Megasquirt Support Forum (MSEXTRA)

Trying to find a definitive answer on this and I'm coming up empty.

Doing some Remote Tuning on Turbo motors with Boost up to approx 170 KPA. Helping members get a baseline Tune so they can safely drive to work, Coffee cruise's, etc and to the Dyno Shop for final Power pulls and full Boost tuning.

1: Ego control is set with an upper limit of 90 KPA and throttle limit of 90%. I want fueling to go Open Loop above those parameters. I do not trust some Particular brands of WB O2 sensor at Loads above 100 KPA. I've read various articles that state they can give that they can give erratic readings.

2: Incorporate AFR Target = include AFR Table

Question. Will Auto Tune ( VEAL ) adjust Cell limits above 90 KPA, with EGO control filter as set? For some reason I believe that I had read that it could, but not as fast. Not too worried about that as VE Table has been set manually " Safe Rich " above 100 KPA.

Final full power Boost settings will be done on a Dyno, but Road Tuning with Auto Tune and VEAL will be used for the most part. ( And Data Logs of course )

In regards to O2 sensors giving erratic readings at WOT and under Boost. Is this just a old wives tale, or is there some truth to it? I don't mind using a NEW WB O2 sensor to calibrate the Boosted VE cell Values, as long as I can trust the darned things. And certain brands are just too unreliable for my comfort zone.

Once the engines are tuned Fully on a Dyno, then the Dyno operator can decide if he wants to leave WOT and greater than 90 KPA in Open Loop or Closed Loop. His call then. Last hand in the Cookie Jar.....

Autotune does not use the controllers EGO Authority limits. It has similar limits of it's own on the advanced settings tab. By default it will tune the entire table once the base filter criteria is met.

LT401Vette wrote:Autotune does not use the controllers EGO Authority limits. It has similar limits of it's own on the advanced settings tab. By default it will tune the entire table once the base filter criteria is met.

Ok, that's what I thought. Good to know. So Auto Tune works more as a Long Term Fuel Correction and EGO Control works more as a Short Term Fuel correction?

Does Auto-Tune respond any faster better if the EGO control is left unfiltered? IE: EGO control left fully enabled to maximum throttle and maximum Boost.

I set my Auto Tune so that it covers the entire VE Table ( over 160F ) , except for the idle areas. I manually tune those, especially with high overlap camshafts.

EGO Correction is not filtered, it is factored in.

It will work faster and more accurately if you leave EGO Correction on. Do not turn off EGO Correction for autotune.

LT401Vette wrote:EGO Correction is not filtered, it is factored in.

It will work faster and more accurately if you leave EGO Correction on. Do not turn off EGO Correction for autotune.

That's the clarification I was looking for. Thanks Phil.

LT401Vette wrote:It will work faster and more accurately if you leave EGO Correction on. Do not turn off EGO Correction for autotune.

Blowing the cobwebs off this one.

I think I have a basic understanding of EGO Correction and Autotune and based on that understanding, need clarification on the benefit of running both together. I understand the purpose of both is to maintain the target AFR by comparing it to the actual AFR and adjusting the VE table as required. EGO correction makes the fueling adjustment, records the correction % but does not permanently change the VE table. So, if I have that right and EGO correction is maintaining the target AFR, it would seem that Autotune would have nothing to correct, but whatever correction was done by EGO Correction is lost.

My focus is primarily on drag racing and I run both but never together. I use EGO Correction only up to the point that I go WOT on the 2-step and Autotune only after releasing the t-brake. Seems I am doing the opposite of what Phil is recommending. I want the quickest and most effective auto correction, so please help me understand the best setup and how these 2 features work together. Keep in mind that I would really like to eliminate having the laptop in the car as I've broken one and the current is damaged despite being strapped down. Not to mention, fiddling with the keyboard in the dark with gloves on.

If I have to run both, so be it, but what is the approach for analyzing the datalog? Would I also have to look at and factor in Correction %?

Apologize if I am not making myself clear. I read what I wrote and it makes sense in my head but I feel like I'm rambling

EGO correction is trying to match Actual AFR to Target AFR in realtime. Autotune looks at the difference between those AND the Ego Correct % to make a VE adjustment based on how far off all of that is. It is possible to have no AFR Error % because the EGO % correction is high. It will only do 'nothing' if both the EGO% and AFR Error % are 0.

