# Planning Land Rover Defender 90



## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> In the end is that a good starting point or not even close?


All useful information but we need to know your budget


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## jp455 (Mar 28, 2018)

Right...an important part.Well, as I'm very unfamiliar with the topic and don't know exactly what size motor/battery Ill need I'm a bit in the dark. That being said going from other conversions Ive seen I know I'm not up to spending Tesla motor money, but neither do I want to go with a forklift motor. So for an AC motor and parts Id guess it'd be in the 10-16k US dollar range. 

Unfortunately this project will take shape in the UK, so there would be the matter of importing or sourcing here. But I haven't so far seen prices for parts sourced directly in the UK. I know this is just because I haven't looked around enough though...


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## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> So for an AC motor and parts Id guess it'd be in the 10-16k US dollar range.


Ok, that helps... I'd probably start by looking at a wrecked Nissan Leaf which should cost you ~2500 GBP then add more Nissan battery modules if you need more range.

Take a look at Mike Schooling's Leaf based Defender conversion if you need inspiration 

https://twitter.com/Indra_rt/status/976508071718596608



jp455 said:


> Unfortunately this project will take shape in the UK, so there would be the matter of importing or sourcing here.


Lots activity in the UK, look up projects by Mike Schooling (here), Chris Hazell (here), Tom De Bree (here), and myself. Damien (here) is also just across the water 

If you want to see any of these cars let me know...


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## jp455 (Mar 28, 2018)

Hi Kevin

Those are all very helpful...thanks!

I had seen that Defender you sent but havent seen any project details so far. Interesting to know it uses a Leaf motor...it certainly looks like it moves it along quite well!

What other options would there be as far as aftermarket? Im thinking more in the sense of future support, upgrade-ability or even if the first one works out making a second conversion.

Im still very curious though about the correlation between the existing diesel and choosing an electric motor to replace it.


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## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> What other options would there be as far as aftermarket? Im thinking more in the sense of future support, upgrade-ability or even if the first one works out making a second conversion.


You could go more old school and use an motor from one of the smaller manufacturers (see here). However, those solutions are much more expensive than the OEM parts we buy from wrecks (Leaf drive units have been changing hands for 600 Euros). That said, If you are serious about series production then talk to Mike Schooling at Indra or Anne Kloppenborg at New Electric about their certified and supported drive trains


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## DaveP (Mar 29, 2018)

You could also give the guys at Electric Classic Cars a call, I know they've got 2 Defenders they're converting for customers at the moment, maybe you could buy a kit from them.


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## jp455 (Mar 28, 2018)

Thanks Dave, Kevin...excellent info. I didn't think the Leaf stuff would be as inexpensive. That being said it did give that Defender 100 very good acceleration! I'm now curious about cruising speed/range with that motor and how many batteries it would take to get to the 100 mile range goal.

I'm still curious about the correlation/conversion factor between an IC engine and an electric motor. Even if just for my own information as for the Defender in particular there's already the Leaf powered one which does very well.


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## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> I'm now curious about cruising speed/range with that motor and how many batteries it would take to get to the 100 mile range goal.


Given the Leaf curb weight is 3,300lbs, it's pretty aerodynamic, and has an EPA range of 84 miles (24kWh battery), I think you should assume you'll need ~48kWh for a real world 100 miles range, given the weight and aerodynamics of the Defender.

I've attached a Leaf range chart estimator


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## DaveP (Mar 29, 2018)

I think Kevins about right on the kWh estimate. The electric classic Range Rover that Electric Classic Cars built last year was 80kWh and had a max range of 200 miles, so I would have thought that 48kWh should be good for 100 mile range. The weight, aerodynamics and parasitic load of the drivetrain in a Defender are all against you though. When I picked up my Tesla Model S batteries off ECC a few weeks back the main guy there took me out for a spin in his mental Beetle, which had 48kWh too. He said it would get 200 mile range at a push but it's probably half the weight of a Defender.

Whats the plan? are you going to attached a motor to the gearbox via an adapter plate or direct drive it?


