Adjusting MAF with Open Loop Fuelling

[Nah]

Bro, why don't you try this,

After you get your fueling correct at WOT (MAF scale) take a base line pull with your original AVCS.

Than make 3-4 intake cam maps from 1600-6000ish 1.0-1.4 loads set it to one value. For example 20, than 25, 30, and 35. Take virtual dyno results on each pulls than overlay them. You'll see where you gained power and lost.

Than do this with the exhaust cam.

Than timing (blanket effect)

And probably back to fueling. (MAF scale)

Obviously make sure with every pass oil and IAT temps are similar and the road is as smooth as can be.

I know this is how people who have the ability to live tune tune for avcs at WOT. Also there's some good guides out there to help you create your own system of things.

[aagun]

Originally Posted by Tor

How can I calculate the overlap from the two tables? And wouldn't it be on purpose that the intake and exhaust valves are open at the same time to help scavanging?

scavenging refrash the gas in the cylinder . there are limit for it (peak power) set it over will lose more frash air and then lose tourqe . peak power hard to find .it takes many dyno runs and flashs .

[Kodename47]

Originally Posted by Kodename47

My AVCS tool

There's a formula in there you can add to your logs if you want to get the overlap into the log tools.

I've reworked this now, improved with more up to date data and includes the corrected version of @aagun lobe display which now is able to use data from the ROM AVCS tables.

[aagun]

Originally Posted by Kodename47

I believe many of these calculations were wrong, you had both cam settings the wrong way round. Intake is advanced and exhaust is retarded by values in the table. Nice idea though, so I have re-worked it. I'll have it up later,

thx for helping me with that tool i make it really fast . i Stock ot to 0 avcs values . the only error i know it was intake retarded not fixed yet . no time to check int avcs limits

inform me ^^

[Tor]

Originally Posted by Nah

Bro, why don't you try this,

...

Thanks for the suggestion. That would take too many flashes to be feasible and I think VD is too unreliable to get reliable results. Add to that that I doubt I would be able to do this in one day and the uncertainties atmospheric conditions would cause.

Next thing is: Is it really worth the effort? The car runs great, has very very little torque dip, and it really wouldn't benefit the top end.

I think I am done:

- First, no one seems to be really sure if the dip is real and/or "supposed" to be there or not.

- Clearly, it's related to the AVCS (as it disappeared when I accidentally drove with the AVCS off in error mode). So maybe it's "just there" when using those settings (and again the torque is good in that area).

- Looking at it practically: Even if it dips for real in the cylinder, it's not significant (11.5). And it's not in an rpm range my car will see WOT very often with my usage. Driving on the street at 3500 rpm it will be in closed loop most of the time.

- On track, it will almost never see WOT at 3500.

Doing extensive further work on this seems like wasted energy. That doesn't mean it was a waste of time, on the contrary, I learned a lot of how things interact from messing with it.

I do indeed intend to use the method to correct the lean spot between 4 and 5000 rpm (real or not, for knock prevention). Otherwise, my next focus will be to keep an eye on timing and adjust it, I am pretty sure it will be necessary when it gets warmer here.

Originally Posted by Kodename47

I've reworked this now, improved with more up to date data and includes the corrected version of @aagun lobe display which now is able to use data from the ROM AVCS tables.

I tried copying my tables in there, and the lobe display doesn't seem to change?

[Kodename47]

Originally Posted by Tor

I tried copying my tables in there, and the lobe display doesn't seem to change?

The manual input of Intake/Exhaust overrides the load/RPM for the tables. Just delete the manual angles and it will work. Make sure the table values are showing 0s as ECUtek won't copy zero, it leaves the cell blank. Re-download, I made some minor improvements.

[aagun]

Originally Posted by Tor

Thanks for the suggestion. That would take too many flashes to be feasible and I think VD is too unreliable to get reliable results. Add to that that I doubt I would be able to do this in one day and the uncertainties atmospheric conditions would cause.

Next thing is: Is it really worth the effort? The car runs great, has very very little torque dip, and it really wouldn't benefit the top end.

I think I am done:

- First, no one seems to be really sure if the dip is real and/or "supposed" to be there or not.

- Clearly, it's related to the AVCS (as it disappeared when I accidentally drove with the AVCS off in error mode). So maybe it's "just there" when using those settings (and again the torque is good in that area).

