If I had to write this post half year ago, it should be about how to turbocharge a m52b28. It’s not a secret it was and still is one of my favorite bmw engines ever made. Reliable, powerful, everything you might need. But. With every other day, we’re getting more greedy for power and torque.
Please accept my apologies for some of the pictures. For some reasons i didn’t had the chance to keep my DSLR with me all the time.
How everything started.
My plans were to buy a stock, non-modified m52b28 and run a gt28 on it. Goal ? Low boost, topping up few dozens of horsepower and a lot of torque in the mid rpm range. So i did. Bought a forged exhaust manifold, the turbocharger and the engine plus few other bits such as oil cooler, oil filter console out of scrapped euro s50 etc, but haven’t any clue back then when exactly i should start putting everything together. On the one hand i had perfectly running e28, on the other – i was crawling for more power.
I was supplying parts for my build and one sunny day …. my fiance (now my wife) blowed her m42b18 engine in her e36. I was “Great, now im gonna swap my overhauled m52 into her coupé and will do the first step of having a brap-ap-ap-ap-ing e28.” .
Not quite.I’m not a guy who would do a job, just to have it done asap or going for the easiest way and the shortest path. I did some math and figgured out if I had to build a reliable, boosted engine, I had to invest a lot of money. I needed something capable of driving me anywhere in Europe and returning me back with lower as possible risk of breaking down or using a road assistance. So i was thinking what if i sacrifice some of the horsepowers and torque that turbocharged engine provides and go with the N/A M power engine for the same price. I was thinking about the s50 swap. Being greedy for power again,the 286 hp of the s50 engine wasn’t so tempting for me. I had nearly a 240 hp m52b28 and topping up 20% more wasn’t thing at all. Then an offer on the local market for s54b32 out of e46 m3 cabrio catched my eye. It wasn’t a brainer. Few days later, we (me and my fiance ) were both traveling to a town, 450kms away to pick my new, 340 hp stock, m power engine.
It was a donor car, but it still was a whole thing. Nothing was missing so I had the opportunity to test drive it. The cabrio is the heaviest chassis among the e46 models and the s54 was a real blast. Didn’t took me so long to put the cash on the table to seal the deal. Eight hours later we were traveling back, heavy loaded with three point two inline six m power engine on the back, embalming the whole loading section of my Citroen Berlingo with the scent of a hundred octane UK gasoline. Just try to imagine what was in my head back then. My hands got sweaty just by thinking how this engine is going to run in a chassis which is 450 kg lighter than the e46 cabrio.
What would you need for the swap.
Having a modern engine in the e28 and making it look as a factory setup, costed me a couple weeks of measurements and preparations. Luckily I’m glad to be able now, to make a complete list for the things you need if you ever decide to go down this way.
Engine : The complete s54b32 with the harness, itbs, manifolds, ecu, immobilizer, key chip, fuel regulator, heater hoses, throttle pedal with the connector and floor support for it. While disassembling the engine from the donor car, make sure you have the ECU connector #4 with 100 mm of wires cutted too. It’s the connector goes from the chassis harness to the ecu. You will need this one later to hook up with the e28 harness. Also make sure you have the air filter box with the MAF (or just the MAF capsule) .
Oil pan : You need oil pan, dipstick, suction tube and the oil pump itself out of e34 with m50b20/5 engine + brand new gasket.
Engine mounts : Our stainless engine mounts.
Gearbox : None of the oem solutions for s54 in e46 would work for e28. Both trannys are way too big and would’t fit. The only option is ZF out of e36/39 m52b28 or m52tub28. We recommend to change the pilot bearing, clutch bearing and also replace the oem plastic pivot pin with the e28goodies bronze pivot pin
Gearbox support : #23711128517 works just fine for the zf gearbox. Its the support used on 99% of the e28 models (everything but 518s) . You might want to upgrade it with the e28goodies polyamide shifter kit for more firm shifter feeling.
Shifter : The only option here is #25111221540 . The upper arm from any 4 cyl. e36. Lower arm need to be customized. We will talk about this below.
Clutch : We recommend to use the stock s54 flywheel and pressure plate. Anyways if you’re going to use the 2.8 ZF gearbox, you need to source a 240mm friction disk out of e36 or prefacelift e39 to make it happen. #21211223679 . There is a difference in the splines size. We will talk about this below.
Driveshaft : Stock solution would be a shaft out of m21d24 (only turbodiesel, the plain diesel uses small guibo flange) or m30 powered e28. You will be needing also better central bearing support, that’s why we advice e28goodies central bearing mount support to be used.
Radiator, expansion, clutch fan & hoses: The bang for the buck is radiator for e36 318tds, with AC and Auto transmission. See below. You need an expansion tank out of e28 or e30 with m20 engine. #17111707540 . The clutch fan should be #11522243303 , a 7 blade, 420mm propeler out ot e36 325tds. It’s super thin, it uses a 3 bolt fan clutch and you can swap the s54 stock one and the hoop that connects the blades concentrate the air, so you can live without the diffuser. Anyways we highly recommend an electric ac fan out of e36 to be fitted on the kidneys side. In this build i have them both – clutch fan + electric fan triggered by a thermo switch. I’ve used the lower e36 320i (m50) hose as the upper one and universal 38mm , 90 degree hose for the lower.
