Intake calibration has me a bit stumped

kingtut12 · 06-09-2006, 03:26 PM

Ok

As I have been tuning my car over the past few weekends - I finally had a chance to have someone else drive my car while I made realtime changes to the intake calibration table. My AF trims and learned were ALL OVER THE PLACE. Lots of points were pegged at +25.49 -
After about 2 hours of holding the throttle steady and going up and down through the load points - I finally had a good "across the board" calibration. Everyting up to 2.6MAF volts was inbetween -.39 and +2.00 - so I was very happy about that.
Problem was that when I went out driving the next day all the values were back up in the +7 to +12 mark. Not as high as the initial values but up nonetheless. Why would they automatically raise back up after a calibration? Is this the ECU learning something other than my input? Will I need to re-calibrate over and over?
I have a K&N Typhoon 65mm intake short ram and PE800 injectors.

daemon · 06-09-2006, 04:33 PM

Do you have a wideband? If so, what really helps me out is to take longs logs (including a few WOT runs (but make sure you are in conservative territory first!)). Then plot MAF voltage vs. target AFR in Excel. You can see relatively quickly if your intake calibration is relatively good (assuming your injectors are tuned well). Closed loop will articificial make the sub 2.5v MAF area look a little better than it might be, but above that (because you have likely crossed into open loop) the plot will reveal plenty.

At least that's how I deal with intake calibration. I've done a couple intakes on my car this way. The last one only took a few good logs and a little math to nail down.

kingtut12 · 06-09-2006, 06:24 PM

Quote:

Originally Posted by daemon

Do you have a wideband? If so, what really helps me out is to take longs logs (including a few WOT runs (but make sure you are in conservative territory first!)). Then plot MAF voltage vs. target AFR in Excel. You can see relatively quickly if your intake calibration is relatively good (assuming your injectors are tuned well). Closed loop will articificial make the sub 2.5v MAF area look a little better than it might be, but above that (because you have likely crossed into open loop) the plot will reveal plenty.

At least that's how I deal with intake calibration. I've done a couple intakes on my car this way. The last one only took a few good logs and a little math to nail down.

So... log MAF voltage, AFR's (wideband) only? Should I log the trim values as well as the learned?
When I compare the AFR's to my MAF, what correlation am I referring to? Do I plot the RPM and load with it and then highlight the SAME rpm and load that corresponds to MAF and AFR?
How can I tell what really needs adjusting using this method?

daemon · 06-09-2006, 06:41 PM

Yeah. I'd log the trims as well. You will likely need to look at a few things, and it is best if you can get your trims relatively consistent first. But the plot will also sometimes point out where the trims are a bit wacked.

If you plot MAF voltage on the X axis and the difference from the AFR measured from the target in the primary fuel map, then you generally are looking for a straight and horizontal line. If the line hooks up or down as the MAF voltage increases, then you have adjustments to make and you can often figure out what those adjustments are from the plot (once you get used to doing it this way).

FWIW, to do it exactly the way I describe you will want the Excel function I made to take the primary fuel map and interpolate the logged RPM/load into the target AFR. I posted it in here on another thread a while back. I don't have the time to track it down right now, but if you can't find it and want to use this system, let me know.

BTW, nluhr also posted his Excel method for doing intake calibrations. You might want to look at his as well. He is also using a Typhoon I believe, so you might be able to start off by using his calibration.

kingtut12 · 06-10-2006, 05:34 PM

Ok- thanks, I have talked with Nlurh before and tried his excel methods, but had trouble following the equations in the spreadsheet. I will try again.

Christian. · 06-10-2006, 07:04 PM

kingtut12, your throttle must be perfectly constant to tune the intake calibration. Once if moves the Tip-in Enrichments comes into play.

Take care,
Christian.

kingtut12 · 06-11-2006, 05:21 PM

Quote:

Originally Posted by Christian.

kingtut12, your throttle must be perfectly constant to tune the intake calibration. Once if moves the Tip-in Enrichments comes into play.

Take care,
Christian.

