Overview:
Car is a 1979 Volvo 242 with a 1995 Volvo 850 Turbo engine (B5234T).
Some details on the car:
- Inline 5-cyl., 2.3l, turbocharged (TD04H-15G), 4 valves per cylinder. The engine is essentially stock, save for a new (OE Volvo) intake manifold and 350cc injectors. At 15psi on the current setup I flow fuel for approximately 250bhp.
- VEMS 3.3 will replace the current setup of: MSnS-E 029y4 on a V3 PCB with sequential COP, batch fire injection, boost control, fan control, tacho output, two-step, and a Just Another Wideband (JAW).
- VEMS Setup:**
Apart from the standard sensors (MAP, CLT, IAT, TPS), I'm planning on setting up the VEMS with the following major functions:
- Sequential coil on plug
- Sequential injection
- Single channel wideband and EGT
- Dual channel knocksense
- Fan control, boost control, two-step, tacho output, shift-light, 20x4 LCD
- Trigger settings:**
The engine comes from the factory with a 60-2 wheel/VR sensor on the crank and a single tooth wheel/hall sensor on the cam.
- Goals:**
My initial goal with this install is to overcome the limitations of Megasquirt (some of which I have reached, others not), putting me in a much better position to take the car to the next level.
- Shopping cart:**
I have put together a list of items to be ordered from the VEMS Webshop. Ideas, comments, or suggestions are welcome.
- GenBoard v3.3
- Injector or WBO2 heater driver (6)
- Ignition driver (2, running ignition in 2+6 configuration, see Spark page)
- Power Flyback - With wire
- Dual channel knock sensor interface (do I need this, or is it included on the board already?)
- 250-400 kPa MAP sensor - MAP connection 400kPa bare - Supply 5V (webshop is somewhat unclear, is this the correct map sensor?)
- Alubos1600
- Alubos gasket
- Alubos Endplate
- Alubos EC frontplate
- Econoseal18-PCB
- Econoseal36-PCB
- Econoseal18-harness
- Econoseal36-harness
- Wideband connector - With crimped wires
I have decided to purchase the un-assembled GenBoard for a few reasons: I'm doing this as much for the learning experience as for the VEMS feature-set. If I wanted a 'plug-and-play' system I would buy a Haltech or Motec. A much more minor motivator is the lower price.
I will be purchasing power resistors and an LCD seperately, as I can find both for much lower price locally.
- Sections:** (most of these are incomplete, will continue to add info and break into sections as time permits)
x Crank and cam sensors/settings
The crank setup is a 60-2 trigger wheel built in to the flywheel using a VR sensor. Cam setup is single tooth wheel using a Hall sensor.
x Sensors and inputs
x Fuel (Injectors, VE, lambda, enrichments)
I have still not purchased new injectors, but as of writing I am looking at Delphi Multec 1 95 lb/hr injectors (~1030cc). Currently trying to find a detailed spec sheet, but with little luck. Here is what I know (from http://www.racetronix.com/17113744FM.html):
Static Flow Rate @ 43.5PSI (300 KPa) = 95.0 lb/hr / 12.0 gm/sec / 998 cc/min
Dynamic Flow Rate @ 43.5PSI (300 KPa) 2.5ms pulse width and 10ms repetition rate = 2.2 gm/pulse
Coil Resistance: 2 Ohms / Low Impedance / Low-Z (Peak/Hold injector drivers required)
Factory Tollerance: +/-5% (actual +/-7%)
Cone Spray Angle - 17.6 degrees - single spray cone. Approximate cone angle for 90% of spray volume
Connector: Minitimer (Bosch EV1)
Ball/Seat Design with 6-Hole Diffuser Disc
Factory fitted with Viton upper and lower o-rings.
I'd like to have some 'ballpark' figures for the following values. Any suggestions?
- Inj. open time @ 13.2V - 1000us
- Inj. effective rampup - ?us
- injrampup_battfac - ?us
- battfac - ?s
- Injpwm DC - 38%
- -http://www.vems.hu/wiki/index.php?page=GenBoard%2FManual%2FFlyback%2FCalculations
- - Iinj * Rinj = VBatt * dcpercentage/100 - Uflyback * (1-dcpercentage/100)
- - 1A * 2ohm = 14.5V * x - 5.5V * (1-x) -> 2 = 20 * x - 5.5 -> x = 7.5/20 = 0.375
- Injpwm peak time - ?ms
- Divider - ?
- Alternate banks from h[0] - 4..0
- Fire banks while cranking - ?
The low-z injectors will require power resistors. As mentioned earlier, I can source them in almost any spec I want. I understand the resistors are used for current limiting, but how much current am I aiming for? A couple of quick calculations yields a 12ohm resistor for a current of 1A and 5ohm for 2A (both assuming 2ohm injector resistance and 14V supply).
I calculated req_fuel to 2.89 using (6.49 * 2300[cc] / 5 / 1032[cc/min]). Is it worth it to halve this and double my VE values?
As of now I plan to use my current Megasquirt fuel map (with values scaled) as a base map.
x Spark (Coils, Spark advance)
Coils are OE Volvo from an S80 T6. They have built-in power stages and are suspected to be internally identical to the Bosch Motorsport Single Fire PT coils, data-sheet here: http://www.vems.hu/files/MembersPage/KarlBuchka/Single_PT.zip
Coil pin-out:
1 - Trigger
2 - Not Used
3 - Ground
4 - +12v
The coils pull up to +5v to fire.
Connectors/pigtails sourced directly from Volvo:
The plastic connector itself is part number: 9456341
The +12v feed pigtail is part number: 30656689 (will need 5 of these)
The ground and signal pigtails are part number: 30656688 (will need 10 of these)
x Outputs/ancillaries
Fan control, boost control, shift light,