EPAS and castor problems. steering quite unpredictable

[RuskiWeldFab]

Hi Guys.

i am having slight issues with my suspension. it just don't feel right.
almost feels like i have no feedback from the steering. it kinda wonders around in the straight line and while turning doesn't come back. constantly have to fight with it and correct it.
i am really not sure what it is. hard to explain. but feels a lot like cheap PC steering wheel with no force feedback.
i have epas fitted. but even if i completely switch it off, that feeling don't go away completely gets better but not gone.
so i am thinking, is it the feeling that epas is giving people or my castor is all wrong and not positive enough? i have fitted wishbones that i bought on ebay to strengthen them and polly bush. but not sure if they are a cup version or some other reduced caster crap. in the listing is said 172.182 sport. this was a year ago before i did any research. didn't even cross my mind that they could be different.
so the question is, is it the epas or castor? or combo of the 2?

 

[Usr117063]

No matter what what was new or refreshed the steering was numb and same as you the steering wouldnt come back and had to put in extra input to do anything so ended up with a custom welded column, as they are all bushed standard.. It transformed the steering and now responds with the smallest of input. I couldnt really find anything on this when I was looking at it bar some of the older clios they would do this, but I wrote that new inner tres, steering rack bushes, dampers, alignment etc was literally nothing compared to the column in tightening the steering up. I guess you could go for an alignment check and check all the suspension components but IMO you will never get truly solid steering without this, especially if the cars done 70k+...

 

[Usr117063]

I did this vid a while back before I got the column, as you can see the wheel hardly moves, now its pretty much instant

 

[bloke]

Steep castor angle can make them feel odd, almost like it can fall into a corner if that makes sense??

 

[RuskiWeldFab]

Steep castor angle can make them feel odd, almost like it can fall into a corner if that makes sense??

You are quite spot on mate. Does feel like it. Like it’s turning by itself too deep. So that’s when angle of castor is more negative?


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[Martin.]

My epas feels great. Doubt i'd be able to tell the difference back to back compared with a PAS setup. And then you obviously have the rest of the entire adjustment range to benefit from. So from that I'd say it has to be something else giving you issues.

 

[JB21]

I doubt non cup wishbones would make the car change that dramatically. It just sounds like standard EPAS to me. Mine done exactly the same on the road, wandering, not self centring etc. Get it on track and when you go into a steeply cambered corner the steering would really firm up once into the camber then once you exit it would go light again, felt weird at first but you soon get used to it.

Are you using the DCI rack?

 

[RuskiWeldFab]

I doubt non cup wishbones would make the car change that dramatically. It just sounds like standard EPAS to me. Mine done exactly the same on the road, wandering, not self centring etc. Get it on track and when you go into a steeply cambered corner the steering would really firm up once into the camber then once you exit it would go light again, felt weird at first but you soon get used to it.

Are you using the DCI rack?

Yeah that my line of though. Have donny on the 20th will see how it behaves.
Yes it’s a dci rack (1.6 I think) and 1.4 column. With controller of Ebay


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[bloke]

You have got caster adjustable top mounts haven't you?

 

[RuskiWeldFab]

You have got caster adjustable top mounts haven't you?

nope.. thats one thing i dont have.. been looking at PMS top plates but dont wanna hack / weld paint my beatiful fully finished engine bay should have done it at the begining... f**k sake

 

[bloke]

Ah, thought you did have sorry.

Spoken to the guy who set it up to see what he thinks?

 

[RuskiWeldFab]

Ah, thought you did have sorry.

Spoken to the guy who set it up to see what he thinks?

Yep. talking to Anthony to find out would could be the problem. He didnt do anything to do with castor. so its defo not his set up thats a problem. i am fairly certian its the castor. its not positive enough. or the epas.

 

[bloke]

no logic reason why it would be the epas.

 

[RuskiWeldFab]

no logic reason why it would be the epas.

Maybe not the EPAS Itself but a worn column or rack itself. Strange but there is no play in it. Or maybe I just need to get used to it. Kinda need someone to drive it see what’s what...


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[PhillipM]

I'd be checking the UJ's and a good look around the balljoints and TRE's first.

 

[RuskiWeldFab]

I'd be checking the UJ's and a good look around the balljoints and TRE's first.

Everything is brand new. Not a single old rubber left. What’s TRE? Sorry a bit thick today haha


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[bashracing]

Do you have a picture of the lower wishbone fitted the car ?
I think the bushes could have been pressed in the wrong side of the wishbone and giving you zero or negative castor.

 

[RuskiWeldFab]

Do you have a picture of the lower wishbone fitted the car ?
I think the bushes could have been pressed in the wrong side of the wishbone and giving you zero or negative castor.

That’s the best one I have

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[Usr117063]

The pms plates only fit the increased castor wishbones

 

[RuskiWeldFab]

The pms plates only fit the increased castor wishbones

It was actually not that easy to weld. Involved a bit of hammering.
I still think it’s them at fault. Not enough castor.

