Anybody tuned with AlphaN in Megasquirt?

[Grover]

I've been running Speed Density for the last few years but want to create an AN table en route to doing a blended set-up. However, when I switch to AN in the basic Injector Control settings, I assumed that the VE table would now be set up for TPS, vs MAP. This is not happening. Any idea what I need to do to get a VE table with TPS on the X axis?

[Harv]

Im not sure because it's been a long time since I have read up on this. But I THINK when you use AN it simulated a map signal using TPS and rpm.

I could be wrong.

John

[Colin]

Did you get the Extra code upload successfully?

[shauer]

What MS firmware are you currently running and what tuning application?

AN should have TPS on the Y axis and RPM on the X axis of the VE table. The Y axis should be TPS (either as 0-255 or in % depending on version of MS)

You need to set the primary control algorithm to AN but the exact wording of that option and the location of where to do it varies depending upon the version/generation of MS as well as the tuning application used.

You say you are planning on transitioning to blended tuning, which method are you planning on using for your primary table (SD or AN)? I have done both and both work well, it really comes down to personal preference or what you have started with.

It is possible to transition from SD to blended SD/AN without the need to come up with a full AN table first if you already have a good SD table.

http://77e21.info/mstuning_blendedansd.htm

- Steve

[Grover]

Thanks Steve. I'm currently running MSII V3.0, firmware version 2.891 but will be switching over to MS2/Extra pretty soon here so I can utilize ITB load as you outlined on your site (which is excellent, by the way.) I actually sent you an email a couple of weeks back with some questions, not sure if you got it. trichardson AT clifbar DOT com.

Back to the initial post though: The only place I see an option for selecting AN is in the Injection Control setting, nowhere else, and when I switch from SD to AN-only, the y axis still shows at kPA, and I see no option in any of the menus to generate a table utilizing TPS. Any guidance would be appreciated.

I have what I believe is a very good SD VE table right now and I've worked in Megalog viewer to capture a number of TPS points that I can plot as the beginning of an AN table (it looks very similar to the one on your site actually, +/- 5-10% in most areas.) My plan was to get an AN table relatively well dialed in, and then I'd have strong information as I move to the blended table or ITB load option. Just trying to take baby steps here...

[shauer]

Are you using tuner studio for your tuning application?

It is entirely possible that the label on the Y axis for the VE table may not change wording when selecting AN mode. You can easily check if you have enabled AN mode by simply moving the throttle and seeing if the active bin on the VE table moves up and down with the throttle. Load the tune file that you think is set to AN, don't actually start the engine but turn it on so MS is up and running. The active VE bin should be the min-rpm column and move up and down with the throttle.

On my MS3x setup with TS, the Y axis is always called "fuel load" which is a nice generic label that I think the developers selected to simplify needing to change labels with different settings.

If I was in your situation, I would skip the blended tuning step and go directly to the ITB load tuning. ITB mode uses only 1 VE table and not 2 so it is simpler to tune. The VEAL feature of tuner studio is also compatible with ITB mode but not with blended since VEAL does not understand using 2 VE tables together for tuning.

I would complete the data log analysis you are doing with your logs from your SD tune to characterize the throttles. I would then enter the throttle curve in the ITB mode setup and simply start with your SD VE table as an initial set of values for ITB mode. Your SD table should be good enough to get your engine started and idling. I would then use the VE analyze live (VEAL) feature on tuner studio and have TS auto-tune the remainder of you VE table.

I have done this several times where I get the engine warm and idling and then run the engine through the RPM range in the garage using VEAL to rough-out the VE table. I then start driving the car carefully, starting with low-load and low-RPM and let VEAL do its thing to establish the VE table. I then carefully increase load and RPM while driving until I have most of the VE table roughed out using VEAL. I normally do this across several test drives with a little manual editing of the VE table in between runs. I can have a VE table within about +/- 10% this way with a few test drives using VEAL to do the majority of the work. This is really not possible with the dual table blended tune.

Sorry I missed your email. I'm sure i got it but it most likely got lost in my preparations for the Vintage at Saratoga. I'll go back and look for it.

- Steve

[Grover]

Thanks Steve, and no worries on the timing, I know life can get busy at times. I've read and re-read your posts on ITB load several times, but honestly am still struggling with fully understanding it. As such, I was going down the path of getting rolling with the blended approach, hoping that as I learn more, the ITB load process will become more logical/understandable to me, and then I could move to this in the not too distant future. I have also yet to play with VEAL, so just one more thing to add to the learning pile.