Heater system : You can use the stock valve and it’s lower hose. The S54 will fit perfectly, they just need to be shorten a bit.
Exhaust : Stock headers will fit but need to be modified to go around the steering rods and stabilizer link. Exhaust need to be fully customized. Muffler should be Your custom muffler made by e28goodies .
Steering and brakes : For this swap the only oem solution for brake boosting is the hydrobooster out of m30 e28. If you’re going to swap the s54 into your m30 car – you’re lucky, you have it. You might wanna rebuild if it’s leaky with “The everything” hydrobooster rebuild kit . In any other case you’ll need to find a set – the hydrobooster, the brake bomb with the bracket that need to be welded to the chassis, the expansion tank and all the hoses and hardlines except the one that goes from the back of the bomb to the steering pump – you will need our custom one. You might wanna check out our Must-have-brake-upgrade article for this swap. Horsepower is important, but staying alive ha-ha-ha-yeah is even more.
Rear axle, differential and shafts : I’m using a complete rear axle out of 535i with the thrust oem arm reinforcements barts (rare) , pitman arms (rare), e28goodies rear axle polybushes , super thick and fat late model 524td mm output shafts #33211226589 (super rare) and self locking differential out of e34 equipped with m51d25 – 2.65.
Intake : I personally picked up the K&N RG-1002RD-L Universal Cone Filter. The s54 is theoretically a huge air pump that needs a shitload of an air. Cold preferably. I’ll probably talk about the s54 CAI project on another post.
Fuel pump : Bosch 044 pump and the stock 5 bar fuel regulator.
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Few words here and there.
Once you have your engine few things needed to be done. The s54 according to the internet knowledge is a motor with kind of problematic rod bearings. Some say they need to be replaced each 80 000 kms, others say they never had problems with their on 200k+ cars, however im tending to believe it would be a waste to replace something that’s in totally fine working condition, because somebody said so. Believe me or not, you can’t miss the noise that make a failed rod bearing so this is one of the first thing you should listen for while testing your engine. If you have to be sure, then order a dozen of the rod bolts (once untightened they can’t be used again, because they’re stretching ) and check the condition of the bearings. If they look bad – replace them, if they’re good – just put the new bolts. Or don’t mind them at all as i did if there aren’t any “funny” noises and the service history shows the car is under 120k kms and we’re convinced to believe the seller.
Engine preparation.
The first thing that should be done is fitting your new oil pan and the oil lubrication system. The s54 engine originally is using a “scavenging” oil pump that sucks from the front and the back of the oil pan by using two suction tubes (the main one is on the rear side of the pump) , this prevents the engine of oil starvation while cornering with high speed, drifting, being stupid .. etc.
Luckily the m50 and m52 oil pums fits plug and play on the s54 and they’re direct fit to the engine. (S54 pump on the left, M50 pump of the right)
Just put the s54 sprocket (reverse thread) on the m50 pump, put a dot of weld to secure the thread and you’re good to go.
The s54 sprocket is needed because its a bit bigger for the higher revs that the m engine operates and also because it got a bit of offset matching the chain alignment. (the perforated sprocket on the back is out of the m50 engine)
And finally install the e34 m50 suction tube and the oil pan + dipstick. There are 3+ liters of oil in the pan most of the time so don’t worry about the oil starvation.
Don’t forget the weld thing ! No funny business here.
Finally I’ve ordered an ebay an10 hose kit and small oil cooler and hooked up my oil cooling with custom plate just behind the grills. (2 x 1 meter hoses are completelly fine for what you see here)
Make sure you are changing the two freeze plugs on the back of the head while the engine is still out of the car (28mm) and the pilot bearing.
Install the e28goodies s54 swap engine mounts.
Left side
Right side.
Now, since the air filter box is way too big to be fitted in the e28 bay we suggest a quality cone filter to be used. But how since the MAF body is an actual part of the air filter box ?
Super simple. The s54 and m62 engines are using almost same size bodies for the MAFs. The m62 is just 1 mm smaller than s54 but that would be fine. Just unscrew the two bolts, take off the MAF capsule and install it in the body of a m62 MAF then just tight a cone filter to it. Solved.
The instrument cluster sender should be installed somewhere, so our guess was the top of the thermostat body. A small, nice insert need to be done with a proper inside thread and tig welded there.
And finally you need a hose extension for the valve cover breather. Originally it goes to the lowest part of the oil pan, so i’ve decided to bolt it right to the “oil bolt”
“I’m doing that tranny” doesn’t sound good to non car guys.
So, before have installed the ZF on the s54 you need the following:
First – get yourself a new friction plate and install it. If you’re using the stock friction plate on ZF box – you’re going to have a bad time.
The s54 one have bigger inside diameter and bigger splines and this is how it looks on ZF main shaft.
