LTFT on stock car

[Anger]

it is possible that on crv the ecu works in closed loop

Nope, its like the civic. When full throttle it reads from the maps only. When part throttle, the ECU makes adjustments

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[Hondanickx]

So i've retrofitted a SI OEM airbox to my non si Civic.Been driving since yesterday and This morning did some long distance driving.Previously my LTFT was -8 -7 and STFT was -8 -9 .

Now LTFT went down to +2% .STFT also sometimes shoots up to +10 +11% but only for a second or two.AFR under WOT is mostly around 11:1 ,there's only a few Moments under high load at low rpm where it's 12:1 which is a little worrying.
Should i be looking into getting the afr tuned or would this be fine Running like this?
I'm untuned full stock ,only have a Prl stage 1 intake hose and Sprint filter OEM replacement filter.

 

[CAPTS]

So i've retrofitted a SI OEM airbox to my non si Civic.Been driving since yesterday and This morning did some long distance driving.Previously my LTFT was -8 -7 and STFT was -8 -9 .

Now LTFT went down to +2% .STFT also sometimes shoots up to +10 +11% but only for a second or two.AFR under WOT is mostly around 11:1 ,there's only a few Moments under high load at low rpm where it's 12:1 which is a little worrying.
Should i be looking into getting the afr tuned or would this be fine Running like this?
I'm untuned full stock ,only have a Prl stage 1 intake hose and Sprint filter OEM replacement filter.

high load rpm is normal not at 11.1 afr , your trims are fine.

 

[Prozento]

Did anybody ever monitored the LTFT on a stock car ? (1.5t) I've been using the Torque pro app a few weeks now and my LTFT and STFT are always negative . LTFT is -10 on cold start and fully warmed up -8 -7.Is that normal for a stock car to take out fuell all the time ? Air/fuel values are spot on 14.7 on idle and 11 -10.8 when WOT .Max boost i see is 15 Psi peak.

My LTFT and STFT are the same. I can tell you even more - I saw no difference between Ktuner 18PSI and stock either.

 

[Hondanickx]

high load rpm is normal not at 11.1 afr , your trims are fine.

Do you know at what RPM the ECU switches over to the map settings? ( Open loop - closed loop) 3000rpm?
Under 3000rpm the AFR is 12 - 13:1 when WOT. After 3000rpm it goes to 10 - 11:1 when WOT.I thought it always needs to be 10-11:1 when WOT?

 

[CAPTS]

Do you know at what RPM the ECU switches over to the map settings? ( Open loop - closed loop) 3000rpm?
Under 3000rpm the AFR is 12 - 13:1 when WOT. After 3000rpm it goes to 10 - 11:1 when WOT.I thought it always needs to be 10-11:1 when WOT?

depends on your tune, get ktuner & custom tune it ownself or professionally tune then you can also see the numbers or set them where you want them to be.

 

[boibuddha]

So i've retrofitted a SI OEM airbox to my non si Civic.Been driving since yesterday and This morning did some long distance driving.Previously my LTFT was -8 -7 and STFT was -8 -9 .

Now LTFT went down to +2% .STFT also sometimes shoots up to +10 +11% but only for a second or two.AFR under WOT is mostly around 11:1 ,there's only a few Moments under high load at low rpm where it's 12:1 which is a little worrying.
Should i be looking into getting the afr tuned or would this be fine Running like this?
I'm untuned full stock ,only have a Prl stage 1 intake hose and Sprint filter OEM replacement filter.

I would compare the diameter of the MAF housing/tubeof your current setup versus your old one, I have a feeling that the Si housing is bigger than the regular 1.5T.

If that is the case, you would have to scale the MAF sensor using KTuner or Hondata.
The positive fuel trim numbers are showing that the car is seeing more air than the MAF is reading, which makes sense because the MAF doesn't know it's in a bigger tube.

 

[Hondanickx]

I would compare the diameter of the MAF housing/tubeof your current setup versus your old one, I have a feeling that the Si housing is bigger than the regular 1.5T.

If that is the case, you would have to scale the MAF sensor using KTuner or Hondata.
The positive fuel trim numbers are showing that the car is seeing more air than the MAF is reading, which makes sense because the MAF doesn't know it's in a bigger tube.

I did that before i installed the si housing.
https://www.civicx.com/forum/threads/si-vs-non-si-oem-airbox.47467/

The si housing is build the same ,it's only a little larger on the air filter side.The side that connects to the silicone hose is the same size.
All other dimensions are exactly the same,so i doubt that would trow the maf scale off.The Fuel trims going positive just means more air is getting in and more Fuel needs to be added...at least that's what i think it means.

 

[boibuddha]

I did that before i installed the si housing.
https://www.civicx.com/forum/threads/si-vs-non-si-oem-airbox.47467/

The si housing is build the same ,it's only a little larger on the air filter side.The side that connects to the silicone hose is the same size.
All other dimensions are exactly the same,so i doubt that would trow the maf scale off.The Fuel trims going positive just means more air is getting in and more Fuel needs to be added...at least that's what i think it means.

