My project is to turbocharge a BMW E30 325i M20 engine.
A nice link for instaling VEMS on a BMW E30: http://savarturbo.se/~mattias/motor/vems_bmw_e30/
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
- Yellow LPG injectors from Keihin low imp.
- Prins evapouriser
- Techedge WB02 display + logger
Progress
- The engine is in the car. Next on the to do list is to built a wire loom and some other stuff.
I guess we have a lot in common: [MembersPage/GergelyLezsak]
A great guy who's car I deff like to see when it's finished: [MembersPage/MattiasSandgren]
[\ MembersPage/JanSaenen/LPG LPG Section]
[\ MembersPage/JanSaenen/Links Links]
[\ MembersPage/JanSaenen/Buylist Buylist]
EGT
My GenBoard (preassembled serialNr=355 and 356) has two EGT cables connected to the board, at nearby locations.
You can connect two EGT sensors. MegaTune will log both mcp3208channel4 and mcp3208channel3 (raw values). However, only mcp3208channel4 is displayed on LCD page0 (mlp00).
Raw values mean that the
- real_celsius_value = egt1_offs + (raw_value * egt1_cal / 256) where typical values:
- egt1_offs=00
- egt1_cal=49 (that is decimal 73)
Peak and Hold
set the PWM % and how long the peak should last (typically 1.0 ms).
Fuses
These are commonly used :
| Current consumer | Fuse rate | 'Description/Comment |
| VEMS Genboard | 3A | It actually draws a couple of hundre mA, but this is the smallest automotive fuse commonly found in gas stations |
| Lambda | 5A | |
| Injectors | 10A | This could be the main fuse, and a separate 3A fuse for each injector for safety if you get a short in an injector you could fry the driver with only one main fuse |
| Ignition coil | 10A | Possibly even higher, depending on the coil primary resistance |
New Questions
MegaTune is a software to change / tune config/table values in VEMS controller:
- How is a cam trigger supported?
- How can I select full sequential injection?
- alternate=... (cylcount - 1)
- injection sequence h[0]= ...
- See GenBoard/Manual/DigitalOut, GenBoard/Manual/DigitalOut/Table,
Input variables where Inj_out is dependant of...
As my car will be running on Vapourised LPG injection my Inj_output timing will be dependant of Fuelpressure and Fueltemperature. I already have a sensor mounted that's able to collect these values.
Connect the signal to free ADC inputs - mcp3208. Check the shop text for free inputs. Apparently
- EC18pin12 available ADC because secondary_trigger: HALL
- EC18pin6 available ADC because onboard MAP
- injection pulsewidth calculation
- do some research for the formulas. Make tables and examples (octave,matlab, spreadsheet?). You can try to make final functions using +,*,table_lookup operations. Division only with power of 2 (/2, /4, /8... /256, /512 ...)
- I guess the fuel pulsewidth needs a *1/sqrt(fuel_pressure) multiplier (we'll likely use a table for sqrt() for speed.
- I have no idea how the fuel temperature will be used. Most likely another table_lookup for viscosity ?
When the plan is ready, we'll add to the firmware and make it possible to enable it in config.
- Both pressure and temperature will be look-up tables for density. I will try to figure them out. Will excel do??
- I have characteristics of the sensors I'll be using. Like pressure to Vout and temperature to Vout. Shall i put them in excel too?
I don't have much experience in programming and electronics. But am learning to be an automotiv engineer. Please have patience with me if I ask stupid questions. I'll try to figure out how the extra variables can be put in an code. Can you tell me how the Injection Duration for petrol is calculated?? I might learn a lot just from that code. Thx in advance.
mailto: Jan_Saenen at hotmail dot com