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Go Back   Madabout Kitcars Forum > Mad Build Area > Marlin Sportster, Cabrio, Berlinetta and Roadster builds

Marlin Sportster, Cabrio, Berlinetta and Roadster builds Enthused or Confused about your vintage Marlin build? Ask away here or show off your build.

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  #481  
Old 20th December 2012, 10:37
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Cappuccino, anyone?
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  #482  
Old 5th February 2013, 15:49
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As you know, I'm trying to fit electric power steering - just like Lee from the MOC has done in his Cabrio.

I'm working on all the physical engineering - all the adaptors are done and just need welding onto the right places, and it the column should just bolt in. But I've also been researching what and how the EPAS system works - mainly as I want 'proper' speed sensitive assistance, not a box of 555 timer chips fudging the signals.

Anyway, here's all the info I've got:

http://greatoldone.squarespace.com/s...d%20Pulses.xls

There appears to be two ways this could be done on a BMW based car - via the diff speed sender or an ABS ring on one of the hubs.

Regardless of the method, it does give you the opportunity to tailor the assistance, by electronically multiplying or dividing the pulses either method sends to the EPAS ECU - basically fooling the unit into believing its going faster (or slower) than it is, and hence decreasing (or increasing) the assistance range.

The spreadsheet calculates a number of possible multipliers for either pulse source, and you can plug in your own tire & rim sizes and it'll work out the approx speeds the different levels of assistance will work till.

I'm planning on trying the ABS route first, mainly as I'm re-fitting ABS sensors for the Traction Control I'm installing - but also as there's the possibility that the 48 pulse per rev BMW ring will give a workable range of assistance out of the box with no monkeying around with the signal.

Better crack on and get the column welded up now...
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  #483  
Old 6th February 2013, 21:31
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Quote:
Originally Posted by GreatOldOne View Post

There appears to be two ways this could be done on a BMW based car - via the diff speed sender or an ABS ring on one of the hubs.
Fascinating subject and clearly you've done a lot of research.

I would be inclined to follow the route that GM have used (ie ABS sensor or speedo signal) as they have probably done lots of trials and analysis.
The ABS route looks attractive but I wonder what happens if the wheel sensor you pick looses traction and locks up, does your steering suddenly change assistance?
As you only have ABS sensors and not real ABS braking it could be a bit scary??

Maybe just a switch on the dashboard would do, so you just switch the assistance on when parking? Above about 5mph I've never noticed the Sportster being difficult to steer.
A James Bond type switch in a flip top gear knob would be cool.

Just thinking out loud so please ignore if I'm talking rubbish
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  #484  
Old 6th February 2013, 21:59
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As far as I know, the non abs equipped Corsas only used one abs pick up and the amplifier. This fed both the speedo and the abs ECU. The abs equipped ones didn't need the amplifier as the abs ECU amplified the signal internally, used it for the abs and also presented it as an output for the clocks and EPAS.

From what I've found, what happens if it loses the speed signal is it will default to a single map - the same as what corsa vans have as they have no speed sensitivity.

And the speed sensitivity thing is a bit of a misnomer - the amount of assistance given is down to the torque sensed by the column. More torque = more assistance. The speed signal just switches between assistance maps, which gives more or less assistance for a given torque... So, even if you lost the signal at speed and it defaulted, if there's no steering effort going into the column there's no assistance.

According to the sources of the info, in real terms you wouldn't really tell if it had defaulted or not.
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  #485  
Old 14th February 2013, 17:00
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Change of direction - after offering the EPAS unit in the foot well, I've come to a critical realisation. The bloody thing won't fit.

Well, actual it could be made to fit, by dropping it so low almost interferes with the pedals - or by re-arranging quite a bit of stuff under the dash - but to be honest, it's just a hell of a lot of work for very minimal gain.

I'd measured all of this before I started turning all the bits and started mucking about the second BMW column I had and the corsa column... But it's only after really trying to shoehorn it in that I've realised it's not really going to work.

So, no power steering for Vikki.

Anyone want a corsa EPAS column to play with?
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  #486  
Old 14th February 2013, 17:08
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Quote:
Originally Posted by GreatOldOne View Post
Change of direction - after offering the EPAS unit in the foot well, I've come to a critical realisation. The bloody thing won't fit.

Well, actual it could be made to fit, by dropping it so low almost interferes with the pedals - or by re-arranging quite a bit of stuff under the dash - but to be honest, it's just a hell of a lot of work for very minimal gain.

I'd measured all of this before I started turning all the bits and started mucking about the second BMW column I had and the corsa column... But it's only after really trying to shoehorn it in that I've realised it's not really going to work.

So, no power steering for Vikki.

Anyone want a corsa EPAS column to play with?
Hi GOO

Before you quit, have a look at my conversion on my flickr site, as I ran into a similar issue with my Cabrio - I suspect there is a lot of commonality between the two chassis.




My problem was the body of the Corsa system was too long and fouled the brake pedal, so I modified various parts to shorten the overall assembly.

Perhaps you could achieve the same?

Mike
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  #487  
Old 14th February 2013, 19:11
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Goo

If you decide to abandon the epas route I would be interested in having a play, please let me know if you decide to move it on.

John
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  #488  
Old 14th February 2013, 20:01
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Well, I've just been down to the garage again, and taken off the ECU & steel mounting bracket (pig - bolts stuck, heads made of plasticine). This makes it narrower toward the output end, like yours Mike.

