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Thread: MSD Boost Timing Master 5462 testing & function.

  1. #1

    Default MSD Boost Timing Master 5462 testing & function.

    Purchase an BTM 5462 made for Vortech superchargers by MSD, the unit was listed as new/installed but never used.
    The rivets have been drilled down, I pulled 3 out with my fingers.

    Needed to open the BTM anyway but I have concerns about it functioning.

    Question 1: Will the MSD BTM 5462 pull timing at idle?
    To elaborate:Wondering if I can wire in the BTM and use a compressor and pressure regulator to deliver activation boost pressure to the BTM with the engine at idle and with the MSD timing control knob set to pull 0*, put a timing light on the pulley confirm factory timing and turn the MSD control knob and read (with the timing light and timing marks) the timing being pulled at idle by the MSD BTM. confirming it works.
    Or does the BTM only engage above a certain RPM.

    Question 2: What happens at and above maximum psi does the unit continue to pull the total set timing: Say- Start point 5psi, pull set 1° per psi = set to pull 10° total timing at 15psi, does it only pull the 10° above that boost when the map puts out full signal voltage 40mV (actual from 38.5mV min to 41.5mV max) or does the MSD BTM pull the full 15° it's capable of?

    Was really hopping to find a 2.5 bar Gauge sensor 0-36psi above atmosphere I don't need to pull factory timing until I pass 22psi, (see pressure sensors below) stage 1 boost is usually 21-22psi no water meth on factory timing, stage 2 runs above 30psi.
    Because of the rarely used voltage output of the MAP sensor in this MSD unit I am limited to 2 bar above atmosphere. so I am hoping the unit pulls set total timing and not just total timing (15°). I can accept the unit pulling a bit of timing on stage 1 boost, boost can be raised to make up for it, I can also work with an adjustable fixed timing pull above 29 or 29.5 psi because there is no boost lag so if I need to pull 10* at 32psi I can pull 1* per psi at the max start point so I would at least have control over the total timing pulled at the total boost ran but if it pulls a full 15° above it's threshold than I would be running boost decided by the MSD BTM, previously it was the extra injector controller with a 2.5 bar MAP that hit full injection duty cycle above 21.6 psi and with water/meth injection that decided boost, it required 30+psi to get air fuel ratio's above 10.0, swapped the MAP for a gauge pressure sensor and have fuel control from 0-36 psi now.


    For anyone interested this particular model used a MPX2200AP MAP sensor.
    The specs are 0-200 kPa /0-29 psi absolute pressure range
    6-16VDC input, typically 10VDC
    output type is analog, output signal is 0-40mV /0-040VDC
    It is a board mount 4pin sensor mounted in a 4-Sip module

    The only replacement (withing or close to the range I want)is the MPX2200GP
    all the specs are the same but it's a gauge pressure sensor so it's range is 0-29 psi above atmosphere pressure, this sensor will move the timing retard start point from 1-5 psi to 16-20 psi and pull timing to at least 29 psi but MSD states it pulls timing to 15* so it should now pull timing to 29.5 psi.

    When charting out map and gauge pressure sensors and voltage I find it easiest to ignore pressures bellow atmosphere, so instead of calculating negative PSI or inches of mercury, I enter 0 psi in the chart. All the MPX series NXP brand sensors are rated in kPa,
    100 kPa = 1 bar = 14.5 psi, 5 kPa = 0.725 psi. When charting a MAP and GP sensor that are both rated at 0-200 kPa you can A)count 0 to 100 twice for the MAP sensor for below and above atmosphere or simply start the gauge pressure sensor at 100 kPa and climb to 300 kPa.
    So a 2 bar gauge pressure sensor can be considered a 2 bar MAP sensor with a range of 100-300 kPa/ 2-3 bar/ 14.5 - 43.5 psi of absolute pressure outputting it's total signal voltage range 0-5VDC, 0.2-4.8VDC, 0-40mV, within the pressure range.

  2. #2


    1) The unit will remove timing at idle in order to test it by supplying controlled pressure to the boost reference port.
    2) The 6462 can remove a maximum of 15° and is intended for up to about 15 psi of boost. The unit has a 2 Bar absolute transducer.
    In order to support higher boost levels, it'll be necessary to use a higher output ignition box. Based on what you're describing, it would be best to use one of the programmable ignitions where you can map the boost retard on a graph as you have described.
    MSD Tech Support

  3. #3


    What do you mean "Higher output ignition box"?
    The MSD BTM 6462 gets a 0-40 mV signal from the pressure sensor and uses it to pull timing based on the position of the start dial variable resistor (potentiometer) and the degree adjustment potentiometer (0-3° per psi).
    I've changed the absolute pressure transducer to a gauge pressure transducer that puts out the same 0-40mV signal, but at higher pressures, both the original absolute pressure sensor (MPX2200AP) and the replacement gauge pressure sensor (MPX2200GP) have a maximum pressure rating of 800 kPa (116.03 psi).

    I could've (should have) and still can just run a Normally Closed solenoid valve on the MSD BTM boost line that opens only when stage 3 boost is active, or at 26 psi using a pressure switch and relay to active the solenoid, the important thing is to set the BTM to pull the total amount of timing I need to pull at max boost (my guess is 6 to 8° at 30+ psi).

    Another work around to have full control over the BTM 6462 would be to use an Arduino controller getting a 3.5 bar MAP sensor signal 0-5V and outputting 0-40 mV to the BTM 6462 board, it could pull any amount from 0 to 15° at any boost pressure from 0-36 psi based on programing. But this car has no programmable electronic on it, it's a 1988 daily/winter car, all controls are manual dial and push button adjustments, but the electronic injector controller (and possibly the MSD BTM) pressure sensor has got pinned down by freezing condensation from the boost vacuum hose in -20° Celsius and colder weather, now they will both operate off an 80 amp main relay and can be shut off with a toggle switch that puts the engine at 15 psi (wastegate setting pressure) boost by default.

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