MyE28.com

Long has been my suffering. It's been exacerbated in recent years by my nasty habit of crossing the continental divide. My efforts to help my situation have not been futile, but they have been underwhelming. I purchased an entire another running/driving 528e for the 5 speed transmission. While the 3.25 LSD and the Mark D chip help, they don't do enough. I've been daydreaming about this for almost two decades. I've been telling all my friends about the project so they'll hold me accountable. I've been racking up one hell of a credit card bill.

It's time... to turbocharge my 528e.

If Corky Bell taught me anything, it's that you need to set a hard horsepower goal in order to be able to calculate the numbers required to correctly size the turbocharger. I needed to dream up a number. 300hp seemed reasonable. After all, my truck makes that stock.

However, this is complicated by the fact that I've been turning into a cheap ass in my old middle age. My father raised me well. Some time ago, when I wasn't paying attention, old BMW parts got expensive. While I am fully aware of the many advantages and general moral superiority of the 885 cylinder head, I have two perfectly functional non-super-eta b27s and I plan to use them, unmodified. When I'm in the market for a 325i engine you'll know I've blown both of them up.

This projects seems to illustrate my approach to projects in general. On on hand, I'm using good tools and nice hardware to explore what I can learn and achieve. On the other hand, I'm throwing together garbage just to see what happens. Either way, it's a good thing I own more than one functional vehicle.

Goal: 300rwhp
Engine: 1986 M20B27 with ARP head studs, otherwise stock. 5,250 RPM redline
Turbo: Ebay GTX2860R (internally gated)
Turbo manifold: The Kangaroos Team M20 log manifold w/T25 adapter
Turbo coolant feed/return: unused throttle body heater circuit. Ebay turbo adapters and 3/8 heater hose
Turbo oil feed: T fitting from factory pressure switch (don't know if this fits yet), Ebay 1mm restictor to -4an, Summit racing 1/8 npt to -4an ­­ 90° fitting, summit racing -4an soft line
Turbo oil drain: Ebay 5/8" hose barb adatper, I am planning using hose barb fitting tapped into the engine block
Exhaust: Ebay 5/8 bolt flange to 3" V band, rest of exhaust TBD
Engine management: Speedy EFI Fishdog
Injectors: RockAuto Bosch 42/lb hr (p/n 62695)
Throttle position: BMW M50 type on an AngryAss adapter
Cam sensor: none
Crank sensor: BMW M50 type (hall effect) on a ridiculously expensive bracket. M20B25 crank trigger/pulley.
Coolant temp sensor: stock
Wideband: AEM 30-0300 w/FAE brand sensor
Ignition: Delphi GN10408 from a 2006 Monte Carlo
Spark plugs: NGK BPR7EIX
Spark plug wires: LS-style ignition coil terminals and standard spark plug terminals. Parts purchased from Ton's Performance
Idle control: 2-wire Bosch-style "Alfa Romeo" valve
Blow off/surge control valve: Ebay Bosch style, will live on a 1" hose barb adapter
Boost control: Speedy EFI generic
Charge piping: I'm trying this very generic Ebay 2" charge piping set
Intercooler: 24x11 Ebay air/air unit w/bottom inlet/outlet, Ebay 2" to 2.5" elbows to adapt to 2" charge piping
Clutch: Ebay Gripforce six puck sprung disk

Other non-negotiables:
-Retain air conditioning
-Retain cruise control
-Functioning factory tachometer

Would be nice:
-Electric fan(s) controlled by ECU
-Supply vacuum to brake booster at all times
-Make econometer and OBC range/mileage functions work
-Add adaptive cruise control (yes, really)
-Heads up display


It's hard to believe that this car has been with me for almost 17 years. When I got it, the odometer read 199,000. It now reads 312,000, and I know for a fact that the odometer died for a few months that one time. We have a sort of symbiotic relationship, one shaping the other. I'm looking forward to the next chapter.

this makes me happy inside. godspeed, BROTHER

The eta cam will be an obstacle. It comes on very strong around 3k and falls off hard and fast. An M20B25 intake manifold helps mitigate and spread out that big spike in cylinder pressure. You'll be able to run more boost and make more top end with that combo. 

300rwhp is going to be a big ask but it may be doable. I boosted an eta motor with my most recent project just to see what it would do and it didn't stay that way for long. It was underwhelming for sure. 

I'll be curious to see how that kangaroos mani works. It looks like it should be pretty effective. 

To get electric fans, you'll need some time of PWM setup. Easy enough with standalone ecu. And effective shroud will be your best friend too.

Keep us posted! 

Hi folks,

I edited the top post with links so maybe someone in the future can get some help. That person may be me.

Some interesting things:

• The stock b27 throttle body has a 64mm hose size, which is 1mm over 2.5in. I have ordered another 2in to 2.5in elbow to make this connection.
• The stock throttle body heater hose barb on the engine block seems to accept 3/8 heater hose well. Time will tell if it's close enough.

Problems I have not solved yet:

• Intake air filter, couplers and tubing
• Crankcase ventilation
• Continuous vacuum supply for brake booster. I spoke with a gentlemen with a very nice Porsche 928 and he told me that some supercharger kits for those cars use a venturi to supply partial vacuum under boost.
• What muffler to run. I want the exhaust to be quiet.
• 3/8 heater hose fitment on thermostat housing hose barb.
• Ignition coil mounting
• Distributor delete plate
• Cold start valve bock off plate
• Engine harness wiring. I got the 8' harness from Speedy EFI, but i need to review a few things
• IACV mounting. The new idle valve is fatter than the old one. I don't have a hose barb for it, either (inlet).
• General turbo fitment. I am daily driving the car now, but when I take it apart in a couple weeks I should know more

Any advice is appreciated!

The M20B25 uses a very nice end cap on the intake manifold that you can use to get rid of the CSV. A super eta or B25 throttle body has provisions for an ICV, which you will need if you use the B25 end cap. The stock brake booster feed has a check valve built in to trap vacuum, this works perfectly to prevent boost from entering the booster. 

Crankcase ventilation can be done to atmosphere or to the compressor inlet. If the bottom end is healthy you wont have much vapor to deal with. If its producing a substantial amount of oil through the breather you may need an oil separator.