1989 M50 Turbo Build

**Nutzy** · 08-02-2021, 01:15 AM

Preamble: Although I have made many posts here on BFC over many years, I never got around to actually making a build thread for theE30. Given the disaster that FacePlant has been for forums like this, I’ll try and do my bit to add to this resource of info and help that is BFC. Facebook will never match a forum like this, so let’stry to keep it alive!

In 2007 I bought a1989 318i auto with 133,00kms on the clock. It was such a mint carand looked like no one had ever sat in the rear or used the trunk.

Capture1.JPG Capture3.JPG

I bought two E30 to junk, one was a 325e that was a write off due to rust, the other wasa 320i that had been T-boned. The 325e gave up the 2.7 bottom end, aG260, a 3.15 diff, and an uncracked dash! The 320i got me the 731head, manifold, and a bunch of other stuff.

I pulled the M40B18and the auto and went to work on the rest of the car. The idea was tobuild a modest 2.7 turbo with good street performance and maybe about180rwkw. Well, the rest is history because the chase for power is a sickness.

The B27 started out with a small Garrett on it. I think it may have been a GT2871 or something. Of course, this choked the living shxt out of the motor, and while it boosted up quick, it choked quick, too. So I built a new twin scroll manifold to mount up a Schwitzer S256 with a 65mm turbine exducer.

Capture4.JPG Capture2.JPG

This made 225rwkw on the dyno at about 11psi, IIRC. The detonation limit of the 98 fuel had been reached. The compression was probs nudging 10:1 and the 731 head design wasn't doing any favours either. I ran it like this for a while until the fuel pump went dodgy, leaned out the motor, and boom! Four cylinders with broken rings.

Plans for an M50B28 conversion began...

**Nutzy** · 08-02-2021, 02:11 AM

The plan with the M50 was to build a 2.8 liter with forged pistons and rods, but no other mods other than MLS, ARP head studs, and ARP main studs. The head would remain standard other than Supertech black nitride valves. The cams are still OEM 228 degree.

I did have a lot of trouble getting the head work done in my town, with one shop ruining the first head when installing new valve guides, then almost ruining the replacement head. The second engine shop managed to cut the valve seats offset. The third guy installed the Supertechs and got it done right! It was a huge drama and inbetween bad shops and cracked heads, it was done right in the end.
Capture6.JPG

The bottom end was done perfect and the bores mic'd out spot on; East-West, North-South, top, middle, and bottom. The pistons are JE custom and I chose a stupidly low 8.5:1 - a compression ratio I wouldn't have chosen in hindsight. The rods are Pauter 140mm.
Capture5.JPG
Capture11.JPG

The MLS headgaskets proved to be trouble with both of them leaking. This ended up being solved in the end with a cut-ring gasket. Doing it from scratch, I'd go with an OEM headgasket, O-ring the block, and use studs. Proven for big power and uses an off-the-shelf gasket.
Capture7.JPG

The manifold is another homebrew job with a 6-1 collector. Initially I had the wastegate port coming off the side of the collector. I was told that this would boost creep, and boy did it ever! There was no stopping the boost rise after about 4000rpm and the rise was dramatic. This ended up being solved with the wastegate mounted off the side of the turbine housing which gives perfect boost control.

The motor was tuned up to 18psi on E85 and turned out 358RWKW (480HP). At this point I think the turbo is out of puff and way over to the RHS on the compressor map. The IAT is high as well. Still, it comes on at about 3000rpm and makes a ton of midrange power.

This video was taken of it being tuned on 98RON @ 14psi.

**Nutzy** · 08-02-2021, 05:16 AM

I'm breaking these posts up because I'm only allowed to post 5 images at a time.

The manifold was made with good old steam pipe and weld-els using carbon steel this time as I couldn't give a fart about stainless. The flanges were laser cut by a local company for me using a CAD file that I've got no idea anymore where I got it. Getting old, forgetting stuff...

