1.8 with FM hot side and .86 GT2860R
#21
I see your concern, but I do believe that the ecu supplies +5v sensor power. This should be the case with both stock ecu and ms. If the stock baro sensor receives +5v from the ecu, then it is getting it from the ms, and thus will be correct for my external MAP measurements.
Have you checked for +5 with a voltmeter, or just a wiring diagram?
--Ian
#22
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How are multiple sensors normally fed power? Splices in the harness.
The factory baro sensor likely gets +5v from the same lead that the ecu supplies power to the TPS from. I have measured +5v at the oem baro sensor plug with a meter, that's what I did when I said I had confirmed there was +5v at the oem baro sensor.
#24
I'm reasonably sure there's no generic "+5v output" line coming out of my MS3. I built a wiring extension harness for it, and to do that I opened up the case, identified every pin that was actually connected, looked up where it went in the factory wiring diagram, and put it all in a spreadsheet. I only have access to the spreadsheet right now (diagram is at home), but nothing in there looks like it could be a generic +5 output unless it's one of the "instrument cluster" wires (there's more than one and I didn't bother to trace out which did what). I'll go look it up when I get home.
It's also possible that the factory ECU doesn't need that much precision on the few +5 sensors it has. I would expect that if the TPS is off by 5% then it doesn't matter, and the stock MAP sensor is only used for EGR control which is closed loop so can probably tolerate errors. That's not true of the 3 bar GM MAP sensor you're using for primary fuel control.
--Ian
#26
ECU pin 2I on your 99. That 5v reference is definitely used for the TPS. 5 volts goes into it then voltage drops depending on throttle position due to a change in resistance with a voltage dividing network if I'm not mistaken.
#27
https://trubokitty.com/#/ms3xassembly
ECU pin 2I on your 99. That 5v reference is definitely used for the TPS. 5 volts goes into it then voltage drops depending on throttle position due to a change in resistance with a voltage dividing network if I'm not mistaken.
ECU pin 2I on your 99. That 5v reference is definitely used for the TPS. 5 volts goes into it then voltage drops depending on throttle position due to a change in resistance with a voltage dividing network if I'm not mistaken.
Are you mounting the GM sensor in the engine bay or under the dash next to the ECU?
--Ian
#29
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Shitty chinese turbine housing needs porting. I can't get less than 22.7 psi above 6k rpm. Spool is a LOT better with .64.
So yeah, 2871R with .64 housing and something holding it back 40 hp.
So yeah, 2871R with .64 housing and something holding it back 40 hp.
#30
Looks good. I would keep the wastegate as-is, the extra boost up top is flattening out the torque curve! That's what you want, or, at least what I want. Flat, broad torque curve.
I went from 0.63 to .82 A/R turbine, yeah, I'm going to swap back to the 0.63 A/R. I think I gained 5-10 HP, and lost a ton of spoolage which ultimately made it slower. Cool to see how much it helped your setup!
I went from 0.63 to .82 A/R turbine, yeah, I'm going to swap back to the 0.63 A/R. I think I gained 5-10 HP, and lost a ton of spoolage which ultimately made it slower. Cool to see how much it helped your setup!