bmwe21.net forums

Project still ongoing.
So i was still waiting for painting, the guy took longer than usual but now next month should get the chassis painted, then I can continue the project in full motion again.
In the meantime I did service on the M54B25 engine, replacing all of the gaskets,seals, PCV system etc. I had to make a custom oil pickup tube for it from the M54 pickup tube since M50/M52 E34 pickup tube wont work with M52TÜ/M54 due to different design. Still probably have to modify E34 oil dipstick tube to accommodate PCV oil drain but i have done that already once before for a different project...
Using the bigger 240mm clutch which was bolt on.

Since I've had time I designed all new wiring harness for the whole car, i did not want to keep the original fuse box under the hood due to room constraints anyway. I'm going to be putting everything in the trunk(custom fusebox, battery etc) and I'm utilizing E39 LCM module (from the donor) so there won't be fuses for lights and i can control output voltage as I see fit, doing USA park lights in case i want to with soft mod etc.
I'm making new schematics in wiring diagram software for this which are basically finished. It's quite simple car anyway regarding electronics so there wont be much.
Doing a lot of streamlining and trying to keep everything to minimal, for example using E60 M54 alternator since it doesn't need external voltage for excitation coil, so i won't need a seperate fuse for that.

Probably also have to use E28 rear differential speed sensor to drive the speedometer which i will have to modify also accordingly. But I did find in another forum that i could possibly use E30 G240 transmission internal gear to fit G250 so theoretically I could run the original cable system. But will see which route should I decide to go.

I have also found this rather useful project for Arduino in case I will go the route of custom fuel tank and i want to convert for the E21 fuel gauge since my tank has pinholes in it and i can't seem to find a reasonably priced fuel tank that can be reliably salvaged. I would probably use E39 or E36 fuel tank sender along with fuel pump in this case. It has the added benefit of in-tank fuel pump.
This can also be used for coolant temperature gauge possibly, since the characteristics of E21 coolant temp sensor are probably way different from M54 engine.
https://kswichit.net/E21gauge/E21gauge.htm

Also in Ebay I found from Turkey you can buy brand new door cards for ~200€ for set of fronts in case anyone needs. Haven't bought them yet though.

interesting project, I'm following

Nice looking project, and serious work on the body.

I'm building a M54B30 in en E21 as well, checkout my page on the Dutch part of the forum!

https://www.bmwe21.net/forum/viewtopic.php?t=28071

Not sitting still, nice!

Thijsse wrote: Wed Apr 23, 2025 4:37 pm Nice looking project, and serious work on the body.

I'm building a M54B30 in en E21 as well, checkout my page on the Dutch part of the forum!

https://www.bmwe21.net/forum/viewtopic.php?t=28071

Checked that, you have kind of similiar ideas as me I see. I was thinking of other chassis axles as well but decided against it so i would get the car finished faster so E28 rear axle and 323i front axle was a good choice.
Fusebox & LCM I was thinking also of putting underneath dash but decided against it because there is not a lot of room there.
For my application I'm up to 9 blade fuses right now + 5-6 main fuses(high current) for which i will use factory E39 battery distributor. There is a 8fuse hella blade fuse holder which is small and compact which i will use.

I also want to integrate subwoofer in rear parcel shelf, an 8" sub should fit and i'm going for infinite baffle application. But this will also require doing something with the boot opening mechanism since it will be in the way. I'm thinking of using smaller shocks to open boot like in newer cars.
Sound wise i sourced a 5channel class D amp. I was thinking of going 6" components in the front and modify the opening but i'm unfortunately probably going with 6x4" coaxials since it is kind of impossible to make the hole bigger due to frame... I really do not want to put a speaker inside the door card for now.
So all of my fusing, LCM battery etc will go into the trunk wall keeping rest of trunk area clean for holding crap.

I'm probably going electric power steering at some point, so the E60 155A amp alternator will help with that aswell compared to 90A I had originally on the M54 which had bad slip rings anyway.

Actually i wanted to put an N52B30 which is lighter than M54 because its from aluminium-magnesium alloy and has more power but realistically i have too many ideas i want to implement and M54 was easier right now because of the bolt-on tested mounting kit. Maybe in future i will do it.

I get your ideas. Not putting a soundsystem in just listening to the turbo whistle.

There are a lot of more powerfull engines to choose from, depends on how much you want to spend