MyE28.com

https://imgur.com/a/tN0VsFO
https://imgur.com/a/OPKw8Fk
https://imgur.com/a/VvrUZ17
Color is savanna beige

Current setup
Engine

M52b25TU with b28 Crankshaft = m52b28TU intake and exhaust vanos is in use.
m54b30 Intake cam
m52b25tu exhaust cam
m50 Nonvanos con-rods
stock mls headgasket
new bearings
Pulsar gtx 3067 gen 2
selfmade manifold " agricultural looking "
intercooler Core: 450x300x76mm Connections: 76mm (3´)
3 inch downpipe and 2,5 exhaust with 2 silencers ( cheap from local "walmart")
44mm no name wastegate
m52b25 intake and throttlebody ( ill chance this to m54/m50 intake with abit bigger throttle body)
3-way MAC valve for boost controlling, e36 radiator 440mm x 540mm , most houses are random hoses from farmers market / hydralic market)

im running e85 its like 70-85% ethanol and rest something else.
MaxxEcu-Race, e28 goodies engine mounts, 320 zf gear box, 3,66 lsd type 188 diff.
540 / 34 front brakes, 34 touring rear brakes ( same as 540 sedans/tourings)
e39 / 523IA Driveshaft ( its like 2-3mm short but works good enoght)
340L AEM intank, and 2 x "china044" in 3L surge tank ( e28 fuel tank pumps air very easily when fuel lvl is like sub 35l)
BC-racing springs and shocks ( kinda stiff for e28)
e46 front seats for some side support e28/e30 ERA sport seats in decent condition are like 1000e here
e39 power steering pump and e28 steering box

i had m52b25 before blew head gasket it made like 340 on rear hubs 1 bar of boost .. but it was abit lower than expected from setup.
this had 1 bend rod and gasket was burned between 4 , 5 cylinders. it was "un opened" engine with new headgasket and valve seams, with 350tkm

this TU engine started slipping clutch at 3700-3900 rpm and 560 nm. so dyno session was over.. waiting for better clutch.
hopefully i get new dyno run next weekend, hoping for something like 450-500 hp from engine, and looks like we need to hold boost down at lower rpm ( better to have torgue peak later than now at like 3900 rpm.

- ecu has safety warning and power cuts for following

Boost limit,water temps,oil-temps,oil-pressure, fuel pressure ( also if lambda goes past 0.9 on load its "lean cut")

After like 27 Edits i think i have most of the basic things listed.

Stock compression ratio I presume?

That seems like an obstacle on the 24v motors. I know the combustion chambers are an improvement over the M20 but even then, I would feel better being around 9:1.

End of these engines as far as i know is too much low end torque, or bad tuning ( knock,heat,going lean, limiter too high -> vibrations and ofc just trying to run too much boost when you dont have H-Profile conrods and aftermarket pistons.
not sure how much lowering compression helps on that ( im no expert ), running ethanol lowers chance of Knock greatly.
i will be running max 1,5 bars , limiter at 6800/7000. 2,5 and 2,8 Liters should be not as "shaky" as engines with b30 Crankshaft.

Compression ratio determines knock threshold on any given fuel. Higher CR, more adiabatic heating. Regardless of combustion chamber design, PV=nRT still applies. BMW gets away with high comp on their DI turbo motors by using multiple injections to cool the chamber. With port injection we don't have that capability. E85 helps but even then, at 1.5 bar you may not get away with the stock CR. I am under the impression that .5-.6 bar is near the limit on the 24v motor with the stock CR on pump gas. That's one thing I like about the M20, the super e comes in a 2.7 capacity and an 8.5:1 CR. Used to run 1.4-1.5 bar on 91 pump fuel, stock pistons, rods, crank and head gasket.

If you end up going into the motor again a thicker head gasket would be an inexpensive and effective way to keep that motor together.

m52b25 had stock headgastket ( non mls), as far as i know anything after 1.0 bars is asking for trouble on that gasket.
torque was around 500nm m52 has very "flimsy" conrods.
got like 6000-7000 km of boosted driving out of that and almost every "trip" had some amount of 100% throttle driving.

no clue whats "safe" boost on stock compression, atleast tuner who has done "Hundreds" of m5x engines tunes was running it at 1.3 - 1.4 bars before clutch gave up. Anway ill find out at somepoint how it holds, i would be happy with abit over 400hp on rear wheels.

This setup with dual vanos and small turbo, wanted to throw Torque to around 580 at 3000 rpm

So there was some dialing down off torque with igniton / timing --> moveing it on higher rpm to keep engine alive, result was 385 HP / 545 NM at hubs.

also wastegate or mac valve was acting up, it was now running agains 0,4bar spring 43mm wastegate ( in not so ideal location ) and pushing 1.2 bars to engine..

Next step on this "build"

turbine housing from 0.62 to 0.82 AR + m50 intake, both should be "bad " for low end torque and move "power" to higher RPM.

Athena Cooper Ring headgasket, making sure to keep pressure in cylinders

So outcome was something along following... Turbo seems to wake up early and if i hear right there was no sign of it falling off before rest of engine "falls" out.