15.7 PSI reading on my torque pro app today

[BiGMaC]

I am still trying to get my head around the boost numbers I am seeing with my Aeroforce gauge. 

When I first installed the gauge, I saw a spike of 13.6 but I have NOT been able to duplicate it since.  It must have been a fluke or some weird set of circumstances.  Last night, I did a couple of WOT runs.  In 1st gear, WOT caused the boost to literally jump to 12.1 and it stayed there until the shift when it dropped to about 9.  Through most of 2nd gear, it showed 10.6 -10.9 - but no higher.  It again dropped at the shift to 3rd.  I didn't go to the top of 3rd because I was not in Mexico.  Doing some pulls in manual mode 6th gear from about 1500 RPM only showed about 7 PSI. 

With my tune, I seem to get more boost in 1st gear than in the higher gears.  It also seems to maintain the higher boost all the way to 6200 RPM - at least in 1st and 2nd.  Again, I don't know how accurate this is.  The car is running great so I am not complaining.  Is this behavior consistent with what you guys see with other electronic boost devices?

The ECU determines boost (OEM or aftermarket tuned) using requested torque as the primary info... So your findings are as they should be.  Ambient temp is important in boost levels ECU calls for (OEM or aftermarket tuned) as colder (denser) air requires less compression to reach a certain level as compared to warm air which is less dense to start.  So you should expect to see lower boost level in cold weather, but the same performance as with a higher boost level in warm weather.

 

[DJE624]

That's the way I understand it also.

 

[TSS]

Thank you BiGMaC for that explanation.  Makes sense as I was struggling a little like Bruce was understanding it all.  I too am completely happy with my cars performance, but was wondering why my readings were lower than most but my performance numbers were right on target.  It's pretty cold here in MI and my "testing" usually occurs very early in the morning when it's the coldest (Yes, I do make sure the car is fully 100% warmed up to 190 degrees first).    Bruce is in a cold climate too...but I think it's a bit colder here - plus the timing of my testing.

 

[Larrylu]

I am still trying to get my head around the boost numbers I am seeing with my Aeroforce gauge. 

When I first installed the gauge, I saw a spike of 13.6 but I have NOT been able to duplicate it since.  It must have been a fluke or some weird set of circumstances.  Last night, I did a couple of WOT runs.  In 1st gear, WOT caused the boost to literally jump to 12.1 and it stayed there until the shift when it dropped to about 9.  Through most of 2nd gear, it showed 10.6 -10.9 - but no higher.  It again dropped at the shift to 3rd.  I didn't go to the top of 3rd because I was not in Mexico.  Doing some pulls in manual mode 6th gear from about 1500 RPM only showed about 7 PSI. 

With my tune, I seem to get more boost in 1st gear than in the higher gears.  It also seems to maintain the higher boost all the way to 6200 RPM - at least in 1st and 2nd.  Again, I don't know how accurate this is.  The car is running great so I am not complaining.  Is this behavior consistent with what you guys see with other electronic boost devices?

So far I've played with two OBD2 devices, the MYCAL, and Torque Pro. Both have shown somewhat less boost than I may have wished for, but since they both read similar numbers, their credibility is enhanced a bit in my mind at any rate. I spike in the 12lb. area and usually hold 9 to 10 lbs.  My highest boost is usually when WOT is first initiated. You have done a better job of testing and documenting than me but even though we have differences, we seem to have quite a bit in common. I have yet to be convinced that these OBD2 value displayers are inherently not accurate. My car also seems to be running very strong. I'm giving the new, colder, smaller gapped plugs some credit for that.

 

[Brucelinc]

Larry, I think our findings are very close.  The only time I am at sustained boost of 12 is in first gear.  In 2nd, I did not even reach 11 but it remained in the high 10s until the shift to 3rd.

As  BiGMaC said, temperature is a factor.  If our cars were in the same place at the same time, they might be nearly identical in boost behavior.  Since I presume the ECU uses this information for other engine parameters, I have to assume it is pretty accurate.  I fully admit to not knowing much about how all of these engine parameters come together.

 

[BiGMaC]

So far I've played with two OBD2 devices, the MYCAL, and Torque Pro. Both have shown somewhat less boost than I may have wished for, but since they both read similar numbers, their credibility is enhanced a bit in my mind at any rate. I spike in the 12lb. area and usually hold 9 to 10 lbs.  My highest boost is usually when WOT is first initiated. You have done a better job of testing and documenting than me but even though we have differences, we seem to have quite a bit in common. I have yet to be convinced that these OBD2 value displayers are inherently not accurate. My car also seems to be running very strong. I'm giving the new, colder, smaller gapped plugs some credit for that.