I do a lot of drag tuning and having the laptop in the car is near dangerous. I am using almost only MS3 now and SD card logging because of that. The VE Analyze feature in MLV will do something similar to autotune, but do it based on the log files. You can set similar filters as well. This keeps me from doing too much math in my head to make the adjustments manually. You just need to watch and make sure its not doing things like adding fuel for misfires, bad AE events, etc.

The only downside to using EGO downtrack is if you lose a sensor, or one drifts, you may want to think about how things are handled. Some of my customers are more likely to lose a sensor (lead, shrapnel) some are more likely to lose a cylinder, or more. Think about how you want the car to react to those kinds of events if they may be common.

Also if you are on MS3 the latest beta versions have much better EGO PID loops.

Scottie-GNZ wrote:

LT401Vette wrote:It will work faster and more accurately if you leave EGO Correction on. Do not turn off EGO Correction for autotune.

Blowing the cobwebs off this one.

I think I have a basic understanding of EGO Correction and Autotune and based on that understanding, need clarification on the benefit of running both together. I understand the purpose of both is to maintain the target AFR by comparing it to the actual AFR and adjusting the VE table as required. EGO correction makes the fueling adjustment, records the correction % but does not permanently change the VE table. So, if I have that right and EGO correction is maintaining the target AFR, it would seem that Autotune would have nothing to correct, but whatever correction was done by EGO Correction is lost.

EGO Correction is factored in. To elaborate, if EGO Correction is is 90 and AFR is right on target, then Auto Tune knows the fueling was right with 10% pulled out. So in turn it will adjust the current VE value to achieve that same fueling with EGO Correction at 100.

Another consideration, most wide bands get less accurate away from stoich, especially on the lean side. So by letting EGO correction pull the fueling closer to stoich/just rich of stoich, Autotune will have a more accurate AFR reading to work with.

First, thanks for the replies. That really helped me have a better understanding.

Paul,

- glad someone else understands the concerns with having the laptop in the car.
- If I ran EGO only, I rely heavily on AFR Safety and feel that would prevent carnage in the event of something going wrong.

Paul and Phil,

if I understand Paul's approach correctly, he runs EGO downtrack and then VEAL on the log? If so, would VEAL be looking at the EGO correction % to make the adjustments, like Autotune? Whole lot better than me having to do it

Phil,

I know I keep harping on running Autotune without the laptop and wondered if the following idea is possible: I am assuming the Autotune settings are in the MSQ, could it optionally be started with a trigger and a timer for stopping it or a button ("Same as Datalog" would be awesome )

In many cars I use Auto Tune at WOT, but not in my drag car at the track.
For street driving or on the dyno, yes. But at WOT on the track, EGO Correction goes off, and I either use VEAL or hand tune the WOT cells when not hitting my target AFR.

MLV does pay attention to EGO correction as well.

know I keep harping on running Autotune without the laptop and wondered if the following idea is possible: I am assuming the Autotune settings are in the MSQ, could it optionally be started with a trigger and a timer for stopping it or a button ("Same as Datalog" would be awesome )

What if your dashboard could autotune?

LT401Vette wrote:In many cars I use Auto Tune at WOT, but not in my drag car at the track.
For street driving or on the dyno, yes. But at WOT on the track, EGO Correction goes off, and I either use VEAL or hand tune the WOT cells when not hitting my target AFR.

MLV does pay attention to EGO correction as well.

know I keep harping on running Autotune without the laptop and wondered if the following idea is possible: I am assuming the Autotune settings are in the MSQ, could it optionally be started with a trigger and a timer for stopping it or a button ("Same as Datalog" would be awesome )

What if your dashboard could autotune?

Does "EGO Correction goes off" mean you do no correction on a pass? If so, is that just a personal preference or are there specific reasons?

Does your reference to the dashboard doing Autotune imply using a Windows tablet or a start/stop "button"? I currently have an Android.

In my mind it's personal preference and setup dependent. First is how much you trust whichever O2 to work correctly ALL the time. I use 2x NGK AFX O2 on my car and I would trust them more then any other sensor on the car and most people. If it were two Innovate setups I would feel differently! I leave up to 10% authority at WOT on my car but it's a simple NA setup on methanol. That did save my ass on one race last year where my IAT connector snapped off and was reading about 15F in 90deg weather. Didn't feel a thing but saw it on the log and was able to fix it.

Yeah, personal preference and depends on the car. Mine car is Nitrous car that runs a low 8's.
I use Ballenger AFR500's with the NTK sensors, haven't had a failure since going with those.
On other cars I have used EGO Correction at WOT fine.

Gentlemen, great info. THANKS!

When you guys say VEAL a datalog do you mean the VEAL built into the MLV?