'94 E34 Touring slicktop, forged M50B30 powered, S362SX-E boosted, daily driven

[Northern]

I've been following on ig when I see posts, but I think it "hits different" when I see the detailed updates here.

Looking really good.

[varg]

I haven't been documenting it very well but I've had a couple of updates, I dropped the block and internals off at the machine shop for the block to be bored and cleaned, rod bushings sized. No ETA. Was hoping to have it done by the end of April but that looks unlikely. Sorry, all phone pictures here. I'll probably document the build itself better with my real camera.

I got my rapid spool header, it's nice and shiny. I'm concerned about wastegate routing, it's not going to be easy to route it around to the downpipe. I do not do screamer pipes, they are idiotic. Toward the end of my tuning career I refused to tune cars with them because it made it impossible to hear mild detonation, and the noise could trigger false knock detection on some cars if the exit was near the block.


I verified that I can fit an intercooler between the condenser and radiator by eliminating the mechanical fan. I may have to upgrade the stock pusher fan and will put a small fan or two in the corners of the radiator if they'll fit. 4-3/8" from radiator to fan trailing edge. So no water to air intercooling for me. I'm still in the decision making phase for intercoolers, difficult because my flow demand is around 1,100cfm and I do not feel I have room for a vertical flow intercooler with the radiator core being 21" wide and 18" tall, it would require hacking a lot of sheet metal which I'm trying to avoid.


Replaced my driveshaft with a used one on ebay, the CSB was completely torn apart because one axis of the u joint was basically locked up, below is a screenshot from a video I took so it's terrible quality. I had to just barely touch the throttle until 20mph or so or the driveshaft would knock around horribly. It squeaked at low speed which was annoying while commuting.


The ebay driveshaft arrived with a little bit of notch to the u joints that wasn't apparent with it assembled, and it vibrates just a little at low speed and full throttle from a stop but it was cheap and it's not anywhere near as bad as before. I think it'll last until I have the new drivetrain ready to go. On the plus side with the driveshaft out I was able to verify that the $200 535i driveshaft I bought, which has a greaseable, clipped u joint, will work with the ZF310. That's a major win. Protip for E34 525i owners: you do not have to remove the exhaust to remove the driveshaft, just undo the mounts and prop it up, I used my transmission jack for that. There are two mounts on the muffler, one is a real pain to get to.





Oh and I bought a new key from a dealer so I have a master with which to cut duplicates instead of duplicating the worn out one that came with the car. A key is now twice the price I paid for my E30 key years ago somehow so there's that.

(EDIT)
I also bought a dragy, which is an interesting little gadget though it is annoying that it doesn't have an off switch. I bought it because can be used to do timed 3rd gear pulls for A-B testing which is critical for good tuning especially with a powerful car. It's a lot easier than using logs to see the elapsed time of a pull. I did a few 0-60 and 1/4mi runs with the wagon, it's so slow 0-60 in 9.77s/9.52s with 1ft rollout, best 1/4mi 17.45s, best trap 80mph. Related news, my local drag strip is closing this month so it will be difficult to do any drag strip runs, a drive of a few hours will need to be made to do so.

[2mAn]

Solid update.

[econti]

I reckon the wastegate will be fine, as long as you don't run a massive one.

[DEV0 E30]

Slicktop wagon owners unite. Loving the way the wheels look on there.

[Digitalwave]

Subscribing, project is looking good Tyler!

[varg]

Thanks, guys. I really do like this car despite its flaws and slowness. It is a good car. 269,000mi on it and it runs well and is quiet and comfortable. With its rarity and unusual wheels it gets a lot of attention, which is a bit of a drawback outside of a car show.

Seems everything in this project has been majorly delayed. I recently got the block back, it's a thing of beauty. Clean, ready to be painted, O-ringed, and oil pump chain tensioner installed. I had ForcedFirebird do the decking, cleaning, freeze plugs, drill the holes for, and install the tensioner pins for me.



Using the wagon as it was intended to be used.


With the build so delayed I got the AC working. E34 525i AC lines are in the worst possible place for a turbo car, right where the turbo and downpipe need to be. Conveniently E34 530/540i lines are a lot closer to what you need, but I still had them modified by the hydraulic shop for maximum clearance.



Continued...

[varg]

The modified lines installed.


And the downpipe stand-in. A piece of 4.25" OD flexible dryer duct. Very close, but it fits. Will not be fun to fabricate. The downpipe crossover tube will also be a real treat.



While I had the AC apart I cleaned an ungodly amount of gunk and debris out of the radiator support and passenger side frame rail, and got rid of the grungy old tube and fin condenser.


