2003 UK M3 CSL

[heinzboehmer]

Awesome! Looks like a great time.

The only non-genuine interloper was Andres Diaz (off this forum), but as he was prepared to ship his car over from Cali (and it featuring every genuine CSL part apart from the rear glass), it would have felt pedantic to not have let him join us.

Oh cool, helped him set up his DME when he got his intake on. Great guy.

[0-60motorsports]

The blue one is wrapped (and owned from new) and the two white ones and titanium silver one (which you may spot in subsequent Instagram posts) have been subject to full colour change resprays. I must admit that the white ones look particularly good in the flesh.....

The only non-genuine interloper was Andres Diaz (off this forum), but as he was prepared to ship his car over from Cali (and it featuring every genuine CSL part apart from the rear glass), it would have felt pedantic to not have let him join us.

I thought they were asking about the Saudi LSB M3 there with the CSL bits. Sorry for the mixup.

[Mike RT4]

I thought they were asking about the Saudi LSB M3 there with the CSL bits. Sorry for the mixup.

The blue Saudi one didn't stay long, he came in to have a picture of his car taken with the CSLs (they turned up together with a NSX, a NSX-R and a R34 GTR Nur-spec). This car also had many genuine CSL bits on, but retaining the steel roof, it was clearly not a CSL. However, as the owner was obviously a CSL / E46 fan and the guys were all genuine petrolheads, we didn't have any objection to them having some photos that they would remember for a long while .

[0-60motorsports]

The blue Saudi one didn't stay long, he came in to have a picture of his car taken with the CSLs (they turned up together with a NSX, a NSX-R and a R34 GTR Nur-spec). This car also had many genuine CSL bits on, but retaining the steel roof, it was clearly not a CSL. However, as the owner was obviously a CSL / E46 fan and the guys were all genuine petrolheads, we didn't have any objection to them having some photos that they would remember for a long while .

Oh yeah i was following him. Nice of you guys.

[Mike RT4]

So I've been mainly enjoying the car, doing a few track days and the like. In the background. I've also been doing some detailed mods, as I wanted to accurately measure the oil temps for the engine, transmission and diff. As most will know the OEM gauge (using a sensor that also measures the oil level) doesn't actually measure the temperature in the traditional way, so therefore isn't hugely accurate. I also know that diff oil temps can get quite high on track (hence the Schirmer cars running diff coolers), so wanted to know the exact data for that.

However, I didn't want to have unsightly gauges in the car, start cutting anything about or lose the OEM oil level sensor (as it being a CSL, it doesn't have an easily accessible dip-stick.

As stated, the OEM oil temp sensor is not particularly accurate (as it works like a MAF sensor and does both the level and temperature by sending electrical current through the oil and measuring the resistance) and also does not display sufficient detail IMO. In addition, judging by the way it operates, I am surmising that the factory temperatue read-out may change with differnet oil viscosities (I know some people use thinner oils than 10w60).

With this in mind, I scoured the internet for something off the shelf and everything looked either too after-market, required modification to panels (or sacrificed vents) or had features I felt I didn’t need (as it duplicated what I already have on the IBUS part of my AVIN 4).

This meant I had to come up with my own solution and I'm fortunate enough to have some very helpful / talented people within our CSL chat group (as well as some great contacts developed over the years through my own business).

I decided that I wanted the design to look like a cross between the OEM speedo and rev-counter and work in a similar way to the rev counter lights, but the light-bars coming on instead of going out until the desired temperature ranges were reached. E46/CSL guru New Zealand Tom kindly provided the information on when the lights extinguished on the dash (the last one should go out only when the oil has reached 80°C), so that was my blue "cold" range 40-80°C (104-176°F) and then the green "normal" operating range would be 81°C to 120°C (178-248°F) and then the yellow "track use" temperature range being 121°C to 140°C (250-284°F). The “slow-the-feck-down” red” range is then anything above 141°C (286°F). Although the manual states that you should not exceed 150°C (302°F), I never really want to go that high, so decided to set the upper limit lower (especially as the OEM gauge is optimistic anyway), so at the > 141°C (286°F), the bars go red as well as flash to ensure it attracts your attention.




So I did some photoshopped images of the design I had in mind and over the coming weeks these were refined into the finished article you see here by a friend of mine who I’ve known for almost 30 years and his son (a talented app programmer).




I knew exactly where I wanted it mounted, wanting somewhere that would require no modifications to trim panels and another friend came onboard and kindly offered up his talents with the 3D printing of the panel that now slides into the ashtray area (as if BMW made it), and is where all the electronics for the gauge reside.





Prototyping for test fitting etc:







First "finished" version:


It was at this stage that I realised that we could easily also measure the gearbox and diff temperatures using the same gauge with just another couple of sensors. So the buttons you can see (touch sensitive items that pick up the electrical energy from your finger) on the panel are to cycle through the different monitoring parameters, as well as doing the peak recall for each of them. This peak is wiped clean every time the ignition is shut down, so that it only ever shows the peak temperature of that particular engine run-time cycle.

If you’re wondering about the sensors, we felt the easiest solution was to build these into the sump plug for the engine oil temp and the drain plugs for the gearbox and diff. Obviously this will mean that the time to fit these is at an oil change (unless you've got a quick hand and don't mind a little mess LOL).

