Q&A

Where can i get new parts for 745i turbo?

There are several online retailers selling OE/OEM parts, here are some i have used:

autohausaz.com
bmw2002.com
wallothnesch.com
shop.bmw-classic.com

For correct part numbers online go to see realoem.com

How much boost can a stock M106 engine handle?

First thing likely to fail is old headgasket past 1 bar of pressure. It can be avoided with head studs and special headgasket. Then again stock fuel system and turbocharger just do not follow up.

What are main differences between M102 and M106 turbo engines?

Obvious are  displacement, compression, digital motor electronics and 4-spd transmission. Minor changes were made to turbocharger, intercooler, charge piping, piston cooling and boost pressure.

How much it costs to rebuild engine parts by a professional workshop?

Here are some five years old prices from top of my head:

Short block without parts 1300 euros
Turbocharger 500 euros
Cylinder head 700 to 1000 euros
Fuel injectors 200 euros

What ways there are to identify my wastegate?

M106 parts usually have punched b-letter in cast iron part, with M102 part it is not true. M102 spring is much harder and you need two thumbs pushing it down, as M106 spring is “soft to touch”.

How bigger fuel pump affects fuel pressure?

In no way, pressure is controlled by fuel pressure regulator in end of fuel rail. Regulator only adjusts pressure according to manifold air pressure. High capacity fuel pump can be loud.

Can Nimonic exhaust valves be machined?

Yes, as long minimum edge thickness of 2 mm is respected. Valve must be replaced when minimum edge thickness cannot be held. New OE exhaust valve is just over 100 euros from BMW.

Is there online E23 repair manual available?

Go to see http://repair.bmw-e23.com/

What is stock boost pressure in 745i turbo?

According to BMW documents it is 0.7 bar for M102 engine (tolerance +0 -0.1 bar ) and about 0.5 bar for M106 engine. Often something else can be seen because of wastegate spring wear over times.

How many times can i resurface M30/M106 cylinder head?

Head with thickness of 128.1 mm was run trouble free with Ross pistons. This was with thick OE head gasket. Ross spec for piston to valve cleareance is 2.3 mm on intake and 2.8 mm on exhaust.

Why there is no bypass valve in 3.4L engine?

With automatic transmission throttle plate is always open in acceleration. When throttle closes, position sensor signals computer to open wastegate solenoid, decreasing boost pressure to minimum.

How can i get 745i chip so i may increase boost?

Chip can be done with PC, eprom burner, empty chip and binary file. Binary files are available in FILES-page or make your own as instructed in PROGRAM-page. Also ready chips are sold in CHIP-page.

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