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## jp455 (Mar 28, 2018)

Kevin Sharpe said:


> Given the Leaf curb weight is 3,300lbs, it's pretty aerodynamic, and has an EPA range of 84 miles (24kWh battery), I think you should assume you'll need ~48kWh for a real world 100 miles range, given the weight and aerodynamics of the Defender.
> 
> I've attached a Leaf range chart estimator



Cool...thanks for that!


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## jp455 (Mar 28, 2018)

DaveP said:


> I think Kevins about right on the kWh estimate. The electric classic Range Rover that Electric Classic Cars built last year was 80kWh and had a max range of 200 miles, so I would have thought that 48kWh should be good for 100 mile range. The weight, aerodynamics and parasitic load of the drivetrain in a Defender are all against you though. When I picked up my Tesla Model S batteries off ECC a few weeks back the main guy there took me out for a spin in his mental Beetle, which had 48kWh too. He said it would get 200 mile range at a push but it's probably half the weight of a Defender.
> 
> Whats the plan? are you going to attached a motor to the gearbox via an adapter plate or direct drive it?


Looking at the Leaf battery pack as an example it looks like this to me...

24kWh = 48 modules 
48kWh = 96 modules

Lets round up to 100 modules just for the math...50kWh, each module is 303 x 223 x 55 mm then a battery pack of 100 modules (only modules no other hardware) split into 4 stacks of 25 modules would be a box of 606 x x446 x 1375 mm. Is that math making sense? If so splitting that box into two taking up the space where the fuel tank used to be and on top of the motor at the front looks to be totally doable.

As for the motor attachment plan there's two options, attached to the gearbox or dump the gearbox and attach it to the transfer case. If they would have made 2 wheels drive Defenders with IFS then Id consider direct drive. But doing that on the Defender would make the front axle completely useless. I think the gearbox attachment route would be best as it gives the option of the 5 gears to play with.


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## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> each module is 303 x 223 x 55 mm


That should be 35mm not 55mm 

You might find this thread useful;

Leaf Modules - Gen 2

Also some posts about the 48kWh Leaf battery that I built;

http://www.diyelectriccar.com/forums/showpost.php?p=805713&postcount=7


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## Kevin Sharpe (Jul 4, 2011)

jp455 said:


> I think the gearbox attachment route would be best as it gives the option of the 5 gears to play with.


No electric OEM cars have a shiftable gearbox today, they just don't need it... that said however, you may find it simplifies the conversion and I suspect that's what Mike did with the Leaf based Defender


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## Linukas (Feb 22, 2011)

some time ago I done some calculations for my friend as he wanted to convert it to electric, we discussed about an option to use leaf motor and connect it to central diff (it have 2 speeds, low and high, as I know) so you get couple possible reductions to wheels and can place motor in gearbox place.
unfortunately my friend went to a different car, so not done defender project...


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## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> No electric OEM cars have a shiftable gearbox today, they just don't need it... that said however, you may find it simplifies the conversion...


Well, no mass-production pure battery electric cars have a multi-speed gearbox, since the original Tesla Roadster transaxle failed and is long gone, the Rimac cars are nearly custom exotics, the cars using GKN's two-speed eTwinsterX are all hybrids, and no one is currently using any of the several available two-speed transaxles intended for electric drive in production. 

I agree that with a modern motor (not so much for a forklift motor) only one ratio is needed, and that's the current normal practice.

I also agree that

you likely need some gear reduction between the motor and the final drive, and the stock transmission may be the cheapest and easiest (although not lightest or most compact) way to get it, and
you may not know the best gear ratio in advance, and shifting the stock transmission is an effective way to change ratios.


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## jp455 (Mar 28, 2018)

Linukas said:


> some time ago I done some calculations for my friend as he wanted to convert it to electric, we discussed about an option to use leaf motor and connect it to central diff (it have 2 speeds, low and high, as I know) so you get couple possible reductions to wheels and can place motor in gearbox place.
> unfortunately my friend went to a different car, so not done defender project...



That's only sort of accurate though. Yes, it does have 2 speeds, but only in 4WD, and the Defender 4WD system can not be used on asphalt as it doesn't have a central differential. In 2WD its only 1 speed. The only reason to connect it directly to the transfer case is to lose the gearbox.


