Reading Boost

[KEVINS]

Id check the the sensor manufacturer or others who have used this sensor as an analog input.

This F***King sucks. I'm getting tired of buying pressure xcdr's. This new 4 BAR MAP sensor I just bought (this is the THIRD XDCR) starts at 1.3V with key on. I can't find ANY that operate from 0-5v where I can log up to 35psi of boost.

I'm going to ask YOU: What pressure transducer do YOU recommend so that I can log boost up to 35psi??

ks

[mikel]

I dont think it is going work how you want it to, as they are ideally going to read 14.7 psi for atmospheric then you'll have to subtract that from the total value to see actual boost.

[KEVINS]

I dont think it is going work how you want it to, as they are ideally going to read 14.7 psi for atmospheric then you'll have to subtract that from the total value to see actual boost.

So how do others log boost? This doesn't make any sense to me. Everyone that runs a blower or turbo logs boost.

ks

[mikel]

as mentioned, we provide a boost gauge for most applications on trinity that subtracts BARO from MAP to show boost.
You eithe rlog it like that or some OE FI applications have a Boost pid.

[KEVINS]

UPDATE:
As was stated the Diablo cannot log boost as-is b/c MAP and pressure sensors always start at a voltage greater than 0 Volts. So even with the key on (engine off) the sensor is putting out the minimum voltage that the sensor operates at which equates to some amount of boost being logged even when the car is not running.

SOOOooo, to fix this I hired an electrical engineer to design a Op Amp circuit that alters the voltage coming out of the MAP sensor. Now the voltages coming out of the Op Amp circuit and going into the Diablo range between the desired 0V and 5V which is the voltage the Diablo needs to data log boost correctly.

I will also have to have one made for the XDCR that logs my meth pressure but now I know what it takes to do this..

What a PITFA..

ks

[mikel]

No, you are not following, they are all going to read 14.7 psi at atomspheric pressure.

[KEVINS]

No, you are not following, they are all going to read 14.7 psi at atomspheric pressure.

I know this and that's what I said above. Other data loggers allow the user to change the voltage offsets (or they have a list of XDCR's to choose from) so the data loggers will read true pressures but the Diablo Intune will not allow the user to change these voltage inputs. So I had to have a circuit made that fudged the voltages coming out of the pressure sensor in order to log the boost accurately from the Intune. This new circuit converts the output voltage from the sensor to a true 0v-5v range which is what the Diablo needs in order to graph the boost accurately. It data logs as needed now.

ks

[mikel]

they are all 0-5v, a PRESSURE sensor will always read 14.7 psi at atmospheric pressure, as thats what the pressure is....you need a vacuum/boost gauge if you only want to see boost above atomspheric.

[KEVINS]

they are all 0-5v, a PRESSURE sensor will always read 14.7 psi at atmospheric pressure, as thats what the pressure is....you need a vacuum/boost gauge if you only want to see boost above atomspheric.

READ what I I typed. That's what I've been stating. Other data loggers are ADJUSTABLE and will compensate for this so they WILL datalog the correct pressures no matter what output voltages they have. The Power Logger that I had for my Grand National did this. I just typed in the brand of XDCR I was using and it compensated for the voltages. The Diablo is NOT adjustable so it cannot log boost w/o extra circuitry.

KS

[mikel]

OK, you may need another logger then, but I am confident that I know what I am talking about, it seems you are finding info that seems to agree with what you want, yet you have yet to show me anything that works how you think it should.

It is not going to work that way with any of our devices or anything that uses a raw 0-5 signal.

[KEVINS]

OK, you may need another logger then, but I am confident that I know what I am talking about, it seems you are finding info that seems to agree with what you want, yet you have yet to show me anything that works how you think it should.

It is not going to work that way with any of our devices or anything that uses a raw 0-5 signal.

Here’s Power Logger which logs boost among other things. Just type in the MFR’s XDCR you’re using and it already has it in its database so it knows what voltage offset to use. You can also program a different XDCR if you don’t have a standard one that is listed in the Power Logger.
http://www.fullthrottlespeed.com/itemde ... LOG+eq++Tp+


Here’s AEM’s:
http://www.andersonfordmotorsport.com/a ... ta-logger/

Both of these log boost.

Logging boost is supposed to be a no-brainer with todays cars but it depends on the market the company is going after.

ks

[mikel]

first one is specifically for a Grand national, which is factory turbo charged...not really relevant here.

The 2nd one is a stand alone logger, that will interface with a MAP sensor, but even if it does show boost the way you want to see it, it does not log any OBDII data....

good luck