The e36/e39 friction plate (left) is same size as the s54 one, but everything is just right for that box. Use it. Also keep in mind that “Getriebeseite” means “On the side of the gearbox”.
Install everything back together. I’ve personally use a shaft from trashed gearbox as alignment tool.
Be advised the s54 uses self-adjusting pressure plate which need to be “reset” before reassembling, which means the three little springs should be compressed like this. Check this this super useful diy video which i found on youtube : https://www.youtube.com/watch?v=08aYbyejOm4
Second : oem plastic pivot pin is tending to break. Replace it.
Also install new clutch bearing, slave cylinder, guibo and maybe is a good idea to replace the reverse light switch.
I’ve had some bad experience on the trackdays with the guibo bolts, so i secured them with the Loctite thread locker.
Mate the box with the engine.
The 4 cyl e36 shifter would fit the whole thing as a charm with 2 slight mods.
First : You need to cut off 20mm of the tail.
Then you need to fabricate exactly 225mm long lower shaft (pins center-center).
( This is the beta, should look better in the final ver. )
And finally you might want to install the e28goodies polybushing shifter kit, just to avoid the wobbling caused by the oem rubber insert.
and tilt the gearbox side with exactly 5 degrees counterclockwise while the shaft is in horizontal position with the pins facing the ceiling, otherwise you won’t be able to shift in reverse and you’re going to hit the central console while switching to 1st and 2nd gear.
Electronic throttle pedal.
The s54 engine is operated by electronic throttle body. You need also the pedal support to get it fitted. A really nice and fast procedure.
Drill a 8 mm hole where it’s shown, cut the side edge so there would be enough space for the ratchet insert.
Use a 40mm m8 bolt and grind down its head till it passes between the pedal and the support.
Click the support in the floor hollow on the bottom and screw the bolt on the place of the old throttle body pedal stopper on the floor. Then slide in the pedal in and you’re ready.
With the kick panel off, this is the exact moment to have your brake booster replaced. Keep that in mind.
Since we’re here is the best moment to mention something about the
Cooling system.
Believe or not for this setup there is nothing better than e36 318tds radiator for a vehicle equipped with A/C and automatic transmission combined with m20 expansion tank and e36 325tds mechanical fan (on the left, don’t mind the 325tds diffuser – it won’t fit ) because few reasons.
1. Fits great without any mods, covering the whole empty area between the headlights and clearing enough space for the hood.
It has those two openings on the side supposed to water cool the auto tranny ATF oil, but this time we’re going to use them for the steering atf – good idea since we have hydrobooster AND powersteering.
It has the side threaded hole where we could install the temp. sensor that could trigger the electric fan.
Oem e28 heater hoses fits plug and play to the s54, just need to be shortened a bit. You can also cut down the clamps holding the oem connectors to the s54 cooling hoses using them to make a custom ones.
Fuel supply.
One option. Bosch 044 + oem filter hooked up to the oem bracket plus the s54 fuel regulator installed as close as possible to the engine. Period.
Other tricky bits that may cause you trouble…
Exhaust.
Exhaust system is a matter of cutting pipes and welding. There is no other way to get around steering links.
I’ve bought ebay stainless headers so i could have complete stainless shiny exhaust but …
turned out to be huge mistake, because this is what i’ve received after month of waiting.
I’ve ditched them in the trash, rolled back my sleeves and modified the oem “basket of snakes”.
The 4-5-6 cyl. side was the easiest part. I’ve just cut a bit of the pipe and weld the adapter and fitted it right back in there.
The 1,2 and 3td cylinder header was the real PITA, long story short this is how should look yours if you want to get it in there.
Rest of the exhaust was pretty much straight forward easy peasy lemon squeezy and I’m definitely far away from the ” best welder in the world ” reward.
Drive train, rear axle and brakes
In case you didn’t came across our diy about fitting e34 brakes, please search for it on our blog now. The s54 got A LOT of power and trust me you do need that mod.Also let’s talk about drive train and the rear end. For this swap, using the m52b28 ZF gearbox the only drive train that might fit without any mods is the m30 one and the 524td. Length is just about right and it got the large guibo flange.
In case you’re swapping 535 you got already all the tuff components, but in case you’re swapping m10 or m20 powered car you might think of sourcing complete rear axle out of m535/m5, some thick shafts and probably LSD diff (I personally picked S2.65 out of e34 525td)
ECU
Best choice would be if you get someone (e28goodies.com for example) to mod your s54 ecu. There is lot of stuff that need to be “ignored” by the system such as speed signal, DSC, exhaust temperature sensor, ews and few other things. The MSS54 got funny sense of humor and it’s tending to “overreact” and put the engine into a “limp mode” (2k rpm limiter) for almost every stupid reason… in my case it was the low volume of air caused by using too small cone filter before installing the real deal big arse K&N.So if you encouter that issue, make sure you didn’t mess something up.
Wiring.
Head ups. On the e28 C101 connector is the black connector sitting on the right side of the fusebox. You might wanna cut your old engine connector and solder the s54 cables to it so everything could look nice and clean. C103 connector is white, 5 pin located behind the glovebox.
That’s all Folks !