If you don't mind, I might send you a separate email with a few more questions, as now the old email might be a bit outdated as I've picked up odds and ends here and there. Let me know if you might have some time to help a less than stellar computer guy hobble through this...

Thanks again. Tom

[shauer]

No problem.

shauer at rochester dot rr dot com

- Steve

[Colin]

Tom, VEAL is wonderful and really the single best thing to happen to megasquirt, IMO.

I have found the trick to getting it working well is getting your PID settings working well so your wideband provides more meaningful data to VEAL. The developer on for Tunerstudio explained to me that VEAL works most accurately when the mixture is closer to 14.7.

[Grover]

Thanks Colin, sounds like VEAL is something I should investigate more seriously. I'm a creature of habit I suppose. Remind me what PID is? Sounds like something I would see a drug advertised for during 60 minutes.

[Colin]

Thanks Colin, sounds like VEAL is something I should investigate more seriously. I'm a creature of habit I suppose. Remind me what PID is? Sounds like something I would see a drug advertised for during 60 minutes.

PID is the correction algorithm for EGO. The default is "simple" and that sort of sucks.

If you scroll to the very bottom of my blog, you will find the PID settings that I am currently running with fair success.

http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,373796/

[Grover]

Oh man, my head hurts!!! I'm not using EGO control for the time being, yet another thing to look at as the project progresses.

[shauer]

Actually, EGO correction and VEAL are completely different features and do not rely on each other. However, having poor VE table values, bad accel enrichment settings, and having closed loop EGO enabled as well as VEAL is a recipe for poor results all the way around.

What I do is turn off EGO correction completely and get a baseline VE table using VEAL. If your wideband O2 gauge is accurate and providing good data then I have found that VEAL does not care what the target AFR is set to. I suspect that the recommendation around a 14.7:1 AFR target with VEAL has more to do with other factors such as incorrect accel enrichment and closed loop EGO control confusing things. I use VEAL to tune my car with a range of AFR targets from 12.5:1 to 16:1 and it does a great job.

One consideration is to set up the tune so you understand where the correction is coming from and only use one form of correction at a time.

I turn off closed loop EGO control and get my VE table roughed-in with VEAL. I do progressive drives with VEAL setting the change control on VEAL to "harder" settings so that it makes smaller and smaller corrections until I converge on a VE table that is within a few percent of ideal.

Then I go back and get my accel enrichment dialed in so that I do not go over rich or over lean. Only then do I turn on closed loop EGO correction.

You do no want closed loop EGO correction fighting with VEAL and both getting thrown off my bad accel enrichment settings. The different algorithms end up chasing their tails and you get confusing, contradictory results.

In summary, this is what has worked best for me on several cars and tunes:

1. Turn off EGO correction

2. Use VEAL with progressively more conservative settings to get a good VE table

3. Use log data to tune accel enrichment correctly

4. Turn on EGO control. You should not need more than +/- 5% control authority on the EGO control if your VE table and accel enrichment are correct.

- Steve

[TKMad]

You don't have to turn off EGO control to use VEAL. The Tunerstudio programmer said VEAL takes the EGO difference in consideration when tuning.

[shauer]

You don't have to turn off EGO control to use VEAL. The Tunerstudio programmer said VEAL takes the EGO difference in consideration when tuning.

You are correct but it's not that simple.

VEAL does take EGO correction into account but it is far from perfect. There are time lags involved. VEAL is up on the PC and needs to get its data via the serial connection which introduces a time delay (although not a large one). On top of that, VEAL has a time lag table built in that tries to account for the delay in the EGO reading based on MAP and RPM. This means that VEAL is most likely looking at a different point in time than the EGO correction algorithm with regards to EGO data. As far as I know, EGO correction does not have a time compensation for the delay in sensor response.

Now, the closed loop EGO control has different delays built into it with regards to sampling interval and integration time. This means that the EGO correction is normally in a state of transition as well. If the closed loop EGO correction is not dialed in correctly or the VE table is way off you will get very large EGO correction values that change very quickly. VEAL will take these corrections into account but if you are accelerating it is likely that VEAL and EGO correction are not going to be working on the same VE cell.

This is why I recommend establishing a base tune using one algorithm at a time. What I have found is that VEAL and EGO correction trying to solve the same problem at the same time with different gains and response times causes poor results with VE table correction especially when RPM or load is changing relatively quickly.

I apologize for getting the thread off track with talk about VEAL and EGO, it's just that I have experienced several folks getting confusing results because of this.

- Steve