Capture15.JPG

I made a thing (I think it is called a die) to press the pipe ends so that they matched the flange / head ports. I've seen some commercially available BMW 24V manifolds that have the most attrocious port matching, and it appears the same zero fks were given when it came to the 6-1 collector. I didn't want to be that guy...

These stubs were then welded to the flange plate. I decided to cut the flange into two plates for the second set I made, this meant that, post welding, I could sand the things flat again on my belt linisher.

Capture14.JPG
Capture20.JPG
Capture19.JPG

Unfortunately version 1 of the manifold needed to be set up in a mill to get it right. But this is the beast once it was all done. The collector was made using DIY jigs on my bandsaw. You can see on this manifold that the WG port is still there as this was prior to cutting it off and welding the hole shut!

Capture17.JPG

**Nutzy** · 08-02-2021, 05:44 AM

The M50 started out in the car with a GS637DZ - ex 320D, but the looow first and second gear did my head in! I sourced a GS637BZ from a Z4, remade the cross member and shifts links, and never looked back. The GS6 has the same ratios as the M3 420G box, but without the price tag and the synchro hassles.

Capture32.JPG

Although the GS6 is a good box, I'm kinda done with shifting, and I had been eyeing off auto conversions and possibilities when I decided to bite the bullet and go DCT. I got a DCT from an F82 - the double OD kind - and adapters and so on for it. I bought a HTG controller, but I put the project on ice as I was not that happy seeing all the issues people were having in trying to get the DCT to behave with this controller. Really, the HTG was released WAY too early, anyone using this thing was a beta tester! As it turns out, the HTG also can control the magnificent ZF8HP70 auto and, having seen plenty of videos of this box in action, I decided that I'd go down that path instead. The ZF8HP70 is from a 535D and rated at 700nm factory. With the aftermarket controller, they take even more, quite a lot more in fact. They also shift like blazes and the torque converter seems to give it excellent street car manners and the HTG can stall-brake the thing too.

Here's the adapter plate for it:

Captur31.JPG

It's a big box, but it'll fit. It also weighs 90kgs, but the lightning shifts will make the car faster, heaps faster cuz my manual shifts kinda suck!

**Nutzy** · 08-02-2021, 09:10 AM

This day had to come, and I'm amazed it never happened sooner TBH, but the stock rear finally took a dump. I'm heading back to work on Jan 2nd on a glorious summer morning, left the lights easy in 1st and 2nd, and just a lazy roll on to WOT in 3rd gear as I moved on down the road. It spun the semi slicks when the tyres hit a seam in the tarmac and it instantly smacked the rev limiter. I stayed WOT, the road dipped, then rose. The now heated up semi's gripped and BANG! See ya later outer CV.

I phoned a friend and we towed the car 2kms back home, made some coffee, and called the office to say 'yeah nah, not today'. I asked around to see who had a CV I could nab, but ended up giving myself an upper cut because I had a Z3M rear end sitting there waiting to be installed for like two years now.

Capture24.JPG

And so started another 12 months of the E30 being off the road...

Installing a Z3M rear end seems simple, but the reality isn't quite so plain. For starters, there is the fact that the rotors are 315mm vented beasts, and pairing that with 280mm Corrado fronts is going to create some serious rear bias and probably a soggy pedal, too. Then there was fitting the E39 camber toe adjusters, sandblasting, removing an axle that refused to budge, and making custom brake lines. Given the bias would suck, I had to learn as much as I could about rotor diameter, piston area, pad friction coefficient, and mixing and matching stuff that doesn't want to be mixed and matched. There was also changing the brake MC to 25x25mm, picking calipers and rotors, designing caliper adapters and so on. To test out the adapters, I bought a 3D printer and then had to tame that SOB, then learn how to code shxt in OpenSCad.

