E36 cluster swap

[treff-7]

For those who considered this swap I share my findings on fitting an e36 cluster in an e30. My reason for the swap is to have a bit more updated look and the 8k RPM gauge to go with the s52 in my car. I dug into the ETM of both cars and there is no reason for an e36 cluster to not work in and e30 with M20 so you don't have to have an engine / DME from an e36 for doing this.

I looked around but couldn't find any comparison between the 2 clusters to see how it could physically fit so I went ahead and got myself one.

Some size comparison:



As you can see an obvious challenge is to fit a sort of round thing into a sort of rectangular (trapezoid to be exact) hole but luckily the E36 cluster is smaller so it fits. I thought about swapping the electronics and gauges over but unlike the E30 cluster where each gauge is separate the E36 one is one piece and they don't line up with the E30 gauges so that plan went out the window.



Another possibility was to try to squeeze the E36 cluster inside the shell of the E30 cluster. The next picture doesn't show it well but it seemed like it could fit.



I decided to sacrifice the old ETA cluster. After a couple days of cutting, trimming and sanding I got this far:



The entire cluster fits inside the area where the gauges were. This gives me the opportunity to use the space below for some custom stuff like oil temperature, oil pressure, exact coolant temperature, voltage, etc.

I also created a cross reference spreadsheet for wiring but I won't share that until I can confirm that it's 100% correct.

I spent some more time trimming the plastic and this is where it stands right now:




I will 3D print a cover for the crescent shaped holes to pretty it up. Another problem I have right now is the trip reset button. It does not line up with the hole on the clear front cover. My current plan is to get rid of the stud, plug the hole on both the gauges and the cover and relocate the button somewhere else. It is just an electronic button unlike on the E30 cluster where the reset button is mechanical. The plug for the gauge will be a 3D printed plastic piece but I'm planning on using clear epoxy on the front cover then sanding it down flat and polishing it to try to make it disappear. I've never done that before so if anybody has an advice on it or has a better idea, please, let me know! Thanks a lot in advance!

[roguetoaster]

Well, that's quite interesting. Perhaps you could make a double offset stalk for the ODO reset and avoid relocation?

[treff-7]

I thought about it but then the offset button would cover the last indicator on the left. IIRC it's the fog light indicator light. I could also patch up the existing hole and drill a new one....

[Irwie'C]

Yeah Toaster has the right idea. Just 3d print the offset reset button.
Also, stuffing the digital gauges where the e30 telltale lamps are, is a heckin' idea! It'll look so good!

[treff-7]

This is the problem:



Look where the original hole is. Right above the last indicator light and I don't want to do a heck job slaping this together.

Ps: I have no affiliation of any kind with the brand visible in the picture but I'd take any money they want to give me. ;-D

[Gregs///M]

Interesting idea but a lot of work. It sounds like it may be easier, faster and cheaper to just customize the E30 cluster to add the 8k tach and any other features you want. We do it all the time.

The electrical should be straightforward. Our cluster tester works on both the E30 and E36 so the signals are the same. You will just need to build an interface adapter. The fuel gauge may not work properly, the speedometer will not be calibrated right. Also, the E36 has a lot of its own issues with spontaneous permanent failure from failed microprocessors on circuit board, intermittent failures with dried out capacitors and failing illumination with the adhesive for the dials.

Regardless, you are off to a good start so good luck.

[ForcedFirebird]

Curious to see the finished product!

The speedo should work the e30 and e36 share the 9 tooth reluctor in the diff, the e36 is just a bit smaller diameter. When doing the e36 dual ear diff cover swaps for the Randy Forbes z3/ti frame kits, I just cut the tabs down on the reluctor (or grab one off an e36 diff if one is in the shop), and they use the same sensor. On OBD2 e36's the ECU uses the RR ABS sensor for VSS, but the cluster still uses the diff sensor. As Greg said, tho, calibration may be slightly off due to stock tire differences.

For the fuel gauge to work, you will have to measure e36 level senders and may have use some resistors to match the e30 senders to it. I wouldn't be surprised if the e36 and the late e30 resistances match, but the early (and 318is) single sender e30 tanks will show full when full, and half when empty - this is how the endurance race car is since we used two e30 pump carriers so we can have pumps in both saddles and we can run the tank completely dry without starvation issues on long sweepers. We could change the coding plug, but the reserve light works and when that comes on, we know we have 4-5 laps left in it.

Also, you will need to change you cooling temp sender (e30 brown one, to the e36 black one), since the e30 and e36 have different resistances - just like when we swap 24v's into e30's. From memory, I want to say the e36 sender is NOT internally grounded (e30 brown sensor is a true single pol), so you may need to add a ground to the second wire on your harness.

