Recommended Torsion Bars - Multi-use Car

[boombang 2]

Have asked about this before but regarding a 309 beam.

 

Now back to a 205 beam on my car and trying to work out what setup to go for.

 

Few people I know run 21mm and happy with it, say they wouldn't want to go harder. The old build manual recommended 23mm for tarmac and 20mm for forest.

Up front have 225lb springs on Gaz gold coilovers, so easy enough to change. Gaz gold on rear too.

Have bought an uprated ARB but would only put it in for track (24mm), figure it a bit on the tough side for road and rally where want the suspension to do the work.

 

Car once on the road will be mainly used for weekend fun, but was originally built for tarmac rallying. Idea is for 6 months prove it on road and track, sort the niggles, then do a few events next year.

 

Thanks in advance

[Anthony 1,003]

How smooth is the surface on a typical tarmac rally - are we talking airfield quality here, or alot rougher with significantly broken, rutted, and stepped concrete/tarmac?

 

I've built a few 205 beams for people with uprated torsion bars, and found even 24/25mm TB's are fine for the road (with a little respect needed in the wet) and work very well on track. They don't however, seem to deal very well with broken and stepped surfaces, and if you're likely to encounter that on a regular basis, I'd run softer TB's and then use a stiffer ARB on the smooth racetrack - I had 22mm TB's on my own 205 for a fair while, and that was happy whatever I threw at it - trackdays, rutted farm tracks, snow - just about everything really.

 

21mm would be a little on the soft side in my opinion.

[welshpug 1,657]

usually airfield, but often including the bits around the sides so sometimes rough but not excessively so.

 

 

I think how far you can go depends on how manly your dampers are, i.e if you want man sized rear bars you need a Proflex sized wallet, or at least a proflex type hole in the wallet

 

don't forget to balance what you have on the rear with the front spring rate

[boombang 2]

If I were going for 21mm at the rear, would definately look at reducing front spring rate - don't want to end up with a spongy sloppy thing though.

 

Way I prefer to drive on smooth tracks has always been to do majority of steering on throttle and let rear end carry car round corners.

 

Some of the surfaces are rough on rallies, some smooth - pretty much pot luck tbh, but as there is no maintenance on most of these venues, they are getting worse. By the time the car is eventually ready I doubt there'll be any venues that haven't been shut down!

 

Do recall a while back someone changing out 22mm bars for 21mm for a rallycar, but wondering if that was used out on gravel/forest type stuff rather than tarmac.

 

At the end of the day can always swap back to standard bars for the odd rough event, and keep the car stiffer for road and track use. Just deciding what bars to go for is so tough, given the somewhat massive cost of them. The last 205 Gti I sold (a decent nick non-sunny 1.9) was around same amount of money...

[Tom Fenton 1,542]

I've got 23mm bars in my 205 (309 beam), I was expecting to be really very harsh, but in actual fact it is really quite acceptable for road use, also means you can steer the car from the rear to some extent as well. Only mod I need to make is a thicker rear ARB to compliment it now.

[Baz 421]

Tbh i reckon about 21 is about as big as you'd want to go for an all-rounder.

[James_R 3]

You'll never be able to have the right bar size for the right venue, merely the least worst all the time, I think you've hit the nail on the head with the idea of swapping back to std bars for rough evens and having bars eering on the stiffer end of the spectrum the rest of the time.

 

Also you can leave the bigger ARB in the rear with std bars to give it a bit more firmness than usual but not overly so.

 

I'd be with tom and be looking at 23mm bars in that case, and then have a 22 and 25mm ARB to go with it. then you have 19 and 23mm TB's and 19,22,25ARB's to swap as you need to alter the car

 

I don't evny you though, it's hard trying to strike a balance, where as going the no compramise route is easy lol.

[SPGTi 2]

I suppose road rallying gives a very multi surface use . I run Bilstein forest inserts with 9" 185lb springs up front and std at the back with bilstein tarmac dampers. I also have a Quaife diff up front. This setup works well for me on smooth fast tarmac roughish c roads and very rough whites. Ontrack it is also Ok with little body roll and LOO on demand.

 

Steve

[boombang 2]

All good stuff! I interesting to hear from people who've gone harder rather than hear-say you usually get.

 

My thinking is that majority of modern(+ish) rally cars running rear springs go for similar or higher to up front. You watch people getting into a WRC car and it barely moves - they cope fine with the harshest of stages.

