More timing = lower airflow??

Tuning my recently installed meth kit, found a strange result: MAF reads lower then before. Same map, only added timing and reduced fuel, slightly added bost. Same temps around..

 

What could cause such behaviour? Engine load(direct) stays relatively low, I think because of low MAF. I did not rescale my MAF for a WI, do not think it is neccesory for a stock turbo. (Should I?)

 

I've attached the log.

 

Pro tuners, please suggest:-)

meth wot.csv

Hug? silence..

 

Was thinking.. I've raised max boost from 18 to 19psi to run with WI.. Running VF40 and stock TMIC.

May MAF drop because of too hot air coming from a small turbo? I'll try to drop it for 0.5 psi and see what will happen with MAF.

My MAF can sometimes vary as much as 15-30g/s depending on outside temps, because I'm pushing the Vf-40 and TMIC to its max. I hope to see more consistent numbers with a vf-52.

The added boost and leaner mixture are probably translating into alot more heat at the turbo...enough to push hot air into the intake manifold (even with meth) I would drop your boost a little and see if anything changes...

 

When i tune i like doing one thing at a time..I may add a little timing and log specifically looking for a favorable result, then lean out the mixture and log then add a more boost...etc.

 

Changing one variable at a time lets you immediatly know what the cause of the problem is.

 

good luck.

^ Thanks, This is what I am trying to do:-)

Thisg gets even more complicated as my LC-1 show about 0.8-1.2 more then actual AFR is.. I was able to run some WOT today, seeing this:

Stock : LC-1:

12.86 13.11

11.71 12.74

11.83 12.97

11.83 12.64

11.71 12.58

11.94 12.83

11.94 13.14

12.17 13.07

12.06 12.95

12.06 13.02

12.06 13.01

12.17 13.08

12.17 13.23

12.17 13.33

11.94 13.24

11.94 12.95

11.94 12.91

11.94 13.16

11.94 13.08

12.17 13.05

11.94 12.88

11.83 12.94

11.94 12.88

12.06 13.04

12.06 13.22

12.06 13.04

12.17 13.17

 

I think I'll contact manufacture asking for a replacement, as this one just useless. No wonder I was always seeing much leaner then i was..

How are you basing your "stock" AFR? Is that off the map or off the front 02.

 

Maybe you need to rescale your maf? I mean, if the WB02 is matching your front o2 in CL..it might not be the WB02 that is malfunctioning.

I use A/F Sensor #1 (AFR) on RR.. Should i use "rear O2"?

May be MAF scale is off.. Need to look how to scale it. it must be a topic on nasioc.

BTW, my learnign view looking normal: 12, 0, 4, 2 for A, B, C D cells.

 

Curtrently i am tuning my AFR blindly, adding fuel, do a WOT, remove fuel , do a WOT again, analysing knock. My LC-1 is really useless at this point.

You should really get the WB02 issue ironed out. Then scale your maf..scaling the maf is fairly easy.

 

I used airboys sheet..

 

Basically you zero out your WGDC (so you are runnng only WG boost), log MafV, Maf g/s, LC-1 and engine speed and load...do a WOT run from 2000-redline. Paste the log into airboy's spread sheet, go to the maf scale tab and copy and paste your fuel map, and hit the interpolate button. You will then get a sheet that shows your % error at each log point. So if at 4V you're maf is scaled for 200 g/s and the sheet shows that you are running 10% lean, you know you need to scale 4V = 220 g/s (instead of 200)..you do that for each MafV point.

 

After scaling I am within 0.10-0.20% of my A/f target. It makes it much easier to tune, you simply input the ratio you want on the map...if scaled right, it will hit it every time.

Your playing with fire tuning meth w/o a correctly reading wideband o2. Unless you want to build a new motor, I suggest you stop now and figure out the o2 situation. You can't trust the oem front sensor for WOT a/f ratios if its in the stock location.

^ Where's your sense of adventure?

 

Thanks, guys!

I'll recalibrate LC-1 (not sure if this will help) , and do a rescaling of the MAF. will see how it goes.

maf scale tab

Spec B, you mean "AFR interpolate tab"? I do not see maf scale tab..

 

BTW, I have to rescale it with WI on or off? Runnig it on will really affect my afr targets.

^ Where's your sense of adventure?

 

 

It left my pocket with the 3500 it took to rebuild my motor

Thanks, guys!

I'll recalibrate LC-1 (not sure if this will help) , and do a rescaling of the MAF. will see how it goes.

Spec B, you mean "AFR interpolate tab"? I do not see maf scale tab..

 

BTW, I have to rescale it with WI on or off? Runnig it on will really affect my afr targets.

 

Yes..sorry the AFR interpolate tab. When you paste your map you need to realign the load header..took me 2 hours to figure it out.

 

I would do it with the meth off..less variables!

Meth off? But, if I scale it without meth, I would never match my AFR targets when runnign meth! Right? I plan to use meth 24/7, so probably I'll do a scaling with meth on.. Let me know I do not know something, which makes my conclusion wrong.

 

BTW, with WGDC 0 - do I need to zero out Max WGDC table as well? or Initial WDGC shoudl be only zeroed?

 

 

 

^ Where's your sense of adventure?

Yeah. I have it a lot. :-)))

Good point...meth on.

 

I zero'd out both tables...but you probably can zero out just initial.

Your target AFR's with meth ON will target a much leaner number than what you will actually be running. For example, you might be shooting for 12:1 A/F, so in order to achieve this, your target A/F on your map should be something like 13:1 depending on the meth mixture you are running.

 

But you can't go about attempting this w/o knowing your wideband is functioning properly. If you keep trying to tune the car, I'm afraid its going to end badly.

^ This is why I am will be scaling MAF with WI on, so it will be shifted for a meth. After such scalling I should have my WI AFR really close to a target.

 

You are right about my wideband.. It might be very dangerous to relay on it.

to Any ideas how I can check its functioanlity? in CL it shows really close readings to a stock sensor, only on WOT it reads sh$t.

Recently I run my regular fuel map with WI (stage 2, 11-10.8 target AFR on high load), and LC-1 showed 11.8 min. Which can't be true.

I tuned mine the other way. I calibrated my MAF with the meth off and made sure everything was very close to what my wideband was stating. I then turned my meth system on and saw things richen up a bit. To get things where I wanted them, I then adjusted the fuel tables and not the MAF calibration. So to hit 12.5 I actually had to target a value of around 13.1 or 13.2 in the fuel table.

^ Thanks for the advice. I may do the same, if I will be sure my wideband is OK.

I am thinking it may show unaccurate reading at WOT because of it's placement. Lachute DP has is about 3 inches from a turbo.. Could it screw up LC-1 readings? I've read most guys put it like 10-15 inches away..

 

 

BTW, tunig my fuel "blindly", I was getting very nice LV, last time it was like this for a fuel trim: 9.8, 0.0, 0.3, 0.9 for a A, B , C and D cell. I think I might hitiing just right fueling for a meth, right? No FLKC as well