Replaced with a nice junkyard find; a parallel flow condenser.


And the result, cold AC even in traffic at 88°F and 71% relative humidity.


I'm going to paint and assemble the longblock over the next couple of weeks and use that time to make my intercooling decision. I do not know which path I will take.

• Air to air between condenser and radiator
• Air to water with a heat exchanger between condenser and radiator.

Neither is optimal. Air to air is cheaper, lighter, and more reliable... but the intercooler will obstruct airflow and put the radiator too close to the engine for anything other than a couple of small fans mounted directly to the radiator wherever the accessories don't interfere. Even the best 16" pusher fan will move nowhere near enough air to cool the engine with the AC on while blowing through an AC condenser and 3.5" thick intercooler. Air to water would solve that issue but there isn't a good place to put any off the shelf intercooler large enough for my application. My measurements lead me to believe that the airbox mounting area is too small, and I would have to build a custom unit from a Garrett core. Even if I did have an AC TIG welder, I'm nowhere near good enough to weld up a custom intercooler. I also have the task of building a differential ahead of me, I need to take the 2.93 LSD I have out of an E30 case, rebuild it, and put it in an E34 case. Not trivial. If only BMW hadn't screwed us by putting a 1:1 fifth gear in the ZF310/320

[varg]

I really let this thread go. Progress has been slow but the wagon is almost there, I basically only have to finish the interior (gauge pods, shifter trim installation, etc), finish welding the exhaust up, install the driveshaft and heat shields, and weld my intercooler end tanks and piping. Then it will be ready to run. I'll go chronological on the updates until I'm caught up.

I assembled the engine and painted it.












I had ForcedFirebird rebuild and put the E30 2.93 LSD I bought inside an E34 case, and I painted it.


Old greasy 275,000mi engine out!


Engine bay cleaned


Shiny new M50B30 in!




More to come, there is still a backlog of pictures and updates. The slow progress and parts issues have really sapped that non-stop build drive I had when I built my E30. Progress is progress.

[varg]

Current status:



I'll start with the downpipe. This was super tricky with this car. My modified AC lines gave me a lot of extra room vs tock, but just not enough. The 3.5" pipe basically has to make a sharp 95° turn then angle back toward the firewall again to go between AC line and header primary. This required some CAD. Here's the bend partway though modification on its cardboard template.




One of dozens of trial fits. Unfortunately the pipe is currently an interference fit. It gets pinched between the header and the AC lines, so I'm going to have to dent the sides a bit and surround it with heat shielding to keep from cooking my AC lines.




This is the tacked up downpipe, complete with a couple of overheated welds. I basically learned the basics of stainless TIG the hard way here. It's a two piece downpipe out of necessity. A V-band, nor any other flange, will not fit down between the header and AC lines, installation requires snaking the small end of the slip joint down there, pulling the downpipe toward myself and rotating it to clear the frame rail, then rotating it more and fitting the marmon flange to the turbo. It's not ideal, but it works. Regrettably, the O2 sensor has to go after the slip joint, because the bung will interfere with the rotation required for installation. The wastegate provision also has to be attached to the bottom half of the downpipe, so real-estate is limited all around. If you're going to do this yourself, run complete custom AC lines including the firewall side fittings, point it straight down the firewall then hug the frame rail. I may do this in the future depending on how I like the job the heat shields do. As an aside, yeah, that's a homemade weight bench and squat rack made out of lumber, I DIY everything I can. That was a pandemic build, and it gave me a decent home gym for less than the cost of a year at a commercial gym.




I got some aluminum welding practice before the next part. It's not easy, but it's a lot easier than the 0.063" stainless exhaust pipe.



On to the intercooler. This was another space-constrained design. In the interest of keeping it realistically achievable as I learned aluminum TIG welding, I made the end tanks as simple as possible. Inlet on the right, outlet on the left. They had to be offset so much because as you can see in the first image in this post, they have to clear the V8 E34 radiator end tanks. In hindsight, the hot side pipe would have been simpler if I took about 1.25" out of the offset on the right, but I didn't have the benefit of hindsight a few months ago when I drew up these end tanks in CAD (computer CAD, not cardboard CAD this time).






These end tanks were a flat-pack design. I had them water-jet cut by a local engineering firm on 3/16" aluminum, and tacked them up using some 3D printed spacers.




Out of fear of burning a hole in my beautiful and expensive Garrett intercooler core, I built up a bead around its perimeter to give me a thicker piece to concentrate my heat on and help me bridge the small gaps that were unavoidable in fit up of the end tanks to the welds already on the core.




