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. I wanted to put it together on my M20 and then move the working system (with changed values of course) to the M30 engined car.

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UPDATE

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. We'll need to merge the few lines special IAC code to mainstream stable firmware. Do you have uptodate patch ?
  • are you still using firmware with tps-accel enrichment accidentally disabled ?
• Mapping
• Setting IAC table/PID
• 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?
• PowerFlyback?

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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 2006-01-05 05:50:51

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