Lancia Beta Forum

Technical stuff => Steering => Topic started by: squiglyzigly on January 16, 2021, 10:45:47 PM



Title: Electric power steering on a Beta
Post by: squiglyzigly on January 16, 2021, 10:45:47 PM
Heavy steering is the only thing I donít love about my Berlina. Itís a wonderful drive until you slow down or heaven forbid, wish to manoeuvre into a parking space.
Since putting the Berlina on the road tin 2020 it became apparent that using it as a daily runner in London was going to require me to get down the gym or come up with a way for the car to help me out.
What with gyms being closed due to lockdown (result) I decided to see if it was doable to fit some kind of electric power steering. Now from the off I should declare where I sit with modern car electric steering debate. I HATE THEM. But there are not many options are there? Hydraulic power steering on a Berlina. High parts cost and lots and lots of work put me off of this.
So I done some internet reading and made a hasty eBay purchase or two based on the theory of ďwell if it canít be done or I donít like it then it goes in the bin and £100 worth of spares wonít be the most stupid thing Iíve triedĒ.
So this is where it began. . . .




Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 16, 2021, 10:59:23 PM
The electric column is from a 2008 Toyota Prius. My reasoning was that Uber Prius drivers clock up starship Millage and every Uber driver I speak too has never had a problem with the steering. Then they are cheap and plentiful in the breakers yards. Judging by the driving standard of the average Uber driver I get, I think I know why the breakers yards are full of smashed Priusís (whatís the plural for Prius).

And most importantly, when used with its matching steering control module, its a 3 wire installation! ! !
That sold it to me on what is essentially an experiment to pass some furlough time.
When you connect the control module to permanent live, earth and ignition live, the steering module looks for the main body computer which is of course hundreds of miles away and then after about 5 seconds it simply powers up in ďsafe modeĒ. This is a mid ground assistance level.

So the picture is the starting point of stripping a beta upper column and opening up the Prius column to find it is very nicely made with two half shafts in the upper column. Very useful I thought.



Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 16, 2021, 11:42:17 PM
Onto the precision job of dummying the column under the dash. Carried out with tie wraps and a cardboard tube. What can go wrong? It confirmed that there is very little space even after cutting a gusset into the pedal box to get it up high enough to retain the original rake of the old unit and also to not get in the way of your feet. It then becomes apparent that due to the extra length of the Prius column due to the bulk of the motor the lower link shaft with the two UJís will now go straight through the clutch pedal.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 16, 2021, 11:44:57 PM
So the clutch pedal gets a swan neck and onto cutting the mounting brackets off of a spare column to weld onto the new unit.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 16, 2021, 11:49:45 PM
Brackets transferred over so time to bolt it up under the dash and move onto the lower steering shaft to see if this project is a waste of time or wether it can fit.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:04:50 AM
Lower steering shaft was a case of using the nicely made Toyota shaft upper plus UJ and welding the beta lower UJ to the nice sliding shaft that came as part of the Toyota piece. This was very useful in my view because the shortened lower shaft was now going to be running at more of an angle than before and I had concerns of the shaft pushing and pulling a little as the UJ rotated. So the sliding spline shaft design (collapsible crash design?) would happily take up any slack.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:29:14 AM
Then to make the Toyota upper shaft into a Beta fitment. Transferring the steering lock barrel and welding the Beta steering wheel shaft Ďintoí the Toyota shaft. Lady Luck made this easy to weld straight and true. The cut off piece of beta shaft was an interference fit into the cut down Toyota shaft so it welded up without any heat distortion trying to make it a banana. Then a 1mm thick sleeve and a circlip groove (cut with a dremel and finished with needle file) to fit the original bearing meant the power steering assembly was now Beta fit.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:29:53 AM
Finished upper half shaft. Beta steering lock barrel and upper shaft grafted to Prius upper half shaft and bearing.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:32:01 AM
New power column ready to fit. Almost looks normal.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:35:15 AM
Then to the simple job of 3 wires and a module. With the original factory brackets trimmed off, the compact box found a new home in the corner of the dashboard.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 12:43:14 AM
Wiring done, column bolted in, just put the clocks back and time for a test drive  ;D


Title: Re: Electric power steering on a Beta
Post by: WestonE on January 17, 2021, 09:11:26 AM
Impressive work and creativity. I am looking forward to hearing how the test drive goes!

