IAT mod/upgrade
Discussion
Has anyone here upgraded their IAT sensor? I was slightly leaner than I wanted to be at Thunder Road due to heat-soaking the sensor (OTRCAI with stock '04 sensor in the intake), which cleared up once I got moving...albeit several gear-shifts later. Reading around the Yank forums they go for a 3000 ohm Omega 44005 thermistor. I am tempted to try and go one better with one of these though...which might be better still.
FWIW, I was about 9% lean through first, 6% through second, 3% through third, then fourth/fifth I was spot on commanded AFR.
FWIW, I was about 9% lean through first, 6% through second, 3% through third, then fourth/fifth I was spot on commanded AFR.
ringram said:
1. How do you know you were lean?
2. How do you know its not just your tune that was out?
1. WB02, and not super lean, say 13.7 when commanding 12.7 (through first, then reducing error)2. How do you know its not just your tune that was out?
2. It's dot-on once the IAT drops (69'C idling waiting to run, 29'C once in fourth/fifth)
KMud said:
1. WB02, and not super lean, say 13.7 when commanding 12.7 (through first, then reducing error)
2. It's dot-on once the IAT drops (69'C idling waiting to run, 29'C once in fourth/fifth)
So your air temp compensations are not correct ?2. It's dot-on once the IAT drops (69'C idling waiting to run, 29'C once in fourth/fifth)
The sensor only reports temperature. As long as it's a thermistor type ( ie fast instead of sloww ), it would make no sense to randomly change it for a different sensor.
Just sounds like heat soak at the sensor is the problem and/or some tuning.
If you're n/a even 13.7 is probably costing very little or nothing, especially in 1st gear
stevieturbo said:
So your air temp compensations are not correct ?
The sensor only reports temperature. As long as it's a thermistor type ( ie fast instead of sloww ), it would make no sense to randomly change it for a different sensor.
Just sounds like heat soak at the sensor is the problem and/or some tuning.
If you're n/a even 13.7 is probably costing very little or nothing, especially in 1st gear
I've not touched the air temp compensations from the original tune as far as I know (do you have a specific table in mind?). I'm not sure if the OE IAT sensor is a thermistor. My thinking was the sensor is soaked, the air coming through the airtake is fine (even if the intake itself is hot), so a better sensor could be good. I don't tend to leave it idling for 5-10 mins like queuing at TR to run, so I've never seen such high intake temps before. OTRCAI not optimal in this case it would seem!The sensor only reports temperature. As long as it's a thermistor type ( ie fast instead of sloww ), it would make no sense to randomly change it for a different sensor.
Just sounds like heat soak at the sensor is the problem and/or some tuning.
If you're n/a even 13.7 is probably costing very little or nothing, especially in 1st gear
I was pulling about 10 degrees of spark because of the supposed IAT.
Edited by KMud on Sunday 10th August 11:59
stevieturbo said:
So your air temp compensations are not correct ?
The sensor only reports temperature. As long as it's a thermistor type ( ie fast instead of sloww ), it would make no sense to randomly change it for a different sensor.
Yep Id suggest logging IAT against BEN over a few months and temps. Unless you get a flat 1.0 across the lot then you need to adjust your temp vs fueling compensation. This was common on the LS1 and made quite a difference.The sensor only reports temperature. As long as it's a thermistor type ( ie fast instead of sloww ), it would make no sense to randomly change it for a different sensor.
Id do this first before looking at a new sensor IMO.
ringram said:
Yep Id suggest logging IAT against BEN over a few months and temps. Unless you get a flat 1.0 across the lot then you need to adjust your temp vs fueling compensation. This was common on the LS1 and made quite a difference.
Id do this first before looking at a new sensor IMO.
That slipped through the net somehow, first I've heard of that. Will give it a go.Id do this first before looking at a new sensor IMO.
Retaining the OE sensor appeals, will keep it if I can (though cheap to try swapping it).
MyM8V8 said:
What temp was it giving?
69'C sat in line, 29'C moving. Here's a screengrab.Yeah you can log at idle and let it soak up from cold to see how that works in open loop.
Thats a good baseline as all other factors are held constant.
FWIW mine was 24-29*C sitting in the queue, during the run and coming back.
Im not sure what the temp of the day was. I think maybe 23*?
6-10* over ambient is pretty normal.
Thats a good baseline as all other factors are held constant.
FWIW mine was 24-29*C sitting in the queue, during the run and coming back.
Im not sure what the temp of the day was. I think maybe 23*?
6-10* over ambient is pretty normal.
ringram said:
Yeah you can log at idle and let it soak up from cold to see how that works in open loop.
Thats a good baseline as all other factors are held constant.
FWIW mine was 24-29*C sitting in the queue, during the run and coming back.
Im not sure what the temp of the day was. I think maybe 23*?
6-10* over ambient is pretty normal.
Will do that - good idea to kill STFTs for this?Thats a good baseline as all other factors are held constant.
FWIW mine was 24-29*C sitting in the queue, during the run and coming back.
Im not sure what the temp of the day was. I think maybe 23*?
6-10* over ambient is pretty normal.
I didn't see under your bonnet - not a monaro obviously, but with your power you're anti-OTR aren't you? Big cone down in a corner?
ringram said:
Yeah log in open loop.
otrcai is good depending on if you are stock or not.
Anything over stock and they will rob power. Just calc out the airflow based on sq inch of filter..
Ta. My MAP was 98+ wherever I was 100% TP, so surely not a restriction? My filter is 460mm x 180mm, but will do the calc in a quiet moment.otrcai is good depending on if you are stock or not.
Anything over stock and they will rob power. Just calc out the airflow based on sq inch of filter..
ringram said:
Hmm so how do you know you were not restricted 
If Barro was 103kpa then you are losing 5kpa which is probably 4%!
Fair point...650hp rally cars use the same green filter, I assumed I was probably ok! I guess I could tidily fit a baro sensor and add it as a sensor to EFI live.If Barro was 103kpa then you are losing 5kpa which is probably 4%!
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