MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGF Technical - Lowering an MGF

Bought a 97 MGF 3 weeks, love the car to bits but really want to drop the suspension a little bit. Now i know that it has gas filled shocks and have read somewhere that to lower them all you have to do is let some of the gas out.Is this true?
Ive lowered cars before and am pretty clued up when it comes to doing it, but the others i have done were simply a case of changing the shocks or springs or both. Can anyone help me out, regards, Gary.
GC

Hi.

Yes, it's true you can very easily lower a MGF.
You'll find the instructions on the archives and on some personal sites (Rob's I think), about how to let some fluid out of the hydragas system, not the shocks.
The "trouble" will then be to get the left and right side of the car exactly on the same height. As the front and rear systems are connected, so you will not have a problem on that.

Valter.
Valter

Thanks for that, will give it a try.
GC

Full instructions at http://www.mgf.ultimatemg.com/howto_lower.htm

Pretty easy, so long as your reasonably careful about your rate of progress :o)
Rob Bell

will do. what about tyre wear. ive just read Rob guide to lowering, which is a good help, just a bit worried about going through tyres too quickly, as ive just shelled out 300 quid on a full set of Goodyear F1s. Has anyone done this???and if so is it recommended?
GC

Depends what the issue is here. If the ride height is set too high, you can lower it by letting some of the hydragas fluid out. Be very careful as the suspension settles a lot after the fluid is let out (as I know to my cost).

BUT, if the ride height is in accordance with the factory settings and you want to reduce that (it does look too high in my opinion), lowering it without changing the suspension geometry will give heavy tyre wear AND a much harsher ride.

This can be worked around by fitting lowering knuckles to the suspension - these can be supplied / fitted by Mike Satur, Techspeed and others. The advantage here is a much lower and more atractive ride height without sacrificing ride quality. I gather it also improves the handling by lowering the centre of gravity.
Chris

Just to build on what Chris has said, no problems with tyre wear with lowering per se. Your tyres will happily cope with 1.5 degrees of negative camber before accelerated wear becomes an issue - and you are unlikely to exceed this even with a ride height of 320 mm.

The killer on tyres is incorrect toe angle - and this becomes more critical as the car is lowered.

After lowering the car, use either MGF Trophy tracking settings, or those that we recommend here on the BBS, which are:

front and rear: 0 degrees 5 minutes toe - in (each wheel: total toe: 10 minutes).

Hope this helps
Rob Bell

Just to second Chris' comments,

If you're looking to really lower the car, then get yourself some lowering knuckles from mike S. Cost about £85+vat IIRC.

You can also fit uprated shocks to the 'F', but if doing so should really also use the shocker re-inforcement brackes.

Should get more feedback on this thread when the Treffeners are back from touring Europe!

Leigh
L Reid

thanks for the help, must say that was the easiest job ive ever done! dropped it a little so that the wheels fill the arches, gonna take it down to the garage where i have work done to get the camber etc sorted out, just in case. Nobody warned me how quick the liquid came out though,i was directly above it, when i let it out, stooopid! and got a mouthfull of the stuff.... nice.
Gary

Er....

Not trying to be funny, but if you've lowered it enough to fill the arches, I think you've lowered it too much and:

The car will be very unstable as it'll be running at low pressure.

You may end up damaging the suspension.


Ride height should be between 355mm-375mm from centre of wheel to lip of wheel arch front and rear. I suspect your's may now be at around 325, which is WAY under pressure. Lowering knuckles allow the pressure to be maintained, but at the lower ride height.

Check the ride height before you end up pointing the wrong way in a field! Post your measurement (ride height) here if you want confirmation that they're OK or not.

HTH,

Leigh
L Reid

To be honest with you Gary,

As L Reid, mentioned your ride is too low without lowering kits fitted.

My car is sitting on 310mm with lowering kits fitted. Used to be around 280mm and that was when the wheels filled the arches (well little bit in to the arch). With lowering kits, but that was too low, couldn't even fit a tyre jack underneath!!

If you want your car safe and sound with that sort of height, I would invest some money on the lowering kits for the safety of car (and tyres) and the kidneys that might judder over every little bumps.
:-D

Just my thoughts... and yes 4-wheel alignment. Definately.

Try to keep your height on at least 330mm without the kits.
Hanah Kim

If you want to go lower than say 350mm then I would suggest lowering knuckles rather than just letting fluid out of the system.

Now is a good time to lower the F. Personally I would lower it to say 5mm higher than you want. In the winter it should drop about 10mm. When it gets a bit warmer it will come back up about 5mm. This height should now be pretty stable and will only change +/- a few mm from this point on.

IMPORTANT, if you want the ride height to remain stable and all your tracking setting to remain good, DO NOT: Repeat DO NOT let an MGR dealer touch the height (unless it is really needed, say a broken HG unit) as this will mess it all up and you have to go through the whole process again.