Eric


Title: Re: Electric power steering on a Beta
Post by: peteracs on January 17, 2021, 10:06:36 AM
Hi

Yep, very impressed with the end fit, I also hope the end result is a good one. This is going to be an ongoing need I think. I was surprised you managed to fit that large motor which sticks out of column hidden away so well!

Is there any adjustment to sensitivity on this system?

Peter


Title: Re: Electric power steering on a Beta
Post by: betabuoy on January 17, 2021, 10:55:20 AM
Hi Ian

This is edge-of-the-seat stuff and we certainly need to keep you in furlow to see it through! Terrific work and hugely interesting.

Chris


Title: Re: Electric power steering on a Beta
Post by: frankxhv773t on January 17, 2021, 11:52:24 AM
My daughter's Yaris has Toyota electric power steering and I hated it compared to the hydraulic power steering on a previous Yaris my wife had. I felt there was a lack of connection between steering inputs and response.  I'm inured to it now so you do get used to it. That said, your installation is a masterful piece of work so I'll be interested to see how it turns out. As a solution to heavy steering for town driving it seems an elegant solution.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 01:55:51 PM
Good morning chaps,
Thanks for your interest and kind words. I hope this helps some of you decide if itís worth the effort and Iím always happy to share what Iíve learnt.

Well itís had its shakedown and in short, itís staying.
Itís not without fault but then it never could be. For me it was always going to be an experiment to see if it could be done and if the positives outweigh the negatives.
Iíll try to give my first impressions before I forget them as I think itís always important to be able to refer back to them at a later date as more thoughts and feelings come to light. And Iím happy to share this project for a long as I donít bore everyone to death.

This morning was a nice bright chilly start and the roads are a mix of dryish but slippery winter roads which is a nervous way to start a test which will inevitably end up with me pushing my luck. First up, reversing out of the garage and 3 point turn to get out of the cul-du-sac which is a bit busy with strewn Alfaís and a VX coupe (guilty mílud). The Berlina passed the obstacle course with consumate ease winding from lock to lock and enabling me to control the steering with an air of grandeur in front of the neighbours instead of the usual red face, tugging at the wheel and lifting my backside off of the seat. First notable negative as you pull away is very little or no self centering of the wheel. So thatís the first question ĎĎcan that be improved?í
Then along the wiggly drive to the main road and Iím liking my new found steering muscles. Itís a big positive. The strange thing to note immediately is that this doesnít feel modern and I think this may be due to the fact that it is still running a Berlina 3.8 turns lock to lock rack. Second question Ďtime for a coupe rack and possibly a smaller wooden Nardi steering wheel to quicken it up?í
Then off onto the main road and trundling along at 30mph and the car just feels 90% the same. The steering inputs are the same and the gentle change in direction is the same, it just feels like someone has maybe put an updated steering damper on the rack. Not in a heavy way because you now have assistance but its a kind of plush feel. Positive not negative.

Then out onto the A21 and weíre up to 40-50mph and I wind my senses up incase something unusual happens and I need to react sharpish. Iíve put a switch on the dashboard so that I can power the unit down immediately if things get a bit lively. But thereís not much to add. To answer Peters question Ďthis has no variable assistance provisioní so Iím worried the faster I go the less suitable the modification will be. But no, itís working fine and still steers  90% the car it was. This must be to do with the torque sensors in the shaft not being pulled on by the driver. Little input request equals little assistance given. I guess???

So the bravado is rising and the dual carriageway is up ahead with national speed limits to explore.
Road opens up and itís time to let the tweaked 2.0 trot on. The dual carriageway is uphill, gently sweeping into a downhill with a large roundabout to finish. 90 plus and still itís not scaring me. No lightness, no nervousness, nothing in fact it feels near standard. So the damp roundabout is going to get full tilt midway round and back towards home. Winding the speed up on the big empty roundabout and with the door handles almost scraping the tarmac she gently starts to slide. Just like a standard Beta you steer, you change throttle and it does what a Beta does. But there is no feedback forced from the tarmac to the steering wheel. More questions in my head. ĎWould a dry surface change this?, would a faster ratio rack change this? Is the Berlina on its standard high rise suspension and fluffy 65 profile toyo tires ever going to give much feedback? And would a lowered stiffened coupe be better?í

The final test on the way home was planting it in 2nd gear coming off a roundabout and letting the wheels spin up in turn. Easy to control, really easy, the power steering just lets you decide which direction to choose. No torque steer. Yes a bit PlayStation but itís good to look relaxed in a 40 year old Berlina.

