Mike’s Z3 - Retro Aircon + Cruise etc Project

[MickyG]

I have long liked the “true” wide body Z3 (pre-facelift!) with its gorgeous curved rear quarters, and wide rim wheels all round. So, earlier this year I finally found a very late, March 1999, pre-facelift 2.8 with the improved M54B28 engine, with bodywork in exceptionally good condition and relatively low mileage @ 67k miles.

The drive home revealed a few home truths about a 25 year old car compared to our current daily drives!

The handling is atrocious! It tramlines and wanders all over the road!

There is no cruise control - I use it extensively: on long motorway journeys it makes driving so much more relaxed, whilst driving through towns with (ridiculously?) difficult to maintain 20mph speed limits, so much easier.

The standard leather seats are not particularly comfortable, supportive, or conducive to spirited driving.

Thirdly, lacking air conditioning was a big revelation/disappointment! We have become so used to having it that it took me back to my early days of long journey driving, with windows up, windows down, roof down, roof up , windows down, ………..

So, I have 4 major upgrades to make on my Z3.



1. Renew all the suspension rubber bushes with new OEM rubber. It had a new set of decent tyres fitted last year that have less than 500 miles wear.
Edit:
Also to make the steering more precise, swap out the standard Z3 front lower control arms, with their floating central ball joint, to the more precise sold mount ball joint seen in the E36 & E46

2. Adding cruise control - it’s very easy with the M52TU engined cars

3. Swap my (very good condition) standard seats for a set of M or Sports seats

4. Air conditioning - “The big one” : Retrofit a complete Aircon system from a donor Z3.
This is quite an involved task not to be undertaken lightly by all accounts, but I’m retired and love a challenge!



I will post a progress thread on my retrofits/upgrades for anyone who may be interested, as I have certainly appreciated many posts by other’s showing “how to”.

 

[MickyG]

Cruise Control

Choosing the easy one first, I followed an earlier guide on this forum to order just 3 plug and play components to achieve a factory cruise control system.

Cruise Control Column Stalk

Cruise Control module

Clutch Switch

M52TU engined cars are “Drive-by-wire”, (despite having a conventional accelerator cable -as it activates a potentiometer which electronically controls the throttle) making this retrofit very straight forward, along with the fact that all Z3s left the factory pre-wired for Cruise Control.
It is therefore very easy to simply add the column switch by sliding it into the existing mounting slot on the column, and plug it into the existing loom along with the plug in control module. Finally plug in the clutch switch and mount, and that’s it.
I now have standard factory cruise control
(It took only 45 minutes to install once the parts were obtained).

 

[Ianmc]

I agree aircon and cruise are essential; fortunately mine has both from factory.
Good luck with the aircon retrofit. I would imagine that is a significant undertaking!

 

[MickyG]

I agree aircon and cruise are essential; fortunately mine has both from factory.
Good luck with the aircon retrofit. I would imagine that is a significant undertaking!

Hi Ian
Lucky you with factory fitted options
Cruise was very easy to fit: Aircon will be much less so!!!!!!!!
I’ve managed to get hold of a cheap Z3 2.2 Special Sapphire Edition with Blue/Black M seats (are they exactly the same as the M - does anyone know for certain?). I do know they are much better than my standard seats for support and comfort and will go with my Atlanta Blue car.
The deal clincher was it having Aircon, and a set of Z3 factory staggered Style 32 wheels (my preferred option on a widebody 2.8).
I’ve removed the Aircon already - and am pausing, swallowing hard, and summoning up the courage to tear my beautifully trimmed interior out to be able to swap it over!

 

[Pingu]

I don't think the cruise control will work at 20mph (I've never had a car where it works below 30mph), but let us know.

Your best option for air conditioning is to buy a car with it already fitted.

It is one of the first things to be fitted to the car, so you will need to remove the engine, the dashboard and the heater box. You can avoid removing the engine if you use hoses instead of pipes, but that may not work.

Good luck.

 

[MickyG]

I don't think the cruise control will work at 20mph (I've never had a car where it works below 30mph), but let us know.

Your best option for air conditioning is to buy a car with it already fitted.

It is one of the first things to be fitted to the car, so you will need to remove the engine, the dashboard and the heater box. You can avoid removing the engine if you use hoses instead of pipes, but that may not work.

Good luck.

Hi Pingu
That’s an interesting point regarding working at 20mph.
I have an Audi Q5 with cruise - it works at 20mph, but will not kick in below 20mph.
I’ll try my Z3 and let you know if it will go down as low as 20mph.

 

[Pond]

Your best option for air conditioning is to buy a car with it already fitted.

Having worked in the A/C industry for 40 years, I fully agree. Retro-fitting a/c is NOT something I would entertain.

I did it a couple of times many years ago for money. It is not something I would ever do again, no matter what you paid me.

Ironically I have a perfectly good a/c system in my Z3, but have ditched the controls as I didn't want it.

 

[MickyG]

Having worked in the A/C industry for 40 years, I fully agree. Retro-fitting a/c is NOT something I would entertain.

I did it a couple of times many years ago for money. It is not something I would ever do again, no matter what you paid me.

Ironically I have a perfectly good a/c system in my Z3, but have ditched the controls as I didn't want it.

Ha ha - It will be time consuming, so definitely not something to try for money!
But I like a challenge, and I’m retired…….
Wish me luck, or call me foolish………or both

 

[MickyG]

I don't think the cruise control will work at 20mph (I've never had a car where it works below 30mph), but let us know.