Offering it up in the foot well, it starts to look as if it may fit, but then I realise it still got to go up a couple of inches into the plane of the existing column - and that's when the motor either fouls side of the foot well, pedal box or my centre console and heater.

I'm convinced its a non starter now. It may be a goer for someone who hasn't got all this in the way yet and can engineer round it without too much effort, but I'm not going to start pulling out my heater & console or jump through hoops modifying the pedal box just to get a bit of assistance at stand-still.

All my research is still sound though. Im not too bothered about the 2nd BMW column I bought, as I can strip, that for spares. And the bits I machined where good practice, and may helps someone else out.

So offer still stands - Corsa EPAS Column up for grabs, and I have a Vauxhall ABS pulse amplifier if anyone wants to try driving the speed dependant portion from an abs reluctor ring.
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  #489  
Old 14th February 2013, 22:21
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Quote:
Originally Posted by GreatOldOne View Post
Well, I've just been down to the garage again, and taken off the ECU & steel mounting bracket (pig - bolts stuck, heads made of plasticine). This makes it narrower toward the output end, like yours Mike.

Offering it up in the foot well, it starts to look as if it may fit, but then I realise it still got to go up a couple of inches into the plane of the existing column - and that's when the motor either fouls side of the foot well, pedal box or my centre console and heater.

I'm convinced its a non starter now. It may be a goer for someone who hasn't got all this in the way yet and can engineer round it without too much effort, but I'm not going to start pulling out my heater & console or jump through hoops modifying the pedal box just to get a bit of assistance at stand-still.

All my research is still sound though. Im not too bothered about the 2nd BMW column I bought, as I can strip, that for spares. And the bits I machined where good practice, and may helps someone else out.

So offer still stands - Corsa EPAS Column up for grabs, and I have a Vauxhall ABS pulse amplifier if anyone wants to try driving the speed dependant portion from an abs reluctor ring.
Back to three Shredded Wheat for breakfast then
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  #490  
Old 15th February 2013, 06:19
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Yup!
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  #491  
Old 19th February 2013, 11:45
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It was a good effort Goo, sorry it didn't work out. John
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  #492  
Old 21st February 2013, 16:10
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Small update - The new engine ECU and sensors are working brilliantly. I've set the mixture on the side of the AFM as per the Bentley Manual specs, and after being sat idling out on the drive for 20 minutes or so, she suddenly decided to behave.

When she starts up cold, she idles at 1000rpm. When she's warmed up, it drops to 800rpm. Perfect!

Also, whilst I'm a bit disapointed about the power steering, the Traction Control system is still on the cards. This arrived this morning



It's been done by the same outfit that did my switch panel and vin plate, so all the fonts and colours match. The larger upper hole above the 'OFF' position will take a red indicator lamp that matches the ones I have in the dashboard. The actual control will sit under the handbrake.
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  #493  
Old 22nd February 2013, 17:36
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Bunged an update on my blog:

http://www.greatoldone.co.uk/blog/20...-traction.html
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  #494  
Old 3rd March 2013, 21:57
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Interesting company...........

http://www.ezpowersteering.nl/25/170..._STEERING.html
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  #495  
Old 4th March 2013, 17:24
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Yes - I came across them when I was doing my research. I don't think they're a budget option, and I get the feeling that whilst the engineering may be very good, it's no better than a DIY job with an eBay controller
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  #496  
Old 4th March 2013, 18:30
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That panel is really nice
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  #497  
Old 9th March 2013, 16:26
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New header tank is in:

http://www.greatoldone.co.uk/blog/20...scratches.html

Ran her up to temp, so the system pressurised - no leaks!
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  #498  
Old 9th March 2013, 18:55
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Quote:
Originally Posted by GreatOldOne View Post
New header tank is in:

http://www.greatoldone.co.uk/blog/20...scratches.html

Ran her up to temp, so the system pressurised - no leaks!
Nice work, Jason.
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  #499  
Old 10th March 2013, 20:20
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A work of modern art young man.

Well done.
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  #500  
Old 21st March 2013, 23:22
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Quote:
Originally Posted by GreatOldOne View Post
Well, I've just been down to the garage again, and taken off the ECU & steel mounting bracket (pig - bolts stuck, heads made of plasticine). This makes it narrower toward the output end, like yours Mike.

Offering it up in the foot well, it starts to look as if it may fit, but then I realise it still got to go up a couple of inches into the plane of the existing column - and that's when the motor either fouls side of the foot well, pedal box or my centre console and heater.

I'm convinced its a non starter now. It may be a goer for someone who hasn't got all this in the way yet and can engineer round it without too much effort, but I'm not going to start pulling out my heater & console or jump through hoops modifying the pedal box just to get a bit of assistance at stand-still.

All my research is still sound though. Im not too bothered about the 2nd BMW column I bought, as I can strip, that for spares. And the bits I machined where good practice, and may helps someone else out.

So offer still stands - Corsa EPAS Column up for grabs, and I have a Vauxhall ABS pulse amplifier if anyone wants to try driving the speed dependant portion from an abs reluctor ring.

Goo

Have you seen this guy's site?

http://www.super7thheaven.co.uk/blog...epas-a118.html

What is your view on his speed sensor control?

Mike
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