Some MGR dealers use this to get money out of owners, they pump it up, charge you to set the tracking.
Tony Escort Driver

Thanks for the advice, going to take it to a garage tonight to get it raised a bit, now that the fluid has settled its dropped down more and isnt very comftable. Will get to 350mm and stick at that.

Gary.
Gary

Gary, remember the "Rule of thirds" that applies to lowering and raising hydragas suspension, and remember also to take the car out for a drive around the block between each measurement (the bumpier the road, the better) to get the suspension pressures back into equalibrium.

Explained in more detail (and with pix) at http://www.mgf.ultimatemg.com/howto_lower.htm

I'd agree with Tony, if the ride height is less than 340 mm, then the spring and damper rates get too soft, and the car's ride deteriorates as the suspension bottoms out onto the bump stops. Investment in lowering knuckles from Mike Satur or B&G is a very sensible modification, as this means that the hydragas pressure can be restored to standard specs (approx 400 psi) - and the ride will dramatically improve.
Rob Bell

My advice is to get the MGR dealer to pump it up a little higher than you want as it will be different by the time you get home. You can then get it to the desired height by letting a little fluid out of each side. Do a couple of mm at a time and measure it as you do it to try and keep both sides even as you lower it. This also saves you going too far and having to go back to the dealer to pump it up again so you can start again. This must be done on reasonably flat even ground, as per the instructions.
Tony Escort Driver

Though if you're used to lowering cars by changing the springs and shocks, spending £85 on a set of lowering knuckles is hardly going to break the bank?

Try an independant Metro specialist to get the hydragas pumped up cheaply. Rover will charge you through the nose!

Leigh
Leigh

so how many lowering knuckles do i need and where do they go? sorry to appear clueless.

Gary.
Gary

I once went to a Rover dealer to get the car pumped up. I showed them how to do it and did most of the work myself, all the guy did was pump the handle a couple of times. The whole thing took about 10 minutes for which I was charged 100 NLG (about 30 quid). When I complained about the price they told me I was paying for the gas.

The only gas in the hydragas system is in the sealed domes on each hydragas unit, all they can do is add or remove add hydragas fluid (basically water and antifreeze). I explained this but they still charged me 30 quid.

The most annoying part is not the price but the fact they so easily lie to punters on the basis that joe public knows no better (in theory). I never went to that dealer again and I never will. My theory is that the daealers only pump the car up as a revenue generator.
Tony Escort Driver

Gary, you need four. They sit between the hydras sphere and the upper wishbone.

More info @ http://www.mgf.ultimatemg.com/mgf_suspension.htm and on Dieter's page http://www.mgfcar.de
Rob Bell

to be presise...
Look at http://www.mgfcar.de/lowering1/index.htm

The page needs corection regarding lowering options.
I think after getting more experiance now that cutting the hydragas ally cylinder shorter by 7 to 8mm may do the same job.
Question is then how to get the aluminum parts off and back to the lower diaphragma.
http://www.mgfcar.de/cut_unit/index.htm

Dieter
Dieter K.

The aluminum part is this one.
http://www.mgfcar.de/cut_unit/dk_piston_1954.jpg

(2B cut on the left)
Dieter K.

Mike Satur does the set of 4 for around £85. He'll also fit 'em for another £65 (ex vat I think).

Hopefully someone come up with a before - after picture of their car without and with the lowering knuckles so you can see the difference!

Leigh
Leigh

>> Should get more feedback on this thread when the Treffeners are back from touring Europe! <<

You called? ;-)

Four ways to lower the car:

1/ Depressurise the Hyragas spheres.
Pros are: Free! Looks great, easy DIY job.
Cons are: Poor ride quality, potential to do damage to Hydragas Spheres over time, if too much fluid is removed, need to take the car to a specialist to get it pumped back up.

2/ Lowering knuckles.
Pros are: Relitively inexpensive, looks great, maintians Hydragas pressure so no loss of ride comfort, lower C of G gives better handling.
Cons are: Not really a DIY job (can be done, but is tricky)

3/ Lowering knuckles & shocks.
Pros are: As 2/ above, but also stiffer dampers reduce body roll making the car corner faster.
Cons are: As 2/ above plus should also do shock mounting plates as original mountings have been known to crack. Also, shocks will make the ride firmer, depending on which shocks you go for, ride quality may suffer a little.

4/ Lowering knuckles, shocks and independant Hydragas spheres (the Techspeed 'full nipple job!')
Pros are: as 3/ above plus making the Hydragas spheres independant allows full control over the ride height at each wheel. This is a car that can be set up to suit an individual driver's requirements easily. Also is less likley to nose dive under heavy braking.
Cons are: As 3/ above and pricey.

-----------

Scarlet has the third option along with powerflex poly bushes and Mike Satur's camber adjustable rear tie bars. IMO the full nipple job is only really worth it if you intend doing a lot of track stuff, as the only real benefit is a little less pitching and the ability to set it up absolutely perfectly.

HTH

SF
Scarlet Fever

SF:

How low does option 2 and 3 take the car around 300mm, and how much do they cost?