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## DaveP (Mar 29, 2018)

I think attaching the motor directly to the transfer box and placing it where the gearbox is would free up a lot of space in the engine bay for batteries. Although you'd need to do all the calculations on ratios, both transfer box and diff to see what rpm vs road speed gives you. This page I've just Googled might help.

If I remember rightly the ECC guys were going both ways, one Defender was having the motor attached to the gearbox the other was going to be direct drive. I'm not sure why they're trying both routes, maybe to see which works best, more than that you'd need to ask them. My thinking is that if you're planning on going serious off roading or towing you should keep the gearbox, if it's simply going to be on road then direct drive or through the transfer box could be a viable option, as long as all the ratios are in your favour.


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## jp455 (Mar 28, 2018)

brian_ said:


> Well, no mass-production pure battery electric cars have a multi-speed gearbox, since the original Tesla Roadster transaxle failed and is long gone, the Rimac cars are nearly custom exotics, the cars using GKN's two-speed eTwinsterX are all hybrids, and no one is currently using any of the several available two-speed transaxles intended for electric drive in production.
> 
> I agree that with a modern motor (not so much for a forklift motor) only one ratio is needed, and that's the current normal practice.
> 
> ...



Yes, that's true that no current EVs have a gearbox...this would only be for simplicity sake. That being said though, would there not be a benefit to keep the electric motor in a certain RPM range to extend the battery life? Or is that completely irrelevant for electric motors, and they use the same amount of power regardless at what RPM they're running at?

The other option which I forgot to mention is getting rid of the gearbox, and replacing it with a 2 speed over drive unit which would give 2 speeds.


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## jp455 (Mar 28, 2018)

DaveP said:


> I think attaching the motor directly to the transfer box and placing it where the gearbox is would free up a lot of space in the engine bay for batteries. Although you'd need to do all the calculations on ratios, both transfer box and diff to see what rpm vs road speed gives you. This page I've just Googled might help.
> 
> If I remember rightly the ECC guys were going both ways, one Defender was having the motor attached to the gearbox the other was going to be direct drive. I'm not sure why they're trying both routes, maybe to see which works best, more than that you'd need to ask them. My thinking is that if you're planning on going serious off roading or towing you should keep the gearbox, if it's simply going to be on road then direct drive or through the transfer box could be a viable option, as long as all the ratios are in your favour.


Thanks for that...Ill have a look at the ratio calculator and input a chosen motor in there to see the rpm/speed it would give.

This would be 99% for onroad driving, and getting rid of the gearbox and just connecting it to the transfer case would be the easiest/neatest installation. Direct drive isn't really an option though as it would render the front solid axle useless and way overkill to just do the suspension/steering work. For a direct drive the ideal thing is a 2WD pick up, or an SUV that is sold both in 2WD and 4WD versions like a Toyota 4Runner.


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## DaveP (Mar 29, 2018)

jp455 said:


> That's only sort of accurate though. Yes, it does have 2 speeds, but only in 4WD, and the Defender 4WD system can not be used on asphalt as it doesn't have a central differential. In 2WD its only 1 speed. The only reason to connect it directly to the transfer case is to lose the gearbox.


??? Defenders are permanent 4x4, and can be used on asphalt. There is no 2WD option for a Defender. I think the Series 3 Land Rover had selectable 2WD/4WD though.


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## DaveP (Mar 29, 2018)

jp455 said:


> Thanks for that...Ill have a look at the ratio calculator and input a chosen motor in there to see the rpm/speed it would give.
> 
> This would be 99% for onroad driving, and getting rid of the gearbox and just connecting it to the transfer case would be the easiest/neatest installation. Direct drive isn't really an option though as it would render the front solid axle useless and way overkill to just do the suspension/steering work. For a direct drive the ideal thing is a 2WD pick up, or an SUV that is sold both in 2WD and 4WD versions like a Toyota 4Runner.


I'm pretty sure the ECC direct drive Defender was keeping it's 4x4, but to be 100% you'd have to ask them.

Talking about steering above, whats the plan there? obviously it will need power steering but you're going to loose the pump when the engine goes. Are you going to convert it to EPAS?


