Independant Rear Suspension

[aCe 0]

After my little Eurotrip with the car i managed to pick a few floors with my car, i found under extreme conering and braking that it would cock one of the rear wheels loosing me grip over all.

 

I'm now keen and committed to creating and making a independant rear suspension set up to overcome this poroblem and the skitting motions produced mid conering from the FRB and RARB.

 

I'm thinking 205/309 rear wish bones mounted on a space frame with a solid mounted hub or at least attacthed to the wishbone to eliminate bump steer, with turrets like thirdtimeluckys (box section) in the car.

 

I would be iterested in peoples feedback and if any one knows of any other peugeot models with independant rear suspension that i can steal parts from.

Edited May 12, 2009 by aCe

[Rippthrough 98]

They're already independent on the rear, it's a torsion bar system, not a torsion beam.

 

Most FWD's will cock the rear wheel under heavy cornering, even the ones running double wishbone rear ends, try some stiffer rear springs/arb or a soft rear arb if you don't like it.

[aCe 0]

Would it be benifical then to remove the RARB and go for stiffer torsion bars(as obviouslt they don't have springs) would this prevent it? I was under the assumption of a Mccpherson strut type being more active and responsive than the standard rear beam set up?

[Rippthrough 98]

It would reduce it somewhat, but you'd want to uprate the front at the same time, it's the diagonal weight transfer that's causing it, so the front corner needs to come up.

 

Even then, there'll still be bugger all weight on the wheel even if it is in contact with the road...

[AdamP 0]

Cocking a rear wheel isn't necessarily a bad thing, it just shows that the inside rear is completely unloaded. On a FWD car that isn't where you need the grip, famous jeremy clarkson quote 'the rear wheels are just there to stop the sparks'. Most of the quick FWD hatches I've seen cock a rear wheel at every opportunity.

[aCe 0]

I can't help but think the rear set up at the moment can be massively improved with a single wishbone mccpherson setup.

 

I understand about the diagnol weight but no matterhow little weight there is on the back if its not in contact its useless!

 

Also Jermey Clarkson doesn't claim to be a race driver or understand all the priniciples he just gets in car and tests/reports on what he likes

[Rippthrough 98]

If there's no weight there it can't generate grip anyway...

[BERTMAN 40 1 Cars]

cocking a rear wheel is a charachteristic you will find with any good handling FF car

[aCe 0]

Also i am thinking of the adjustablility factor- with the normal setup you have zero adjustment that can be made where as with a mccpherson setup toe camber and castor become adjustable.

 

I understand the principles of upgrading the torsion bars and maybe changing the rear arms but everything becomes non adjuastable and therfore you loose out on what you can tune your car too especially quickly!

 

"cocking a rear wheel is a charachteristic you will find with any good handling FF car" Reasons???????????

 

I'm not claiming to be a guru and alot more people surley know the answers?

 

Also is it possible to run a rear beam without an ARB (i beleive the base models fdon't - if so how do the arms saty in /)?

Edited May 12, 2009 by aCe

[Rippthrough 98]

You wouldn't be able to adjust castor on the rear, and if you did fit a Mcpherson strut setup straight off the front of another car and welded it in place, the roll centres would be all over the place, unless you were very, very lucky, it'd handle like a greased pig.

[pug_ham 242 3 Cars]

You can get a kit from Skip Browns that allows you to adjust the rear camber but I can't remember if it also allows you to adjust the castor but is that strictly worth while at the back.

 

Different radius arms give different toe & camber settings but changing this requires machining & bespoke stub axles to be made, Martin (crf450) has done a few of these for the 306 to fit to his race car.

lso is it possible to run a rear beam without an ARB (i beleive the base models don't - if so how do the arms saty in /)?

Some of the base models do run without a rear arb, the beam is held together by the torsion bar stud & nut on the tube end & the torx bolt / offset washer at the radius arm end.

 

The arb has nothing to do with holding the beam together, the bolts at each end are just there to connect it to the radius arms.

 

Graham.

[aCe 0]

Ok cool thanks for that graham i was under the impression the brackets that go into them help but obviously that cant be the case if its not there.

 

Yes castor on the rear wouldn't matter that much as long as the wishbone and strut were aligned rigght so that the travel was optimised. I have seen heard of those kits but its just totaly non adjustable and therefore you can't adjust them until it feels right

[Tom Fenton 1,526]

I don't understand what you are trying to achieve here? In good fettle a 205 GTI is a good handling car and is widely believed to be so by lots of folk. With carefully thought out suspension mods it is a very good handling car. With badly thought out suspension mods or knackered components it can become a pig.

 

Which of the above does you car currently fit into?

[VisaGTi16v 1]

Cough Visa GTi cough....

[aCe 0]

It handle ok as its currently on Gaz coilovers at the front with 280lb springs and poly bushed all round, I just want the same amount of control the front coilovers gives me but on the rear.

