Retard timing for N20 through IAT sensor?
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Retard timing for N20 through IAT sensor?
I asked this in the PCM section, but got no responses....
Ok, I run a TNT F1 wet shot, and will be stepping up to a 150 this fall. I have read about being able to use Edit to make the PCM go to a lower timing table by running a dry shot and passing it through the MAF. I want (need) something like this, but for my wet shot.
I remember reading about people using like a 5 hz resistor in the IAT sensor to make the PCM think the IAT was 57* F I guess, maybe celcius. I noticed that the timing tables are in Celcius, not Farenheit. So that 57* F would be about 14* C. Therefor, couldn't we just figure out what size resistor we would need to tell the PCM that the IAT is 90* C (194 F)?
Then just put in the 90* C column how much timing we want taken out? I dont think that we would actually ever see a real IAT of 90* C anyway. Thats seems awefully high.
I just dont want to have to run a seperate file for good N/A and another for safe N20...
Will this work?
Ok, I run a TNT F1 wet shot, and will be stepping up to a 150 this fall. I have read about being able to use Edit to make the PCM go to a lower timing table by running a dry shot and passing it through the MAF. I want (need) something like this, but for my wet shot.
I remember reading about people using like a 5 hz resistor in the IAT sensor to make the PCM think the IAT was 57* F I guess, maybe celcius. I noticed that the timing tables are in Celcius, not Farenheit. So that 57* F would be about 14* C. Therefor, couldn't we just figure out what size resistor we would need to tell the PCM that the IAT is 90* C (194 F)?
Then just put in the 90* C column how much timing we want taken out? I dont think that we would actually ever see a real IAT of 90* C anyway. Thats seems awefully high.
I just dont want to have to run a seperate file for good N/A and another for safe N20...
Will this work?
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Re: Retard timing for N20 through IAT sensor?
how low? Like how much timing is reduced at the highest IAT? My stock 98' file claims to remove 3* at the 90* celcius reading?
How much timing should I pull to be safe on the 150 shot?
How much timing should I pull to be safe on the 150 shot?
#4
Re: Retard timing for N20 through IAT sensor?
Use a 750 ohm resistor. Only problem now is that it pull some fuel out too because the air is supposed to be less dense at 100 F. It works fine with a wet kit cause you can jet the fuel up, but not a dry, you end up starting to run lean.
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Re: Retard timing for N20 through IAT sensor?
Use a 750 ohm resistor. Only problem now is that it pull some fuel out too because the air is supposed to be less dense at 100 F. It works fine with a wet kit cause you can jet the fuel up, but not a dry, you end up starting to run lean.
#7
Re: Retard timing for N20 through IAT sensor?
If the computer doesn't add or subtract fuel if the temp goes up and down then what is the IAT there for? If the temp is 120 one day and 2 the next, you better believe it adds the extra fuel when its colder and pulls some when its hot to keep A/F's correct. Cartek believes the same, heres the link: http://www.cartek.net/tip03.html
Part throtle should be based off of O2's, and WOT should be based on MAF, air temp, RPM, and maybee load. I won't pretend to know anymore then that.
Part throtle should be based off of O2's, and WOT should be based on MAF, air temp, RPM, and maybee load. I won't pretend to know anymore then that.
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Re: Retard timing for N20 through IAT sensor?
Guys, I am talking about taking timing out, not taking fuel out with the resistor.
And I am not talking about running the resistor all the time, just when you are going to spray. Plug it into the IAT sensor like guys do with the 5 ohm one for a temp of 57*
And I am not talking about running the resistor all the time, just when you are going to spray. Plug it into the IAT sensor like guys do with the 5 ohm one for a temp of 57*
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Re: Retard timing for N20 through IAT sensor?
If the computer doesn't add or subtract fuel if the temp goes up and down then what is the IAT there for? If the temp is 120 one day and 2 the next, you better believe it adds the extra fuel when its colder and pulls some when its hot to keep A/F's correct. Cartek believes the same, heres the link: http://www.cartek.net/tip03.html
Part throtle should be based off of O2's, and WOT should be based on MAF, air temp, RPM, and maybee load. I won't pretend to know anymore then that.
Part throtle should be based off of O2's, and WOT should be based on MAF, air temp, RPM, and maybee load. I won't pretend to know anymore then that.