Capture37.JPG

Once the caliper adapters were printed and verified, I got a machinist friend to produce them. Initially I ran OEM 325x25mm E46 rotors, but it needed spacers, locator rings, and a custom bearing dust cap that also served as the wheel locator. In short, it was complex. It worked, but it was complex. Two piece rotors was the only way to fly. Looking through the Wilwood catalog, I found a 325x25mm rotor ring that was compatible with the caliper, and a center hat that was compatible with the rotor and had the right offset. Happy days, or so I thought. OK, so the hat needed its center bore machined out to 72.5mm, and I thought that would be it, then when I find that despite all these 'compatible' items from the Wilwood catalog actually aren't so compatible after all. Turns out the periphery of the hat hits the caliper, FFS! Wilwood can't offer any light on the subject and do not, as it turns out, produce anything such as 'This caliper goes with this rotor ring goes with this hat'. Funny eh, considering this is their core business. Anyway, there is enough material in the hat to shave a little off.

Capture28.JPG

All in all, it works great, and bias is maybe a little more to the rear. I know this is a bit simplistic given the system pressures have changed, and that alters where the 'knee point' of the OEM bias valve takes effect, but it brakes really hard without locking up. So hard in fact that 6 liters of oil buggers off up the front of the engine and the oil pressure alarm goes off! Who'd have thought it?

I have designed a new rotor hat, and if I can be bothered, I'll get my CNC machinist buddy to whip them up.

Capture38.JPG
Capture39.JPG

EDIT: One of the neat things about custom centre hats is the ability to tweak your ET without spacers. In Aus, spacers are not allowed, period. With custom hats, their thickness matters.

**Nutzy** · 08-02-2021, 09:39 AM

I am REALLY skipping tons of things that have tinkered with on this car over the last 13 years or so, but there is just too much of it to start writing about it now or I'd be typing for a day or so.

Right now it has been off the road again since end January due to plans with the gearbox etc. My plan was also to pull the motor and do some work on that, change out the Autronic SM4 ECU for an ECU Master black, a complete new engine loom, wire in the HTG with flappy paddles on the steering wheel and an F82 M4 shifter. This is all CANBUS control, BTW. I also just got a Racetune touch screen digital dash. I've been busy pulling out loads of wiring, WB02 controller, and all sorts of stuff that I'm not even sure what it does anymore.

The motor was put on the engine stand and I pulled the sump off and the crankshaft out. The piston oil jets were removed and plugged with brass slugs I machined. They look like an oil jet, just without the hole. While I was at it I was keen to inspect the bearings and got a shock. TBH, prior to pulling them, I wasn't totally sure the big end bearings were OK. The noises at idle led me to think that all was not well, and, well, they were not in a good way.

Capture25.JPG Capture26.JPG

This is called 'mosaic cracking', but also known as 'fatigue of overlay'. Now this might be seen in situations where the bearing is simply overloaded due to it being too soft, or extreme power being produced, or detonation. OK, soft, yeah sure I can see that; as they are only OEM Glyco bearings. But, the motor isn't making that much grunt that this should have been an issue. Curious, I researched the F out of it and found plenty of other examples of Glyco bearings with the same issue, and all bought around 2012 when, allegedly, Glyco 'had issues'. So I left it at that and bought a set of ACL Race Series for it. Their pressure ratings are way higher and are top notch Aussie-made bearings.

The other little task was to sort out the disastrous OEM oil pump shaft. Once again I got my good friend of 30 years to whip me up a part to replace the OEM shaft. Made from 4140 chrome moly, then heat treated, then cylindrical ground to perfection, this little part ought to give no trouble. It was fitted into an M52 pump which is 25% bigger volume than the M50 pump.

Capture34.JPG Capture35.JPG Capture36.JPG

**NOTORIOUS VR** · 08-02-2021, 10:09 AM

Awesome! Love seeing these kind of posts! Long live web forums!

**Nutzy** · 08-02-2021, 08:03 PM

Originally Posted by NOTORIOUS VR

Awesome! Love seeing these kind of posts! Long live web forums!

The change in this forum from just a few years ago is massive. There was a huge amount of activity here in the Forced Induction section and now it has really died out.