Your best option for air conditioning is to buy a car with it already fitted.

It is one of the first things to be fitted to the car, so you will need to remove the engine, the dashboard and the heater box. You can avoid removing the engine if you use hoses instead of pipes, but that may not work.

Good luck.

Hi Pingu
The cruise does work at 20mph
(Again like my Audi, it will not set below 20mph)

 

[MickyG]

Aircon Retrofit

Edit:
Before embarking on an Aircon system removal and refit it is imperative to ensure it is set to “Recirculate” - this closes the
flaps on the blower motor. It is impossible to re-fit the flaps, after removing them to pass through the firewall, with them set open.
(I spent several hours finding out the hard way!).

My Aircon journey did not start well!

I found a guy via EBay breaking a Z3 with Aircon and agreed a price of £175 for everything, which I thought was an absolute bargain - I had been quoted £400 from a well known Z3 breaker.

6 weeks later it had still not turned up!

After a bit of chasing he removed it from his car, sent photos of it in good order and couriered it all to me.

Unfortunately this is how it arrived:

Note the blower flap front left is open - they will not pass through the firewall in this position!

The plastic case was smashed in transit
Fortunately EBay were very quick to refund me
Doubly fortunate was the condenser arrived without damage - see later).

Not to be deterred I bought a complete Special Edition Z3 Sapphire with M seats and interior plus Aircon at a bargain price ( I hope to recover most of my outlay selling parts).

Phase 1 - Remove Donor Aircon
This requires both seats, centre console, complete dash and offside headlight removal to gain access to the Aircon system.

Phase 1. Complete
I’ve now removed the entire Aircon system
Compressor
Condenser - (later noted as damaged)
Fan
Evaporator
Pipework
HVAC blower unit from under the dash
Switch from console

Next step:
Phase 2 - Remove all seat centre console dash and heater matrix from my Z3 !

 

[Pingu]

Holy Moly - you look like you are having fun

 

[MickyG]

Aircon : First Hurdle Cleared

When I bought my donor Z3, I took a bit of a punt on the compressor mounting bracket transferring from an M54B22 to my M52B28TU - I reasoned that the blocks are very similar. Google had persuaded me that the compressor is the same for both engines, although the wiring for the electronic clutch is different.
And so it has all proven to be.
The mounting bracket and compressor mated perfectly to the block, and the belt runs central to the idle pulley.

I had to splice the 2.2’s compressor trigger wire on to my 2.8’s wire, and that’s the first hurdle cleared.

 

[MickyG]

The point of no return…….
Earlier this morning my car still looked very nice….

Then the strip down began……
First the seats

Next the centre console

Then the last piece of uncertainty has been resolved: The bulkhead hole for the Aircon pipes.

BMW kindly produced all the Z3s with provision to fit Aircon: those that did not leave the factory had a blanking plate inserted in the hole and a liberal covering bodyguard applied.

The plate is simply press fitted into the hole, so was very easy to remove.

The view into the engine bay from the footwell.

I am now quietly confident I can make the retrofit work.
There is still a lot of work to do and no doubt will be time consuming and at times difficult, but non the less I see no reason why it will not be possible.
Today, right now, I’m happy…………

 

[MickyG]

Next Stage -Remove the Dash
For this stage I owe huge thanks to Dave L2 on here who provided a brilliant “How to “ guide on Dash removal: I followed his guide to the letter and found it extremely good.

Final Stage : Heater Assembly Removal
BMW don’t make it easy!
Before the Heater unit could be removed 4 nuts have to be removed from the engine bay side of the bulkhead. Access to them is behind the windscreen wiper panel.

Once removed and a few internal fixings and the two heater pipes removed the whole unit can be extracted.
And at 7pm I have completed Phase 2 (of 3).

A good days work

Next Up…….
Phase 3 : Aircon System Install.

 

[AntStark]

Impressive.. if not a bit scary

 

[Scooblitz]

Really nice work. Kudos due.

 

[Mint]

Wow, great progress. Well done that man

 

[Pond]

Yes, well done. You obviously know your way around a set of spanners.
I just hope the electrics are straightforward, as the a/c controls are complicated beasts these days.

 

[MickyG]

Yes, well done. You obviously know your way around a set of spanners.
I just hope the electrics are straightforward, as the a/c controls are complicated beasts these days.

Ha ha - if they are complicated I’m in a lot of trouble!
Blind faith and intelligent assumptions are keeping me going. Z3s were all fitted with one standard wiring loom for every option so I just need to determine which currently dormant wires/sockets/plugs are the ones to connect up and it should work………
So far I’ve found the ones I’m expecting - the compressor trigger, the main feed to the HVAC assembly and the pressure sensor.
There are just two more to find - the On/Off to the cabin switch and the fan in front of the radiator.
I’ve a delayed start tomorrow, but I think that will be when the hard work begins……..

 

[MickyG]

Impressive.. if not a bit scary

You are right - every now and again I look at what I’ve done to my perfect car and wonder if I can put it all back together again

Perversely the issue concerning me the most is retro fitting my facelift M seats into my pre- facelift car ………. Although the wiring loom is there BMW changed the plugs and colour coding, plus the M seats are heated, so working out how to wire them up is currently an unknown, to be left to the end of the project.