My project is to turbocharge a BMW E30 325i M20 engine.
Engine specs:
- cyl count=6
- main trigger= 60-2 on crank http://www.vems.hu/wiki/index.php?page=MembersPage%2FGergelyLezsak%2FTrigger
- stock internals
- T3/T4 turbo 50 A/R Compressor, 0.63 A/R Turbine .57 Trim 3" inlet stage 3 wheel
- Oil cooling on pistons http://www.e30tech.com/forum/viewtopic.php?t=5223
- Intercooler will be as big as possible
- Lime green 440 cc bosch high imp petrol injectors
I guess we have a lot in common: http://www.vems.hu/wiki/index.php?page=MembersPage%2FGergelyLezsak
read: original MegaSquirt documentation besides VEMS manual, since MegaSquirt is basically the same.
[GenBoard Version User's Manual]
http://www.vems.hu/wiki/index.php?page=GenBoard
Q: Which parts do I need to get full control of injection and spark?
Assembled v3.3 controller
- ignition driver 8
- Knock and EGT knock and 2 EGT
- LCD and PS2 yes
- MAP connection offboard(electronic)
- primary_trigger VR
- secondary_trigger HALL
I want to use a bosch map/temp sensor I'll get the number later on. Pro's con's mapsensor
- mounting
- line though firewall
- speed
IAT sensor: GenBoard/Manual/IntakeAirTemperature
- faster then stock bosch
Spark control
With your stock 60-2 wheel you can control a wasted spark coilpack directly with VEMS without any additional triggers. You can borrow a coilpack for a 6 cylinder car from an EDIS6 equipped car, like a Ford V6 (You don't need the EDIS module itself, just the coilpack!).
Laptop connection: Basically you use the serial port on the computer, and the corresponding port on the Genboard is either through the smaller EC18 connector or from a pin header inside on the board, which is usually routed to an end-plate in the form of a regular DB9 (standard serial RS323) connector.
LPG section
I wil be running LPG with a Vaporised Sequential Injection System. http://www.prins-lpg.com/en/products/vsi/index.html
Stage one plans:
- Use Prins vapouriser, injectors and use VEMS to control the amount of fuel.
- LPG doesn't have a steady fuel pressure in the fuel rail. So I will have to make req_fuel scaled according to the 1/sqrt(lpg_pressure). There is no need for an extra variable, since req_fuel is already there! All that is needed is 1 bit to enable the lpg_pressure dependent scaling (maybe 3 bits so the mcp3208 channel can be chosen: well, 1 byte might be more future-proof). You can add a variable at the end of config. Actually, the same would be suitable for gasoline as well, if one trusts his fuel-pressure sensor.
- Pressure in the fuel rail isn't constant because off the liquid to gas transformation and the volume flow trough the vapouriser. By a fuel cut off, liquid gas is still in the vapouriser and increases in volume building more pressure. These effects are much to big to compensate with a pressure tank and are much bigger then the pressure fluctuations in a petrol injectorrail. A solution for this might be adding a pressure regulator with a blow off valve in the injectorrail. Or atleast a pressure relief valve set at about 4 bar. Problem with a higher pressure then 4 bar the injector won't open anymore.
- * Injection duration is dependant of temperature of the LPG in the rail, pressure in the rail, rpm, requested mixture (Lambda), Vbatt, and of cause load dependant (MAP).
- * Volume flow can be calculated if you have the pressure in the rail, the temperature, rpm and know how much the displacement is.
Future problems:
- Injectors are to small.
- Vapouriser might be to small. (Might have to use two of them.)
- I don't know customers prices, not my department :) You can send them an e-mail if you want to know.
Second stage:
- Add an other base map to Vems. I want to be able to run on petrol too.
- This option isn't available jet
- Running both high and low impedance injectors.
links
BMW on LPG: http://zymo.homemail.com.au/bmw2.htm
More info on nitrous systems: http://www.diy-nitrous.fsnet.co.uk/index.htm
VEMS GenBoard/VerThree (v3.x, like v3.3) has 8 output channels that are capable to drive low impendence injectors.