Hydraulic steering conversion - N52-engined Z4 models

Hydro_Z4 · Post by **Hydro_Z4** » Tue Jun 14, 2022 5:38 pm

Only difference between E46 LCI and Z4M steering racks would be the ratio (13,7 vs 12,8) and of course the price...
Technically the conversion would be very similar.

spec-al · Post by **spec-al** » Tue Jun 14, 2022 5:49 pm

Hydro_Z4 wrote: ↑Tue Jun 14, 2022 5:38 pm Only difference between E46 LCI and Z4M steering racks would be the ratio (13,7 vs 12,8) and of course the price...
Technically the conversion would be very similar.

thanks! I have a lead on a z4m rack at a comparable price so I was curious.

yg54sg · Post by **yg54sg** » Tue Jun 14, 2022 6:02 pm

From what I gather its the same rack as the purple one I used :

Standard E46 M3: 15.4:1
E46 M3: CS / CSL = 14.5:1
Purple Tag: 13.7:1
E46 330 ZHP: 13.7:1
Z3 1.9 or 2.2: 13.7:1
Z4M Roadster: 13.7:1
Z4M Coupe: 12.8:1

yg54sg · Post by **yg54sg** » Tue Jun 14, 2022 10:42 pm

Looks like the coupe has a quicker turn ... interesting

Special Kay · Post by **Special Kay** » Mon Jul 18, 2022 4:26 pm

I know this is quite an old thread, but kudos to Hydro Z4 for a very comprehensive write up. I will definitely keep this thread in mind if I start to have problems with my steering. Thank you for such a great write up

Hydro_Z4 · Post by **Hydro_Z4** » Mon Jul 18, 2022 4:30 pm

Thank you for the compliment

portculisz4 · Post by **portculisz4** » Thu Jul 21, 2022 3:10 pm

Scanning through the forum I came across your informative description on the hydraulic steering conversion. I am now seriously considering doing this to my 2005 E85 2.5i Z4 so I am going through the various steps to make sure I have thought about all the detail. I have a number of questions which I would like to ask (I will start with one now and add further questions later as I progress through the list)
The first is the intermediate shaft - I take onboard the different size splined fitting of the Z4 shaft going to the racks splined input shaft and the solution to use the Z4M intermediate shaft, but is it possible to swap the lower splined knuckle joint on the Z4 shaft with the lower knuckle joint used on the E46 intermediate shaft by removing the hardy spicer joint at the lower end. Would the length of the modified Z4 shaft be adequate to connect the end of the steering column shaft to the steering rack input ??

Hydro_Z4 · Post by **Hydro_Z4** » Thu Jul 21, 2022 4:30 pm

portculisz4 wrote: ↑Thu Jul 21, 2022 3:10 pmScanning through the forum I came across your informative description on the hydraulic steering conversion. I am now seriously considering doing this to my 2005 E85 2.5i Z4 so I am going through the various steps to make sure I have thought about all the detail. I have a number of questions which I would like to ask (I will start with one now and add further questions later as I progress through the list)

No worries. Happy to help.

If I'm not mistaken your Z4 2.5i isn't N52 engined but M54 engined.

As mentioned in my initial post that actually simplifies the conversion...
This guide should map quite well to M54-engined cars, with adjustments to take into account LF-20 instead of LF-30 steering pump. This should be limited to high-pressure line from pump to rack (specific to LF-20 steering pump - there are LHD and RHD versions), V-belt 6PK 1538 (11287636379) and mounting screw M8x22 (07119905739). There is a M54 mounting bracket for the reservoir (32411092940) with screw (7119904524) and 2x screw (7119905529).

portculisz4 wrote: ↑Thu Jul 21, 2022 3:10 pmThe first is the intermediate shaft - I take onboard the different size splined fitting of the Z4 shaft going to the racks splined input shaft and the solution to use the Z4M intermediate shaft, but is it possible to swap the lower splined knuckle joint on the Z4 shaft with the lower knuckle joint used on the E46 intermediate shaft by removing the hardy spicer joint at the lower end. Would the length of the modified Z4 shaft be adequate to connect the end of the steering column shaft to the steering rack input ??

As mentioned in my initial post, that's it's exactly what BMW did for the Z4M intermediate shaft. Any decent machine shop should be able to perform this step. However, considering new price from BMW of around €/£/$ 200-300, there would be little to no financial incentive to undertake this in my opinion though. In terms of length there is no notable difference between Z4, E46 or hybrid (Z4M) intermediate shaft...

yg54sg · Post by **yg54sg** » Thu Jul 21, 2022 4:38 pm

After doing this conversion I think it’s peace of mind just buying the z4m intermediate shaft rather than machine shop or any modifications … I’m a tight Yorkshireman and always go for the cheap option but realised if this fails your doomed … plus your already saving £2500 on electric rack replacement … might make you feel better about handing over 250 quid for a bit of metal with a couple of universal joints

portculisz4 · Post by **portculisz4** » Fri Jul 22, 2022 10:32 am

Thanks for your reply, will almost certainly go the Z4M way but interested to know whether others have looked at this. Also, very interested to hear of others experience in doing this conversion, did you go for the E46 purple rack, I have read threads on suggestions to use the Z3-E36 rack which has a lower turns ratio (2.7) but not sure if this swap is directly compatible with the E46 rack swap.

portculisz4 · Post by **portculisz4** » Wed Jul 27, 2022 10:30 am

hydro-Z4
I have now got a E46 purple rack (which I will service with a new seal set) and an LF-20 pump (which I have just serviced and it looks to be in excellent condition) so this will be my hydraulic conversion base for the steering. Can you confirm on the pulley diameter you are using since the pulley P/N listed above seems to list a whole generic set of items and I cannot see the pulley listed amongst them so will buy seperately. I have seen sizes referenced from 119 - 135mm, the size will obviously affect the pressure output so would like to get the most appropriate for my setup

Hydro_Z4 · Post by **Hydro_Z4** » Wed Jul 27, 2022 2:11 pm

All 6-cylinder E46 use a pulley with D=135mm
Partsnumber 32421740858

Mounted using 3x hexbolt with washer
Partsnumber 07119905527

Robson · Post by **Robson** » Thu Feb 02, 2023 12:56 am

Hello, is there any way to change the cross on the connector to fit the E46 gearbox

fearty · Post by **fearty** » Mon Jun 05, 2023 9:57 am

Hello,

I made my account just to share my experience related to the conversion of electrical to hydraulic steering. With no using new shaft from Z4M.

1/ The conversation was done on M46 engine, on the car which I converted from right-hand drive to left. Only a hydraulic pump is needed, not any additional pulley, belts, etc. The hydraulic pump is behind water on the same shaft.

2/ I did not buy a middle shaft from Z4 M, just exchanged the top part E46 to Z4 one in my leaving room. It is not hard, I used dremmel tool to "unlock" small bearings and pull them out.

3/ To turn off the steering dash light I used Scanner 1.4. Very easy just put out the tick for the steering light from the dash menu. Also the same tool to adjust the steering sensor.

Hydro_Z4 · Post by **Hydro_Z4** » Mon Jun 05, 2023 1:09 pm

Great to see others expanding on my original post.

Awesome addition

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