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BMW S54 into S30 Chassis - Build Thread


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On 2/21/2020 at 4:01 PM, Neverdone said:

You gonna use the BMW steering rack, or go with a Subaru or something?


Leaning toward going with the BMW rack, primarily for cost reasons since I already have one on the shelf. Also I'm not a huge fan of most electric power steering racks. I much prefer hydraulic and BMW is one of the best in my opinion.

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making a mount for it would be easy as it's just two flat bars that enclose the ear mounts of the BMW rack will actually lower the rack down to make more space for whatever you need. You need to shorten the inner tie-rods about an inch (from what I've read anyway) and Subaru Forester outer tie-rods mount to the knuckle and inner-BMW rods.


Add in that they're super cheaper and widely available, I'm surprised more people haven't looked into using them sooner.


Looking forward to your progress!

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Yup, I will definitely be moving the rack down from where the original would be since I need clearance to the front sump of the oil pan. You're right on with the mounts, they should be pretty straight forward. Once I have a mocked up location I'll have some brackets laser cut and weld them to the sub frame. 


It is just a delicate balance with placement. I want to make sure I'm not going to induce any weird steering characteristics by moving the rack.

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  • 4 weeks later...

well, back at it. Couple of updates today... lots of pictures too.

I got the BC coilovers welded up, and painted along with the front hubs and rear stub axles.

I also got the bearings and wheel studs put in and am just waiting on the rear brakes before I put the rear assemblies completely back together.

I also got the gauges all mounted up in the new dash, aside from the AFR gauge and voltage. Those 2 will go down lower in the center stack below the climate controls.


Alright so... in order...

Coilover sleeves welded to the original knuckles.

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Everything all prepped for paint.



Everything all painted up. I just went with an industrial Primer and Flat black top coat (2 coats primer, 3 coats top coat). I went pretty heavy on the coats to try to give it the best shot at durability. It's not powdercoat, but I think it'll hold up reasonably well in the conditions I'll be driving in.

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ARP Wheel Studs and Lug nut test fit onto a wheel

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Arizona Z car front brakes installed and fit into the wheels like they were meant for it. Plenty of clearance in all directions.

IMG_20200307_150029.jpg.8dd4e3a1cc609066e31859fed48b7510.jpg   IMG_20200307_150114.jpg.e33ac5fea38742f5f450ce181a280e71.jpg   IMG_20200307_150839.jpg.32f2c2aa866e305b99d2a08cac7003b8.jpg


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I'll post up a few pictures of the rear brake kit when it comes in, but for the most part, this pretty much wraps up all of the wheel assembly work.


Here's a few pictures of the dash with all of the gauges. I used the Skillard adapters for the larger SpeedHut gauges and the smaller ones are using some 3D printed adapters from a fellow on one of the FaceBook Groups (Nick Clark)

IMG_20200311_223850.jpg.9c11c01b81a0f4ed3d8d0dc1d0599951.jpg   IMG_20200311_224118.jpg.f5df9183d0b2446e247d2bc6ef5ad78d.jpg


Next is to keep working on putting the dash back together, but then, like I mentioned before, I'll be getting back into the heavier fabrication work on the car itself.

Spring can't be here soon enough ... and if Covid-19 could just go away, that'd be nice


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  • 3 weeks later...

Hey Everyone!...Good progress being made. I finally took all of the wheel assemblies, control arms, brakes, etc and got them all installed onto the car which definitely brought some life to the project for the first time in a long time. It's got wheels!! (no tires yet, but let's ignore that) I also took the Skillard radio delete plate, drilled a few holes for my switch pack, push start button and extra AFR and Voltage Gauge. 

IMG_20200401_203905.jpg.50cf8204ad4d457c2fa6c25aef113c1f.jpg   IMG_20200401_203931.jpg.cc6b7647214c57e9f1baff2356af608a.jpg   IMG_20200405_193434.jpg.52c1c2816d106744140c6d2a2fda75ac.jpg


I also finally finished removing the original seat mounts and put the Recaros into position. Granted, for now they are just sitting on the floor, but I don't have any intention on the mounts for the seats being any taller than they need to be to get a wrench in to tighten down the bolts. I'll put some pictures up once the mounts are done to document what I did.  In the same day, I put the steering column back in (with new wheel and quick disconnect) along with the shifter and old pedals to get a feel for how the ergonomics were shaping up. I have to say I was extremely pleased. I had ample head room, the steering wheel came to just the right place as far as distance and height, and to top it all off, the shifter fell exactly where my hand naturally falls to coming off the steering wheel. It'll need a bit of a notch on the original shifter opening to give a little more clearance, but overall I'm very happy with the current situation.

