Parameter Settings: Absolut Pressure Change

[Dzaster]

What is the function/purpose of this checkbox?

http://i525.photobucket.com/albums/cc340/dzaster96799/Tuning/AbsolutePressureOpt.png

[BOOSTED_CRX]

wow ive never seen that but then again ive never really used the greddy software on the comp. Does it dissapear when you change sensor option?

[Dzaster]

Its directly related to the Greddy PR. If I change the drop down box to teh left of it, becomes unselectable.

I found an explanation. It was in the manual.haha!
http://i525.photobucket.com/albums/cc340/dzaster96799/Tuning/AbsolutePrDesc.png


So based on that explantation, should a person like myself, turbo charged with a NA ECU/electronics, should I have this option selected/checked?

And what are they talking about with two last lines with asterisk's(*) in front of them?

[Accord2nrz]

yes you should be having a pressure change.


There is an asterisk there becuase there is a difference between relative pressure and atmospheric pressure. Relative pressure is what your motor is seeing, atmospheric pressure is the combined pressure of what your turbo is adding in addition to atmosphere (which is like variable depending on your location and barometic pressure).

Being in hawaii you should at sea level so your atmospheric pressure is low compared to someone in colorado. Hope that helps.

[messiahx]

I think it may be what determines where the scale is at 0.

With absolute checked, the scale would be like this:

0&nbsp;&nbsp;&nbsp;<-- Max. Vacuum
10
20
30
40 <-- Atmoshperic (0 on the boost gauge)
50
60
70
80 <-- Max. Boost

and for Relative:

-40 <-- Max. Vacuum
-30
-20
-10
0&nbsp;&nbsp;&nbsp;<-- Atmoshperic (0 on the boost gauge)
10
20
30
40 <-- Max. Boost

Of course I may be misinterpreting or switching those around, but I'm pretty sure that is what is it asking. Don't you wish those manuals were easier to decipher?

[Dzaster]

Good "headz up" on the different pressures. However, the settings where those pressure types would apply would be in the different maps right? However, I don't know when I'd want to use those pressures types to tune, when what I really need to use is the Gredyy MAP sensor for tuning.

Yes sea level most the time, but can get a bit elevated on my island. The highest elevation of all Hawaii. Where we often get snow in the winter.:eek: I don't normally drive there. Mostly low.

So Lin, I should have this box checked then?

[Accord2nrz]

Actually its the same map, but you can custom the scale to whatever you need, example if you run low boost you can put that as the max value at the bottom giving you greater ability to fine tune the system

[Dzaster]

I see.

[Accord2nrz]

lol that didnt help much did it.

[zamiex]

question:

ive done sone research but still cant quite understand about the optional GReddy pressure sensors which connected to the boost port?

what ive read is from Greddy:
If the factory range of map or airflow meter is surpassed, you can incorporate a larger airflow meter or our "Optional GReddy Pressure Sensor and Pressure Harness" to set larger scales of adjustment

Q1: so, how do u know if u have surpaseed your stock airflow meter?

Q2: ive install a outsource pressure sensors and how can i know that my pressure sensor will work? is there a way to check it?

by the way my car is a mitsu 4G93 gsr,upgraded to td05 16G, 450cc injectors
on the road tunnning with innovate LM1. thanks

[maxgtr2000]

question:

ive done sone research but still cant quite understand about the optional GReddy pressure sensors which connected to the boost port?

what ive read is from Greddy:
If the factory range of map or airflow meter is surpassed, you can incorporate a larger airflow meter or our "Optional GReddy Pressure Sensor and Pressure Harness" to set larger scales of adjustment

Q1: so, how do u know if u have surpaseed your stock airflow meter?

Q2: ive install a outsource pressure sensors and how can i know that my pressure sensor will work? is there a way to check it?

by the way my car is a mitsu 4G93 gsr,upgraded to td05 16G, 450cc injectors
on the road tunnning with innovate LM1. thanks

If you use the support tool and look at your logs you can see your maf voltage. Depending on the maf it maxes out at a certain voltage, meaning even if the car sees more airflow than the max maf voltage the ecu cannot compensate and add anymore fuel. For example if my maf maxes out at 12 psi and is reading the maximum 5 volts, at 13 psi I can be running lean then kaboom. What the pressure sensor does is allows you to add fuel after the maf hits its limit through the additional injection map. You can also use the pressure sensor to add injection when only in boost. Most people start adding fuel through the pressure sensor readings starting at 3 psi. You can also retard timing only when the sensor senses boost also, this is better than trying to do timing retard and additional injection based on rpm and maf voltage or throttle position. It is worth getting imo. I have a a32B nissan, everybody and their mom covets the z32 maf, with the pressure sensor I can run my stock maf and not worry about maxing it out since I can add fuel through the pressure sensor readings. A z32 maf is around $150, my pressure sensor was $50 shipped.

[Dzaster]

For some cars, MAP sensors will usually cause fuel cut--as well as whiplash.

[zamiex]

If you use the support tool and look at your logs you can see your maf voltage. Depending on the maf it maxes out at a certain voltage, meaning even if the car sees more airflow than the max maf voltage the ecu cannot compensate and add anymore fuel. For example if my maf maxes out at 12 psi and is reading the maximum 5 volts, at 13 psi I can be running lean then kaboom. What the pressure sensor does is allows you to add fuel after the maf hits its limit through the additional injection map. You can also use the pressure sensor to add injection when only in boost. Most people start adding fuel through the pressure sensor readings starting at 3 psi. You can also retard timing only when the sensor senses boost also, this is better than trying to do timing retard and additional injection based on rpm and maf voltage or throttle position. It is worth getting imo. I have a a32B nissan, everybody and their mom covets the z32 maf, with the pressure sensor I can run my stock maf and not worry about maxing it out since I can add fuel through the pressure sensor readings. A z32 maf is around $150, my pressure sensor was $50 shipped.

thanks dude.. i kinda got the picture now....
so meaning that i need to tune my map if my MAF voltage is exceed using the additional injection map right? or izzit using the airflow map?

[Dzaster]

Yes basically, that is what it is. However, I am not sure how it works with MAF, but with my car MAP sensor, I have the signal clamped just before it sees boost. Reason being, the MAP sensor may freak out if it sees boost or will just be unable to operate efficiently. I think the same applies for MAF sensor.

If adding fuel--which is what maxgtr was referring to--you want to always use your additional injection map assuming you have the provisions(injector harness).