1984 BMW 745i Turbo Engine (M106)

[Ives]

Assembling another M106 engine. Thinking of putting it on BaT. Can’t make up my mind to have the long block rebuilt or offer it as a project. All the important bits are there. If I do offer it I’ll include the steps to get the close to 400HP and 450 lbs. I get in Sixto. Should fit E3, E9, E12, E28, early E24 and be period correct. Included are pictures of the engine so far and how it looks in Sixto my 1974 3.0 CS.
Regards, Jon

 

[rblongboarder]

Very interesting. What ECU runs this engine? Stock or aftermarket?

 

[Ives]

I use an Emtron and a Link also works. Started with a MegaSquirt but not enough precision. I’m running a Garrett GTR 3076 turbo and have both a crank and cam sensor for tuning.

 

[rblongboarder]

In your Turkis '74 E9, the Entron is the small black box adjacent to your battery ?

Thanks for the other information, including the Garret turbo. How much boost? (I also drive a '04 Subaru STI w/ 6 speed, so I dig turbo'd engines.)

 

[Ives]

The Emtron ECU is in a small hidden shelf inside the glove box. The unique hidden shelf is the invention of my upholstery guy in SoCal. That black box next to the battery holds 4 relays for the electric fans, ECU and other custom features of the engine. I'm running 10-12 lbs and when I get on it the turbo gauge shoots past 25 lbs.

 

[Clubsport_CSi]

The M106 is such a capable engine; a buddy of mine has approx. 650hp in his E9. Another buddy same in his E24 before he built an S38 Turbo. The gearbox and driveshaft are limiting...
Congrats, great engine!

Edit: You are switching the intake to make it look more period correct?

 

[Ives]

Clubsport,
The original build was to make it period correct. That puts some limits on the engine flow. My Dyno guy has tuned it for volumetric efficiency with this set. Some flow limits are airbox, C tubes and throttle body at a minimum. Took Sixto to a show where a number of BMW knowledgeable people were there and several missed it was an M106 engine. That puts a smile on my face. I’m happy with 400HP/500lbs but if it was further modded for more air, head work, exhaust work this engine should easily pass 600HP. For me drivability is the key as I drive it primarily when I go out. The biggest affect in acceleration is between 60-100 mph. I’ve surprised a few locals in Detroit iron as well as a 2020s M2. The litmus test for Sixto and the engine will be the long term drivability. I plan to be buried in this one.
Thanks for the comments.
Regards, Jon

 

[Clubsport_CSi]

Took Sixto to a show where a number of BMW knowledgeable people were there and several missed it was an M106 engine.

Hi Jon - I can imagine that
It appears very "undercover", at least from the driver's side. At the passanger side you see at least the intake hose diving down, e.g.
But I think I never saw an M106 with the old Jet style intake. A very nice idea!
Agree on the driveability and durability/long-term fun; more can also be too much sometimes.
Enjoy (is there a driving video available?)!
Kind regards, Dan

 

[Ives]

Dan,
I don't have a driving video because I'm by myself most times and when I punch it my complete concentration is required. There is so much torque that it's almost like driving an automatic. No matter what gear I'm in it takes off. The biggest problem we encountered is heat and the evacuation of it. It's solved now with the combination of compartment outlets, electric fans (2) and Flex Fuel at around 40%. Most of the Dyno runs we did in hot temperatures but will be doing some more in Oct. The interesting engine dynamics show that significant power comes on around 2700 RPM in comparison to the much higher reading for an S38. Almost finished but having a great time driving it and looking forward to showing it. here are some shots I took lately.
Regards, Jon