2004 BMW 760 N73 "A big mistake"

[Abricos]

Probably a lot of CAN sniffing and making transmission happy with rusEFI messages.

Good joke

[AndreyB]

2005/2006 US v12 take rate was 2.5% also did not realize they had short wheel base in 760 US

while global E32 v12 take rate was 22%. That's the v12 decline in action?

https://www.theautochannel.com/news/2007/01/03/032847.html
https://www.bimmerforums.com/forum/showthread.php?1788238-E32-Production-Data

[Zeiss]

Yes, it is, sadly.

I am watching the F02 760Li market because I want to replace my E66 sooner or later. And, result? It is hardly possible to find a V12... they are soooo rare. So, I guess I will keep my 760Li for a while.

[AndreyB]

Yes

Since you are nice to me any chance I can ask for the kind of help where you would be MOST overqualified? https://github.com/rusefi/proteus-N73-adapter/issues/1

I've already granted you edit permission on

https://docs.google.com/spreadsheets/d/1W5Unmn0BxpyJrF7ygtsBidWyytZWV2f26zL1YWcE44c

[Zeiss]

Hey Andrey,

you want to have the pinout of the both DMEs from N73, correct?

The DMEs in N73 have different names from N62, they are called A6010 (DME 1) and A6020 (DME 2). Accordingly, the connector names are also different.
But it's no problem, I'll write it down for you.

Meanwhile you can implement support of second MAP/MAF sensor in Proteus for me and after that ETB sync for engines with two ETBs

EDIT: I have entered the pinouts for the N73. What is still missing is the N73TU, there the pinout of the main DME is a bit different. I will add that tonight.

[AndreyB]

I have entered the pinouts for the N73. What is still missing is the N73TU

Thank you! I have appointment to get the plates today While this N73 is not on top of the priority list it's definitely somewhere on the list Slowly but steadily.

[Zeiss]

Nice! I'm excited to hear what you report after the ride with the N73. It is an awesome engine, absolutely overengeneered but awesome

[AndreyB]

Nice! I'm excited to hear what you report after the ride with the N73. It is an awesome engine, absolutely overengeneered but awesome

Well, I've driven it what, 40 miles a week ago? It's in rough shape but at the moment I do not have time to even hook it to laptop Steering warning light, check engine light I think Sergey said CAM sensor error and timing chain issue is worst fear, air suspension leaking etc etc.

[Zeiss]

Sounds like a bit of work, a bit more work....

[mk e]

Well, I've driven it what, 40 miles a week ago? It's in rough shape but at the moment I do not have time to even hook it to laptop Steering warning light, check engine light I think Sergey said CAM sensor error and timing chain issue is worst fear, air suspension leaking etc etc.

I had a cam sensor error on my 6 cyl bmw I couldn't find....ended up being oil pressure I guess because the engine seize on my "is it fixed now?" test drive

I'd say verify oil pressure unless this engine doesn't have variable cam timing then never mind and just enjoy it

[nmstec]

I had similar problem on n52. Fucking PCV failed, and I guess due to the engine shaking its ass off it kept throwing cam-crank correlation

[mk e]

I had similar problem on n52. Fucking PCV failed, and I guess due to the engine shaking its ass off it kept throwing cam-crank correlation

had that too, fix it, no change on the cam sensor issue....its usually just the sensor but on a high miles engine it could also be a plugged up oil pickup. Must be a german thing as I had a VW that lost oil pressure due to the pickup plugging.

[nmstec]

I don't know if this would help, but n52 also had those pressure relief valves with strainers on them (filters of sorts?) mine were fucking full of shit.

[AndreyB]

OMG I have plates!

What next?

[mk e]

OMG I have plates!

What next?

Have you ever seen the show "pimp my ride"?


....don't do anything you saw there

but street racing would be fine use of a V12 bmw

[AndreyB]

Now that I have the plates straight pipes in Holland tunnel and/or Lincoln tunnel are feasible.

1) shall I?
2) depends on rusEFI running the car obviously
3) are all straight pipes created equal or not? do I need equal length or other drama considerations?

@Zeiss do you know catalytic layout? Would it be one cat per 4 cylinders? I wonder how reachable are those from underneath the car. I could be wrong but I was assuming that I need to remove cats while developing GDI?

