What Dampers With Uprated Torsion Bars

[welshpug 1,657]

Is anyone else wanting/needing bars? that we could persuade 309pug to do a batch?

 

best ask Chris first before getting peoples hopes up !

 

I could be interested in some for my ZX.

[dobboy 231 2 Cars]

I've spoken to the guy who makes bars.

 

He say's if I can give him the holy grail of the spec, he can price and make accordingly.

 

Just now he uses 25.5mm bar, cuts the splines, and then turns the bar down. Then finally heat treats the ends only.

 

He makes about 50 sets of bars a year for various cars, and never had any issues, however highlighted that he doesn't know what the cars were used for.... road, rallying etc etc.

 

He's up for making them to any requirements, if I can give him all the info he needs....metal spec/heat treatments etc.

[dobboy 231 2 Cars]

here's a starter for ten

 

http://forum.205gtidrivers.com/index.php?app=core&module=attach&section=attach&attach_id=5619

[dobboy 231 2 Cars]

best ask Chris first before getting peoples hopes up !

 

I could be interested in some for my ZX.

 

Maybe, but I thought it would be better to say 5, 10, whatever, amount of people confirm they want bars, will you make them please?..... assuming we can get a hold of him.

[S@m 156]

I'd be in for a group buy on TBs (probably 21mm), depending on price and provided they are to the standard of 309PUG's bars.

 

Just now he uses 25.5mm bar, cuts the splines, and then turns the bar down. Then finally heat treats the ends only.

 

Just out of interest, as i said i know little on the subject, but why heat treat the ends only?

[dobboy 231 2 Cars]

I'd be in for a group buy on TBs (probably 21mm), depending on price and provided they are to the standard of 309PUG's bars.

 

 

Just out of interest, as i said i know little on the subject, but why heat treat the ends only?

I don't know tbh. Maybe because he considers the bar/metal he buys already heat treated? and heats the ends just to harden the splines?

[dobboy 231 2 Cars]

Heat treatments

 

http://www.meritheattreatment.co.uk/metal-treatments.htm

 

 

You know the guns that they have in scrap metal recyclists, are they capable of showing precise metal make up?

[dobboy 231 2 Cars]

Well little bit of an update.

 

I wnet to the local machine shop with the drawing and asked if it was possible for them to make them.

 

Guy (who i know) say's to use 24T, he says he could do everything except cut the splines, he say's it's quite specialist (£15k bolt on bit of kit for his machine). The heat treatment could also be done locally for around £150 for 4 or 5 sets, although he was a bit concerned what it would do to the bars i.e buckle them etc. He also knows where to get splines done.

 

Told him other costs i've had and he said prob just buy a set already done by the time i've paid everyone.

 

Aw well.

[Tom Fenton 1,542]

I know what Chris uses, and it's not EN24T.

[S@m 156]

This is turning into a "COME BACK CHRIS!!!" topic.

[dobboy 231 2 Cars]

I know what Chris uses, and it's not EN24T.

Maybe not, but without knowing exactly what Pug Sport use i'm relying on people who have more knowledge about it than me.

 

Is it a secret what Chris uses?

This is turning into a "COME BACK CHRIS!!!" topic.

It would save me a lot of hassle ....and money!

[petert 588]

Attached is a stress-strain diagram for 3140. Not really a suitable material for torsion bars, but one which increases strength by heat treating. The slope of the elastic limit line is the same, the Modulus of Elasticity, as that's very similar for all steels, at approx 203-210GPa. However, you can see how the elastic limit is approx. twice as high in the hardened sample (sorry it's imperial units). Put simply, it can now take twice as much stress before entering the plastic deformation range.

 

Hardening just the ends is pointless, as the entire bar experiences the same torsional load along its length. As the middle is smaller in diameter than the ends, it will fail there first.

 

Here is a link for EN25, detailing properties and suggested uses. Data sheets for other high tensile steels can be found at the same site. I've only ever used 4340 however.

 

http://www.interlloy.com.au/our-products/high-tensile-steels/en25-high-tensile-steel/

 

Notice that its 0.2% proof stress increases from 635MPa to 1125MPa with suitable heat treatment.

 

Hardening torsion bars is difficult and expensive because they bend like bananas if not handled correctly.

 

I always supply the female ends (cut from trailing arms) when getting torsion bars made. This ensures the company has to supply the correct product.