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[bozothenutter]

It was actually not that easy to weld. Involved a bit of hammering.
I still think it’s them at fault. Not enough castor. View attachment 1380911


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it's the wishbones, look at the outer hole on the bottom one in the picture, it's not centered.
did you use a socket to centre the plate?
time to break out the grinder....sorry

on closer look iy might even be you have two different wishbones?

 

[bozothenutter]

No matter what what was new or refreshed the steering was numb and same as you the steering wouldnt come back and had to put in extra input to do anything so ended up with a custom welded column, as they are all bushed standard.. It transformed the steering and now responds with the smallest of input. I couldnt really find anything on this when I was looking at it bar some of the older clios they would do this, but I wrote that new inner tres, steering rack bushes, dampers, alignment etc was literally nothing compared to the column in tightening the steering up. I guess you could go for an alignment check and check all the suspension components but IMO you will never get truly solid steering without this, especially if the cars done 70k+...

View attachment 1380773

View attachment 1380774

could you explain what a bit more mate, what bushes where in the column, what did you have welded to what?

 

[RuskiWeldFab]

it's the wishbones, look at the outer hole on the bottom one in the picture, it's not centered.
did you use a socket to centre the plate?
time to break out the grinder....sorry

on closer look iy might even be you have two different wishbones?

Have original Cup ones on the way here. Will weld new plates and bearing kit this time.


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[Usr117063]

could you explain what a bit more mate, what bushes where in the column, what did you have welded to what?

Cant answer this exactly as I bought it already made up, the whole thing is custom. But basically its the lower uj joint as they are made part attached with a bushing, this one looks welded straight to the column so no chance for play

 

[bozothenutter]

Cant answer this exactly as I bought it already made up, the whole thing is custom. But basically its the lower uj joint as they are made part attached with a bushing, this one looks welded straight to the column so no chance for play

Thanks mate!
Just what I wondered about.
So basically find the lower in and replace with solid one.??

 

[CamMoreRon]

Just adding my thoughts to all this before you chop your wishbones up!

I don't think it's possible for you to alter caster enough with some modified wishbones for it to have such an effect.. you would have to have the ball joint quite far out to alter the caster angle enough to have a drastic effect.

If you had made your own wishbones without using a jig then maybe, but welding some plates to a set of standard 'bones isn't going to cause this problem.

From what you've said, it seems like your issue is poor "on-centre" feel - i.e. the car wanders and feels unpredictable while in the centre (or near centre) of the steering travel. Since you've changed the rack, and I assume also the column, this would be my first port of call.

Much of what you described can be caused by incorrect orientation of the UJs in the steering column, so the most obvious question to ask is: did you pay attention to the orientation of the UJs when you installed the rack?

This is because a universal joint is not a constant-velocity joint, so the output speed does not match the input speed at certain points of rotation. If you have two (or more) UJs oriented "out of phase" you will find the output speed after passing through the UJs to be all over the place. If you also happen to have one of the fast or slow spots on-centre (in the middle of the rack) you will find the steering to be either overly sensitive to inputs and difficult to control (fast spot), or unresponsive / dead with lots of handwheel feedback (slow spot) and wandering. To me it sounds like it's the latter.

As for the poor return-to-centre you mentioned, this could be the EPAS, as many EPAS systems do this to make the steering more stable and predictable.

Can you check the orientation of your universal joints in the column? How many do you have, and how did you set them up when you installed it?

 

[bozothenutter]

learn something new every day! thanks @CamMoreRon

 

[RuskiWeldFab]

That is very interesting! Thank you! I already chopped the old ones and used oem cup replacements. Very noticeable difference. But still not %100. But I though that was just feel the EPAS gives. By CV joints, you mean the wobbly wiblly thingy at the end of the column? Where is attached to the rack?

Please explain about orientation if you can.

Wbones I had

vs cup

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[PhillipM]

Yes, those - if the input and output are at the same angle to each other the joints should be aligned 90* to each other, but other than that the phasing depends on what angle the respective shafts are to each other from the steering wheel to the rack input.

 

[RuskiWeldFab]

Yes, those - if the input and output are at the same angle to each other the joints should be aligned 90* to each other, but other than that the phasing depends on what angle the respective shafts are to each other from the steering wheel to the rack input.

All makes sense! But doesn’t at same time lol!


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[CamMoreRon]

Wow, firstly.. shut my mouth, because that's definitely a noticeable difference in caster!

Yes the wibbly wobbly bits at the start and end of the steering column are the universal joints.. you have two UJs on your column. Each UJ has two "yokes", which are the U-shaped bits - on the upper UJ (by the motor) you have the input yoke on the motor output shaft and the output yoke on the steering column intermediate shaft, these are joined by an X-shaped pin, then on the lower UJ you have the input yoke on the column intermediate shaft and the output yoke on the splined bit that attaches to the steering rack, again joined by the X-shaped pin.

