Torsion bar rear suspension
Turbo Mini Forums

Seeing how PaulH has relocated the doughnuts on his autotest car has got me thinking about alternative rear suspension options.

A number of OEMs use torsion bar rear suspension, Peugeot for instance. The bars sit in a rear subframe, mounted transversely across the car. The Beetle has torsion bar front suspension with a single bar fixed in the middle. The Jag E-type has longtudinal front torsion bars.

A coil spring is a torsion bar afterall, just wound into a coil.

Has anyone ever tried this on a Mini?

I just thought that a rear beam type arrangement could be made to accomodate a centrally fixed torsion bar within modified radius arms.....

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

what jumps to mind paul is the spring rate on a currently available setup may be much too high , i suppose one could slim down the bar with a grinder ..

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I was thinking about just using a bit of spring steel.

http://springsteelstrip.co.uk/2010/03/21/s...ring-steel-bar/

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

ahh i see , what , and then cut a spline on the end with your mill ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Haven't got that far yet !

It would need some way of fixing to the radius arm and an external bearing. Plus some height adjustment.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

What you don't get with a torsion bar is variable rate.

Well not unless you could get a straight piece of tapered round section like the variable rate coils springs are wound from :)

Schrödinger's cat - so which one am I ???

sounds heavy......

"Cars are a lifetime of pain"

I guess the question to ask is why have car makers done it in the first place? The original morris minor and then the marina had torsion springs with rotary shocks, perhaps we should look into that.

As far as I can workout it is mainly done for space. A torsion between the radius arm reduces intrusion to the rear, but then Issigonis managed this already on the mini.

What are your reasons for thinking about it. The main disadvantage I can think of is where is the exhaust going to go?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

It could be lighter than a standard rear beam setup.

What concerns me is putting all the rear suspension loads onto the healboard.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I have two vehicles with torsion bars, both are flawed in my opinion

No 1, the Shogun has longitudinal torsion bars to the front wishbones which provide front springing.
Flawed as this gives them quite limited articulation.
Good due to nice independant front suspension and thus decent road manners.

No 2, the 205 GTI.
Rear beam assembly using 3 torsion bars, two splined and fixed at one end, splined in the trailing arm at the other. One connected to both trailing arms as the anti roll bar.
Flawed due to the limited articulation, and massive weight transfer forward on lift off, giving rise to many cars backwards in hedges due to lift off oversteer. Also the beam is a heavy lump for what it achieves.
Good due to lift off oversteer!

Thanks Tom,

I wasn't really thinking about going around corners. Are the 205s problems more related to trying to drive a shopping car too fast? :)

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

No, the 205's problems are mainly due to people with insufficient testicles and/or judgement lifting off mid corner....

OK, I'll add large gonads to the design brief. :)

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

more power required to over come the bigger balls, bigger balls required to cope with more power......

maybe thats what the passenger seat is for?

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

You didn't Veg no. Did I mention I've bought my 3rd?

Turbomini's 205 owners club :)

im positive someone fitted an ax rear beam (same as saxo/106) to a mini on the 16vminiclub. i just cant for the life of me remmeber who.. tbo though i cant see any advantage over a rear beam with light radius arms. pretty sure a 106 rear beam is comparible in weight to a mini rear subby. they aint exactly light, cast iron radius arms and all.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

was it? lol thats an old build!! just had a search and the 16vminiclub only goes back to '05 and "mivic" was built around the time of the old 16vmini guest book as i recall. so cant find any pics!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I dont see how it could be lighter, ally beam and home brew arms surely mated with some coilovers it will be miles lighter than a beam, or are you thinking of a beam more like the current honda civic (not 2kc) with a beam springs and dampers also like the 307?

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I'm not thinking of using anything from another car, just using a fabricated rear beam and replacing coil overs with torsion bars. Shocks would be mounted as usual.

I could use the standard radius arms but it may be easier to fabricate some new arms to facilitate fixing of the bars, then I could make them semi-trailing as well :)

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."