[ssmith]

Now that I have the plates straight pipes in Holland tunnel and/or Lincoln tunnel are feasible.

1) shall I?
2) depends on rusEFI running the car obviously
3) are all straight pipes created equal or not? do I need equal length or other drama considerations?

@Zeiss do you know catalytic layout? Would it be one cat per 4 cylinders? I wonder how reachable are those from underneath the car. I could be wrong but I was assuming that I need to remove cats while developing GDI?

https://www.realoem.com/bmw/enUS/showparts?id=GN83-USA-09-2004-E66-BMW-760Li&diagId=18_0512
Looks like one cat per 6 cyl, built into the header. Might be tough to reach the exhaust nuts from under the car depending if you have a lift and if you remove all the underbody panels.

I would want to gut the cats (or remove them) while tuning, because it'll probably take some time to get right. I wouldn't say GDI cares about cats one way or another, but in general you need to tune to keep cats happy (heat them up quickly, have the right mixture). But then, I have 0 experience tuning with cats.

As for straight pipes, hell yes. NA V12 would sound awesome! I would think the equal length business is more important at the header size rather than the rest of the exhaust; do you get much scavenging from a V12? BMW did merge the exhaust...
https://www.realoem.com/bmw/enUS/showparts?id=GN83-USA-09-2004-E66-BMW-760Li&diagId=18_0514

[ssmith]

ok now I'm looking into this, some of the stuff will be different than the HPFP I'm used to / than the code I implemented.

1. You have two pumps, two rails, two pressure sensors. Double the fun!
2. The pumps are always pressurizing the rail. You activate the valve to RELEASE fuel, not pressurize the rail.
3. 50bar - 120bar, 3 lobes/rotation.
4. There is an emergency relief valve but I don't see what the rating is.
5. I don't see notes on the rating of the pressure sensor.
6. Injection nozzle is 70 degree to the head, so it isn't center inject like later BMW motors. I think mixing is generally trickier with this style of injection so injection timing matters more. On the plus side, the doc keeps saying how BMW does NOT use lean burn / inhomogeneous mode, so no need to try to emulate that.
7. It seems the low pressure fuel pump is standard for that era (or earlier) - external filter with external regulator with return line. Pressurizes to 6 bar. Sounds like the pump will be run 100% if it loses signal to the DME (or maybe always runs 100%, doc is unclear).
8. Separately, this engine has valvetronic. That might be problematic, as the wires they use are 4mm^2 / 12awg. It looks to be a brushed DC motor. It may take more current than you want to design for. Do you plan to lock them open? I use BTN8982 for the N20 valvetronic but it's the newer brushless style that uses half the current (I think). Maybe you want to use two in parallel per pole? Also it sounds like the angle position is sent "in digital form." This all sounds more like the N52 valvetronic system which I think OrchardPerformance has some experience with.
9. Hahaha 6 knock sensors!

You should probably read the manual on this forum page: https://www.bimmerfest.com/threads/n73-training-manual.631053/
Though it doesn't look at useful as the N20 documentation I was able to find. Still.. "85V-100V and up to 16A"? Hmmmm...

[AndreyB]

I am starting to think that the proper roadmap to N73 GDI is via Passat GDI project. Open question if Passat GDI execution depends on selling the unused red Miata.


Anyway some cool links https://www.bmw7club.nl/wp-content/uploads/2015/06/05_MED-9.2.1-Workbook.pdf

Some diagrams added to https://github.com/rusefi/rusefi/wiki/BMW-N73#starting

[AndreyB]

8. Separately, this engine has valvetronic. That might be problematic

That's the fifth control module and that one I am definitely not touching in the foreseeable future. Best case I keep it happy via CAN, worst case it's disconnected.

[AndreyB]

PS: thank you for some great info and looking into this!

[ssmith]

8. Separately, this engine has valvetronic. That might be problematic

That's the fifth control module and that one I am definitely not touching in the foreseeable future. Best case I keep it happy via CAN, worst case it's disconnected.

I'm betting if it can't talk to the DME, it just opens 100% and expects the DME to control the throttle body. In fact I think I saw reference to that in TIS.

