What Dampers With Uprated Torsion Bars

[dobboy 231 2 Cars]

I'm thinking of uprating my rear torsion bars to 21mm to try prevent the squat I get. I don't mind how the car handles at the minute as i'm beginning to play with the LOOS, (that I assume I have on tap because of my standard bars.)

 

Just now I have:

 

Front - fairly new 205GTI Bilstein B4's on Eibach Pro (-30mm)

 

Rear - fairly new Xsara Bilstein B4's, solid mounted/lowered beam

 

 

After reading various threads it seems an uprated damper is recommended when uprated bars are used?

 

A few questions.

 

1. How would the back end behave if I never upgraded the rear dampers for the time being?

2. If I was to upgrade the rear shockers to GrpN in association with the bigger bars, would I need to upgrade my front shockers also?

 

TIA

[welshpug 1,656]

I've found that Bilstein 205 Gravel work well with 21mm bars on the road.

[dobboy 231 2 Cars]

I've found that Bilstein 205 Gravel work well with 21mm bars on the road.

Thanks for the reply WP.

 

I take it the Bilstein Gravel, are the GrpN/Challenge shocks like this:

 

http://www.peterlloydrallying.co.uk/index.php?route=product/product&path=130&product_id=890

 

 

How would the car behave with different spec shockers on the back; I assume by uprating the torsion bars to 21mm i'm getting closer to matching the back spring rate? to suit my Eibachs on the front, but if I then uprate the shockers on the back only, would I imbalance it again making the front feel soft?

 

 

TIA

[Anthony 1,002]

Might be worth trying the dampers you've already got, as top spec Xsara's (ie VTS) came with 21mm bars as standard (along with obviously being a much heavier sprung mass for the damper to control) so the damper probably should theoretically be up to the job. I've never personally tried them though!

 

If you find the damping a bit lacking, then something like Bilstein Challenge spec should do the job nicely - I've run those on 20 to 22mm bars in the past and they worked well, certainly firm but still retaining sufficient compliance/comfort for the road.

[welshpug 1,656]

no, not those ones, but I can't remember the part number!

 

damping on those is 350/200, the ones I've used I'm sure is 360/250.

[allanallen 528 2 Cars]

I preferred the grpA (2313), I reckon the grpN will be ok on a road car, not enough rebound damping in my experience.

[dobboy 231 2 Cars]

Might be worth trying the dampers you've already got, as top spec Xsara's (ie VTS) came with 21mm bars as standard (along with obviously being a much heavier sprung mass for the damper to control) so the damper probably should theoretically be up to the job. I've never personally tried them though!

 

If you find the damping a bit lacking, then something like Bilstein Challenge spec should do the job nicely - I've run those on 20 to 22mm bars in the past and they worked well, certainly firm but still retaining sufficient compliance/comfort for the road.

 

Yeah Anthony, it is the VTS ones I've got. I think i'll try what I've got as you say and take it from there.

 

Just need to find bars now.

[dobboy 231 2 Cars]

Got a price today for two 21mm bars.....£440 delivered ...gulp!

 

Can anyone suggest anywhere i can try get a price from?

[allanallen 528 2 Cars]

Where was that from?

[dobboy 231 2 Cars]

Allan, i best not say in case i've picked him up wrong

 

He said 220 each, maybe he was meaning a pair?

 

Will call them to clarify today.

[welshpug 1,656]

there seems to be two price points, 220 a pair and 220 each, from different sources.

 

im not so sure on the quality or processes the cheaper ones are up to the job, as theres never seemed to be a straight conclusive answer as to what they do to them and why they are so much cheaper, whereas the more expensive manufacturers have supplied peugeot sport and ive never heard of any issues.

Edited August 12, 2015 by welshpug

[dobboy 231 2 Cars]

Thanks WP, are you saying the cheaper ones are up to the job (but missed a comma?^)

 

I think i would try them as i'm only on the road with an occasional track day, it's not as though i'm battering it through a forrest every weekend.

 

Who supplies/manufactures them (that doesn't pop up high on google)?

 

I'm a bit reluctant to phone this guy back in case i offend him! Lol

[allanallen 528 2 Cars]

Cheap ones with un disclosed manufacture process

http://www.torsionperformance.com

 

Not sure where you'd buy the other ones online? It's Chris penrose off here that used to do them.

[dobboy 231 2 Cars]

Phoned them (torsion performance), and it is indeed 220 each delivered. Guy was nice enough and wasn't offended at all ????

[dobboy 231 2 Cars]

Thanks Allan, yeah it was them i tried.

 

Pug1off might be an option as i can reclaim the dreaded at £290 + vat a pair.

Edited August 12, 2015 by dobboy

[allanallen 528 2 Cars]

Haha! 220 each! Wtf? Avoid those then. I believe pug1off supply the same bars for less?!

 

http://www.peugeot-tuning-parts.co.uk/205-torsion-bars-bar-peugeot-gti-suspension.html

[dobboy 231 2 Cars]

Yeah, it doesn't really make sense does it?

[welshpug 1,656]

Haha! 220 each! Wtf? Avoid those then. I believe pug1off supply the same bars for less?!

 

http://www.peugeot-tuning-parts.co.uk/205-torsion-bars-bar-peugeot-gti-suspension.html

 

 

not a lot less, £365 delivered.

[allanallen 528 2 Cars]

 

 

not a lot less, £365 delivered.

We're not all on rock star wages! £75 is a decent lump of money as far as I'm concerned!

[dobboy 231 2 Cars]

I can wangle the VAT so I get them for £302 delivered.... which is a bit better.

 

Now I've came across this:

 

It's the Youngs modulus, not the tensile strength (as asked in a later post) that decides the spring rate. And the Youngs modulus is about the same in all steel. So, the spring rate (wheel rate) is almost solely dependent on bar diameter when using steel/spring steel (somewhat lower rates on 309 or 306 beams) :

 

 

Short Swedish dicitonary; stavdiameter = bar diameter, hjulkonstant = wheel rate (spring rate at contact patch).

 

 

If my springs are 70/200 progressive (read on here somewhere), should I be looking at the 21mm or 22mm bars? or would the 22mm's definitely be too much of a load for my current dampers (Xsara VTS B4's)

[welshpug 1,656]

what springs do you have?

[dobboy 231 2 Cars]

Eibach Pro (-30mm)

[allanallen 528 2 Cars]

I'd go 21s with those front springs and fit some more manly rear dampers

[Anthony 1,002]

22mm bars are going to be a bit stiff for a typical lowering spring IMO. You'll really need a stiffer spring up front for torsion bars that thick, which doesn't leave you many options if you're not going coilover - that I can think of you've really you've only got Kamracing 155lb springs or PLR 180lb springs (but they're quite high)

 

To be honest, even 21's are probably a touch stiff for something like Eibach's but they should work OK.

 

And yes, I think 22mm bars would be asking an awful lot of the Xsara B4 dampers - you might find that they're not great with the 21mm bars but given that you've already got them then you don't have anything to lose beyond 30 minutes swapping them over.

 

Also, are you sure that it wasn't £220 for each pair of torsion bars, as they're not the sort of thing you'd typically buy singularly? They used to be in that ballpark for a pair so either you got the wrong end of the stick or they've massively increased their prices in the last year or so.

[allanallen 528 2 Cars]

That's what I thought Anthony! I paid £200 for a pair a few years back and material prices haven't rocketed since.