Here's a video which should help understand things a little better:




Phasing of two (or more) UJs is about the angle of the input and output yokes on the intermediate shaft - if you have the pin axis on both aligned they are said to be "in phase". When a UJ operates at an angle, the output speed varies at certain points of shaft rotation, so having two UJs aligned in phase cancels this out and makes the overall output speed equal to the input speed. You can see this in the video when they guy holds a card to the teeth on each disc.

However..... this only works when the angles of the two UJs is the same, and the whole assembly (input, intermediate and output) are on the same plane - if you have different upper & lower UJ angles, or the output shaft kinks off to one side (very common in steering columns) then this will no longer work! You then have to adjust the phasing of the UJs to get a constant output speed.

Sadly this isn't something that has a specific "set it up like this and it'll be fine" answer, but might require some tinkering. However, a good starting point is below!

Focus entirely on the intermediate shaft - you have the INPUT YOKE on the UPPER UJ and the OUTPUT YOKE on the LOWER UJ. Notice how in the pic below, the pin axis of the input and output yokes are not aligned on the intermediate shaft:

This is because the steering column steps over to the side, as the rack input is further inboard than the steering wheel.

However, if you look at one UJ at a time: the input shaft, yoke in question, and output shaft are all on the same plane.

So, on the UPPER UJ: the input shaft, INPUT YOKE, and the column intermediate shaft are all on the same plane..

And on the LOWER UJ: the column intermediate shaft, OUTPUT YOKE, and the steering rack shaft are all on the same plane..

Just to reiterate, when I say INPUT and OUTPUT yoke, I'm speaking in relation to the intermediate shaft, not the UJ.

If you look at the first pic again, you'll see then even though each UJ has been set up in-plane, the input and output yokes are not aligned on the intermediate shaft - they are "phased" by about 30deg around the intermediate shaft.

Check each UJ on your steering column while it's fitted to the car and see how the alignment compares to that above. This might be a little difficult though, as you have the engine in the way! You may need to adjust the phasing of the UJs to get linear steering feedback and better on-centre feel. If it's impossible to see with the engine in, you can always adjust the lower CV a spline at a time on the intermediate shaft and note the difference until you get something that feels right.

It is sadly a bit of a faff to get set up, but the rewards are worth it!

 

[RuskiWeldFab]

OMG! I am lost for words mate this is explanation and a half!!! Thank you soooo much!! This makes sooo much sense now! Especially the video. When I was fitting the column after I painted it, I literally just fitted it as is, had no idea about all this. So almost 100% certain it’s out of phase! Will take the thing apart and try to sync it now. Will report back! This should be made a sticky!! 100% will help others! Can’t imagine this is common knowledge! Blown away that a bit of angle on UJ makes such a difference. Madness!


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[RuskiWeldFab]

@CamMoreRon ok so this is how my UJs are positioned. The issue with adjustability is that the lower one is fixed position and can not be rotated (can only slot one way to the rack)
The top one, I can only rotate the input shaft on the motor, but this won’t change the orientation of the UJ. The middle shaft is fixed (don’t think if can be rotated) and actualy ofset in relation to each other. However I can possibly change the angle of the top one.

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[CamMoreRon]

It's hard to see, but does your intermediate shaft come in two parts? It looks like your upper UJ has splines going into the intermediate shaft, so possibly could be rotated?

I assume it does split, so you can get that big rubber whatsit over it.

 

[RuskiWeldFab]

It's hard to see, but does your intermediate shaft come in two parts? It looks like your upper UJ has splines going into the intermediate shaft, so possibly could be rotated?

I assume it does split, so you can get that big rubber whatsit over it.

As far as I know, it’s a telescopic shaft (folds on the impact) but not sure if it can be split and rotated... going to test my old one non EPAs


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[CamMoreRon]

Yeah have a quick check.. I'd be surprised if it didn't separate somehow. There might be some kind of feature that only allows it to go in one position, though.. such as a flat or a wider spline somewhere. If not, you can adjust it.

 

[RuskiWeldFab]

Yeah have a quick check.. I'd be surprised if it didn't separate somehow. There might be some kind of feature that only allows it to go in one position, though.. such as a flat or a wider spline somewhere. If not, you can adjust it.

Good news is that it does indeed separate (at least the non EPAs) the question remains, which way do I rotate? Hmm

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[bigfella2]

I was going to say if you can't separate it, your simply not hitting it hard enough!! I split mine and put it back in no particular way. Is it really noticeable the steering?

 

[RuskiWeldFab]

I was going to say if you can't separate it, your simply not hitting it hard enough!! I split mine and put it back in no particular way. Is it really noticeable the steering?

I would say before I changed the castor, it was underivable. Now it’s a lot a lot better but still lucking that feel when the wheel wants to comeback to the Center. In corners it’s like you have to return the wheel manually when exiting a corner. But at least straight line stability is there.


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[robzracing]

Ilya, have you checked there's no slack in the DCi rack? My Epas has been absolutely spot on. No problem returning to centre. But I'm running with a looped HPAS rack at the moment. Still haven't fitted my DCi rack.