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adrenaline
07-04-2008, 08:14 PM
OK,

I intend to seriously upgrade the power in the back of my Nova, so it might be an idea to improve the steering as I gather the beetle steering box is not exactly the best, especially with its' unequal length steering arms.....

What do you guys (and gals) do or recommend.....??

Spacenut
08-04-2008, 07:30 AM
Hi Carl - well, rack and pinion obviously, although opinion is divided as to what rack to use. If you are going to stick with the Beetle front beam, my recommendation would be for a rack from a FWD hatch with McPherson strut suspension. This gives the closest approximation to the Beetle suspension geometry. The Beetle steering uprights are front steer so you will need a front steer rack (or worst-case, a LHD rack mounted upside down - Reliant did it successfully on the Scimitar, so there is precedent).

Strut steering racks come with a sliding central sleeve with very long equal-length track rods either side. This minimises the bump-steer problem on the Beetle beam, although the problem can never be eradicated from this type of suspension.

Most Novas suffer from poor scrub radius geometry, mainly because owners fit large offset wheels to compensate for the narrow Beetle track. This gives a fearsome kick back through the steering which is waaaaay worse than the bump-steer effect. For this reason, many people have fitted more conventional long-rack/short track rod systems and found considerable improvements in directivity and feel just from that. Dave (Islandman) Skinner has fitted this type of rack and is quite happy with it. David Iles recommended a Metro rack, but he worked for BL so there may have been some bias there. Other racks that have been used are Triumph Dolomite (but without the associated height/reach adjustable column? How strange...) and Ford Escort, but just about anything is possible. There has been a lot of recent discussion about electric assist columns off Vauxhall Corsas, but there seems little need for power steering in a lightweight rear-engined car.

Because I have a double wishbone set-up I have used a Cortina rack, but I wouldn't recommend it for a Nova application as it is relatively low-geared (although you can get quick-racks for it) and the Cortina uprights have a very poor scrub radius geometry so even though I have zero bump-steer and have a conservative wheel and tyre combination (185/65 on 15" rims, ET16), I still get a lot of kick-back (so much so I have engineered a steering damper using a VW Bus damper and custom alloy clamps - I took my cue from the Lamborghini Miura, which had the same problem, so I am at least in exalted company :D).

So the choice is yours - good luck with whatever you decide to do!

Lauren

adrenaline
08-04-2008, 04:03 PM
Lauren,

Thanks for a very in-depth reply.......

I have a few questions that immediately spring to mind......

I have never driven a Nova so have no idea what the requirements are regarding the strength needed to drive one. I am however a bit of a croc as I broke my back a few years ago and am now held together with a pile of titanium.....I worry that I may be woth most if weighed in for scrap value..... :laugh: :laugh:

Just how heavy is the steering on a Nova and is pursuing power steering worthwhile......

I appreciate that if this is the case then the column from theCorsa is probably the easiest solution as it is the column that is powered rather than the rack and with an after-market adjuster can be 'fooled' into working by mimicking the speed inputs that the column relies on from the original Corsa to change the amount of assistance.......

I have bought a Mondeo ST24 as the donor car for my Nova......the engine runs a dream and sounds gorgeous even in the donor, so I can't wait to hear it on short pipes.....I must admit my initial thoughts were to 'incorporate' some parts from this......the power steering pump for instance is very compact and attached to the block....and the steering wheel assembly has all the switchgear and radio controls.....anyway.....

Fitting a steering damper seems to be a good idea......but doesn't the original beetle steering incorporate one...?? On a steering rack presumably you would use one from something like an off-roader as they generally have steering dampers fitted due to the nature of where they are driven....??

Carl

Alzax3
08-04-2008, 08:06 PM
How Novas are to drive is largely dependent on the size of tyres you go for and the diameter of steering wheel your cockpit can accommodate. If you have the original huge American bias-belted tyres, and a ten or twelve inch steering wheel - the car is not going to be fun to park. However, once you get it moving, even with that sort of set-up, steering is a care-free, one finger job, as the car is so light. This is why there is a running debate about power steering: is it worth going to all the trouble of fitting a system that will only be useful for low speed manoeuvring?