I used to be on E30tech.com years ago, from around the year 2000 or thereabouts. I had a massive build thread on that forum that detailed all the trials, fails and wins of my build. The owner was not updating the forum and it croaked a few times and had to be restored, but in the end he let it die and wouldn't even entertain letting others buy the domain and carry on. A huge amount of info just got flushed!

These days it is just too easy to open FB and post a question on a group. FB is an easy 'single pane of glass' type of platform, but as a resource it is absolute rubbish and will never match a web forum. And yet, despite that, witness the drop in traffic on this site. :-/

**vollosso** · 08-02-2021, 10:46 PM

Awesome post!

Sent from my iPhone using Tapatalk

**wgknestrick** · 08-02-2021, 11:37 PM

Yeah, there is very little traffic here anymore, and so many trolls. Great build and makes me want to get to the bottom of a couple of my nagging issues.

**Nutzy** · 08-03-2021, 06:08 AM

The move to 5 stud meant that the mesh wheels had to go. I played around for ages with measuring this and that and trying to work out just how the wider Z3M rear and the spindle adapters on the front would change the track, but in the end there is only one thing for it - borrow wheels, lots of wheels! In the end I borrowed some 68's from a local guy and was stunned at how the 8.5" 50ET rear wheel was perfect. The only problem then was the front at the 7.5" was a 41ET. Playing about with some spacers, I worked out that ~ 25ET on the front would be good. Then somehow I cottoned onto the fact that there is a third spec 68, a 25ET! This wheel is off the rear of the E46 M3. Although the ET was different, they were a squre 7.5" fitment. As far as I know, these M3 wheels were never available in Aus, so I ended up ordering them from Pelican Parts.

I can now get a 235 semi slick in the back with no rubbing. The front is still running a 215.

Here she is rockin' the Style 68's!

I'm pretty happy with the look and I don't think the 68's look too out of place.

**NOTORIOUS VR** · 08-03-2021, 09:21 AM

Originally Posted by Nutzy

I used to be on E30tech.com years ago, from around the year 2000 or thereabouts. I had a massive build thread on that forum that detailed all the trials, fails and wins of my build. The owner was not updating the forum and it croaked a few times and had to be restored, but in the end he let it die and wouldn't even entertain letting others buy the domain and carry on. A huge amount of info just got flushed!

As was I - I feel the same way about E30tech.com... such a shame!

**The Great Decay** · 08-03-2021, 04:49 PM

Great post. As others have said, this makes me nostalgic for car forums 10+ years ago

**Nutzy** · 08-03-2021, 06:53 PM

Originally Posted by NOTORIOUS VR

Awesome! Love seeing these kind of posts! Long live web forums!

Thanks! If we want the forums to survive, gotta revive!

Originally Posted by NOTORIOUS VR

As was I - I feel the same way about E30tech.com... such a shame!

E30Tech going down was just totally unwarranted and was still a really busy forum.

Originally Posted by vollosso

Awesome post!

Cheers!

Originally Posted by wgknestrick

Yeah, there is very little traffic here anymore, and so many trolls. Great build and makes me want to get to the bottom of a couple of my nagging issues.

Get on it and make a build thread!

In the days before web forums, I was on a mailing list called SER-List. It was all about SR20DE powered Nissan's in various chassis. Mike Kojima, Rob Cadle, Merlin, and various other dudes were our source of inspiration. Mike has gone on to acheive amazing things in the world of all things auto. Rob was a math savant type who ended up working for Garrett.

Ah the early 90's, when a collegue installed this thing on my Macintosh LCII called a 'web browser'. I was a bit confused about the purpose of such a thing...

**R.Thomas** · 08-04-2021, 08:23 AM

Cool build. The amount of custom work is amazing. Is traction noticeably better with the Z3M rear end?

**Nutzy** · 08-04-2021, 08:41 AM

Originally Posted by R.Thomas

Cool build. The amount of custom work is amazing. Is traction noticeably better with the Z3M rear end?

Thanks!