Therefore I believe that wiring up the IAT sensor through a relay with a resister than can be switched on and off with the solenoids/relay of a nitrous system would be perfectly fine and not screw up fueling so to speak. Oh yea, I have done this on a wideband to verify my hypothesis that what I have said is correct. Worked great with no fueling adjustment.
#10
Re: Retard timing for N20 through IAT sensor?
Therefore I believe that wiring up the IAT sensor through a relay with a resister than can be switched on and off with the solenoids/relay of a nitrous system would be perfectly fine and not screw up fueling so to speak. Oh yea, I have done this on a wideband to verify my hypothesis that what I have said is correct. Worked great with no fueling adjustment.
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Re: Retard timing for N20 through IAT sensor?
my stock 98' table will only pull 3 degrees at max....
so how do we find out what size resistor will give us the 194* F reading...?
so how do we find out what size resistor will give us the 194* F reading...?
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Re: Retard timing for N20 through IAT sensor?
It's not
The motor's been rebuilt and is ready to put back in. I should have it running again by the end of the month.
The motor's been rebuilt and is ready to put back in. I should have it running again by the end of the month.
my stock 98' table will only pull 3 degrees at max....
so how do we find out what size resistor will give us the 194* F reading...?
so how do we find out what size resistor will give us the 194* F reading...?
#15
Re: Retard timing for N20 through IAT sensor?
Nic00Z28M6'
http://www.kemparts.com/TechTalk/tt06.asp sais:
" As air flows across it, it cools down. The heated wire or film is a positive temperature coefficient (ptc) resistor. This means that it's resistance drops when it's temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is changed to a frequency or a voltage which is sent to the computer and interpreted as air flow. Adjustments for air temperature and humidity are taken into consideration since they also affect the temperature of the heated wire or film. Humidity always affects the density of air since humid air is denser than dry air. No other compensation is therefore needed for this factor. Air temperature affects density since colder air is more dense than warmer air. Many systems use an air temperature sensor to compensate for this factor since similar amounts of air can enter an engine at different temperatures. Some MAF sensors use an internal "cold" wire to send ambient temperature information to the computer. Some use an intake air temperature sensor in the manifold or the intake piping. This sensor is almost always ntc in design (negative temperature coefficient). That is, it's resistance goes up as air temperature goes down. This "thermistor" works just like a coolant temperature sensor and usually has identical resistance to temperature values. By the way, these values are very different from manufacturer to manufacturer and are available in most repair manuals. They are also programmed into scanner software."
That site explains the use of an AIT for fuel trimming perty clearly. You can find quite a few if you do some searches.
You wont find a temp/fuel table in LS1 edit because the air temp/density ratio is a constant which means you wont ever have to change it. The computer knows that if the temp goes up by 1 deg there will specific amount it will increase by.
You can see the match for this at these sites:
http://www.davisnet.com/product_docu.../apnote_14.pdf
http://www.elji.se/kund/apnote_14.pdf
http://wahiduddin.net/calc/calc_da_em.htm
And here is a link for an Air Density calculator using Excel so you can run it on a laptop without a web connection : http://pages.globetrotter.net/equipekcm/densite.xls
Bottom line, the AIT sensor helps determine the density of the air so the MAF can determine the correct airflow and the PCM can add the correct amount of fuel. The PCM will also add or subtract timing based on the air temp in order to keep from knocking at the higher intake charges temps.
http://www.kemparts.com/TechTalk/tt06.asp sais:
" As air flows across it, it cools down. The heated wire or film is a positive temperature coefficient (ptc) resistor. This means that it's resistance drops when it's temperature drops. The drop in resistance allows more current to flow through it in order to maintain the programmed temperature. This current is changed to a frequency or a voltage which is sent to the computer and interpreted as air flow. Adjustments for air temperature and humidity are taken into consideration since they also affect the temperature of the heated wire or film. Humidity always affects the density of air since humid air is denser than dry air. No other compensation is therefore needed for this factor. Air temperature affects density since colder air is more dense than warmer air. Many systems use an air temperature sensor to compensate for this factor since similar amounts of air can enter an engine at different temperatures. Some MAF sensors use an internal "cold" wire to send ambient temperature information to the computer. Some use an intake air temperature sensor in the manifold or the intake piping. This sensor is almost always ntc in design (negative temperature coefficient). That is, it's resistance goes up as air temperature goes down. This "thermistor" works just like a coolant temperature sensor and usually has identical resistance to temperature values. By the way, these values are very different from manufacturer to manufacturer and are available in most repair manuals. They are also programmed into scanner software."