Yes the original Beetle system incorporates a damper (and you will notice the need for it if it's knackered!)

adrenaline
08-04-2008, 08:28 PM
...thanks....I appreciate that once moving most cars don't 'need' power steering.....but they all need parking sometime so with that in mind I think I may need to incorporate power steering....I suppose the only debate is how to go about it.....

I know the Corsa powered column is a favoured option but most 'vendors' have caught on to the versatility of this system and prices that they go for reflect this......another system I may consider is an electric pump system with a powered rack.....as I am going to have to change the rack....to minimise bump steer amongst other things.....this would keep any hydraulic runs to a minimum length...using a belt powered pump,attached to the engine, the runs would have to be the entire length of the car.....twice..........mind you one of my lads works for Coleman Hydraulics so sourcing the pipe for the runs wouldn't be too dificult.....

Big Birds Car
08-04-2008, 10:09 PM
Corsa's aren't the only power steering columns, I think some of the MG's/rovers are as well. Renault have an electric set up on a couple of their cars also, however I am no help right this moment as I can't recall the particular models but have a friend that works for Renault UK that could tell me if needed.
I myself would fit power steering and a rack if I had the time but will use the stock set up for now as if I keep changing my mind I will never get the car done.
I would possibly try to use the set up you have from the donor car as then you will know what spares/parts to get in the future, likewise I would utilise the braking system if you could as you will have abs etc. If it stops the donor car you can bet it will stop a lightweight Nova, would need to fabricate caliper mounts and the like but nothing too complicated. Also use the donor's wiring loom if it hasn't been butchered, that way you know the wires can be traced from a proper wiring diagram.
The reason I suggest this route is because I am currently building another kit which is a one donor car system and it is far easier than the Nova where everything is from different cars or ideas.
Finally do all yor planning now and try to stick to it as changes make for a really long build and I'm not the only one who has found this out on this site.
Good luck.

vpogv
09-04-2008, 12:46 AM
Do most take the plunge for a different steering rack when they swap the steering column? For example Nic just got a camaro column I do believe, is he now forced to change the box out or is now the best time to do so?

CyCo
09-04-2008, 02:21 AM
I've read about a few people on both sides of the pond using mkI VW Golf/Rabbit rack & pinion steering racks. I was thinking of going this way myself at some stage, so what do people think about using the Golf/Rabbit bits?

letterman7
09-04-2008, 02:23 AM
Any column other than a VW is going to have to be modified to fit the box's shaft. I swapped into a Fiero column on my car, and sourced a double jointed steering extension from a Porsche 911. I can't remember exactly what the fittings were...I know the box side had a splined cup which fit almost exactly over the VW shaft (secured with a drilled through hardened bolt), and the column side was a non-splined cup. I think what I wound up doing was fitting a short piece of pipe that fit into the cup (again, secured by drilling through the cup and pipe and inserting a bolt) and inserting the other end over the D portion of the steering shaft. That portion was welded into place. The nice feature on the Porsche unit is that it is a telescoping unit, so I was able to position my steering column exactly where I needed it.

MicksRedNova
09-04-2008, 07:35 AM
I was recently looking at a Ford Focus column in the breakers yard (someone on the forum suggested it). It has both rake (up/down) and reach (in/out) adjustment with short multi-knuckle shaft and short control stalks that will probably work well in the Nova (with modification to match steering box/rack end). I think the Mondeo is similar.

I didn't get one because they didn't have one with all the bits on (already plundered by others) but suggested the whole thing from wheel to rack link would be about 60, which seemed OK. I will keep a look out and do intend to change sometime in the future.

Mick

Spacenut
09-04-2008, 07:36 AM
Hi Carl - interfacing different columns to the steering gear is relatively straightforward, but does obviously require quality welding!

I'm using a Rover SD1 column (height and reach adjustable, with lights, wipers, blink/toot/flash all on stalks), but a Ford Cortina rack and obviously the splines don't match. I have a Ford spline in a sleeve welded to the base of the Rover column so that I can use a standard Group 4 Escort UJ.

Alex is right, with a typical 10" wheel and wide front tyres, steering can be heavy. If you sort the seating position out you should be able to increase this to 12" easily, maybe 14". This will significantly reduce the steering effort required. I wouldn't recommend a 4WD steering damper, they are too big and heavy duty. I used a VW Bus damper (Brazilian, COFAP) instead of the Beetle unit because it has eyelets at both ends (the Beetle one has a "hook" on one end, which is difficult to interface).