Hope your all still awake

Ian


Title: Re: Electric power steering on a Beta
Post by: Nigel on January 17, 2021, 02:19:46 PM
Really impressive Ian. This mod will become a go-to for many folk.

I wonder if the Coupe/HPE version has less vertical space ,and whether the pedal box etc
is in the same spot relative to the column? Questions for another day perhaps.

Compliments to you!

Nigel


Title: Re: Electric power steering on a Beta
Post by: smithymc on January 17, 2021, 04:35:38 PM
Fantastic work- in awe.


Title: Re: Electric power steering on a Beta
Post by: WestonE on January 17, 2021, 05:08:17 PM
Hi Ian  A new role in motoring writing beckons!

More significantly this is a modification with a ready market for you to earn some much needed money. Especially if you can get it to neatly fit S2FL Coupes and Spiders which probably make up the bulk of cars left on the road wanting PS. It would be great to see the effect of using a smaller steering wheel and then a Coupe rack with the large factory wheel and the far nicer Italian aftermarket smaller items. Of course playing with wider tires will also give a feel for what works well. Have you kept standard Camber and Caster?  NB adding caster could fix your self centering question mark and potentially improve turn in.

Modern cars have a lot of caster compared to our cars and rally cars have a huge amount.

I installed OE Hydraulic PS to my Beta Spider build knowing I would add 1.5 degrees Negative Camber, wider tires (195) and a Momo Competition smaller steering wheel. This was based on my experience from doing this on my previous Beta Spider and getting nicely weighted steering over the speed range.

In fact my old car in light blue with Thema wheels and PS added by me is on the 2021 Forum banner to the right of the date!

Keep up the good work and think about offering this to other owners. I believe you have a ready market.

Eric       


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 17, 2021, 06:03:16 PM
I feel I should apologise for the graphic equaliser hanging from the steering motor on a tie wrap but it and the original drivers side under dash speaker were made homeless in the making of this project. So a sound system rethink is next.
As a test run it was a short 20 miles or so and didnít include the kind of lovely B roads which most of you more northerly chaps enjoy but lockdown rules suggest I shouldnít be out for steering checks.

Nigel, I think the pedal box/adjustable steering column layout looks incredibly similar between the berlina and coupe/spider/HPE version. Iíd bet the same.  I did notice the spare column I cut about (a coupe/HPE version) was about 20mm longer. I chose to follow the dimensions of the coupe column as I feel the steering wheel is way to far forward for me to the point of banging your fingers on the windscreen every time you thank an oncoming courteous  driver for letting you through. This meant modifying some coupe column plastics to suit.
So I think mounting the motor assembly should be much the same and the module can easily have wires extended to wherever space permits.

Eric, thanks for you compliments.
Yes the car is on completely rebuilt but standard suspension. Only notable change being poly wishbone bushes.
Iím in complete agreement with the camber caster principal. Especially the caster as this is the big self-centering govenor. As front wheel drive cars naturally pull themselves straight under acceleration they run less castor, by contrast RWD cars do not. So they run big castor. And the modern fwd cars run more because they can with the PS and the advantages it brings. The Beta has very little and with the power steering available it surely is a useful avenue to explore. I probably wonít try this on the saloon as I want to keep it looking as original as I can. Special top mounts and custom wishbones really arenít for this car. Thatís what my VX is for.
But a coupe/HPE rack and smaller steering wheel are very likely although I somehow do not have a manual rack laying around. Will have to source one if anyone has one laying around.

Once I get out and about I will see how it drives on motorways and on twisty B roads.

Update to follow.

Ian



Title: Re: Electric power steering on a Beta
Post by: frankxhv773t on January 17, 2021, 09:34:23 PM
What you say about the change in feel is a good description of how I experienced the difference between hydraulic and electric in the Yaris. It'll be interesting to see what a difference further modifications to the suspension etc makes to the project. I'll not be spending any time trying to copy your findings on my daughter's Yaris but if that has to be scrapped in the future I might just be saving the steering column for my Spider.