Traction is no different because of the Z3M rear, but it did allow me to go from 215 RS-RR semis to 235 RS-RR semis. It was the wider tyres that helped. As it is now, it's a 50/50 thing if it will smoke 3rd or not. If it lets go, it lets go quick and goes straight to the limiter. If it doesn't let go, it is still usually turning the tyres some. I'd say the slip is somewhere around the 10-20% mark. 1st and 2nd have no chance.

Come hell or high water, I will be setting up the traction control with the new ECU and putting in place boost-by-gear as well as RPM-TPS based boost. The new digital dash has a built in GPS for performance testing. This is going to be fun!

Attachment 694193

**ba114** · 08-09-2021, 10:30 PM

about time you put some history up. I was shocked when you told me it was originally a 318i!

**Nutzy** · 08-10-2021, 08:15 AM

Originally Posted by ba114

about time you put some history up. I was shocked when you told me it was originally a 318i!

Yep, the 30 started out as a very sedate M40B18 auto.

So, who has had a play around with shimming the M50 / M52 oil pumps for more pressure? I thought maybe I'd aim for 70psi, but shimming is just pot luck.

Bear with me here... The oil pump has a cap that captures the pressure relief spring and is retained by a circlip. The cap compresses the spring by 20mm once it is retained. I machined a 4mm delrin spacer to go inside the cap. I hope this is not too much and that the pressure isn't berserk!

**someguy2800** · 08-10-2021, 02:24 PM

Looks awesome. I am very excited to see how the ZF8 works out. I think that will be a better solution than the DCT.

**Nutzy** · 08-10-2021, 08:26 PM

Originally Posted by someguy2800

Looks awesome. I am very excited to see how the ZF8 works out. I think that will be a better solution than the DCT.

Proper control of a DCT is no snack, that's for sure. OEMs put HUGE amounts of R&D into it, so hoping to come along with an aftermarket controller and make it behave, is a tall order.

The ZF8 is also a complex beast, but from what I have seen of it with the HTG controller, it is a lot more forgiving. Having a TC is a step up from a DCT in terms of take-up from a standstill, so there is that.

**NOTORIOUS VR** · 08-10-2021, 08:28 PM

Originally Posted by someguy2800

Looks awesome. I am very excited to see how the ZF8 works out. I think that will be a better solution than the DCT.

I think they both have their place - ZF8 is really, really good though in 90% of the cases.

I'm actually curious about the weights now, the DCT is quite a heavy gearbox.

**Nutzy** · 08-11-2021, 12:02 AM

Originally Posted by NOTORIOUS VR

I think they both have their place - ZF8 is really, really good though in 90% of the cases.

Good enough for an M3 even! ;-)

Originally Posted by NOTORIOUS VR

I'm actually curious about the weights now, the DCT is quite a heavy gearbox.

They both weigh in at a porky 90KGS (198lbs).

**dominator293** · 08-11-2021, 12:45 AM

Cool thread Nutzy, sounds like quite a ride! Where abouts in Aus are you located? I'm in ACT. I actually will have some custom rotor hats in the process of being made, but need a place to machine them. Do you reckon your mate would be able to do a run of 4 hats for a reasonable price? At this stage I'm looking at getting them done over in China to save on cost because Aus prices are ridiculous! Flick me a PM to discuss if you like

**Nutzy** · 08-11-2021, 01:43 AM

Originally Posted by dominator293

Cool thread Nutzy, sounds like quite a ride! Where abouts in Aus are you located? I'm in ACT. I actually will have some custom rotor hats in the process of being made, but need a place to machine them. Do you reckon your mate would be able to do a run of 4 hats for a reasonable price? At this stage I'm looking at getting them done over in China to save on cost because Aus prices are ridiculous! Flick me a PM to discuss if you like

Yes, prices in Aus are very high, if you can even get shops to reply.

I'll send you a PM.

**Dano66** · 08-11-2021, 08:38 PM

Great condensed build! I can’t imagine convincing my wife to allow me to spend the time and effort you have on this car. Looks amazing! Thanks for contributing. I will be taking my inspiration from you and rehashing my 7 year project here soon.

Sent from my iPhone using Tapatalk