- Looking at it practically: Even if it dips for real in the cylinder, it's not significant (11.5). And it's not in an rpm range my car will see WOT very often with my usage. Driving on the street at 3500 rpm it will be in closed loop most of the time.

- On track, it will almost never see WOT at 3500.

Doing extensive further work on this seems like wasted energy. That doesn't mean it was a waste of time, on the contrary, I learned a lot of how things interact from messing with it.

I do indeed intend to use the method to correct the lean spot between 4 and 5000 rpm (real or not, for knock prevention). Otherwise, my next focus will be to keep an eye on timing and adjust it, I am pretty sure it will be necessary when it gets warmer here.



I tried copying my tables in there, and the lobe display doesn't seem to change?

pull out 1 degree in ext at dip area and check

[Tor]

Originally Posted by Kodename47

This could explain why it goes lean after the rich dip, not why it reads rich. The sensor won't see the fuel in the exhaust. It's also highly unlikely at low RPM that there is enough vacuum to pull the charge straight through the cylinder, this is where the load logs will be of some use. Those logs show a dip in VE where these fluctuations are happening so it's not a sudden vacuum. Also, most of the fuel is provided by the DI. There is a much lower possibility (almost impossible?) of this being blown through the exhaust valves.

Coming back to this quote. Would increasing the GDI firing angle help prevent if indeed some of the charge goes straight through?


Or would injector ratios play a part in the selection of firing angle?

I noticed in the stock MY17 tune that GDI firing angle at e.g. 3600 rpm has been increased from 300 to 320 and 4000 rpm from 300 to 330.

Except for the area where the ratios have been changed the rest of the table is virtually unchanged?

Given that I have almost the same injector ratios as the MY17 (and OTS doesn't) I'm tempted to try to increase the 320 values to 330 from 4000 and load 0.8 and up and see what it does...

My (OTS) injector values vs. stock v.s. MY17:

[aagun]

what the dyno say

[Kodename47]

Originally Posted by Tor

Coming back to this quote. Would increasing the GDI firing angle help prevent if indeed some of the charge goes straight through?

Think about it, if you increase the DI angle you are firing earlier in the cycle when there is more chance of overlap. It's hard to determine what will happen, but from what I've read you want later injection to cool the charge down at the right time of the cylinder fill. Honestly, I'd probably leave it. It won't gain you anything noticeable and you can't tell if it's good or bad either.

[Tor]

Originally Posted by Kodename47

Think about it, if you increase the DI angle you are firing earlier in the cycle when there is more chance of overlap. It's hard to determine what will happen, but from what I've read you want later injection to cool the charge down at the right time of the cylinder fill. Honestly, I'd probably leave it. It won't gain you anything noticeable and you can't tell if it's good or bad either.

Doh, I guess I got the directions reversed. So theoretically it should be a lower number, not a higher.

A bit late to realize that, since I just did 2 flashes. First I did as said above and increased with +10 to match the MY17 tune. No difference (also smoothened the exhaust cam below 3600, and it felt like sh!t). So I flashed again with 340 like this (and normal cam):



Then I went for another drive. First, a short log, upload and check that nothing was wrong. All looked okay and then I went and just enjoyed driving the car, what I actually didn't do for months.

Result? No difference noticeable...

A Haltech supporter wrote the following in their forum:

In practice the easiest way to do this is by tuning your engine to a known AFR. Next, adjust the injector firing angle until the engine becomes as rich as possible, now we know that the engine is burning the maximum amount of injected fuel. Do this for each RPM site you require.

I guess it is more complicated for our cars because of D4S. (Also, it probably helps adjusting in the right direction. )

[freerunner]

Originally Posted by aagun

pull out 1 degree in ext at dip area and check

Or say 10-15 @3600 in my case (catted 4/2/1 EL header).

Don't think 1 degree suffices if the valves really overlap at 4 mm.

[aagun]

Originally Posted by freerunner

Or say 10-15 @3600 in my case (catted 4/2/1 EL header).

Don't think 1 degree suffices if the valves really overlap at 4 mm.

interesting on ur map

[freerunner]

Originally Posted by aagun

interesting on ur map

It's not ready yet. I'm currently redoing everything after discovering 86inches/kodename47's new maf scaling spreadsheet. The math really exposes all the dirty deeds.

Here's a log from the wip though: Click