M50b20 Vanos stroker, need details

[Seyfettin777]

Hi all, I’m new in this forum.I have questions about stroker.

I have an E34 with M50b20tu engine.I want to stroke it, but I dont want to bore engine block, I will go with 80mm pistons.Someone told me that if I use M54b30 crank, M52b28 head and connecting rods with 80mm piston, I will get 2702cc.Compression will be high so this is an advantage or disadvantage?

Another thing is the pistons go out of deck or touch valves, etc? I couldnt take these informations.Thanks for any help.

[pazi88]

M52b28 crank and connecting rods give you about 2,5 displacement and bit higher compression ratio. That is tested to work. B30 crank and b28 head will not work.

But you also need custom remap to the ecu and you probaply have ms40.1 siemens in it. Which as far as I know can't be remapped. So you will need different ecu also.

[Seyfettin777]

We will use M52 ecu, if I’m not mistaken, they can remapable.

Thanks for your reply but, why I cant use 3.0 crank with 80mm bore?

[pazi88]

We will use M52 ecu, if I’m not mistaken, they can remapable.

Thanks for your reply but, why I cant use 3.0 crank with 80mm bore?

Ok that's fine. M52 ecu is tunable very easily.

The pistons will hit the head, so no room to rotate. You woule need shorten than 135mm connecting rods, but that's not good idea, becsuse with b30 crank the 135mm ones are already on the short side.

Of course with custom pistons that would work, but for the price of those, you can get whole m54b30 engine, so I don't see point in that.

[Seyfettin777]

We will try different thing with this project.I’m curious about how to react an M50b27 with high compression.Many people stroke their 2.0 engines to 3.0, we dont have many 2,5 here, with this combination against 3.0 M50, will be interesting.

I want to go with M50, It’s more reliable and in Turkey, parts are very expensive.I can take hole M54b30 about 15.000-20.000 TRY and my car costs about 25-70k according to its condition.Complete rebuild for M50b25 about 8-9k TRY.

So, building an M50 will be more efficient here.By the way, thank you so much for your attention again.

[Seyfettin777]

Hi everyone, and sorry for the flood btw.




My mom had breast cancer, so everything kinda stopped for me and my family for a long time. After this long and tiring journey, mom is ok happily.




The car was sitting for 2,5 years due to overheating issues, water radiator was damaged in a small fender-bender, but this happened around Covid pandemic, so I didnt get it done immediately but We had to use the car with leaking radiator because of mom's chemotherapy every day, when radiator is changed with thermostat, water pump and fan clutch, overheating issues continued. I think cylinder head is cracked or head gasket is done, Anyway, this is the perfect time for complete rebuild and stroker, also this will be my way to pay respect for service the car gave us for struggling hard times...




I have a few questions. Many people said that m54b30 crankshaft can be used in 2.0 block with 80mm pistons, which will give 2.7 liter displacement. They even added that "You should hone pistons from top to down in size, other way pistons go above deck height."

That's ok, I will buy 3.0 crankshaft but no one share more info about this.

Which conrod should I use?

Cylinder head is another concern, which head should I buy for this setup?

I'm planning to install M50b25 intake, 4.4 throttle body, full custom exhaust setup and m52 harness(ms41) then finally remap it.

With these combination, I want to keep compression low but don't want to keep it low with thick head gasket, what will be the final cr?

We have 95 octane(ron) pump at station legally, and sadly most of the fuel barely gives 93-94 ron, so high cr will be a problem in these cituation.

I wont swap m50b25 or other engines, 2.5+ engines are rare in Turkey and as I mention, I want to pay my respect and make it heart beat again stronger than ever, so everything will be rebuilded, not swapped...




Thx