Title: Re: Electric power steering on a Beta
Post by: betabuoy on January 17, 2021, 10:14:22 PM
Hi Ian
I do have a spare manual rack lying around. If you msg me with your address, Iíll send it down to you to play with.
Chris


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 18, 2021, 08:06:29 AM
Thanks for your offer Chris,
Let me have a dig around in the loft first. I must have one after the amount of cars Iíve stripped.
But if I fail to find one Iíll take it thanks.

All the best
Ian


Title: Re: Electric power steering on a Beta
Post by: HFStuart on January 19, 2021, 11:31:39 PM
Great piece Ian. I'm not sure it would fit a pre f/l car but as Eric says it could well do in the F/L versions.

On caster, Hillman Imps were very light at the front (obviously) and ran 8-11 deg castor to improve feel and centering.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 20, 2021, 11:44:50 AM
Great piece Ian. I'm not sure it would fit a pre f/l car but as Eric says it could well do in the F/L versions.

On caster, Hillman Imps were very light at the front (obviously) and ran 8-11 deg castor to improve feel and centering.

Iíve never owned a pre f/l, so Iím not familiar with the shape of the under dashboard layout.
I think the main snag point is the line behind the steering column pivot point. If that pivot point is roughly inline with the edge of the lower lip of the dashboard then I expect it will be doable.
That point is where the motor and gear housing bulk needs to go.

When I get time Iíll have a look under the dash of the VX to see if post f/l cars look doable just in case someone feels the urge to give it a try.

Ian


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 20, 2021, 11:56:02 AM
Hi

Yep, very impressed with the end fit, I also hope the end result is a good one. This is going to be an ongoing need I think. I was surprised you managed to fit that large motor which sticks out of column hidden away so well!

Is there any adjustment to sensitivity on this system?

Peter

Peter, Iíve done a little nosing around and further down the line I will try a few experiments to see if adjustability is a possibility. I canít find any information to suggest anyone has done it but I have a few suspicions that it maybe possible.
There is an input on pin 5 of the Prius steering module that is for speed input. I intend to play with that at some point in the future. I also suspect a module from a Yaris may work on my Prius adapted column. That has a similar feature and I believe some people have played with a potentiometer type adjustment through an eBay module. Although Iím not into fiddling with knobs whilst Iím driving I think it might be possible to give a speed input to it via a Brantz speedo cable interface. These are used for classic rally computers etc.
So maybe, just maybe there will be future upgrades to this project.

Ian



Title: Re: Electric power steering on a Beta
Post by: peteracs on January 20, 2021, 01:46:25 PM
Hi

That is interesting. I did see on one supplier of new kit that there was an option for speed input and that would make total sense if you already have a controller in place.

What make is the motor on the one you have used?

Peter


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on January 20, 2021, 02:21:42 PM
Iím not completely sure how to answer that.
The motor is Denso as is the control module but the torque sensor is made by JTEKT.
But as a complete entity I believe they Ďmayí be referred to as Koyo products.
I gather it was a joint collaboration between ĎKoyo Seikoí, Denso and Toyota to develop these steering controls so Iím not sure what you would call them singularly.

These Koyo units appear to be fitted to a good number of different manufacturers.



Title: Re: Electric power steering on a Beta
Post by: chrisc on January 21, 2021, 03:35:22 PM
Fantastic implementation, and a nice usability upgrade. I actually prefer heavier steering for some reason, my old alfasud sprint was enormously heavy - it was undoubtedly a pain sometimes, but also in my memory it's one of the fondest things I recall about the car.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on February 13, 2021, 07:57:32 PM
The electric steering project has moved on a little.
As mentioned in the first test drive the lack of self centering out of junctions and roundabouts felt a little odd and out of character. So I decided to carry on exploring in the hope of a more complete package. I decided to explore the Castor angles as previously mentioned but of course there is no built in adjustability. My chosen route was two fold as I was aiming to double the standard beta castor angle. My car measured up at 1.3 degrees n/s and 1.4 degrees o/s. (Factory spec)
With a couple of spare wishbones to hand it was time to experiment.
My plan was to cut and shut the leading edge of the wishbone where the lower ball joint bolts in and then weld up the bolts holes and ball joint hole and re-drill them all 10mm further forwards. Then slot the top suspension turrets 5mm rearward and slide the top mounts back.
To my joy I got 2.4 degrees Castor n/s and 2.5 degrees o/s.
Whilst I was down there I removed the factory positive camber and dialled in 1/2 degree of negative camber.

