Changes by last author:
Changed:
| Car is a 1979 Volvo 242 with a 1995 Volvo 850 Turbo engine (B5234T). |
| My name is Karl Buchka. I am an Electrical Engineering student at The University of Massachusetts Amherst. The car is a 1979 Volvo 242 with a 1995 Volvo 850 Turbo engine (B5234T). |
| PIC |
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| VEMS Setup: |
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| Apart from the standard sensors (MAP, CLT, IAT, TPS), I'm planning on setting up the VEMS with the following major functions: |
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VEMS Setup:
Apart from the standard sensors (MAP, CLT, IAT, TPS), the VEMS is so far set up with the following functions: |
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* 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?) |
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* Single channel wideband
* 20x4 LCD |
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* Alubos1600
* Alubos gasket * Alubos Endplate * Alubos EC frontplate * Econoseal18-PCB * Econoseal36-PCB * Econoseal18-harness * Econoseal36-harness * Wideband connector - With crimped wires |
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Forthcoming functions are:
* Dual channel knock * More temperature logging (EGT, oil temp, pre-intercooler IAT) * More pressure logging (exhaust backpressure, oil pressure, possibly intercooler pressure drop) * Fan control * Boost control * Tacho out * Two-step * Shift light |
| 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. |
| Trigger settings: |
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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/questions 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? |
| 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. |
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* 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 - ? |
| Goals: |
| 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). |
| 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. Also to have a good time with it, and possibly learn something useful along the way. |
| 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? |
| I purchased 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 more minor motivator was the lower price. |
| As of now I plan to use my current Megasquirt fuel map (with values scaled) as a base map. |
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| Sections: (most of these are incomplete, will continue to add info and break into sections as time permits) |
| x Spark (Coils, Spark advance) |
| Assembly, testing, installation, and start up: MembersPage/KarlBuchka/Installation |
| 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: *link* |
| Crank and cam sensors/settings MembersPage/KarlBuchka/Trigger |
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Coil pin-out:
1 - Trigger 2 - Not Used 3 - Ground 4 - +12v |
| Sensors and inputs MembersPage/KarlBuchka/Sensors |
| The coils pull up to +5v to fire. |
| Fuel (Injectors, VE, lambda, enrichments) MembersPage/KarlBuchka/Fuel |
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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) |
| Spark (Coils, Spark advance) MembersPage/KarlBuchka/Spark |
| x Outputs/ancillaries |
| Outputs/ancillaries MembersPage/KarlBuchka/Outputs |
| Fan control, boost control, shift light, |
| (Fan control, boost control, shift light) |