So what's the solution to parking? Narrower tyres help, but they compromise the looks. No problem, offset the wheels. That puts the scrub radius up, increasing kick-back. Reduce caster angles? From what I can gather the Beetle caster angles are minimal anyway. You could try some negative caster, but this will lead to high speed instability (wandering) as well as making the steering lighter at slow speeds.

My recommendation would be to replace the VW beam suspension with something better, but I would say that, wouldn't I? But it really is the best solution in my view. If you are going to stick with the VW beam, I would certainly change the steering to rack & pinion (use the Mundane-o rack by all means, you could rig up an electric assist that only cuts in at parking speeds and the rest of the time revel in the ultra-quick ratios that power racks have!), and go for a conservative wheel and tyre choice (minimal offset, no more than 205mm section at the front). Dial in some negative camber by using higher-offset top trailing arm eccentrics, adjust for full inboard, and if the caster is negative or not positive enough (I would say you need at least +5 for a lightweight rear engined car, although +3 is probably OK), slip in a set of caster adjustment shims under the lower front beam. All these parts are available through custom VW outlets.

The negative camber should cause the tyres to exert more contact pressure on the inside of the tread, closer to the steering axis, making low speed manouvres less strenuous!

BBC is correct, use as much as you can from any one donor, it makes life a lot easier. Just be careful with ABS - it may be tuned to a specific weight/weight bias (the classic lowered XR3 problem comes to mind), so be careful! If you adapt the servo-assist (you might have to fit a remote servo), you should have more than enough Whoa! Just adjust the brake balance as there will be far too much effort on the front wheels in a Nova application.

Good luck!

Lauren

Big Birds Car
09-04-2008, 07:43 AM
I have used a Sierra Saffire column which comes with all the switches for the wipers and lights etc. (again from the same car that donated the engine and complete wiring loom, unfortunately not adjustable in anyway :cry: ) I modified the bottom end to match up to the flexi disc of the VW box, works ok and all the column surround fits nicely with the new dash I've made so looks far better than the original VW column that was there.
Only issue I have is trying to wire up the horn in the centre of the steering wheel. the issue is I've fitted a quick release system so the wheel can be removed for a bit of added security. (don't think big bird will have a problem getting in and out with the wheel in place, I might if she lets me drive it that is :laugh: ), but there is no provision in the mechanism to add wires so might end up with a push button on the side somewhere.

Spacenut
09-04-2008, 11:38 AM
Yes, that would be a problem with a quick release wheel. Running the horn wire through the centre of the column is never a very nice idea (think how much winding and unwinding it suffers with 3+ turns lock-to-lock), but if there is no provision for a horn switch on the stalks there's not much more you can do!

I did notice that rally cars have foot-operated horn switches (usually by the navigator, but its one possible solution). My Barracuda had the rare optional "rimblow" steering wheel, where you squeeze any part of the inner rim and the horn operates. Obviously after 35 years of abuse the contact strip had been ripped out so a long stalk operated panel switch was fitted under the dash. It was one of those momentary toggle switches with a 4" paddle extension...

Until I perfected my (slightly ungainly its true) entry and egress procedure, I found that the column stalks were very vulnerable to damage, although that was mainly during the build phase. I got a replacement set of SD1 stalks with a serviceable shroud which I will get round to fitting eventually. The big plus is that it is a pre-'78 set, so the indicators are on the right of the column (I had to make do with a post-'78 set before so all of the graphics are upside down)

Lauren

Kym
09-04-2008, 12:04 PM
In Australia you are not allowed to weld steering components. I ran a subaru column with a VW box. Many steering universals are the same size so quite often using the yoke from the column then finding a yoke to suit your box and connect the yokes via either a resurrected uni or buy and fit a new Uni joint or keep the flexible connector off the original VW set up and get a shaft made to go from the uni off the column to the flexible connector which is what I did. I made my shaft up on my milling machine.