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## tylerwatts (Feb 9, 2012)

I agree, Defenders are permanent AWD. Only hi & low ratios. I'd recommend trying to lose the AWD completely and go directly rwd. Either use the transfer box for 2 speeds and lock/weld the diff without a front drive shaft or if you can get a crawler crown & pinion ratio (or swop to a different axle with crawler ratio like a Dyna) go directly to the axle. Only trick then is running an empty front axle or swapping to a solid beam?
Personally it's alot of work but I'd build a custom independent suspension subframe for the front and also the rear and mount entire leaf motor into subframe in the rear. You could pack all battery into the engine bay in a nice brick/block of cells easily removable.
Whatever way it has potential to be a brilliant conversion.


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## jp455 (Mar 28, 2018)

DaveP said:


> ??? Defenders are permanent 4x4, and can be used on asphalt. There is no 2WD option for a Defender. I think the Series 3 Land Rover had selectable 2WD/4WD though.



Yes duh...sorry, forgot to engage brain before writing! I was thinking the older style Toyota/Jeep transfer cases.


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## jp455 (Mar 28, 2018)

tylerwatts said:


> I agree, Defenders are permanent AWD. Only hi & low ratios. I'd recommend trying to lose the AWD completely and go directly rwd. Either use the transfer box for 2 speeds and lock/weld the diff without a front drive shaft or if you can get a crawler crown & pinion ratio (or swop to a different axle with crawler ratio like a Dyna) go directly to the axle. Only trick then is running an empty front axle or swapping to a solid beam?
> Personally it's alot of work but I'd build a custom independent suspension subframe for the front and also the rear and mount entire leaf motor into subframe in the rear. You could pack all battery into the engine bay in a nice brick/block of cells easily removable.
> Whatever way it has potential to be a brilliant conversion.


Yeah...this would be waaayyy beyond the scope of this project. This is meant to be a straight forward electric conversion, not a complete redesign of suspension systems etc etc

If I were to go this route Id do something different. Im working on a few small bits and pieces for my other "project car", a 73 Firebird, and one of those is working with a metal shaping guy (http://www.chris-isaacs.com) who also does customs chassis work so a completely new chassis with IFS and only rear wheel drive would be the ticket! Some other time


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## jp455 (Mar 28, 2018)

DaveP said:


> I'm pretty sure the ECC direct drive Defender was keeping it's 4x4, but to be 100% you'd have to ask them.
> 
> Talking about steering above, whats the plan there? obviously it will need power steering but you're going to loose the pump when the engine goes. Are you going to convert it to EPAS?


There is a company doing EPAS for classic cars...that may be an option. Ideally Id love a front driven accessory plate like the one EV West does which includes the AC compressor and such. I'm still on the fence about this one. There's also electric power steering pumps...that might be the most straight forward solution.


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## brian_ (Feb 7, 2017)

jp455 said:


> Yes, that's true that no current EVs have a gearbox...


Just to be clear: they all have a gearbox, but they don't have a _multi-speed_ gearbox (just a single ratio or "single speed" gearbox).



jp455 said:


> ...this would only be for simplicity sake. That being said though, would there not be a benefit to keep the electric motor in a certain RPM range to extend the battery life? Or is that completely irrelevant for electric motors, and they use the same amount of power regardless at what RPM they're running at?


Motor speed does matter both to available power and to efficiency. In most production EVs, the manufacturers have decided that the efficiency benefit of changing ratios is not sufficient to justify the cost, weight, and complexity.

To me, the main reasons for wanting multiple ratios would be:

use of a motor which does not have as wide an effective speed range as the high-voltage motors used in production EVs, or 
wanting to operate well at both highway speeds and very slowly, such as crawling off-road.
For just crawling off-road, the low range of a typical "transfer case" (which is really a multi-function device with auxiliary transmission, front drive disconnect, and "drop" or "transfer" gear or chain set) would provide the desired reduction gearing... especially if extra-low gearing is available, such as 4:1 rather than the more typical 2.5:1 or so.



jp455 said:


> The other option which I forgot to mention is getting rid of the gearbox, and replacing it with a 2 speed over drive unit which would give 2 speeds.


