Do you guys know how the stock sensor system works with a SC kit? Since the voltage is clamped at 0+psi@3.1v via a black box does this must mean that the hardware system is relying on values other than what the ECU can provide? That is unless the ECU has parameters for conditions above atmosphere, but it throws a CEL and that is all. Also, what kind of CEL is it and does it put the car in some kind of limp mode? I wonder what the steady state conditions must be in order for it to go off? Do you guys at 15+psi compensate by running an AEM 3.5bar MAP sensor? I guess this makes sense since you'll be on an AEM standalone. What about people at 11-12psi on a piggyback? Please chime in!

 

stock sensor is good to 10-11psi. I took mine to 9psi and no more with a gt30r turbo. if you want more than that use an aem 3.5bar its very accurate.

 

I already have a GM 3bar MAP I use to monitor boost via a PLX R-500 wideband. I also plan to use a piggyback which means I will need to clamp the MAP output to 3.1v and no more. This means that it doesn't mean squat that a 3bar MAP can read read up to 28.8psi@5v. Check this out:
http://www.robietherobot.com/storm/mapsensor.htm
Assuming I'm 1mi above sea level since I'm in San Diego that means at 3.1v the boost reading will be 15.604psi.

 

You guys get it? I just want to know what kind of CEL it is and under what conditions it goes off, IE boost over 11psi for 2sec. Also what effects it is if it stays on.

 

Nobody or anybody?

 

If you are clamping voltage, you are no longer using the map sensor as the measurement to control fueling and timing etc... Most voltage clamps are used with a variable rate FPR as a bandaid to run boost on a stock ECU. If you are using an EMU, you can use a separate 'greddy' map sensor that can be used to better read boost pressures above the level the stock map reads.

In regards to why the cel is going off. I'd presume the ECU is seeing a voltage that it wasn't designed to see. It would then think the map sensor is broken and go into Limp home mode. Thats only a guess though, as i've been running a standalone for over two and a half years now.

 

you can't plug a non standard map sensor into the stock ECU. Its been calibrated to correlate the voltage it sees to a certain vacuum. You need at least a EMU to do what you're trying to do. Then you wouldn't need a voltage clamp.

 

The MAP sensor is still being used, but only up until the point where it sees atmospheric pressure, or 0psi boost at ~3.1v. Does the variable FPR basically increase stock fuel rail pressure by 10psi for every 1psi of boost, or something like that? What is the point of doing this?

The reason for me bringing this all up is because I found it is common to use a GM 3bar MAP, or similar, to halve the injector duty cycle since it measures 1.6v@0psi. At near sea level this equates to just over 3.1v@15psi. This allows one to run injectors slightly less than double the oem size while still having them run roughly like oem injectors with 50% more headroom.

 

A map sensor is a map sensor. They all have a 5v, ground, and output sire. It just so happens that Honda uses the same 1bar on all their cars, but one can easily swap that out for one that can measure a greater amount so as long as the injectors are scaled accordingly.

 

yes, for every pound of boost the Fuel pressure is increased at a ratio larger than 1:1. I dont remember the ratio on the CTSC i had, something like 12:1 or something.

Are you considering running a gm map sensor with your stock ECU? What about all the partial throttle and vacuum scenarios that the ECU will see that don't correlate to the OEM map sensors voltage? I can't see that working very well.