I had images of the tanks splitting at the seams in my mind, because of my low quality welds and the pressure they may see (30psi+). To mitigate these fears I welded a 3/8" reinforcement rod at the center of pressure of each tank. This will be under tension when the plates are under pressure, it should take a lot of the load off of the welds and probably outright eliminate tank deformation.




Welding the tanks on went OK. The results weren't pretty, but I think I expect too much of myself for someone with torch time not even measurable in the dozens of hours. I did make a couple of mistakes that had to be filled in, but luckily none on the core, which was the last part I welded. I still had to stop-start weld this, I'm not at the point where I can do a nice 12" long continuous stretch, at least not with the workbench setup I'm using.



Coming soon:
More CAD

[Digitalwave]

That's some seriously impressive fab work, Tyler!

[Northern]

That aluminum welding is way nicer than any I've ever done and I've had mine for like 5 years now.

I've been next-car shopping for a year now and keep bouncing around various newer touring options, but this thread really makes me want to find a clean E34 touring.

[varg]

Thanks guys. I've not been too happy with the results of my fab work here, and the blowoff valve fitup went really poorly and looks like a mess, I swear that coped vband fitting for the BOV was contaminated in some way. That will be for the next update though.

I've been next-car shopping for a year now and keep bouncing around various newer touring options, but this thread really makes me want to find a clean E34 touring.

I think the E34 is like the best kept secret of the classic BMW world. Nobody seems to talk about them or appreciate at all, I hardly ever see them at meets, but it is a great car and I fell in love with it once I fixed the transmission and AC issues. As much as I love my E30 and initially wished I could fit an E30 wagon into my budget instead of an E34 I now am glad I got an E34 wagon, its larger size is an advantage for this being a utilitarian but fast DD. The car is well built, it's quiet, it fits big 275 nittos with no body mods, it handles well, the steering feels great for box setup, the AC is way better than E30 AC, and it is definitely better looking than an E30 wagon imo. The proportions of an E34 wagon are so are pleasing to the eye, even at stock ride height. It has the classic long and low look that modern cars lack, and it is far more aerodynamic and quieter at highway speed than an E30. I would not want an M20 powered E34 though unless a swap was the plan, the M20 is just too small and underpowered, the M50 was borderline and it makes 10% more torque. A 3,700lb car (I haven't weighed mine yet) should not have a 2.5L engine. FWIW I chose it over a Volvo 7/940 wagon because they have super weak rear suspension and axles, a ford 8.8 swap and aftermarket suspension arms with reinforced pickup points are mandatory for the kind of power I wanted.

It has its problems, it is fancier than an E30 and a more modern design so there is more to go wrong.

• The door cards are a pain in the ass
• The extruded sections that clamp onto the window glass and engage the regulator are prone to coming off of the glass for some reason
• The hatch wiring harness disintegrates and is a pain to re-wire
• The door bottom clip on trim/seal is an absolutely moronic design
• The hatch glass struts are hidden under the headliner so I don't feel like replacing them
• There is weird one piece plastic trim around the window frame on the interior that is a nightmare to remove an reinstall
• The door seals are possibly worse than the shrinking E30 door seals
• The electric lock system leaves me paranoid I'll be locked out if the battery dies and the "override" lock technique doesn't work (I wouldn't be, the hatch lock is mechanical and you could get in through it)
• The differential uses a different case than an E30 (it's a far superior design) that is far less common in good ratios (as far as I was able to find, there are no 2.93LSDs, which are basically mandatory with a ZF's dumbass 1:1 top gear imo)
• The solenoid based heater valve system is failure prone and expensive to replace
• Door bottoms are rust prone, I got lucky
• Slicktops are rare and the double sunroof is 100% a liability, I only bought this car because it was the only slicktop I found, otherwise the paint and body work it needs would have sent me elsewhere
• ZF310/320s became rare and expensive at some point over the past few years, I blame the fact that they seem to be a fairly common swap in drift car projects especially since so many Japanese cars have absolutely ass or extremely expensive transmissions

And somehow, despite the car being way bigger than an E30, it doesn't have any room at all for an intercooler behind the valance. My core is about the same size as the one in my E30, it would have fit behind an E30 valance with minor trimming and made this silly 3-stack configuration unnecessary.

[Dj Buttchug]

sub'd as I am doing an e34 turbo project as well. Nice clean work so far!