 

I'm planning on running the front with 309 bottom arms and shafts with eccentric top mounts. I'm just a little concerned that all the work at the front will be worthless without having the same level of control at the rear

[DrSarty 90 1 Cars]

I'm planning on running the front with 309 bottom arms and shafts with eccentric top mounts. I'm just a little concerned that all the work at the front will be worthless without having the same level of control at the rear

 

*Places cat amongst pigeons.*

 

Are you possibly trying James to achieve something which is not possible with a 205...and furthermore will you be creating something which stops the car being a 205? In other words removing a set of characteristics which are what 'we' like about it?

 

P.S. The same question is relevant with what I'm doing with Project Sarty phase II, but I just wanted to see what you'd say.

Edited May 12, 2009 by DrSarty

[taylorspug 7]

*Places cat amongst pigeons.*

 

Are you possibly trying James to achieve something which is not possible with a 205...and furthermore will you be creating something which stops the car being a 205? In other words removing a set of characteristics which are what 'we' like about it?

 

P.S. The same question is relevant with what I'm doing with Project Sarty phase II, but I just wanted to see what you'd say.

 

This is pretty much the way i see it, and why i wont be using anything like a fully independant rear setup on my car. Even though i see the torsion bar setup has downfalls if you ditch it IMO its not a 205 anymore.

 

280lb springs are a bit hard with a standard rear setup aswell.

[Batfink 201]

just go to colin satchell, slap your cash down and use his rear suspension setup. You will gain more damper control, but you will still cock a wheel.

I'd suggest the reality really is you just need bigger torsion bars and antirollbars on the rear to bring the suspension up to spec compared to the front spring rate....

[AdamP 0]

Also Jermey Clarkson doesn't claim to be a race driver or understand all the priniciples he just gets in car and tests/reports on what he likes

 

I realise this, it's just one of the few things he's said that has an element of truth about it

[aCe 0]

I want to remove my ARB's after finding out at the ring that if i hit a bump in midcorner on one side, it would upset the other side and cuase the front to skit across the track! I will be running my front 100% without ARB once i change the springs, arms and mounts also it would be so benificial once set up correctly.

 

I do understand peoples worries regarding the characteristics but i just want to update the system to improve it for harder handling (and drive faster), it was probably only ever desgined as a beam unit to keep the costs down and ease of production, it doesn't mean it was the best way!

 

Richard it is possible as it would be a very simular setup to pauls minus the diff etc, i'm not to concerned on it charcteristics i just want it to corner as effeicently as possible

[Batfink 201]

I dont understand why you would want to ditch the rear antirollbar or the front for that matter- neither are a problem. Infact for track use it could be argued they are too small! The front possibly can be removed. Try it and see if you like it, though you then push a lot of stability control onto the springs so may have to run stiffer to compensate.

I seriously think you need to look at what has been tried and tested rather than trying to reinvent the wheel. There are plenty of people here with fast road, trackday and racecars with fantastic handling.

My racecar is pretty much bespoke and I'm not getting rid of the trailing arm/beam setup as I dont think theres any real advantage. My only plan is to run trailing arms without a beam sometime in the future.

For a FWD car most of your concern should be at the front. Run nice and wide to help weight transfer and decent shocks/coilovers and an LSD will help transform a car.

Edited May 12, 2009 by Batfink

[aCe 0]

I'm against the ARB due to it linking one corner to another, this means that if one side hits a bump the other side also gets effected. A far as im aware and i could be wrong but race cars don't use them?

[swordfish210 20]

A far as im aware and i could be wrong but race cars don't use them?

 

Every race car i've ever seen uses an anti roll bar. I do a bit of mechanicing for a 306 racing in the Castle Combe Saloon championship. Last season it had no anti roll bars and it was putting in fairly average performances but this season it has both front and rear roll bars fitted and it's 2 seconds a lap quicker on tyres that are pretty hard now after being left outside all winter...and the track was pretty manky at the last meeting. Now to me that proves that ARB's are useful.

[DrSarty 90 1 Cars]

Fascinating thread.

 

I've seen James drive (as have a few others), and produce overall performance from a 1.6 that I simply never thought possible.

 

I could be showing my niaivity here, however I know James (aCe) certainly has some credibility in this field from a practical, on road/track point of view.

 

Whilst his suggestions may well be proven ultimately wrong, it's this kind of driven, pushing the envelope style of thinking that makes us collectively achieve great things. This guy's either a potential motorsport driving champ or a suspension/handling tactition...trust me on this.

[Batfink 201]

by all means come up with new ideas but when you are wrong you have to change to something else and listen to the advise being given.

There are people on this forum with a lot of racing experience (and successful too) in a number of disciplines, from Colin satchell (hillclimb, sprints), Miles (circuit racing), Paul from Xsport races frontwheel drive cars (circuit) and the team down there have built championship winning cars as i'm sure many who are a little quieter. All are heavily involved in the building of their cars too so they are seriously worth their salt with their knowledge. The trick is to not start at the bottom of the knowledge ladder but to watch what other people do and build on that.

Edited May 12, 2009 by Batfink