The third photo with the black and silver wishbone is modified next to a standard one. From under the car youíd do well to spot the 10mm modification.

Road test time.






Title: Re: Electric power steering on a Beta
Post by: WestonE on February 14, 2021, 11:30:24 AM
Hi Ian great to see more pioneering development. This is how our cars can become better in ways purists would struggle to notice. This could be built into new stronger wishbones is your testing confirms the improvements I am expecting to hear.

I have used multi hole top mounts with slides to have the scope to make adjustments like these, but because they are solid I expect a harsher ride and I am considering a firm rubber ring at the interface if I can work out how to get one made!

Looking forward to the road test results.

I wish work was not manic so I could make some progress.

Cheers

Eric


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on February 14, 2021, 10:34:25 PM
Hi Eric,
Yes I think itís the way to go to keep the original look and feel when originality is a priority.
Slotting the original top mounts 5mm was easy to disguise with a slightly larger washer.

The first 100 meters with the changes and itís obvious the castor angle increase does its job. As soon as I start to negotiate the S-bends out of the drive to get to the main road the steering is centring up of its own free will and Iím grinning like a child. It works.  But before I go any further I want to know what it feels like without the steering damper. So a quick pit-stop and damper is relaxing on the bench.
Now weíre off to B&Q for some emergency supplies and a Long way home via the A20/M25/A21 to get a full understanding of this project.
I find it difficult to quantify all of the feelings and observations but the words that keep coming to mind are that this is how it should be. Yes the steering is lightíish all of the time with minimal feedback, but then the original steering with its saloon spec 3.8 turns lock to lock was like that until the speed dropped below 15mph. And yes it feels a little different on the move, but thatís not a criticism.
Every car feels different right? I believe every beta feels different because they were all made like that for one reason or another, and they are all maintained differently with different wheels and tyres. Even a small change to front suspension toe makes a beta drive differently. Or tyre pressures.
So now Iíve made it feel different again. And Iíve decided I like it and wouldnít go back. Itís now easy to drive in town and itís as stable on the motorway as it was before. The faster you go the easier it seems to be to hold a line. Castor.
When you pull out of a side road the steering straightens up in a way that lets you slip the steering wheel through your hand but tighten your grip just a little and it stops spinning. When your navigating a large roundabout itís just the same. It straightens up but is easy to stop and turn to the other lock and take your turn.

In essence the e-steering project is all but finished. The cherry on top will be a 3.5 turns coupe/spider rack which is pencilled in for this year when I drop the drivetrain assembly for a gearbox overhaul. The faster rack will undoubtedly be slightly heavier and slightly quicker. Perfect I expect.

Today, Sunday, was my seventh straight day at work and I needed a smile. So I took the Berlina to work on the cold salt covered roads and grinned for 45 mins each way whilst listening to Ď80s greatest hitsí with one arm on the door panel. Itís an easy car to drive now.


Title: Re: Electric power steering on a Beta
Post by: WestonE on February 15, 2021, 08:42:45 AM
Inspiring and an opportunity for others to benefit. Few old car designs are so good that you can bring them bang up to date with relatively minor changes. If it was a Ford Escort you would be throwing most of the OE suspension away.

I am looking forward to hearing how the 3.5 turn rack works and if no damper is an issue longer term with sharp bumps and pot holes kicking the wheel? FYI the Monte and X19 do not have a steering damper.

Eric   


Title: Re: Electric power steering on a Beta
Post by: peteracs on February 15, 2021, 10:53:31 AM
Hi

Can I ask a simple question on the subject of castor.

I understand from reading that the larger the castor angle the more self centering, however does this also mean heavier steering, hence the current manual steering setup is a compromise on the two?