[varg]

There's going to be a huge inconsistency in photo quality here and I apologize. My iphone's camera has been messed up for a little over a month now, the focal plane is rotated and the image stabilization just twitches like mad so it can't take a good photo. As a result some of these are taken with my DSLR, which is very inconvenient to have in the garage while working, and others are iffy phone images. The E34 is getting close to being on the road now. There have been some delays, like damaging the O2 sensor bung and having to cut a patch out and weld it on my downpipe with a new fitting. The downpipe slip joint also got ovalled out from all of the clearancing and welding, so I had to weld a new one on. I could not find a single shop around here with a pipe expander that can do 3.5" pipe. Then while welding the new one on it started to oval a bit too, so I bought a pipe expander kit from harbor freight anyway making the rework feel like a waste of time it wound up fitting in the end, I haven't even opened the HF expander yet and may return it if I don't need it for the final assembly. This welding also altered the wastegate pipe fit, so I had to re-work that as well. No pictures of any of it.

This week I finished off the interior, the gauge pod next to the A-pillar is the CAD I was working on before, it's a weird looking pod but it was necessary to retain all functionality. It has a defroster vent, and it holds both gauges far enough away from the windshield that I can use a reflector. A pillar pods aren't available for the E34 and I didn't want to attach anything to the dash through adhesive of any other means, so this was the solution. Also, in place of the OBC, there's an oil pressure gauge. Just like my E30. The other printed parts aren't visible here, plugs for the holes the auto shifter was bolted into, and the ring that holds the shift boot in the surround. I also epoxied a piece of bent aluminum filler wire to the bottom of the big dashboard center vent to replace one of its broken clips. Seems to be a common problem in E34s that the clips break and that big vent sticks up from the dash. While we're at it in the interior, the twin disc clutch is super heavy and will take some getting used to.


Here's the current state of the engine bay. The downpipe and turbo need to be installed, fluids added, EBC solenoid wired, and it's ready to run. The radiator straps are the other type of CAD from before, I decided to change the way they attached. The intercooler has mounts welded to it that drop into the stock radiator mount cups, they were very ugly, I didn't take any pictures. the radiator and intercooler need to be securely mounted so they don't slide back and hit the pulleys, clearance is very tight. Also not pictured; a duct that fills the gap between the condenser and the radiator below the intercooler, so cooling air doesn't go around the radiator. It's just made out of corrugated plastic from signs. It's buried so it doesn't have to be pretty, just functional.


The radiator fans are an interference fit. The passenger side fan touches its hose clamps and the driver's side fan comes close to everything.




The radiator fans are controlled by a relay I added to the E34's convenient relay box, which contains the condenser fan relays. I like to scavenge BMW relay holders from junkyard cars that are ready to be crushed or not likely to be a harness donor for someone. The stock condenser fans relays will be needed for my big brushless delta pag condenser fan.


Getting a little out of sequence here, but I had to torque the crank bolt down to the M50's ridiculous 300lbft figure and that required a counterhold tool. They're ridiculously expensive, so I drew one up in CAD and had it cut, for something like $35 shipped. A block of wood against the AC compressor mount served as the brace point. Easy.



I probably would have had this thing running last weekend if it weren't for the fuel injector issue. Turns out the plastic manifolds don't butt up against the injectors, they just have a smooth bore, so Fuel Injector Clinic's direct fit application injector for an E36 M3? Not direct fit at all since it has no clips and doesn't bottom out. The injectors will pop out of the rail and spray fuel everywhere, which I found out when I tested the system for leaks after installing the new fuel pump and lines.


I was going to make some spacers but I was too busy this week so I wound up just fitting the nice spacers I ordered for just this problem from RallyRoad. Silver ring, visible at the bottom of the injector. A friendly PSA to anyone searching in the future, Fuel Injector Clinic's E36 M3 1200cc High Z injectors will not fit your M50 or S52 without spacers and a modified injector harness box (it hits the valve cover because the connectors are lower). Just like everyone else, their service seems to have gone down the tubes since COVID too. They didn't have spacer rings and didn't have upper spacers with clip grooves and a ridge for the necessary dual clips.


The fuel pump fit is pretty easy, luckily. you just slide the stock pump out of its plastic case, slice the case open to fit the much thicker DW400 pump, and slice most of the bottom of the case off so the pump can rest on the remaining portion and fit its sock. Wiring harness connector needs changing as well, of course.


Finally, a rear view showing the rear muffler and single tip. I may fabricate a dual 2.5" tip for this later, I would really like to since it would look better. I just need to figure out how I'll go about that. The brown paper taped to the hatch is to keep it from hitting the garage door when the car is lifted higher, which already happened once and left a scratch.


Fingers crossed, I should be able to install the condenser fan, fill up the fluids, and have it on the road tomorrow.