IMG_20200411_155140.jpg.4c91d0664717e433d42b757cef7339d8.jpg     IMG_20200411_155231.jpg.f8560881f867795649d4717392368954.jpg      IMG_20200411_155203.jpg.7234e71c666466b45c1e4c9ce0178fb2.jpg




The original pedals did leave something to be desired though as far as position though as my legs were a little cramped up with their current position. Luckily, I planned to retrofit in a set of Tilton pedals anyway, which will let me move the pedals closer to the firewall giving my legs a bit more room to stretch out. Some of my progress into that process is pictured with some more CAD (cardboard aided design)



I also decided to put my fuel pump into the fuel cell. That lead to the decision to get a smaller Deatschwerks unit vs the Bosch 044. This should be quieter, and recirculate less fuel than the Bosch which was way over-sized as I eventually realized.



Decided to pick up a set of 240z tail light panels than are in fantastic shape. I'll eventually get the lamps to match but for now, they look nice just sitting on the car.



Lastly, I went to fit the BMW A/C compressor and I'm about 1/4" away from it fitting up against the frame rail. I'll probably need to bump the engine over to the driverside by about 0.5" with my rev2 engine mounts, which will help center the engine better at the same time and get the driveshaft pointed more toward the center of the differential input.



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  • 4 weeks later...

For those of you still following along, The past few weeks have been pretty productive. I took step one to see if I needed to go the custom camber plate route, and cut out the strut tops to all the BC's a bit more freedom. Turns out, it looks like these plates are capable of well north of 3 deg of negative camber, especially when paired with the adjustable lower control arms from T3. So, for now, i'm going to leave the front and rear strut towers cut like this and just use the BC camber plates, and not cut more than I need to.



Next, I played around with getting the fuel cell mocked up. I had to cut out the whole spare tire tub and decided to fab up a new one that would allow the cell to sit lower, while still not protruding below the rear valence. I made some CAD files of the new enclosure and sent them out to get cut, so we'll see when those are done given the lock down situation still being pretty restrictive.  Basically the way it's going to work is the black top surface of the plastic tank will sit flush with the rest of the floor, and there will be an aluminum cover that covers up everything except for the center top plate with all the fittings and such. Hose routing still needs to be finalized, but I have a few thoughts about that.

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The project I kept working on was the Tilton Pedal box. I finally got everything cut out of steel and welded up to the original pedal box frame and I'm pretty happy with the results. Just needs cleaned up, and painted and boom... adjustable pedals with individual master cylinders.

IMG_20200507_213207.jpg.43ced3309da2487dccce6c57aebb0fb4.jpg  IMG_20200507_213203.jpg.8dd0fc276d8f95731461336314532243.jpg  IMG_20200510_191804.jpg

Edited by carbuilder723
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  • 3 weeks later...
On 5/11/2020 at 6:25 PM, grannyknot said:

It's coming along well, are going to use the throttle by wire pedal?

Yup. I'll be using the electronic pedal. Since I'm not going full stand alone, there wasn't a great way to get the manual linkage to work. On the engine stand the electronic pedal worked great, and there is a pretty simple mounting bracket that the pedal comes with.


I've got another pretty big update coming soon. I'm going a bit off the reservation with some new engine mounts, modified front cross-member and steering rack placement. It's been a bear to get the BMW rack fit in to this car. The only other time I've seen a BMW rack installed was in a right hand drive set up, with out AC. But since I want it all, I have the AC compressor, power steering pump and original engine mounts all fighting for the same space.   More to come....

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  • 2 weeks later...
  • 2 weeks later...

Update time:

Drive shaft adapter was sent out to the machine shop, of course after one more revision and 3D printed mockup with the actual differential and CV joint.

IMG_20200617_123527.jpg.96d1b9ba68af49a123ba77f6db097e6a.jpg    IMG_20200617_123059.jpg.36a72156b0bf9cca5c360f200a3f5ecb.jpg


Fuel Cell Enclosure in the rear floor pan is complete. The steel is all 16 gauge which is, let's say significant... I probably could've easily gotten away with 18 or 20 gauge and cut the weight down substantially, but I figured having a little extra weight on the rear axle isn't the worst thing and it makes for an extremely stout enclosure.