A more compact and simpler two-speed gearbox - intended as an auxiliary unit behind a conventional transmission but used in this case as the only transmission - is an appealing idea. A couple of notes, though:

You probably need an *underdrive* (with one direct ratio and one reduction ratio) rather than an overdrive (which has one direct ratio and one overdrive ratio), since you probably want the motor to run faster, not slower.
These are not nearly as easy to find as they were a few decades ago.


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## brian_ (Feb 7, 2017)

tylerwatts said:


> Personally it's alot of work but I'd build a custom independent suspension subframe for the front and also the rear and mount entire leaf motor into subframe in the rear.


At that point, wouldn't it be a completely custom chassis which happens to have a Defender body - and perhaps some of the frame - on top? Like this:


jp455 said:


> Im working on a few small bits and pieces for my other "project car", a 73 Firebird, and one of those is working with a metal shaping guy (http://www.chris-isaacs.com) who also does customs chassis work so a completely new chassis with IFS and only rear wheel drive would be the ticket! Some other time


Some people do stuff like that, but it's pretty extreme.


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## brian_ (Feb 7, 2017)

jp455 said:


> Ideally Id love a front driven accessory plate like the one EV West does which includes the AC compressor and such.


This one?
EV West Accessory Plate & Pump System For HPEVS AC-34/35/50/51
I can't imagine wanting power steering that doesn't work under 5 MPH or air conditioning that shuts off when stationary or creeping. I suspect that they built this for people using Powerglide transmissions (which make the motor turn all of the time), and then decided that it was usable even without idling.

In contrast to what EV West says, a separate motor for each accessory - suited specifically to that accessory and running only as required - makes far more sense to me. Even using their accessory mounting and drive set with a single motor dedicated to the accessories (and running at constant speed) would be more effective.


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## brian_ (Feb 7, 2017)

jp455 said:


> I was thinking the older style Toyota/Jeep transfer cases.


... and lots of current pickup truck and Jeep transfer cases, too.


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## DaveP (Mar 29, 2018)

I agree with Brian, I can't see how an accesory plate thing would work with a power steering pump. Surely when you need it most is at very low speeds, but then the motor wouldn't be turning enough to make the power steering pump work.

Also, I'd be surprised if the companies that make EPAS solutions for classic cars have a Defender kit. The reason being that they usually make kits for classic cars that didn't originally have power steering. Making a kit for a car that originally had power steering would be a very VERY small market for them  Maybe they can sell a generic kit that you can fit to any car, although it would need to be powerful enough to deal with the Defender's steering torque which is huge. I'd be wary of getting one off a production car that has EPAS like a Vauxhall as it might not have the grunt for the Defender application.


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## DaveP (Mar 29, 2018)

I just thought..... the classic Range Rover that ECC converted to electric last year must have originally had power steering on. A quick search on ECC's facebook page turned up this EPAS converted steering column they made.










Maybe it's the same or similar to a Defender one, or maybe they can convert your column for you as they're going to have a similar problem to overcome with the 2 Defenders they're converting. If they're building 2 anyway maybe they can build a 3rd for you cheap


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## brian_ (Feb 7, 2017)

DaveP said:


> ... it would need to be powerful enough to deal with the Defender's steering torque which is huge. I'd be wary of getting one off a production car that has EPAS like a Vauxhall as it might not have the grunt for the Defender application.


That raises a question: if you want to use the original hydraulic rack and just provide electrically-pumped fluid, what's the heaviest car that came with electro-hydraulic power steering (EHPAS or EHPS)? My Mazda 3 has it, along with all the other cars built on the Ford C1 platform, probably using TRW pumps, and maybe all the same model of pump; however, TRW does offer different pumps with different capacities. The 2006–2013 Volvo V70 isn't small, and the Defender probably has slower steering which would reduce the load on the pump.

Toyota pioneered production use of this system in the W20-generation MR2 (to avoid long hydraulic lines between the steering rack and the mid-rear mounted engine); however, I don't know what else they have used it on, and I have read that Toyota has discontinued this system. They apparently don't even sell the fluid for it any more, so the system probably hasn't been used in new Toyota vehicles for at least a decade.

