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Brummie

Brummie's G50-into-an-SC transplant

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Wow, the steering mod looks really cool. Care to elaborate on this and what you have to hack about?

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Loving your work Brummie - it's a cracking car and looks much better as an IB. Keep the updates coming.

 

I'm sure there is a company in the states that does a bolt on leccy steering rack? Your adjustability sounds like a brilliant idea.

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Wow, the steering mod looks really cool. Care to elaborate on this and what you have to hack about?

 

+1 on this, would love a few more details.

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Holy cra*p! You've set the bar pretty damn high.

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Proper innovative engineering ! like it .

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Loving your work Brummie - it's a cracking car and looks much better as an IB. Keep the updates coming.

 

I'm sure there is a company in the states that does a bolt on leccy steering rack? Your adjustability sounds like a brilliant idea.

Thanks everyone for your comments... it makes all those days of working outside in a cold garage seem worth it in the end.

 

I don't know about America Northy but there is a Dutch company out there doing this sort of thing. There's an article in "911 & Porsche World" magazine - (November 2013 edition) by Johnny Tipler which features a Carrera 3.2 having a similar PAS system. It was fitted by a company called "EZ Electric Power Steering". The article's on their website under publications which is well worth a read. They modify various makes of classic cars.

 

I'll dig the info out next week and put together a little write with some pix of what I did.

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I spoke to EZ power steering about a kit but they have never converted a RHD car, and didn't seem that interested in trying either...

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One of the best bits about an old 911 is the steering. Madness to replace it with something else IMO.

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Here's a few pics and write up about how I fitted a power assist steering system...... It may have been possible and easier to fit the PAS up behind the steering column or inbetween the steering joints just behind the dash. I wasn't too happy with this idea though and a bit concerned the steering joints would suffer. Instead I opted for mounting it directly above the cars steering rack that way keeping all the steering joints above the PAS. Another advantage is there's no lost movement in the mechanics other than the steering rack joint. Aesthetically it's position is better too as it's hidden away out of sight so win win.

 

I used the Vauxhall Corsa B type PAS unit but it may be possible to use other manufacturers units. Vauxhall also make a C type unit which looks very similar and may fit ?.... It has adjustable rake built into the column but none of this gets used anyway.
The Corsa's PAS is manufactured by NSK and uses a Mitsubishi controller to signal it. I bought a complete steering column assembly along with the control unit from ebay for about £100. All I really needed though was the main housing with it's motor and the controller.

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This PAS is speed sensetive, it gets a signal from the ABS to vary the sensetivity of the steering dependant on speed. With the lack of ABS on our cars however this can't be connected but there is an alternative in the form of an "ECU power steering controller kit".... it's a bit of a mouthful but essentially it links this bit out and enables you to vary the sensetivity manually via a pot. This kit again I bought from ebay for about £30.

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I started by cutting the front baulkhead area out a bit at a time until the unit could be fitted as I wanted. It was a case of lots of measuring and bending pieces of steel until I got the right shape and form of something that could be welded into the baulkhead that also allowed the PAS unit to bolt to it. I made it so the top mounting face was split into two pieces, the idea being to help with fitting and removal of the PAS at any time in the future. Again it was just a case of trial and error until it became possible. The baulkhead was then sealed from the outside elements with shaped steel plates. The water drain tube from the fresh air blower also needed moving as it fouled the electric motor on the PAS, I just used some rubber tube to re-route it.

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Inside the PAS unit there's not much to see, there's a torque sensor and adjuster which is nicely made along with a few bearings and a gear that's driven from the electric motor. This all seemed in excellent condition so I just rebuilt it fitting new bearings. I made an adaptor which fits directly onto the rubber coupling on the cars steering rack and the other end onto the output shaft of the PAS. It has a profile machined into one end to suit the PAS output shaft with a split down one side and an M8 clamp screw to lock it up in position. I then chopped the PAS input shaft down to length, this allowed the universal joint clamp of the cars steering rod to bolt to it.

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The input shaft on the PAS would normally be supported by a bearing in the Corsa's steering column but I wasn't using any of that which meant the shaft was now able to float. To get round this I made an aluminium housing which I pressed an oil-lite bush into. The bush was machined out to suit the input shaft so now when bolted to the PAS the shaft is supported.

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The universal joints/clamps and rods on the cars steering have a fine spline on them to prevent slipping once bolted together, the input shaft on the PAS doesn't. This shaft is also made from a very tough steel, possibly forged so getting a matching set of splines onto it was a problem however machining a keyway in it wasn't. Luckily the input shaft was the correct diameter for the clamp. I added a 5mm keyway to the shaft then modified the clamp to allow a 5mm key to fit it too. A key then fits between both pieces making it secure from tortional forces. Finally a 6mm locking screw clamps everything in place tightly on the input shaft.

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The "ECU power steering controller kit" came with some electrical instructions which are pretty good. In the kit there's a 60 amp fuse which supplys the main power to the Mitsubishi control unit, it connects directly to the battery. The controller also requires a 12v supply from the ignition so the PAS is only active when the ignition is switched on. The controller unit needs earthing with a large earth strap attatched to a suitable ground point on the car. Also in the kit there's a white plug with flying leads, this plugs into the Mitsubishi controller and connects to the sensetivity control pot. The control pot I mounted up on the dash between the clock and speedo. By modding the pots diameter slightly a Porsche dashboard dimmer knob fits quite nicely and it doesn't look out of place....... easy to adjust if needed too. I fitted the controller unit on the passenger side baulkhead but it could be fitted anywhere. Mounting it here again keeps everything out of sight and it's protected behind the passenger footboard. This also needed reshaping slightly to add clearance on the electric motor.

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I find the sensetivity level works best somewhere set around 15-20 percent. At this setting there's still plenty of resistance through the steering to feel exactly what's going on. The steering precision feels more accurate and it's quicker to respond which is high lighted when direction changing or heavy cornering on uneven road surfaces. Inside the car the PAS is silent in operation and you're completely unaware of the motor adding a little torque as your steering inputs increase. When parking you're reminded there's something there by a slight buzz through the steering as the motor reaches full lock but that's the only indication of anything. With the sensetivity control pot set to zero the PAS can be completely turned off returning the steering back to it's unassisted condition. For me though it stays switched on as I much prefer the added control it brings, the car just drives and feels better with it on.

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Nice install and write up. Did you do the machining yourself? keyways and whatnot? Proper skills there!

 

Do you reckon if the whole mechanism was rotated round so the motor poked out the top of the smugglers box, it could be installed with cutting the body?

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Nice install and write up. Did you do the machining yourself? keyways and whatnot? Proper skills there!

 

Do you reckon if the whole mechanism was rotated round so the motor poked out the top of the smugglers box, it could be installed with cutting the body?

Yes the machining I did myself, my job gives me access to this type of equipment which is a huge benefit.

Unfortunately Jonny the unit's just too big... it may be possible using a different manufacturers PAS though ?

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