suspension

[steve4063]

so i've been reading throiugh various posts. anmd not really had my question answered.

if you uprate the suspension ie put telescopic on for instance do you need to keep the torsion bars or can you do away with them.

i ask because my saloon is missing them completely for some reason. and the spare trav that i want to do mup with bigger engine and really upgrade has got some on so if i don't need them i'll whip them off that if i don't need them.

thanks steve

[dunketh]

Torsion bars and dampers are two different things.
Think of the torsion bars as springs and the dampers as, well, dampers.

If you fit 'coil over' dampers then yes, you can do without the torsion bars as the springs are wrapped around the damper - like the McPherson strut system used in say a Ford escort.

If you just fit a tele damper 'kit' from ESM or the like you will need torsion bars.
The tele dampers merely replace the lever arm dampers that mount to the box section under the bonnet. (although in most cases you need to leave the lever arm ones connected too as they form the top suspension link)

[steve4063]

"Think of the torsion bars as springs and the dampers as, well, dampers"

true and very helpful i hadn't thought of it like that.
i suppose if i got rid of the torsion i'd have all sorts of problems with all the rest of the steering arms and uprights etc.

is there much difference betyween buying second hand units from a supplier and just using a second hand one from a car.

i don't suppose there's anything they can do to refurb them apart from new bushes which i always change anyway.

i'm asking because there's a set on ebay which ends pretty soon which would be brill becaus ei obviously need them now and at present they're on £4.99 only trouble is its west london area.
but as i go to suffolk regularly i could do a detour on the way back.

[dunketh]

Are you referring to 2nd hand torsion bars?
If so I'd imagine the metal would stretch with age but that can be taken up with adjustment. You'd basically fit them to the car, lower the car off the jack and look at the ride height.
You would have to repeat this process until you were happy you had enough suspension travel. I'm sure theres a proper figure somewhere about how far away the wheels have to be from the arches, that sort of thing, but I dont know what it is.

As for dampers, I'd only buy them new.

[ricombi]

Remember with torsion bars, its adviseable to fit them back onto the car from the side they came off, as they will have "worn" differently depending on which side of the car they have been on originally, due to going round roundabouts the same way all there life, driver being on one side etc.

If you have a Haynes manual for the car, this will give you some dimensions of how to set the torsion bars to give correct, standard ride height. Even better, if you have one, a BMC (I think its BMC anyway) workshop manual, which is in a lever arch file, gives more accurate dimensions. I'll try and dig my copy out and get some of those dimensions on here ASAP if it helps.

[alex_holden]

[steve4063]

thanks for that Alex

[bmcecosse]

The torsion bars ARE the springs - very clever design - spreads the loads around the chassis. To do away with them is a fairly major engineering exercise - and to no good avail! Torsion bars were (still are) used on many cars - notably the E type Jaguar! They are an excellent means of providing suspension with the advantage of built-in height adjustment. Not many cars have that !

[jonathon]

'....and to no good avail!' on what are you basing this statement BM. How many coil-overed minors have you driven? May I suggest that you at least have some experience of what you are talking about before you make such ridiculous statements.

[bmcecosse]

Because the coil overs I have seen are still linear rated springs - so no difference to linear rated torsion bars! The standard bars are perfectly capable of handling the weight of the car. The suspension geometry is far from ideal of course but that's a different matter - it may be coil over kits have better geometry - but that's not what is being discussed here. The use of a torsion bar as the spring is a GOOD idea!

[downsey]

I agree with BM, the torsion bars have huge advantages such as there load spreading and adjustability. For the average minor owner, torsion bars are fine in my opinion and unless geometry is refined i dont see any drastic handling improvement with coils.