Using your photo from your link, it does seem like the Si housing is larger where the sensor is located. My lines are exaggerated but I'm sure your can see that the non-Si tube gets smaller towards the sensor, where as the Si tube looks to be straight.

I'm guessing a 4mm difference in diameter. It doesn't seem like a lot, check out the math...

Area = pi * radius^2 and if non - Si diameter = 50 mm and Si diameter = 54 mm (unsure about those numbers but it's close)

Non-Si Area = 3.14 * 25^2 = 1,963 mm^2
Si area = 3.14 * 27^2 = 2,290 mm^2 (which is roughly 17% larger than non-Si)
Your change in STFT is 18-20% since swapping air boxes. I don't think that's a coincidence.

 

[Hondanickx]

Using your photo from your link, it does seem like the Si housing is larger where the sensor is located. My lines are exaggerated but I'm sure your can see that the non-Si tube gets smaller towards the sensor, where as the Si tube looks to be straight.

I'm guessing a 4mm difference in diameter. It doesn't seem like a lot, check out the math...

Area = pi * radius^2 and if non - Si diameter = 50 mm and Si diameter = 54 mm (unsure about those numbers but it's close)

Non-Si Area = 3.14 * 25^2 = 1,963 mm^2
Si area = 3.14 * 27^2 = 2,290 mm^2 (which is roughly 17% larger than non-Si)
Your change in STFT is 18-20% since swapping air boxes. I don't think that's a coincidence.

Look a little further ... I also posted sketches of both maf housings with all dimensions ?.

"
I've also added the dimensions of the Si and Non Si oem MAF housings.
The intake side of the Si is bigger then non si.
60mm Vs 57mm which equals to aprox. +10% in surface area!"

My Fuel trims went from -8 up to +2 which is 10% .

 

[PowerPerLiter]

I did that before i installed the si housing.
https://www.civicx.com/forum/threads/si-vs-non-si-oem-airbox.47467/

The si housing is build the same ,it's only a little larger on the air filter side.The side that connects to the silicone hose is the same size.
All other dimensions are exactly the same,so i doubt that would trow the maf scale off.The Fuel trims going positive just means more air is getting in and more Fuel needs to be added...at least that's what i think it means.

No. The Si and standard maf sensor housing differences, although small, make a large difference to the maf scaling. You haven't leaned the car out by giving it a couple mm larger housing, you've simply skewed the mass airflow calibration (the end long term result is the leaner long term trim your seeing but that is a averaged trim number based on short trim adjustments made over time).

You could have a BUNCH of spots in the map that are absurdly rich that simply are not causing a change to long term trim.

I'm curious how all over the place the short term trim is at certain points during the drive cycle.

 

[CAPTS]

I'm curious how all over the place the short term trim is at certain points during the drive cycle.

weather, location, wear & tear, driving pattern/styles & of course the tuning (that's if it's tuned)

 

[fenix-silver]

No. The Si and standard maf sensor housing differences, although small, make a large difference to the maf scaling. You haven't leaned the car out by giving it a couple mm larger housing, you've simply skewed the mass airflow calibration (the end long term result is the leaner long term trim your seeing but that is a averaged trim number based on short trim adjustments made over time).

You could have a BUNCH of spots in the map that are absurdly rich that simply are not causing a change to long term trim.

I'm curious how all over the place the short term trim is at certain points during the drive cycle.

Spot on. Having a properly scaled MAF is so important. It doesn't take much to throw it off as even with a MAF housing size IDENTICAL to OEM, differences in flow characteristics through the MAF can greatly impact things, which is why some aftermarket intakes that don't have any actual engineering behind them *cough* Injen *cough* can throw off the scaling so much.

 

[Hondanickx]

No. The Si and standard maf sensor housing differences, although small, make a large difference to the maf scaling. You haven't leaned the car out by giving it a couple mm larger housing, you've simply skewed the mass airflow calibration (the end long term result is the leaner long term trim your seeing but that is a averaged trim number based on short trim adjustments made over time).

You could have a BUNCH of spots in the map that are absurdly rich that simply are not causing a change to long term trim.

I'm curious how all over the place the short term trim is at certain points during the drive cycle.

Here's a few screen shots from a log of the torque app.
From left to right LTFT,STFT,AFR,RPM.

Isn't it normal for the Short trim to go up and down?
If it's too much off i'll trow the stock airbox back on.This is a just a experiment to see how it runs without maf scaling or tuning.

 

[PowerPerLiter]

I am actually impressed they really are not bad!
From this small sampling I should say.

Wide open throttle or higher loads may be a different story but if they resemble what you posted I see no cause for concern.
Yes you are correct + or - 10ish percent on the short trims is completely normal while driving around.
Interesting.

Id say carry on!

This is useful information long term for the folks who like to do small fiddling around.....

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