Kym

Mr Whippy
10-04-2008, 11:18 PM
You will find that there's not actually much wrong with the original VW steering box setup itself, the problems with bump steer & the like are more usually down to forcing the VW components to adapt to the Nova design without due consideration of how VW designed it to work.

IMHO, if you have a beetle floorpan based Nova, with Beetle torsion bar front end, you might as well keep the VW steering setup and concentrate your "modding" energies into other areas, like engine tuning and disc brakes.

If you're going down the "tube frame chassis" route, then yes, you might as well get a R & P setup.

The problem with using the VW steering box in the Nova, is that because the Nova has a very low rake steering column, you have to angle the steering box downwards to line up with it. This causes the steering arm to drop lower than standard, which means that the track rods will have an upwards slope towards the wheels when the weight is on the car. This is what upsets the steering geometry as VW designed it, and gives you bump steer. Stock height Beetles (or KG's) don't have bump steer.

So - what you need to do is either - turn the track rod ends around on the stub axles (mount the track rods from underneath instead of on top at the stub axle end)
OR - Put one or two UJ's into the steering column so that you can run the steering box at the correct VW angle and still have the steering column sitting at the right angle to suit the Nova body.

I went for the second option - Here - http://myweb.tiscali.co.uk/newlancsvwclub/Nova_Pages/Nova_Pages_page0004.html
If you want to go for the first option there's several VW tuning outlets that sell "bump steer" kits that allow you to reverse the track rod ends. (VW owners run into the same "bump steer" issues as Nova drivers, not because they move the steering column but because the cars are often radically lowered, which gives you the same net steering problem - angled track rods.

When the car is on the ground with fuel and driver, the track rods should be as close to parallel with the ground as possible to avoid bump steer.

BTW - the technique of removing torsion rods from the front beam to lower the suspension is very "70's - Man. !" It makes the suspension soft and saggy. Fitting beam adjusters is the modern way to lower (or raise) a VW front end. Replacement beams are available with the adjusters ready welded in, or you can cut the beam and weld them in yourself.

Useful link - http://www.vwspeedshop.com/store/home.php?cat=334

adrenaline
11-04-2008, 12:24 AM
Mr Whippy,

thanks for the info......can't get enough info/advice/ideas/suggestions........

Carl

Spacenut
15-04-2008, 08:14 AM
I would say that steering kick-back from large offset wheels has the biggest influence on Nova steering. The bump-steer contribution is secondary to this, but it is always there.

This is because the VW front suspension uses trailing arms, which describe a radius as they move in one plane, while the track rods describe an arc in a conflicting plane. Because the track rods are of unequal length, the effect will always be worst on the side with the shortest track rod, i.e. the driver's side. So the car will tend to veer to the right (for RHD cars) if both trailing arms move the same amount on each side. If just the right hand wheel hits a bump, you can rest assured that the effect will be worse than for the equivalent left hand wheel. This translates into instability, and it only gets worse with increasing speed.

In a way, the Nova partly compensates for this failing (which is a feature of this design shared only with old Morgans and the Lancia Aurelia which both had the equally-flawed "sliding pillar" suspension), by having virtually no front suspension travel due to the springs being too stiff for the lightweight body. Whether you consider this a virtue or a curse is up to you, but that is the way it is. Nova cars attempted to compensate by specifying softer shocks (Armstrong Red Max originally), but this cannot compensate for the sky-high spring rates. The ideal solution is softer springs which provide better grip especially on rough surfaces (modern roads unfortunately :( ), together with minimal scrub radius (maybe 0.5" positive) and optimum (zero bump-steer) steering geometry. Everything else is compromise.

By contrast the rear suspension is too soft, as it was designed for a saloon car and now has the extra burden of the fuel tank (front mounted on Beetles) and the occupants sat where the rear seats were. The mis-matched spring rates cause the car to skip about at the front, and wallow at the back, often hitting the bump stops, resulting in a need to increase the rear static ride height until you get the characteristic "Funny Car" stance.

I agree with Mr Whippy that the VW set-up can be made to perform adequately in most cases, but Carl is considering fitting a powerful V6 engine to his Nova which could show up most of the above failings in quick succession (plus the inevitable steering play around the straight-ahead position common to all manual steering boxes of the worm-and-roller type). If he's got the necessary finances in place to do the job properly, why take the risk?

Lauren