[treff-7]

Interesting idea but a lot of work. It sounds like it may be easier, faster and cheaper to just customize the E30 cluster to add the 8k tach and any other features you want. We do it all the time.

The electrical should be straightforward. Our cluster tester works on both the E30 and E36 so the signals are the same. You will just need to build an interface adapter. The fuel gauge may not work properly, the speedometer will not be calibrated right. Also, the E36 has a lot of its own issues with spontaneous permanent failure from failed microprocessors on circuit board, intermittent failures with dried out capacitors and failing illumination with the adhesive for the dials.

Regardless, you are off to a good start so good luck.

Curious to see the finished product!

The speedo should work the e30 and e36 share the 9 tooth reluctor in the diff, the e36 is just a bit smaller diameter. When doing the e36 dual ear diff cover swaps for the Randy Forbes z3/ti frame kits, I just cut the tabs down on the reluctor (or grab one off an e36 diff if one is in the shop), and they use the same sensor. On OBD2 e36's the ECU uses the RR ABS sensor for VSS, but the cluster still uses the diff sensor. As Greg said, tho, calibration may be slightly off due to stock tire differences.

For the fuel gauge to work, you will have to measure e36 level senders and may have use some resistors to match the e30 senders to it. I wouldn't be surprised if the e36 and the late e30 resistances match, but the early (and 318is) single sender e30 tanks will show full when full, and half when empty - this is how the endurance race car is since we used two e30 pump carriers so we can have pumps in both saddles and we can run the tank completely dry without starvation issues on long sweepers. We could change the coding plug, but the reserve light works and when that comes on, we know we have 4-5 laps left in it.

Also, you will need to change you cooling temp sender (e30 brown one, to the e36 black one), since the e30 and e36 have different resistances - just like when we swap 24v's into e30's. From memory, I want to say the e36 sender is NOT internally grounded (e30 brown sensor is a true single pol), so you may need to add a ground to the second wire on your harness.

It is a lot of work but that has never stopped me before...
I wanted the backlit gauges, needles and LCD as well. I find the original odometer too old school for me. If the microprocessor fails I will have a good arduino project on my hands. I might get another cluster for spare parts. If caps fail fixing that is no problem. I might do it now while I'm in there... Thanks for the tip!
For the 8k tach I don't have a way to create an 8k face. I don't know if it's available somewhere to buy. I didn't research it.
Electrical is pretty much sorted out. I just need to double check everything before I post it here.
Thanks for pointing out the fuel gauge being off! If it is off I'll retrofit the E36 one or modify the original. I have both early and late model one so I can test both.
The difference between the E36 M3 and E30 wheel is 5.37% if my math is correct. That's not a big enough difference to concern me. The speedo shows more than the actual speed anyways so most likely it will be more accurate this way. I'll test it with a GPS when it's in the car.
Right now I have the OBD1 ECU temp sensor and the brown top E30 sensor in the head. I will swap the brown top E30 to the OBD1 E36 cluster temp sensor. AFAIK the E36 OBD1 setup is the same as the OBD2 except for the 2 sensors being in 1 housing for OBD2 (black top). Right now my S52 is OBD1 but I will change it back to OBD2 and then the temp sensors will be also swapped back.
ForcedFirebird I believe you are correct about the sensor ground.

Also my MPG indicator will be correct again! The gauge I never look at...

[ForcedFirebird]

The e30 tire diameter is smaller, so the speedo will actually read higher than an e36 tire.

I have never personally tested the OBD 1 vs OBD 2 ECU cooling sensors but OBD1: 68°f = 2.2-2.7kohm, 176°f = 290-360ohm for the ECU according to test procedures.

[treff-7]

Oh, crap! You're right! My gears were spinning backwards... So the speedo will be even more off. I'm planning on running 235/40R17's so the difference should be minimal. 1.3%
We shall see soon hopefully how OBD1 vs OBD2 compares. At least on the cluster end.

I replaced all capacitors to be safe. Now I'm trying to find a paint that's close to the original, preferably the E30 color. It has a graphite color that's hard to match.

[treff-7]

I had some time to work on the cluster. The E36 face is now attached to the E30 frame, seams and holes are sealed. I will sand it a bit more to try to make it prettier. I'm not a painter so I don't expect factory quality.

[e30dreamin]

Subscribed! Getting ready for an s52 swap. This is perfect!

[TobyB]

Oh, just swap in the whole ti dash, and then the cluster fits perfectly....


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[e30dreamin]

Is that a thing? Swapping the ti dash to an e30? I cant find any diys...

[reelizmpro]

Great idea. Can't wait to see the finished product! I always thought it would be great if someone created a kit to make the E36 M3 cluster plug and play.