TIA.
Chris

Personally I would not take the car down to 300mm as I believe that it would make the car undrivable on most roads. If you have to negotiate a speed bump at this height you will not have enough ground clearance. I would say 330mm is practically the lowest you could go for urban road use. Personally I would go no lower than 340mm for normal everyday use.
Tony Escort Driver

NEVER EVER lower than 340 if have speed humps - the car will be undrivable as you will always be bottoming out. Whatever pleasure you get out of the better looks and handling will be completely swamped by the gut wrenching feeling of the car running aground all the time!

The voice of experience!

Cheers

Patrick
Patrick Beet

Ive just lowered my F to 340. I havent YET noticed a significant difference in the ability to absorb bumps. Aside from the fact that I ended up with fluid in my face due to a mis-placed jam jar!! I am very happy with the look, and would be inclined to say that it handles a little better (in the dry anyway).

I did notice that the mud flaps scrape a little when going down carpark ramps, but that doesnt bother me too much.


Roger.
Roger

Roger...
happened to me too lol

at that point I decided it was low enough.

Ian
R925BWU
Ian

Personally I just used a rag to cover the valve as I let some fluid out. And yes on the first squirt I nearly got it in the eye.
Tony Escort Driver

on the first squirt I nearly got it in the eye.

Was that from a male or female escort.

Do you make a living driving these male/female escorts,I bet you end up in some right seedy joints.
Rob

>How low does option 2 and 3 take the car around 300mm, and how much do they cost?

325mm is really the minimum with modified knuckles alone. The hydragas units need standard 400psi and going lower then approximate 340psi will result in the bottoming out inside the units. They don't work any more. Bump stops required in any way to prevent the hydragas unit fixture brackets from dents.

If you wanna *whyever* go lower, then modified gas shocks with stiffened shafts will be required.

Looks like this then ;)
http://www.mgfcar.de/mike.enders/web_Image30.jpg
http://www.mgfcar.de/mike.enders/
Not my car !

Cheers
Dieter
Dieter Koennecke

330 mm is about the practical limit of lowering - which coincides with the height that Dieter mentions with the lowering knuckles. IT IS HIGHLY ADVISIBLE NOT TO GO THIS LOW BY LOWERING HYDRAGAS PRESSURE ALONE. This is a point well worth stressing.

310mm is painful, even with knuckles. Been there, done that, got the T-shirt ;o)
Rob Bell

Interesting article in "Car mechanics" October issue on lowering the suspension. Worth a read if you are considering this option.
Mike.
mike

As standard, measured vertiaccaly at the front wheels from centre to underside of wheel arch the car should be 368mm +/- 10mm

Lowering knuckles reduce this by up to 30mm, making the ride height 338 +/- 10mm.

It is not recommended (for the reasons given above) to go any lower than 320mm as below this level the Hydragas spheres are underpressurised. Scarlet is about as low as she will go at the moment, 325mm (400 psi int he spheres). This is due to the TSW Blade wheels, which have a greater offset from the hub. If i go any lower than this the wheels bang the underside of the wheel arches (causing the dents i have in my rear wings - ouch!) This is the primary reason why my Spax adjustable shocks are stiffened to the max.

Am thinking about pumping the suspension up say 10mm ready for the winter in the next couple of months, she will loose most of this height as the weather draws in a the temperature drops.

SF
Scarlet Fever

I'm not sure there is any benefit in lowering an F, a local VVC owner runs some very fast times at the local hill-climb. He has found that he is just as quick at the standard height as when lowered and has a comfortable ride to and from the circuit as a bonus!

Some may like the look of a lowered car but the increased risk of damage to the nose-cone & suspension needs to be considered,

Cheers

Alan
alan mackew

>I'm not sure there is any benefit in lowering an F, a local VVC owner runs some very fast times at the local hill-climb. He has found that he is just as quick at the standard height as when lowered and has a comfortable ride to and from the circuit as a bonus!

You can say that when your dealer returns your car in 4x4 mode.....
Tony Escort Driver

Benefits of lowering your F:

Improved looks.
Reduction in instability at motorway speeds
Lower C of G = better handling (providing Hydragas is at normal pressure)

Drawbacks of lowering your F:

Speed humps and potholes need to be negotiated with care.
Potential for increased inner rim tyre wear (can be sorted out through correct tracking settings though).

To date i hvae been driving a lowered MGF since mid 1997, approx 60,000 miles and have had no real problems other than wear and tear. You as a driver just need to be a little bit more aware of your ground clearance that's all.

SF
SF

>>I'm not sure there is any benefit in lowering an F, a local VVC owner runs some very fast times at the local hill-climb. He has found that he is just as quick at the standard height as when lowered and has a comfortable ride to and from the circuit as a bonus!<<

I found similar when I had the car lowered on pressure alone. Much better now with lowering knuckles :o)
Rob Bell

This thread was discussed between 09/09/2002 and 19/09/2002

MG MGF Technical index

This thread is from the archives. Join the live MG MGF Technical BBS now