The diff sensor was fed through the grommet in the boot (trunk ):


The sump and transmission sensors went through the grommet in the passenger footwell (RHD car) and come out exactly where you want them to (as if BMW had planned for it ):


Sensors (on waterproof connectors so that they can be disconnected for draining the oils). Because the diff one is in a particular exposed area, this is also sealed for protection:
Diff:


Transmission:


Sump:



The opening of the ashtray panel turns the gauge on (and off), so you don’t have to have it running all the time and it even goes into night mode when the lights are turned on to ensure it mimics the dash.
Lights off:


Lights on (the colours mimic the dash with the lights on, but the phone camera doesn't show that exaclty).


And here is a short video showing the various developmentt stages of the build and with the gauge in operation (be aware that the camera gets some glare back when filming directly head on, but is not what your eyes see. Once I realised, I tried to do another (which was more successful), but the temps were a lot cooler by then):

https://youtu.be/WnPnpQHDj6o?si=VS09vnyGSNMnBsDg

I'm not completely happy with the gauge yet, as I have realised that scrolling between the screens is a bit of a faf, so intend to make it three separate gauges (which should fit comfortably within the tray - and look nicer IMO). I also haven't tested it on track yet to see what temperatures it gets up to in extreme use, this will take place on 18th July and I will take some more video then. At present in the short amount of (road )testing done, the oil temps pretty much match the water temps (87°C / 188°F) and the transmission and gearbox oils never went much above 50°C (122°F) in the short journey I did. This was in a straightline cruising in 6th gear at around 85mph (and interestingly the diff and transmission practically matched each other as they warmed up, where it is just rotational friction heating up the oil - the true test will be on track).

[0-60motorsports]

Love it Mate! Thanks for the hard work on this. That seems very very handy to have especially in a Hot environment like mine.

[heinzboehmer]

Awesome work on the gauge! That place is great for it, have something similar in my car. Might have to steal the idea of the microswitch to turn it on/off.

Also, I'm guessing that you're grabbing light status from the cluster over CAN to control dark mode. If you do have the gauge wired into CAN, you might consider using some other buttons in the car to control the display. Gauge.S uses the cruise control buttons to do so and it works great, but that's not really useful for you cause CSL. I bet you can find some other buttons that aren't used much though. Could also wire into I bus and use the radio buttons.

[Mike RT4]

Awesome work on the gauge! That place is great for it, have something similar in my car. Might have to steal the idea of the microswitch to turn it on/off.

Also, I'm guessing that you're grabbing light status from the cluster over CAN to control dark mode. If you do have the gauge wired into CAN, you might consider using some other buttons in the car to control the display. Gauge.S uses the cruise control buttons to do so and it works great, but that's not really useful for you cause CSL. I bet you can find some other buttons that aren't used much though. Could also wire into I bus and use the radio buttons.

Thanks, it means a lot coming from you .

As the next stage will be three indivual gauges, there will only be a need for the peak recall switch, which can basically go anywhere (as there are no spare buttons in a CSL, I was thinking maybe in the panel where the three buttons reside under the HVAC controls:

[heinzboehmer]

Oh! Android head unit, interesting...

I like the three gauge approach, but yeah you should definitely add a way to control the gauges in place. As accessible as that space is, removing the gauge from the car for a simple tweak gets old fast.

How about an app for the head unit? Bluetooth or I bus should both work fine. I bus would be cool cause you could feasibly control it with other things as well (e.g. BlueBus), but bluetooth means you could also control it from your phone.

Always here if you need more ideas for your project to go way, way out of scope

[Mike RT4]

Oh! Android head unit, interesting...

I like the three gauge approach, but yeah you should definitely add a way to control the gauges in place. As accessible as that space is, removing the gauge from the car for a simple tweak gets old fast.

How about an app for the head unit? Bluetooth or I bus should both work fine. I bus would be cool cause you could feasibly control it with other things as well (e.g. BlueBus), but bluetooth means you could also control it from your phone.

Always here if you need more ideas for your project to go way, way out of scope

Yeah, as stated in my OP, I have the AVIN 4 with the IBUS and Appple Car Play.

Thats quite some mission creep LOL.

I just want to know what everything is doing temperature wise on track, so although nice, the above suggestions would extend the project time considerably.

The main reason for the interest in transmission temps is that when we were shown around the cars at Schirmer on the CSL 20th Anniversary trip, I was astounded at the size of the cooling arragement they had on the rear diff of Jangobipbip's CSL build and Tom explained that when lapping continuously at the Nordschliefe, without it, the diff oil cooks itself and then it looses all it's locking ability with such high temps.

Sadly, we weren't allowed to take pictures, Best images (sort of) showing the set-up are here:

https://www.instagram.com/reel/CprnQPeIhLS/?utm_source=ig_web_copy_link&igsh=MzRlODBiNWFlZA==

[Obioban]

Would you be willing to upload the CAD file for the ash tray insert? Having something that fits plug and play into that area without cutting seems like it would be a good starting point for all sorts of projects.

[Mike RT4]

Would you be willing to upload the CAD file for the ash tray insert? Having something that fits plug and play into that area without cutting seems like it would be a good starting point for all sorts of projects.

Do you have a preference to a particular format (as I can email it to you, so you can upload / host here)?

[Obioban]

Personally I'd like a solidworks part file, but a step file would probably make it the most universally useful.

I'll PM you my email.

[Johnydesmo]

Hi, my first post, Mike sent me, I am the very lucky owner of a (faster SB ) CSL here in the UK - bought within weeks of Mikes in 2013 ...although his has seen much more proper track use!
I have uploaded a blank panel here: https://cults3d.com/en/3d-model/gadg...ay-blank-panel for anyone wishing to create a project that fits directly into your ashtray...
Feel free to contact me if you wish a different format

[Obioban]

Thanks!