That site explains the use of an AIT for fuel trimming perty clearly. You can find quite a few if you do some searches.
You wont find a temp/fuel table in LS1 edit because the air temp/density ratio is a constant which means you wont ever have to change it. The computer knows that if the temp goes up by 1 deg there will specific amount it will increase by.
You can see the match for this at these sites:
http://www.davisnet.com/product_docu.../apnote_14.pdf
http://www.elji.se/kund/apnote_14.pdf
http://wahiduddin.net/calc/calc_da_em.htm
And here is a link for an Air Density calculator using Excel so you can run it on a laptop without a web connection : http://pages.globetrotter.net/equipekcm/densite.xls
Bottom line, the AIT sensor helps determine the density of the air so the MAF can determine the correct airflow and the PCM can add the correct amount of fuel. The PCM will also add or subtract timing based on the air temp in order to keep from knocking at the higher intake charges temps.
#16
Re: Retard timing for N20 through IAT sensor?
FinalTA. I have a wiring diagram that I have scanned that shows how to wire up the relay and resistor so it is only hooked up when the N20 system is armed. If you want, I will send it to you. And if you get stuck I can walk you through it.
#17
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Re: Retard timing for N20 through IAT sensor?
http://www.kemparts.com/TechTalk/tt06.asp That site explains the use of an AIT for fuel trimming perty clearly. You can find quite a few if you do some searches.
You wont find a temp/fuel table in LS1 edit because the air temp/density ratio is a constant which means you wont ever have to change it. The computer knows that if the temp goes up by 1 deg there will specific amount it will increase by.
You can see the match for this at these sites:
http://www.davisnet.com/product_docu.../apnote_14.pdf
http://www.elji.se/kund/apnote_14.pdf
http://www.davisnet.com/product_docu.../apnote_14.pdf
http://www.elji.se/kund/apnote_14.pdf
http://wahiduddin.net/calc/calc_da_em.htm
And here is a link for an Air Density calculator using Excel so you can run it on a laptop without a web connection : http://pages.globetrotter.net/equipekcm/densite.xls
Bottom line, the AIT sensor helps determine the density of the air so the MAF can determine the correct airflow and the PCM can add the correct amount of fuel.
#18
Re: Retard timing for N20 through IAT sensor?
FinalTA, just got back in town. Will get it out to you tonight. The pic shows how the relay is latched with the N20 arm switch on.
Nic00Z28M6,
called Cartek today and asked them about their warning for their tech tip. They told me that on factory and mild tunes there was barely enough difference to even show up on the W/B. They also said that they have gotten in some cars that where tuned from other people/places with highly modded tables that it showed up signifigantly. I told them how someone scaled the IAT sensor up and down with the ls1eit and how that would affect it. He said they never did it that way for testing . Only by going up and down in resistor sizes in place of the IAT. They said you can run up and down in the resistor sizes and watch the injector pulse width move up and down very slightly.
Nic00Z28M6,
called Cartek today and asked them about their warning for their tech tip. They told me that on factory and mild tunes there was barely enough difference to even show up on the W/B. They also said that they have gotten in some cars that where tuned from other people/places with highly modded tables that it showed up signifigantly. I told them how someone scaled the IAT sensor up and down with the ls1eit and how that would affect it. He said they never did it that way for testing . Only by going up and down in resistor sizes in place of the IAT. They said you can run up and down in the resistor sizes and watch the injector pulse width move up and down very slightly.
#19
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Re: Retard timing for N20 through IAT sensor?
Nic00Z28M6,
called Cartek today and asked them about their warning for their tech tip. They told me that on factory and mild tunes there was barely enough difference to even show up on the W/B. I told them how someone scaled the IAT sensor up and down with the ls1eit and how that would affect it. He said they never did it that way for testing . Only by going up and down in resistor sizes in place of the IAT. They said you can run up and down in the resistor sizes and watch the injector pulse width move up and down very slightly.
called Cartek today and asked them about their warning for their tech tip. They told me that on factory and mild tunes there was barely enough difference to even show up on the W/B. I told them how someone scaled the IAT sensor up and down with the ls1eit and how that would affect it. He said they never did it that way for testing . Only by going up and down in resistor sizes in place of the IAT. They said you can run up and down in the resistor sizes and watch the injector pulse width move up and down very slightly.