Page 1 of 1

745 motor

Posted: Sep 25, 2016 9:30 PM
by fred633
I was offered a 745 turbo motor by a local guy. It is just the engine with no accessories. It is the engine and wiring harness, no ecu, no afm,, no intercooler, no fuse box, etc... I read a little bit saying I can put the engine in just about any chassis as it just bolts right in. What are the common modifications done to get more power out of this motor? I want to keep it drivable so nothing crazy.

Re: 745 motor

Posted: Sep 25, 2016 10:17 PM
by fred633
I read that bmw made two different 745 engines, a m102 and m106. How do i tell the difference between the two visually? I think the m102 has a distributor but was not sure if that was correct way to tell the difference.

Re: 745 motor

Posted: Sep 26, 2016 12:49 AM
by Nebraska_e28
You're correct on the dizzy with m102.

No need to modify the motor for more power. More gains can be had elsewhere.

Re: 745 motor

Posted: Sep 26, 2016 1:46 AM
by Hit Man X
Check the flat spot above starter.

'3,2 T' = M102
'3,4 T = M106

Both should easily support far more power than the lazy 190-200rwhp they tend to make in stock form.
Also, the 106 has knock sensors between cylinders 1/2 and 5/6.

If this is the same guy I am thinking of, it is an M106 from a beater 745i. At least get yourself a leakdown test and hopefully a comoression test before taking the plunge. Last thing you want to do is drop a wad of cash on a clapped out motor.

Re: 745 motor

Posted: Sep 26, 2016 11:46 AM
by tschultz
The oil squirters are nice and the heads apparently have some valves that are made of a different material for resistance to high temperatures, but overall think of it as pretty much an M30B34 engine since the turbo parts aren't included. What are one of those worth to you?

You can add on a KKK turbo and intercooler and such or go with a custom kit like TCD and aftermarket ECU to bump up the performance... But remember that engine has been turbocharged since it left the factory and may need a freshening up .

Re: 745 motor

Posted: Sep 26, 2016 2:55 PM
by fred633
It has a turbo on it, power steering pump, water pump, just not ecu, intercooler. I assume they just unbolted the engine mounts and pulled it out.

No need to modify the motor for more power. More gains can be had elsewhere. What are you referring to?

Re: 745 motor

Posted: Sep 26, 2016 5:34 PM
by tschultz
fred633 wrote:It has a turbo on it, power steering pump, water pump, just not ecu, intercooler. I assume they just unbolted the engine mounts and pulled it out.

No need to modify the motor for more power. More gains can be had elsewhere. What are you referring to?
I think he's saying head/cam/ compression changes will yield less overall power than ECU/controller upgrades and other external upgrades like better manifold design, turbo or intercooler updates.

Re: 745 motor

Posted: Sep 30, 2016 8:57 PM
by fred633
Is there a guide somewhere to installing this motor in a 633? Also what upgrades can I do?

Re: 745 motor

Posted: Sep 30, 2016 10:13 PM
by tschultz
It's pretty much a bolt in but there really aren't any writeups.

Re: 745 motor

Posted: Oct 01, 2016 9:47 AM
by fred633
Talking about the standard mods. Is there a guideline somewhere on installing the standard modifications? When you say "ECU/controller upgrades and other external upgrades" that does not tell me anything. That is very generic. I need specifics on what needs to be done.

Re: 745 motor

Posted: Oct 01, 2016 1:27 PM
by Nebraska_e28
What research have you done on this swap?

Re: 745 motor

Posted: Oct 01, 2016 4:06 PM
by fred633
I helped my oldest son build a turbo 2jz a few years back so I know more about that engine than a bmw engine. The 2jz there are tried and true setups as easy as ABC.

From what I have read on the bmw engine not many people mess with them and there are not pre-established guidelines. What I have read the block, pistons, rods, and crank are good to go. Standard rebuild (bearings, seals, rings, gaskets...)but no new parts or major machine work. Also read the stock 12 valve head will need new rockers, upgraded strings to dual if not already present. Reading mixed information on cam. One person said they are running a 300/110 but that does not sound right. What is stock on lift and duration? I would assume somewhere in the 260-290 range on both with it being a 12 valve. Have not read anything on turbos but I have a local guy that can custom make a turbo to match the flow of everything if need be. I assume everybody uses a 7006 or 7200 if they stay with k27. Will a k27/k29 fit or are there space problems? Have not read anything on waistgates but the way this tread is I assume a tial 46 is what people are using but nobody has given me any specifics.

Re: 745 motor

Posted: Oct 01, 2016 5:05 PM
by Hit Man X
Do a compression test on the thing before you decide what to do... could be good, could be bad. You are dealing with an abused 30 year old motor, not from the power standpoint really, but from 'techs' messing with the EFI system to make them pass emissions. The car was NOT designed to conform to emission standards, no catalyst and no oxygen sensor feedback stock. It lean cruises on stock EFI and idles a tad fat, so many would fatten up the cruise for inspections and leave the idle super fat which is terrible for cylinder walls due to fuel wash out.

I would at minimum strip the thing to a short block and reseal it, replace timing set, and have a valve job done. Depending on your realistic power goals, choose if you want ARPs and a Cometic or not. You do not have the luxury of a 24V head on this motor, so know this going in. These 745i made about 200rwhp stock, you will not make 400 or 500hp with a stock 47mm compressor wheel in the K27 as have been claimed years ago. End of story. I have never seen anyone dyno past about 280rwhp on stock turbocharger/stock EFI...EFI problem is the AFM. Measure it for surface area and you will be surprised how poor it flows, yet is plenty in a stock or near stock vehicle. MS2 is by far most common for what guys run. http://pftuning.com/

'7200' stuff best I can tell is for the Porsche guys to replace their factory turbocharger. I had my K27 upgraded a while back at Pure Turbos in CA, it now has a 360° bearing and a GTX3582R wheel among other gizmos. http://www.bimmerforums.com/forum/showt ... st27877400 Image

Wastegate wise, I am in the middle of an F38 top end conversion. A few guys have seen it, so far so good. Most of the goofy fab work is finished. It bolts directly to the stock elbow. Image