The trend for a decade has been away from this system of steering boost, which was an interim step between engine-driven hydraulics and directly powering the rack or column with an electric motor (Electric Power Assisted Steering or EPAS). There will now be a huge selection of non-hydraulic EPAS systems from production cars, some with the motor in the column and others with the motor on the rack, but any of them will be a challenge to control unless offered as an already sorted-out aftermarket solution because they expect commands over CAN. Even the pumps for electro-hydraulic systems can be difficult to control; the simple operation of the Toyota W-20 system is one reason for its popularity in EV conversions and engine swap projects.


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## goingbush (Jun 20, 2017)

Been away just caught up with this. Following with intrest

Ive been building / modifying LR for 35 years

Defenders don't have rack & pinion steering have a PAS steering box . I would not even bother I have armstrong steering in mine & its a non issue. 



If you do there is no problem putting an RRC column in a Defender , Ive done it in a RRC/ Series hybrid , Defer steering wheel even fits.

This is my Electric LandRover www.goingbush.com/ptev.html

If you want to ditch the constant 4x4 ( I'd keep it) Santana PS10 / Iveco Massif have a 2WD /4WD version of the LT230 transfer case , it will bolt straight in.

or Ashcroft have a 2wd/4WD kit for your LT230

http://www.ashcroft-transmissions.co.uk/miscellaneous/part-time-4wd-kits.html


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## brian_ (Feb 7, 2017)

goingbush said:


> Defenders don't have rack & pinion steering have a PAS steering box .


Good catch... but the electrically-pumped hydraulic assist option is still available... it's just a hydraulic steering box instead of hydraulic steering rack.  The hydraulic cylinder in the Land Rover PAS box is very short, so it may need a lot of pressure to be effective, compared to a typical hydraulic rack.

Of course in the straight electric assist, the only option would be the column-mounted motor, since no one builds a motorized worm&sector box. It could be done, of course, but powering the column is the more obvious solution.


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## jp455 (Mar 28, 2018)

DaveP said:


> I agree with Brian, I can't see how an accesory plate thing would work with a power steering pump. Surely when you need it most is at very low speeds, but then the motor wouldn't be turning enough to make the power steering pump work.
> 
> Also, I'd be surprised if the companies that make EPAS solutions for classic cars have a Defender kit. The reason being that they usually make kits for classic cars that didn't originally have power steering. Making a kit for a car that originally had power steering would be a very VERY small market for them  Maybe they can sell a generic kit that you can fit to any car, although it would need to be powerful enough to deal with the Defender's steering torque which is huge. I'd be wary of getting one off a production car that has EPAS like a Vauxhall as it might not have the grunt for the Defender application.


Th EPAS company Im thinking about (cant recall their name right now) doesnt make set EPAS for each classic, they do more of a retrofit to any type of steering column type of thing. So their system would definitively work on a Defender. Essentially its custom made.


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## jp455 (Mar 28, 2018)

goingbush said:


> Been away just caught up with this. Following with intrest
> 
> Ive been building / modifying LR for 35 years
> 
> ...


Thanks for that info! Id definitively leave the stock transfer case...no need to add additional complexity.

On a side note...Ive seen your videos a while ago. Excellent build! My wife actually originally wanted something similar to your lightweight but the UK weather doesnt much lend itself to driving a Land Rover with a canvas roof year round... Its a sham because of all the cars Iv oned one of my all time favorites was a Jeep CJ8/Scrambler (I know, I said the J word) which only had a bikini top pretty much year round. Then again that was in Florida...

Oh and yes, no rack and pinion, but an electric pump to power the stock steering box should work just fine.


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## jp455 (Mar 28, 2018)

This is the EPAS company I was talking about. They're Dutch and actually have done an EPAS conversion on a Series Land Rover already...

http://www.ezpowersteering.nl/type/26/87/Land_Rover_Series.html


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## Snizinskas (Mar 31, 2018)

I think I have read somewhere that for Range Rover electric they have used electric steering pump from new Mini One which also adjusts the assistance based on car’s speed.