Peter


Title: Re: Electric power steering on a Beta
Post by: mangocrazy on February 15, 2021, 11:58:57 AM
Following all this with great interest. So basically it's a question of moving the ball joint mounting inwards by 10 mm? As for the suspension top mount, would something like this obviate the need to slot the top suspension turrets?

https://www.ebay.co.uk/itm/FITS-Lancia-Beta-ADJUSTABLE-TOP-MOUNT-1-pair-CMB4455-135mm-PCD/281762386123? (https://www.ebay.co.uk/itm/FITS-Lancia-Beta-ADJUSTABLE-TOP-MOUNT-1-pair-CMB4455-135mm-PCD/281762386123?)


Title: Re: Electric power steering on a Beta
Post by: peteracs on February 15, 2021, 12:12:29 PM
Hi Graham

From what I understand it is moving the ball joint forwards by 10mm and the upper mount backwards to achieve an increase in the castor angle which is the angle viewed from the side of the effective upper and lower mount points of the hub and the vertical. See

https://en.wikipedia.org/wiki/Caster_angle

The larger the angle the more centering you get is how I read it.

Peter



Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on February 15, 2021, 12:44:46 PM
Morning Eric,
I can already answer the question of torque and bump steer as Iíve deliberately asked for trouble during the drive to work on Sunday morning. It wasnít exactly difficult to find a few pot holes!
Both aspects seem to be dampened/controlled by the e-column. You can tell the wheels are fighting with the road surface but itís no drama in the driving seat.

I did notice during the work grafting the Beta and Prius columns into one, that there seemed to be some sort of steering damper effect within the gear/motor assembly. This primed me in advance to test both with and without the Beta damper fitted.
Also I did have to open up the gear housing as it was necessary to spin it 180 degrees to improve clearance under the dashboard due to the shape of the alloy casting. I couldnít see anything inside that seemed designed to give what feels like a fluid damped movement. So I assume itís simply the resistance of a large cog working against the worm drive of the motor.
Maybe itís this built in design that controls the torque/bump steer or maybe itís in the steering ecu. I really couldnít suss it out.
But the outcome is that it drives better without the damper attached. The biggest improvement is in the straight ahead to near straight area. The damper limits the self centering a little as the castor effect works less when the wheels are near straight and conversely self centering is much greater on lock with extra castor.
So this e-column conversion makes the damper unnecessary.
Iím looking forward to the 3.5 rack but that wonít be for some months yet.


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on February 15, 2021, 12:57:06 PM
Hi

Can I ask a simple question on the subject of castor.

I understand from reading that the larger the castor angle the more self centering, however does this also mean heavier steering, hence the current manual steering setup is a compromise on the two?

Peter

Hi Peter,
In a word Yes.
If you increase the castor you will get heavier steering. Without power assistance youíre going to notice it. One nice performance bonus of more castor means you get increased negative camber on lock. Very handy for cornering and also you donít have to run as much static camber. Again good because having the tyres square to the road gives maximum braking efficiency. On the Berlina with its high soft standard suspension, I expect the factory positive camber is to give a flat contact patch when the car dives under braking giving a square contact patch. This is because the wishbones push the wheel out under braking to remove the positive camber to something near zero degrees.
My knowledge on suspension design is basic so I donít know for sure why older fwd cars run less Castor but I would hazard a guess that itís a combination of reasons. Top of the list is most likely steering weight. 


Title: Re: Electric power steering on a Beta
Post by: squiglyzigly on February 15, 2021, 01:05:42 PM
Following all this with great interest. So basically it's a question of moving the ball joint mounting inwards by 10 mm? As for the suspension top mount, would something like this obviate the need to slot the top suspension turrets?

https://www.ebay.co.uk/itm/FITS-Lancia-Beta-ADJUSTABLE-TOP-MOUNT-1-pair-CMB4455-135mm-PCD/281762386123? (https://www.ebay.co.uk/itm/FITS-Lancia-Beta-ADJUSTABLE-TOP-MOUNT-1-pair-CMB4455-135mm-PCD/281762386123?)

Hi Graham,
Yes those top mounts are designed to allow you to increase castor and or camber. I didnít want to go down that path because a) it wonít look remotely original on the Berlina and b) the ride quality, noise and vibration is again something I didnít want on the Berlina.
However horses for courses, I have got top mounts similar to these on the VX coupe. (Some group 2 escort mounts that I modified)

Also the ball joint position question is as Peter said. The ball joint moves to the front of the car.