[jonathon]

Can we please try and understand that I do not think that the torsion bars are useless and need to be replaced on every minor,they are a good design. I have said that they were 'no good', yet some members on this forum wish to intimate that I have.
From our experience the cars we have fitted with our systems, coils front and turreted/radius arms rear, the handling is vastly improved. Its not just to do with the action of the spring and its rate but more to do with kingpin location. We run an A arm which creates a superior mount for the kingpin, with easy adjustments for camber KPI and caster, these are not quite as simple to perform on the standard set up.
We have been working with Koni over the last year to develop a bespoke coil over unit with different pre loads, and the difference has improved an already good set up.
Remember opinions can only be founded on 'actual' experience, if not then they are illfounded and serve no purpose for advise to others.

[paul.kissick]

Remember opinions can only be founded on 'actual' experience, if not then they are illfounded and serve no purpose for advise to others.

True there is no substitute for exprience.

[bmcecosse]

Ahh - but all that ^^^^^ is suspension geometry improvements which of course will be well worth having (especially on the rear axle) - but the 'coil spring' as a springing medium is no better than a 'torsion bar' - which Izzy clevery fitted to save space and to spread the suspension loads into the centre of the chassis. And that's what was being discussed here!

[jonathon]

Sorry to drag this out, but we set the front suspension up as per standard settings, and then dial in only 11/2 degrees of neg camber. Its driver choice as to caster angles and style of driving and in what environment.
To set the record straight and deal with the original question, if the car is standard then they are perfectly adequate when allied to a good quality gas/oil damper system. Yes you do need to keep the torsion bars.
If modifying or wishing to improve the front end then In my opinion the uprated torsion bars are flawed by a choppy ride which can unsettle the rear of the car, not what you want on a twisty road, which is why we developed the wide A arm coil overs which although a similar spring rate to the torsion bars offer a more compliant ride, add into the equation a good damper setting and infinate set up possibilities then the coil overs pay dividens, in terms of physical grip and excellent turn in od medium to fast corners. Track experience translates very well to road use in offering the best possible control and cornering properties, especially on engine modified cars. We had a track 2dr saloon fitted with a Fiat TC and our rear end set up and a standard torsion bar/damper upgrade at the front. Fitting the coil overs reduced his lap time by 3 seconds on his first outing, improving even more as the settings were more refined. Before you say that this has no relevance to road road use, think, if its good on the track it'll be more than adequate on the road even on standard powered cars. Its not compulsory afterall that these cars are modified, so if one's making a choice please lets do it out of an aquired knowledge rather that a pre deliction for inane argument and bigotry.

[minor_hickup]

So what set up do you use on the rear Jonathon? Is it a 5 bar link setup with turreted coil overs?

[jonathon]

The ultimate system for the rear is a four link with Watts linkage, or a panhard rod, using Avo 21/2" coil overs and 200lbs springs. This incorporates full adjustment for both wheel center distance and 4 wheel alignment. By havind 4 adjustable parallel arms this allows the angle of the diff to be altered for different motorsport activities. The coil overs are long travel with masses of adjustment on the coil over itself and its mounting. This allows for the adjustment of corner weights in setting up the car correctly for either road or track.
We have run the coil over fronts with a turreted rear end on standard leaf springs and triangulated radius arms, which works very well but can be compromised by the additional control and grip of the front end , hence the development of the coiled over rear which redresses the balance, and provides a very stable and balanced system.
Note, although these systems can be best exploited on the track they offer the normal road user a different dimension to road handling, which enhances the already excellent balance of the original car.
Several of our customers have had this system anf the stage 1 kit fitted to a standard minor before the engine upgrades were performed, and reveled in the new control, only to have this level raised again once the power was increased to upto 200bhp and corresponding dynamics.

[minor_hickup]

Blimey, sounds like to dogs to me. How long does it take to develop a system like that?

[jonathon]

Well it does work well, but has taken about 7 years between the release of the front coil kit and us having time and resorces to finally develop the rear kits. As they now stand, I don't think we'll need to do much more apart from fine tweeking. Pop over and I'll take you for a spin!!

[minor_hickup]

Don't tempt me, I'll probably apply for a loan the next day!