 

Just because Pugs have torsion bar setup and inevitably expensive to upgrade, a fair few just uprate dampers to compensate. I've always felt this was wrong, and indeed my favourite setup I've driven was my 309 Gti with a seized rear axle. Obviously wouldn't want to drive that on anything rough, but probably gives an idea of my driving style.

 

What always seemed odd to me was my 106 Gti. That was on standard torsion bars and yet never felt under-sprung on the rear. Every 205 I've driven has done.

[welshpug 1,657]

106 uses a far larger ARB than a 205 does, 24mm!

[Rich_p 23]

That should be a 25mm bar you have there Alex, not 24.

[shalmaneser 26]

This is interesting stuff; can someone confirm the sizes of a 309 rear beam as standard?

[Rich_p 23]

a 309 has 20mm tb's & arb as standard.

 

I have 25's to go on mine once the front shocks are revalved to allow for the front springs I'll need to match - should prove interesting

[boombang 2]

My mistake on the bar Rich!

 

Given that the 106 runs a thicker ARB and I've always prefered the way they handle, sounds ike it might be ideal for me - especially given the fact that even when on the road the car won't be hitting any rally stages for some time.

[feb 47]

I am very happy with the phase II SBC setup which I believe uses 21mm ARBs, not sure of size or torsion bars. The car is very progressive even on the wet, it's a perfect setup for an everyday/ocassional trackday car IMHO.

[boombang 2]

Mine is only a toy, would be used on occassional weekend blast on the roads, but I never push that hard on public highway.

 

I'm eering still on side of caution and thinking of 22mm bars with the 25mm ARB for dry track with option of dropping to standard ARB if very wet or broken surface.

 

Car also runs 309 arms and a Quaife LSD, solid mounts etc.

[philfingers 5]

my ex tarmac car came with 21mm TBs and 23mm ARB. For road rallying I went back to std. It's more composed on the bumpy roads and more forgiving when the road tightens unexpectedly. Whilst it may not be ultimately the 'quickest' setup it's forgiving, the back follows the front and i don't worry about it doing it own thing. Rest of car is PTS gravel at the front, with PTS gravel rear dampers

 

Phil

[feb 47]

I might have got it the other way round, 21mm torsion bars but not sure of the size of ARBs.

[boombang 2]

Right, looking to order bars soon, wanted to open the thread back up for comments.

 

Everything I've read from the 205's from back in the day says 23mm, most people I know who compete run 21mm and IMHO feels soft & very much like a road car.

 

Toss up is 22mm and 23mm. Liking the idea of 25mm ARB for track/circuit, then option of swapping down if doing a rough rally (likely to be next summer maybe?).

[welshpug 1,657]

knew I should have been cheeky and checked what size bars were on the cars out in Belgium, one difference though, they spend as much on just rear dampers as your complete suspension setup, if not more!

 

It seems they all spend a fair bit on dampers even at the lowest level as its the key to controlling the springs on the jittery bits and staying out of the ditches.

 

might be out again very soon, will see if I can find out

Edited September 30, 2009 by welshpug

[boombang 2]

It isn't the amount you spend on dampers, it's how they work that counts.

 

With the adjustables being two way, hoping can make them compliment whatever I use far better than fixed rate Billies. I know you can get Billies re-valved, but you can't tweak them once on the car, or adjust for conditions.

 

Reports from people I know running the Gaz Gold are very good, no matter what bars they've put in.

[welshpug 1,657]

agreed, but they tend to go hand in hand if you spend 4 figures on rear dampers alone

[petert 588]

All this talk of bar diameters is a bit irrelevant if you have a cage, as it has a major effect on rigidity. A quality cage with 21mm bars is a great setup, and better than 23mm and no cage.

[boombang 2]

Car is caged and 99% of seams stitched welded.

[Rippthrough 98]

It isn't the amount you spend on dampers, it's how they work that counts.

 

With the adjustables being two way, hoping can make them compliment whatever I use far better than fixed rate Billies. I know you can get Billies re-valved, but you can't tweak them once on the car, or adjust for conditions.

 

Reports from people I know running the Gaz Gold are very good, no matter what bars they've put in.

 

 

Even the fanciest 4 way dampers can't fully compensate for the wrong internal valving to start with though, so get them valved for what you intend to use from the off so they can get them as close as possible.