Larry, I think our findings are very close.  The only time I am at sustained boost of 12 is in first gear.  In 2nd, I did not even reach 11 but it remained in the high 10s until the shift to 3rd.

As  BiGMaC said, temperature is a factor.  If our cars were in the same place at the same time, they might be nearly identical in boost behavior.  Since I presume the ECU uses this information for other engine parameters, I have to assume it is pretty accurate.  I fully admit to not knowing much about how all of these engine parameters come together.

Larry…. One other factor to consider, to prevent frustration and expense…. 
First and foremost, pick a tool to measure boost…your favorite.  Calibrate it the same every time.  Then look at the change (delta) that your encounter as you mod. This delta is the consistent number across all devices, whether or not they show the correct absolute or altitude corrected boost pressure. Consider that before you used real gauges… you could look at your dash "temp gauge" with no numbers on it…  and tell if the engine was running hotter than usual by where the needle dwelled or which direction it was moving.
For boost I'm going with a manual gauge to get the pressures… but that's just me and I'm a bit OC, LOL.  :-[

 

[Larrylu]

So far I've played with two OBD2 devices, the MYCAL, and Torque Pro. Both have shown somewhat less boost than I may have wished for, but since they both read similar numbers, their credibility is enhanced a bit in my mind at any rate. I spike in the 12lb. area and usually hold 9 to 10 lbs.  My highest boost is usually when WOT is first initiated. You have done a better job of testing and documenting than me but even though we have differences, we seem to have quite a bit in common. I have yet to be convinced that these OBD2 value displayers are inherently not accurate. My car also seems to be running very strong. I'm giving the new, colder, smaller gapped plugs some credit for that.

Larry, I think our findings are very close.  The only time I am at sustained boost of 12 is in first gear.  In 2nd, I did not even reach 11 but it remained in the high 10s until the shift to 3rd.

As  BiGMaC said, temperature is a factor.  If our cars were in the same place at the same time, they might be nearly identical in boost behavior.  Since I presume the ECU uses this information for other engine parameters, I have to assume it is pretty accurate.  I fully admit to not knowing much about how all of these engine parameters come together.

Larry…. One other factor to consider, to prevent frustration and expense…. 
First and foremost, pick a tool to measure boost…your favorite.  Calibrate it the same every time.  Then look at the change (delta) that your encounter as you mod. This delta is the consistent number across all devices, whether or not they show the correct absolute or altitude corrected boost pressure. Consider that before you used real gauges… you could look at your dash "temp gauge" with no numbers on it…  and tell if the engine was running hotter than usual by where the needle dwelled or which direction it was moving.
For boost I'm going with a manual gauge to get the pressures… but that's just me and I'm a bit OC, LOL.  :-[

Good thought. Wouldn't it would be interesting if someone who had a manual Boost gauge set up would plug in/borrow someone's MX/Torque to get a direct comparison of the two.  I'd love to read about the results of that experiment.

I'm planning on the 170 Tstat and 3Bar sensor as soon as the weather breaks. I probably will do little else in performance mods. Although the catted down pipes are very appealing. That's probably going to be the extent of the mods on my DD.

 

[forcefedjunkie]

I'm a little late to this party but my 2 cents on the subject is that the vehicles MAP sensor is going to be accurate to about 0.1 psi.  The key is that the barometer must be accurate and subtracted from the MAP reading to give a boost reading in psig which is what people are used to.  I can only speak for the Aeroforce gauge, and we subtract the ECM barometer reading from the MAP reading.  This typically results in a reading of -0.1 to +0.1 psi with key on/engine off.  This accuracy will carry through the entire boost range.  Ask yourself if you believe you traditional boost gauge is this accurate.  If it's a mechanical gauge, it's unlikely that even if it's this accurate you cannot resolve the value of the needle vs boost scale to this degree.  If it's a digital gauge, the sensor used (at least those that I'm familiar with) are not as accurate as a factory MAP by a factor or 2-3. 

The Aeroforce gauge also allows you to enter your own "barometer" reading if for some reason the vehicle barometer reading is not accurate.  Bottom line is that you want the key on/engine off reading to be as close to 0.0 as your comfortable with, this will be your accuracy throughout the range of boost.

Todd