I think this may be what is killing me - the throttle gets blipped a bit. Even worse, I went out today and once again my trim numbers were whacked out at some points. I am getting 25.49 trim imm. with 0.39 learned at one point and then crack the throttle just a bit and wahlah! it dips back to 1.98 imm and 0.39 learned. Also, my logs seem to show completely nutty figures - for example, my boost reads 9.0 at idle in the logs!!! Of course, it is not 9.0 at throttle--
I am getting to the point where I am considering I may have mechanical issues causing crazy numbers. I know for a fact I have a leak at my header to uppipe junction. Could this be skewing numbers THAT badly? I have tried to tighten it over and over with no luck - even new gaskets and hardware, it still leaks.

06-09-2006, 03:26 PM	#1
kingtut12 Amateur STI Driver Posts: 9 IWSTI Addict since: May 2006 Trader Rating: (0)	Intake calibration has me a bit stumped Ok As I have been tuning my car over the past few weekends - I finally had a chance to have someone else drive my car while I made realtime changes to the intake calibration table. My AF trims and learned were ALL OVER THE PLACE. Lots of points were pegged at +25.49 - After about 2 hours of holding the throttle steady and going up and down through the load points - I finally had a good "across the board" calibration. Everyting up to 2.6MAF volts was inbetween -.39 and +2.00 - so I was very happy about that. Problem was that when I went out driving the next day all the values were back up in the +7 to +12 mark. Not as high as the initial values but up nonetheless. Why would they automatically raise back up after a calibration? Is this the ECU learning something other than my input? Will I need to re-calibrate over and over? I have a K&N Typhoon 65mm intake short ram and PE800 injectors. This ad is not endorsed by this member. Please register or login to hide this ad.

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06-09-2006, 04:33 PM	#2
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 894 IWSTI Addict since: Feb 2004 Trader Rating: (0)	Do you have a wideband? If so, what really helps me out is to take longs logs (including a few WOT runs (but make sure you are in conservative territory first!)). Then plot MAF voltage vs. target AFR in Excel. You can see relatively quickly if your intake calibration is relatively good (assuming your injectors are tuned well). Closed loop will articificial make the sub 2.5v MAF area look a little better than it might be, but above that (because you have likely crossed into open loop) the plot will reveal plenty. At least that's how I deal with intake calibration. I've done a couple intakes on my car this way. The last one only took a few good logs and a little math to nail down.

06-09-2006, 06:41 PM	#4
daemon The Next Petter Solberg Car: 2004 STi Location: Florida Posts: 894 IWSTI Addict since: Feb 2004 Trader Rating: (0)	Yeah. I'd log the trims as well. You will likely need to look at a few things, and it is best if you can get your trims relatively consistent first. But the plot will also sometimes point out where the trims are a bit wacked. If you plot MAF voltage on the X axis and the difference from the AFR measured from the target in the primary fuel map, then you generally are looking for a straight and horizontal line. If the line hooks up or down as the MAF voltage increases, then you have adjustments to make and you can often figure out what those adjustments are from the plot (once you get used to doing it this way). FWIW, to do it exactly the way I describe you will want the Excel function I made to take the primary fuel map and interpolate the logged RPM/load into the target AFR. I posted it in here on another thread a while back. I don't have the time to track it down right now, but if you can't find it and want to use this system, let me know. BTW, nluhr also posted his Excel method for doing intake calibrations. You might want to look at his as well. He is also using a Typhoon I believe, so you might be able to start off by using his calibration.

06-10-2006, 05:34 PM	#5
kingtut12 Amateur STI Driver Posts: 9 IWSTI Addict since: May 2006 Trader Rating: (0)	Ok- thanks, I have talked with Nlurh before and tried his excel methods, but had trouble following the equations in the spreadsheet. I will try again.

06-10-2006, 07:04 PM	#6
Christian. STI Driver Car: 01 Subaru WRX STi Sp Fav Mod: Coming Soon Posts: 260 IWSTI Addict since: Aug 2005 Trader Rating: (0)	kingtut12, your throttle must be perfectly constant to tune the intake calibration. Once if moves the Tip-in Enrichments comes into play. Take care, Christian.