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MG MGF Technical - Gaz shocks - worth it?

I need to make the ride of my MGF less harsh, is the Gas conversion kit worth the efort and expense? I'm not a boy racer, I'm just interested in comfortable open touring in an otherwise superb car.
Any hepfull comments appreciated. Edward.
E W Wine

My car was a fairly comfortable ride to start with, despite original shocks, although handling was iffy. I changed to Toyo T1-R tyres all round and had the tracking setup correctly. Handling and ride was better but I still felt there was room for improvement at speed. Then I found the front wishbones were partly rusted through on the upper surface, despite passing an MOT! So replaced these and changed all the suspension bushes, front and rear for poly, pre-empting problems with worn rubber in the future. Replacements included the rear tie bar compliance items. I had the 4 wheel tracking setup done again and fitted Gaz shocks for good measure. I found the best setting was (from zero) 5 notches up on all four units. What a difference this made. Very pleased indeed, until both rear hydralastic units when "stiff". No doubt the diaphrams inside were ruptured, possibly encouraged by poly bushes having less "give" than worn rubber. Now with replacement used rear units, the handling and ride is really great. Gaz units set to 4 all round suits gentle driving on bumpy country roads. Any less and I find the car to be too soft on undulating surfaces - it wallows front to back. I wind them up to 8 all round for fast road use and long journeys. I reckon 6 is a good compromise, but I'm still experimenting!

I think Charless, who posts here, has Gaz shoocks on his cars and he may comment shortly. Those with big pockets seem to favour Bilstein shocks.

There is a kit from Suplex to replace Hydralastic all round. The kit comes with matching shock absorbers. I've also read about an Australian outfit making a similar set - I think these use Gaz shocks. In both cases, the price and availability will make you whince (c £800)! My Gaz shocks were around £200 for all four.

Jeff
J Lennon

Thanks Jeff, very usefull info, I think that I will be going for the Gaz units but I will wait to see if I receive any other usefull comments. Regards, Edward.

E W Wine

If your OEM ones are getting a bit long in the tooth GAZ ones are a pretty useful mid life upgrade. I have had them on one of mine for 3ish years and use 10 clicks at the front and 12 on the back. I think they help damp both the bounce and the jounce so keep strain on the hydragas spheres to the life preserving minimum possible.
I believe OEM dampers are equivalent to no clicks on the GAZ, more clicks stiffen them progressively. Well worth it in my book - but then I would say that wouldn't I!
Charless

Thanks Charless. Not sure about OEM but think it means original speck. My car is very low mileage so I dont think that the shocks are worn out, and the ride height is as per the book.
you say that a Gaz shock setting of zero clicks is equivalent to standard so there would seem to be no point in fitting adjustables that can only be adjusted to make the ride stiffer, or have I mis-understood you. Regards, Edward.
E W Wine

You may have a broken diaphragm in your Hydrolastic spheres (usually the rears go first). Age and not miles travelled could be the killer. This would result in a loss of nitrogen in the upper part of the sphere and consequently the spring capability would be near zero. It's the nitrogen gas in the spheres that can compress, the fluid cannot. The diaphragm keeps the two mediums apart. The correct ride height is possible even with broken hydrolastics. Shock absorbers are not the "spring" in your suspension.

Just a thought, have you checked there is grease in the upper suspension arm pivots?

If you are close to Dorset from your Somerset location, Daryl Cramer trading as Pocket Motors is just outside of Poole. He will for sure be able to diagnose/help/fix your ride comfort problem. I can recommend him - he pumped my car up for me at the end of my rebuild activities! His contact details are darylcramer@hotmail.co.uk and www.pocket-motors.co.uk
Perhaps others nearer to you could pass an opinion about the ride quality of your car before spending money on parts.

Jeff
J Lennon

Original Equipment Manufacturer. If the ride of an F is harsh something isn't right - this might be just down to age as Jeff suggests, and/or height?
My thinking with a stiffer damping is that some of the shock on the ageing hydragas is relieved by the damping absorbing some of it. There isn't a right answer, but it works for me.
Charless

Thanks to everybody for your responses. Have tried a test drive in another MGF and found the same ride, problem must be in the design. Time to look for a more suitable open sports/tourer. Edward.
E W Wine

mine is harsh now as well, though was a lot smoother when I first got her. Suspect the reason was replacement of 2 front subframe arms, she wasn't the same after that and think the drain / re-pressurise of hydragas system did it.

Maybe try a different F? You could also compare with a TF. If you find the TF more comfortable, there's a problem with the hydragas.
Leigh Reid

You've also reminded me of something else.

There was a bloke from Australia who modified his hydragas spheres to allow him to change the pressure in the nitrogen side of the sphere. I always wondered whether this mod could be used to resurrect "broken" spheres by allowing nitrogen to be pumped in to the top half of the sphere once they'd been installed and filled with fluid. It wouldn't matter if the internal diaphragm had ruptured as the gas would float to the top of the sphere.

I'll try and find it...
Leigh Reid

I located the post. If you search the technical archive for :

hydragas modification nitrogen

you'll find it.
Leigh Reid

Leigh, yes, adding a schrader valve to the upper sphere is an accepted method of reviving the Moulton hydragas sphere :o)

More here too on the work pioneered by Alexander: http://mgf.ultimatemg.com/group2/suspension/hydragas__depressurisation.htm

Edward, what ride height is your car running? If unmodified and standard, the trim height should be around 368mm+/-10mm measured between the wheel centre and the wheel arch lip vertically above. If low, then it will cause a very crashy ride as the springs become softer and reduce the damper effort of the hydragas unit, and combined with less suspesion movement due to the lower ride height, means that bumps are felt through the suspension running out of travel, riding the bump stops and leading to a very crashy ride...
Rob Bell

This thread was discussed between 16/08/2011 and 24/08/2011

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