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## jp455 (Mar 28, 2018)

Cool...that can be an option too. Although a simple pump with no variable assistance would make things easier perhaps.


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## brian_ (Feb 7, 2017)

Snizinskas said:


> I think I have read somewhere that for Range Rover electric they have used electric steering pump from new Mini One which also adjusts the assistance based on car’s speed.





jp455 said:


> Although a simple pump with no variable assistance would make things easier perhaps.


Any recent steering pump should be able to change pressure to vary assistance. The challenge is telling it what to do, which is usually a CAN communication.

It looks like control the unit in the first BMW Mini might be unusually simple, according to this discussion from a BMW forum:
Mini Electric Power Steering Pump...
That discussion is somewhat questionable, because it states that there is no control logic needed, but includes a document showing that the pump's output pressure varies with steering action. It also mentions response to steering action, but not road speed.

Another article suggests only a simple low/high assist logic, based solely on steering activity:


> The electric pump has circuitry which is used to control or "modulate" the power drawn from the car's electrical system as well as control the hydraulic fluid flow according to the steering system demand. This allows the motor to run slower (and draw less power) when there is little or no need for assistance, such as when driving on straight roads or idling in traffic. When the driver turns the steering wheel, the control circuitry built into the pump's motor increases current flow to the motor, making it spin faster and subsequently moving more hydraulic oil through the steering rack at a higher pressure. Sharp turns and tight maneuvering such as city driving, parking and autocross events keep the motor/pump running in an elevated power state. Once the road straightens out, the system returns to a reduced power state to cool off, save power and increase component life.


I also wonder about the motor for this pump - from various Mini forum discussions it appears to be a brushed (presumably PM DC) design, which has wear problems. Surely this thing which runs all the time should be brushless, right?

The whole early BMW Mini setup looks a generation out date in technology to me... but maybe that suits a Defender.


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## jp455 (Mar 28, 2018)

Right, and that's my point...I'm not going to get involved with CAN signals to vary pump assistance etc etc...this has to be a conversion with as few variables as possible, and the ones that are inevitable have to be as simple as possible as well.

In any case...I think there's several options for power steering. First things first, motor and battery selection.


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## jp455 (Mar 28, 2018)

So battery wise I think I will go down the Leaf route. Theyre available, have all the hardware to connect them, and are not too expensive. I need to check the volume where Ill put them (fuel tank position, and on top of the motor, maybe even along driveshaft). If there is enough space I will try to go with the initial calculation of 100 modules.

The motor I need to select. Im leaning towards connecting it directly to the transfer case though and getting rid of the gear box.


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## goingbush (Jun 20, 2017)

Just spotted aftermarket Electric power steering , page 27 Spring issue LRO Magazine. suits early RRC , 90 & 110 , goes inline in the steering column. 469GBP

link http://dcelectronics.co.uk/Products/EPAS/


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## jp455 (Mar 28, 2018)

Cool! Will definitively check it out. Thanks!


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## Kevin Sharpe (Jul 4, 2011)

goingbush said:


> Just spotted aftermarket Electric power steering , page 27 Spring issue LRO Magazine. suits early RRC , 90 & 110 , goes inline in the steering column.


Many of these systems use the Vauxhall Corsa (GM) power steering assembly... I have one for my conversion and hope to eventually have it integrated into the open source inverter software


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## brian_ (Feb 7, 2017)

Kevin Sharpe said:


> Many of these systems use the Vauxhall Corsa (GM) power steering assembly...


Good tip!  That certainly looks like the same hardware.

For those in North America, the Opel/Vauxhall Corsa has never been sold here under any name. Perhaps the same powered column appears in another model? In any case, lots of cars (including GMs) have electrically powered columns here, and have for many years, even if not exactly the same unit.

For example, EV West offers an Electric Power Steering Unit for Electric Vehicles, which appears to be based on a GM unit (but not the one from the Corsa), and they provide quite a bit of information linked to that page about how it works.


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## Kjnevin (Jan 20, 2021)

jp455 said:


> Cool! Will definitively check it out. Thanks!


Brian, 
Did you ever go ahead with this project? 
Please let us know???? 

Keith


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