General rule - if there are multiple computers, expect "proper" behavior when comms fail between them.

VAG GDI is only 4 cyl. Bump it to 6 and run two of them?

[AndreyB]

The DME module receives the request to increase the engine speed over the PT-CAN. The
DME passes that request on via the LoCAN to the Valvetronic control unit (VVT). The
Valvetronic control unit controls the output stage for the valvetronic motors to increase the
engine idle speed accordingly

Sweet.
PT-CAN 500Kbps
LoCAN speed = XXX?

[Zeiss]

hey Andrey,

check this out: https://github.com/damienmaguire/BMW-E65-CANBUS

I just found it by accident.

I far I know, LocalCAN ist running at 500Kbps too.

ETB vs VVT: ETB on this engine are active just during starting and in error case. Normally, the ETBs are fully open and VVT controls the motor. In the event of an error, VVT is moved to a specific position and control is transferred to the ETBs. So that the motor can continue to run, albeit (perhaps!) with reduced power.

[AndreyB]

Damn nothing on pins #6 and #14 we would have to cut into wiring to access CAN

Another weird thing is how transmission line splits OUTSIDE of smart fuse box?!

https://github.com/rusefi/rusefi/wiki/OEM-Docs/Bmw/2003_7_Series_e65/2004-760-data-buses-3.png

image.png (124.89 KiB) Viewed 9909 times

[Zeiss]

Here you can see the local can:

grafik.png (56.26 KiB) Viewed 9906 times

Power train can:

PTCan.pdf

(60.5 KiB) Downloaded 132 times

And OBD plug:

grafik.png (47.04 KiB) Viewed 9906 times

As I said, there is no CAN on OBD. A220 is "safety and gateway module".

So the easiest way is to tap the lines at DME or another ECU. Unfortunately there is no LocalCAN at the IVM.

[ssmith]

ETB vs VVT: ETB on this engine are active just during starting and in error case. Normally, the ETBs are fully open and VVT controls the motor. In the event of an error, VVT is moved to a specific position and control is transferred to the ETBs. So that the motor can continue to run, albeit (perhaps!) with reduced power.

I think you mean VVL (Variable Valve Lift, aka Valvetronic in BMW speak) not VVT. Also in the doc I linked, they describe what they use the throttles for. Short answer - to create vacuum in the crankcase for the PCV system to operate.

[Zeiss]

Yes, correct, I mean VVL, not VVT.

EDIT:
@Andrey: My E66 is an LCI (09/2006, model year 2007), with MED 9.2.1, so that means, that some CAN-IDs could be different to yours.

[mk e]

ETB vs VVT: ETB on this engine are active just during starting and in error case. Normally, the ETBs are fully open and VVT controls the motor. In the event of an error, VVT is moved to a specific position and control is transferred to the ETBs. So that the motor can continue to run, albeit (perhaps!) with reduced power.

I think you mean VVL (Variable Valve Lift, aka Valvetronic in BMW speak) not VVT. Also in the doc I linked, they describe what they use the throttles for. Short answer - to create vacuum in the crankcase for the PCV system to operate.

I'm pretty sure that is a fuel saving system or perhaps emissions improving system not a hp creating system. Normally at lower power the throttle is mostly closed and the engine is creating a vacuum in the intake...so doing negative work. The VVL system minimizes that negative work....at least as I understand it. Seems a fine thing to discard as over complicated German design to me.


Straight pipes. The engine is 330hp? so it would want a pair of 2.5" pipes
https://www.motortrend.com/how-to/what-exhaust-pipes-work-best/

its just about air flow. There is some concern that the pipe becomes a "tuned" or more likely out of tune part of the exhaust system but if sound not HP is not the real goal that doesn't matter. I had Burns SS design the headers on my engine and they said, 6:1 headers don't work well, so 6:2:1 is the go. They also said, at least on my engine, there would be some additional gain adding an X pipe between the 2 banks but it wasn't enough to worry about if I couldn't make the layout work. That general advise probably applies to all V12s. Hope it helps.

[AndreyB]

so 6:2:1 is the go

I am not looking to gain any power, I need to stay within "reasonable change of cool sound result" instead of "if you X or Y you would not have cool sound for sure"