Versatile Engine Management Systems - VEMS wiki

Big Six Turbo

BMW called M30 engines as "Big Six" (M20, just like mine is "Little Six"). This page is about an M30B34 turbo engine, originally in a 745i from 1985.

It's not a weak car even it's stock form (3.5 Turbo, automatic, see pic),

but this engine is now in a light chassis (e30):

This page is about GenBoard-ing it!

Original setup

Car outlines:

• Engine: M30B34 turbo, 3400cc, 6 cyl inline, 12 Valves, SOHC
• Fuel injection: Bosch injectors (part no. 0 280 150 200) maybe 270-300 cc/min @3/3.5bars (different sources say different values). R=~3 Ohms.
• Fuel pump: Stock
• Stock 3 bar pressure regulator, with manifold pressure reference
• Turbo: stock KKK K27
• Idle control : stock. (similar to M20)
• Intake: stock AFM, Small stock air-to-air intercooler
• Factory throttle pos switch (3 state; idle, between and WOT)
• VR crank-trigger: 60-2.
  • M20 baby series engine uses exactly the same crank triggering, see MembersPage/GergelyLezsak/Trigger
• Cam position sensor - coil at plug wire #6
• Coolant sensors - similar to M20
• Knock. Two factory installed knock sensors.
• More sensors: O2 sensor: narrowband , IAT in AFM
• orig ECU: Bosch Motronic 0 046 430 136 0

Buylist at MembersPage/GergelyLezsak/BuyList

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Project

Electronically the M30 engine seems very similar to the M20 little brother (from the same era: motronic 1.3). Even their original ECU can be swapped, and the engine will start up! (mapping is not the same, so don't use this as a common practice)

After i've received[first part of the order] I made a new harness, and ordered a new 3.3 GenBoard. Now, the car is running stable with GenBoard.

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UPDATE

2006.04.03

At least we changed to the latest firmware. (1.0.38)

BMW-style dual IAC valve is fine now. And car had been mapped nice.

One strange problem with MAP: on boost, MAP values are less than real (probably the half of real) values.

• In vacuum it seems OK: decceleration: 15-20kPa
• idle: 45-55kPa
• free air: ~100kPa
• But like 1-1.2 bar boost showed only 150-160kPa MAP instead of 200..220kPa
• 0.2 bar boost showed like 95kPa MAP instead of 120 kPa. (lower pressure than free air ????)

I'm using 250kPa MAP sensor, and double checked the values with two (known good) analogue gauges.

I probably misconfigured something with the new firmware.

Needed:

• mcd
  • most importantly kpa_conf
  • kpafac
  • kpa_offs
• mct
• if you can hook up an external pressure sensor, (or a DVM if you alredy have an external) that could also provide verification info

2005.12.28-29

Car is running with GenBoard :)

We'have removed the whole factory harness. (Took a while to reproduce everything) Some experience: TPS wire's and IAC open/close wire's direction is always replaced :)

Had some difficulties with digital outs; EC36pin15 (Which is P259/5) didn't do anything (with the fuelpump). Tried to move it to the next pin (P259/6), resulted the same. Finally chose a different chip: S259/5, EC18pin5. It's working. Couldn't imagine what could be wrong, at the test time fuelpump out was working.

After we've got fuel I made it flooded. I don't know how but my previous calculations worthed nothing. I thought fuel_req at the 12ms range, but I needed to half that, and maybe we'll half it again. Idle (which is horrible now, but that's mainly pid-related) is around 1ms pw. Don't know why, these are ~300ccm injectors. Maybe too slow to close? Will try to lower pwm value of 30%, and PowerFlyback if necessary...

Since we've got 25cm of snow the day the car started, couldn't tune it yet...

Some pics:

Dashboard:

[in big]

Nice work with the LCD mounting.

The first day at the backyard (no snow at all):

[in big]

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TODO

• LCD with cable connection
  • Done: not exactly with the specified resistors, but it's perfect. [pic1], [pic2]
• Make whole harness
  • Done
• External MAP housing with connections
  • Done
• When GenBoard is ready, flash it with my IAC-tweaked firmware
  • Done. It's included (and fixed) in latest - post 1.0.32(?) firmware.

• Mapping
  • It's going to be a whole new story at MembersPage/GergelyLezsak/BigSixTurbo/Injectors

• Setting IAC table/PID
  • It's still an issue for this and my own car. Valve control seems allright, but can't get through the problems of very low RPMs (and sometimes stalling) at sudden throttle release. Details soon.
• Boost control
• Calibrate and test knock sensors. Checked dox but can't find out what knock1_frequency values actually means?
  • the value directly from TPIC8101 datasheet (table), usually 0x29=41 but check for your freq. What is your freq?
    • That's it! We don't know the freq yet but now I understand what I'll adjust, fine! :)
• PowerFlyback? - Sure!, discussed at MembersPage/GergelyLezsak/BigSixTurbo/Injectors page

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• Here is a similar car: MembersPage/MattiasSandgren/BmwSevenTwentyEight - Unfortunately the owner had to sell it for 1300 euro..
• Another similar car: MembersPage/MattiasSandgren/BmwFiveTwentyEight (Will be my daily driver //Mattias)

and a [movie clip] for motivation

//Emil Larsson

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Document last modified 2006-04-07 00:30:40

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