IMG_20200617_162126.jpg.47313d2294731726a6dbd37f58a39d93.jpg    IMG_20200613_165141.jpg.a59391b92ed9225d2f9549210b63655f.jpg



Fuel cell top plate was designed, and laser cut with the custom holes layout. I had an extra hole added for a second pump should I ever want/ need one, along with a 4 wire bulkhead to let the power in to the pump(s).(ignore the backwards filler neck.. i need to spin the whole top plate 180deg).

IMG_20200606_160142_01.jpg.85514b322d2c828ec27b3f004df81b0c.jpg     IMG_20200613_165039.jpg.d33e5b0c85eacd964bd87125e00f8ea6.jpg


Designed and fabricated a rear shifter bushing mount, with some captive nuts of course so you can just rotate it up into place and screw it down. Along with that I trimmed the shifter opening to give the shifter a bit more clearance. I still kept all of the holes around the opening, but gave it a bit more breathing room.



Test fit the new dash along with the adjustable pedals, steering column, center console, seat etc. This was one of those things that while completely unnecessary, I had time and i think it was worth the effort to remind myself that there is indeed a car in there somewhere. I also wanted to confirm that I would still be able to reach the switches at the base of the center stack that I added. Confirmed! Also helpful was I put the fenders and hood back on to check for hood clearance to the engine... good new... lot's of room under there for a strut brace.

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Lastly, I designed some new engine mounts that will get welded directly to the frame rails (I think). This is all in an effort to make room for the power steering rack, which while it is currently mocked up with a few spot welds, it has horrifying bump steer in its current position. So, I am churning through a few ideas in my head to try to pull the rack back towards where the OE Datsun one would've been. More to come on that. (Tubular front cross member anyone???)

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But in the mean time, I did cut off the original steering rack and engine mounts from the front cross member in addition to sectioning out a portion in the middle to give more clearance below the front of the oil pan. Right now the engine is sitting nearly perfectly (on stands) but it's low, and pushed back to the fire wall as much as I want it. Now I just need to package the mounts, steering rack, and steering column around it.

IMG_20200521_203807.jpg.78432e4d818ae8662fb05b27b657f39d.jpg    IMG_20200521_203742.jpg.57362c047cbd61d04a4ca7d99801b09a.jpg     IMG_20200521_203633.jpg.44df05211bcb95aee27c2931f5226432.jpg


So next up is still kinda the same thing ... getting the new engine mounts developed more and trying to do everything I can to get the bump steer situation better. 


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  • 2 weeks later...

We're getting closer. I've gone through a few 3D printed revisions of some new subframe pieces and rev 4 is going to work pretty well I think (I hope).

The rack now lives behind the front sump on the bottom of the oil pan. This has made the geometry situation considerably better, although being very tight with clearance to pretty much everything. I've shrunk the bracket as much as I can, while keeping the pivot of the LCA rod end in the same place as it would have been originally. I've just given up the ability to use the washers to shim it any further forward.  I included a picture of the CAD that I am working with (the big cylinder is just a basic representation of the steering rack)


IMG_20200630_170233.jpg.522eee230c443cc4c51e7b3990ef0dfc.jpg   IMG_20200630_170257.jpg.377ba160921de35af917d1a968037142.jpg    IMG_20200629_172928.jpg.a5dcb9eda91d73f816152b003325b197.jpg


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  • 2 weeks later...

This is wonderful build, great execution so far and I love the use of 3D printing!


I'm trying to just think of off the cuff reasons why mounting the engine to the frame rail vs your new subframe would be detrimental but can't think of anything right now tbh. In fact, serviceability may be easier if you need to get the subframe off to work on the steering or drop the oil pan.... 

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16 hours ago, Neverdone said:

I'm usually for almost everything you do man...but the steering rack boots sure looks like it's touching the frame mount. 


Even if it's not touching now, when the car starts vibrating and the suspension moves up and down, aren't you worried it'll wear a hole in it?

I am definitely keeping an eye on the clearance between the bolt head and the rubber boot. It is very close right now, but this is still all mockup. When I actually get the metal fabricated, I'm aiming to have at least enough space to fit my finger in between them (that is the minimum clearance I am working toward through out the whole system). If they do end up touching during suspension movement, I designed the joint using a custom carriage bolt that designed and had machined. Those bolts have a nice smooth, rounded head hence no sharp edges for the boot to catch. Hopefully that keeps the chaffing to a minimum.


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