Should I post a picture of the slotted top turret on the Berlina?


Title: Re: Electric power steering on a Beta
Post by: WestonE on February 15, 2021, 01:53:02 PM
Hi Graham

I am using that sort of multi - point adjustable top mount with a central bearing, but I went for the version that has a slide in the center so it can be fine adjusted when it comes to set up with 4 wheel alignment kit. I am nervous about whether I also need to put a hard rubber damper ring between the mount and the body shell to damp harshness. However with the excellent damping in the Gaz Gold coil overs I am using it might not be needed.

Eric
   


Title: Re: Electric power steering on a Beta
Post by: peteracs on February 15, 2021, 03:07:10 PM
Thanks for the update, you sparked a subject which I have thought needed to be aired and resolved. The top mounts which are currently available from memory have not had a good reputation for reliability. It would be interesting to explore actually having a batch of top mounts made especially if they can be made at sensible price by modifying an existing mount.

Are there any suggestions where to start on this?

Peter


Title: Re: Electric power steering on a Beta
Post by: mangocrazy on February 17, 2021, 09:50:26 PM
Hi Ian/Peter,

Thanks for the correction. I think I'm starting to get my head around it now. If this were motorcycle steering geometry it would hold no terrors for me, but the addition of a pair of wheels confuses me greatly...  ;D

Ian will probably be able to confirm or deny this, but what you are doing by increasing castor angle on the front wheels of a car is equivalent to increasing the rake on motorcycle forks; i.e turning your sports bike (steep steering head angle) into a chopper (shallow steering head angle). This gives slower, heavier steering but with a predilection for stability and going in a straight line.

Graham


Title: Re: Electric power steering on a Beta
Post by: WestonE on February 18, 2021, 09:06:28 AM
Hi Graham

As a Mountain biker and holder of a motor cycle License unfortunately the comparison does not work well because bikes steer mainly by response to leaning except for slow speed parking. Cars use turning wheels around an axle point. Caster introduces twist for pressure on the contact patch and changes the wheel angles through turning to introduce negative camber which works against roll to maintain the contact patch. There is a complex relationship between toe in/out / camber and caster before we get to Ackerman angles. There are conditions we want to avoid like bump steer, sudden changes in camber through suspension travel or bush movement or wheel turning. We want the steering to bite into a turn (toe in/out setting & miss matched front/rear track ) with a flat tyre contact patch if possible and maintain strong grip and lead the car through a turn despite body roll.

You need to do some reading because this is a complex inter linked subject. Chad from The Monte Hospital commissioned an analysis of the Monte design from an Aston Martin Suspension engineer before building some excellent modifications to dial out the mistakes

Lancia were pioneers in balanced responsive handling including miss matched front to rear track and wishbones mounts that change load through the wheel travel, but had to build to a budget and ensure comfort. No Power Steering meant compromising the front suspension design. Front wishbone location was/is terrible under load and the cars squat under power (lack of anti squat geometry and little rear spring pre-load). If you want to see some of the design fit a strut with no spring and move the wheel through different positions with a trolley jack changing the strut compression.

Years ago I built in rear spring pre-load with short strut rods, had Barry Waterhouse nylon wishbone bush supports and added 1.5% negative camber after converting to Power Steering. Caster gives a bigger win than just negative camber because it maintains the tyre contact patch better. I deliberately built my car with twin adjustable rear links, fully adjustable coil overs, stronger wishbones with fully supported bushes and multi position front top mounts. This was so I could adjust toe camber and caster. I have gone for an educated guess on spring rates and the platforms on the struts allow adjustment of rake (some nose down attack maybe) and corner weighting. Because of the sliding rear anti roll bar you can even fix 'set back' on a Beta. That is when one side of the car is shorter wheel center to wheel center which creates a desire for the car to steer toward the shorter side.   

Ian knows what he is doing with the adjustments he is trying and it is valuable insight. I will only be able to test again when the car runs!

Eric     


Title: Re: Electric power steering on a Beta
Post by: mangocrazy on February 19, 2021, 03:14:01 PM
Hi Eric.

OK - I was grossly over-simplifying things I now realise. Time to take a crash course on 4 wheel vehicle steering geometry and suspension dynamics, I think...

Graham