoted BEYOND their level of competence' - that does not make them any less competent at their level before they were 'promoted'. In Stokes case read 'thrown-in' for 'promoted' plus I wonder what sort of job he would have made of the 'merger' if he had not had government pressure on him and could have done the things he wanted to do. The only thing that is certain is we will never know! Ted |
| Ted Newman |
| Pininfarina stylist Leonardo Fioravanti (he shaped the Dino, Daytona, 308 GTB...and Maxi!) created two aero prototypes. One on the 1100 platform and one on the 1800 platform. Citroen appears to have acquired these designs. Look at the 1970 GS and the 1974 CX. Read more about it on this website: http://www.landcrab.net/ Boo hoo. However, neither the GS nor the CX of were terribly popular in the UK. So perhaps its wrong to say that these designs might have saved British Leyland. After all, we Brits were feverishly buying up cars like the Cortina and Escort at the time. Hence Stokes decision to make the Marina. On Keith Adams website, "The Unofficial Austin Rover Resource", there's a quote feom somebody which goes something like this, "If the formation of British Leyland was the answer, then it must have been a bloody stupid question." As for Lord Stokes, there was an interview with him in "Classic & Sportscar" magazine a few months back, which portrayed him in a somewhat sympathetic light. The piece showed him to be the inheritor of an unmanageable conglomerate of warring car makers. And then there were the unions, and the artificially engineered energy crises of the 70s. Plus the fact that it was undercapitalised. And BLMC couldn't rationalise its product range because it was selling all the cars it could make but not making enough money to plough into a restructured, slimmed-down range. He was in a catch-22. On the other hand, you could take the uncharitable view of LS: BLMC needed was a visionary, instead it got a bus salesman. Either way, can you imagine having to live with the knowledge that people blame you for the single-handed destruction of an entire industry? He really can't take all of the blame; it was a team effort. After all, we Brits were feverishly buying up cars like the Cortina and Escort at the time. But what was the intention of Harold Wilson's labour government of the late Sixties? If the formation of British Leyland was the solution, what was the bloody stupid question? What were Wilson Benn and their advisors hoping to achieve? And did anybody at that time promote the view that a merger between BMH and Leyland was doomed to failure? |
| JH Gillson |
| >>He really can't take all of the blame; it was a team effort. After all, we Brits were feverishly buying up cars like the Cortina and Escort at the time.<< True, but up until the Allegro (fine car that it is), we Brits were feverishly buying Austin/Morris 1100/1300s! And, in fact, at its introduction, the Allegro was also, for a short time, Britain's best selling car. So we WANTED these cars, and we WANTED them to succeed - but things went pear-shaped. Let's face it, LS was the man last in line to recieve the 'buck'... |
| Rob Bell |
| Nothing wrong with the Cortina! both the Mk1 and the Mk2 were brilliant cars, strong and simple and I covered The Continent several times in Mk2 Cortinas especially the 1300 cc cross flow engine, I did one journey of over 3000 miles and averaged more than 40 mpg and that included crossing the Alps twice. Ted |
| Ted Newman |
| I do agree, its probably not one person's fault. Its incredible that BMC cars were selling 45% of all cars sold, yet still not making much profit. And there was so much infighting and politics, poor old Issigonis was sent off to a little office and disregarded. Altogether, it's a sad tale |
| T Green |
| Here is info on the'ultimate' mod to the suspension! http://www.dpr-racing.co.uk/tech_hydrolastic.htm |
| Derrick Rowe |
| Interesting page, thanks Derrick. I had to laugh too when I spotted my diagrams used! Such is the way of the net ;o) The air valve mod is interesting... I wonder how well this works??? |
| Rob Bell |
| Derrick, Thanks for finding this explanation of the '4 nipple job' - now I understand what TechSpeed did to my car to make it handle so well :-) All, The sub-link about camber is interesting, given how many people used to suffer uneven tyre wear, However, some people's experience seems to be at odds with the theory. Paul Lathwell could never get rid of the uneven wear on his original F, which was not lowered. My car is lowered and has never suffered uneven tyre wear either before or after lowering. Other people IIRC seem to have cured uneven wear by lowering. Does this point to vastly different camber settings on a 'standard' car? Dave |
| Dave |
| Possibly Dave, in my case i got through a set of NCT3 in 11,000 miles when the car was new, inner rims - usual story. After lowering i average 20,000 miles depending on tyre choice. Again when they go it is always the inner rims. In an attempt to cure this i recently had Mike Satur's adjustable rear tie bars fitted, my rear wheels are now camber adjustable and if the inner rims go now, then it should disprove the camber theory. Time will tell. SF |
| SF |
| I guess that amounts to permission to use the diagrams - apologies & thanks - I do make the links explicit! The Rover Sport MGF Cup displacers are the standard units with a lower nitrogen pressure. The air valve mod allows the air pressure to be variable. We have dropped the front air pressure down to nearly zero (at zero fluid pressure) and have tried adding liquid into the air chamber to stop the rubbber diaphram from being over stretched. Some proper engineering and trest rigs are really needed to get this right - any ideas on the best combination of air pressure/liquid content to decrease the chamber volume much appreciated. |
| Derrick Rowe |
| No problem Derrick, no probs if the link is made to the orginal page :o). However, it might be a good idea to change the link to my explanation on camber away from my compuserve web page; I plan to shut this down - and is now superceeded by http://www.mgf.ultimatemg.com/camber.htm Alternative damper and spring rates are also achievable using MGF Trophy units. I don't think that this was achieved using lower N2 pressures, but I don't know this for sure. I think that this was actually achieved using a different size damper valve. All options are well worth investigating. How do your modifed spheres work out in practice? |
| Rob Bell |
| Rover Sport sell MGF Cup displacers that are basically the standard unit but lower N2. I imagine the MGF Trophy unit is similar but would welcome some info? Modifying the spheres allows the units to be run at very low pressures - Much stiffer but limited life before leaks start. That is why we are experimenting with adding fluid to the N2 side - so as to stop the rubber diaphragm from being over stretched. |
| Derrick Rowe |
| >>That is why we are experimenting with adding fluid to the N2 side - so as to stop the rubber diaphragm from being over stretched.<< Ah, that figures - not surprised to hear that the rubber diaphragm is put under increased stress. But my first reaction is that I'm not sure how adding fluid will help - if the pressure gradient is the same, then reducing the volume of the gas by adding fluid isn't going to stop the diaphragm being stretched? Will see what I can find out about the Trophy sphere modifications, and will let you know. |
| Rob Bell |
| Rob As you know the idea is that the fluid pressure pushes the diaphragm against the N2 which compresses acting like a spring. With fluid in both chambers the diaphragm could not move but the supension loses all of the 'spring' component - Not a desireable outcome. Adding fluid to the N2 chamber reduces the area that will compress making the spring shorter and stiffer - compressibility is inversely proportional to the sphere area. It also brings closer the outer point at which the diaphragm can be moved out to and reduces the extreme movement that will cause fluid leakage. For the front displacers, we have arrived at 50% fluid in the chamber and about 70 psi of pressure - any comments on the engineering and a better gas pressure/fluid content will be listened to! |
| Derrick Rowe |
This thread was discussed between 09/08/2002 and 21/08/2002
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