1991 Turbo 306 coupe MS3/PiMPxs tuning adventure

[wiseguyk]

I've spent some more time on my VE table and I think I have it to a spot where I can at least feel good about driving it without it going too lean. I'm taking the car to have the exhaust welded tomorrow morning so hoping I can get a short drive or two in before the appointment

While working on the VE table I started wondering if there any reason I might want to go back to the 8.5 value the required fuel calculator suggested vs my current smaller value of 6.2. Since it's only a multiplier, is there any benefit to changing it back to 8.5 and lowering all my VE values or just keep the req_fuel as is along with my current high (lots of cells in the 100+ range) VE values.

I would imagine there's a way to easily calculate the % change and apply it to the VE table to adjust for a change in required fuel, I just don't know if there's any benefit to doing that since the end result should be the same right?

In other words, would a larger req_fuel value and smaller VE table values be more "readable" or accurate than a smaller req_fuel value and larger VE table values like I have currently. I hope that makes sense...

 

[a91what]

Smaller ve table values give you less resolution. A value of 30 will move the fuel 3.33% for a 1 point change where a value of 60 will only have a 1.6% change per point.
The req fuel value is arbitrary.

 

[wiseguyk]

Smaller ve table values give you less resolution. A value of 30 will move the fuel 3.33% for a 1 point change where a value of 60 will only have a 1.6% change per point.
The req fuel value is arbitrary.

Ok thanks for explaining. The VE and required fuel will stay as they are then

 

[wiseguyk]

Just a quick update. I drove the car a bit this morning before dropping it off at the exhaust shop. I had VEAL enabled this time, with 1300 RPM minimum filter and "normal" resistance. It looks like it almost exclusively pulled fuel out of the VE table so that's good.

Looking at the log briefly it seems like the AFR is pretty close to the target most of the time, but there are definitely some deviations in there of 2 or more in some places. Attached is the log and most recent tune with the autotune changes in it.

Can you guys give me any pointers on where I should go from here? More auto-tune driving? Should I smooth out my VE table from the autotune changes? Does my log look "safe" enough to continue onward? I know, too many questions!

Oh and I've been meaning to ask, is it normal to see brief spots with 19 AFR? Seems to correspond with downshifts but I can't quite tell. I just want to make sure I'm keeping my eye on the things that matter to prevent any accidental damage caused by my noob-ness Thanks guys!

 

[stanglx2002]

My method for fine tuning with VEAL is:

1. Drive car with VEAL enabled and datalog the drive so you can see how you are doing
2. After drive smooth out VE table
3. Repeat steps 1-2 until your car starts driving smoothly and AFR Target is close to AFR Actual

Once you have the initial VE Table ironed out you can move to longer drives for 15-20+ minutes, and run them through Megalog Viewer to be analyzed for fine tuning. You can use @a91what trick and combined multiple datalogs into Megalog Viewer and get a better hit count for a better analysis review.

 

[wiseguyk]

My method for fine tuning with VEAL is:

1. Drive car with VEAL enabled and datalog the drive so you can see how you are doing
2. After drive smooth out VE table
3. Repeat steps 1-2 until your car starts driving smoothly and AFR Target is close to AFR Actual

Once you have the initial VE Table ironed out you can move to longer drives for 15-20+ minutes, and run them through Megalog Viewer to be analyzed for fine tuning. You can use @a91what trick and combined multiple datalogs into Megalog Viewer and get a better hit count for a better analysis review.

Thanks for the tips man! Yesterday was my first time using VE live but it was really cool and I look forward to doing more once the car is done at the shop.

When you smooth your VE table, you just highlight the whole table and hit the smoothing button? If so do you exclude idle cells when you do this?

I saw Steve's tip in another thread about being able to load multiple logs into MLVHD, that's a great idea since my first short drives didn't seem to have enough data for VE analyze to really change much.

To that point, do you leave the VEAL difficulty set to "normal" or would you recommend changing it for these initial drives I'll be doing?

 

[5.0Thunder]

Normal is probably still fine for megalog viewer analysis. I don't typically like smoothing a full table. When you run the analyzer, you'll see the cells that are being changed and the ones that aren't. You don't want to pull the good cells out of adjustment by smoothing the whole table. I like to look at the areas of the table that are changing the most, go to the 3D map, then smooth the edges that transition into those areas. I think this more quickly and closely shapes the table to where it needs to be.

 

[a91what]

I have mixed feelings about VEAL the ms3 works well with it but it almost killed my first engine (albeit I was just learning to tune) always wanted to pull to much fuel.

I really love VE analyzer and using datalogs, I can filter what I dont want to use (transient events) that throw off VEAL.

Smoothing should be done by hand once you start getting past the basics (which you are congrats! Your learning fast) as Thunder said just feather things in at this point.
Now if you ask me what's more important, hitting target afr perfectly OR having a smooth map..... smooth the map you will never notice the table being .1 or .2 off of target but you WILL notice sharp transitional changes during low load cruise... that's just my .02
Let ego do its job from there, if it is setup correctly you will stay within .2 of target which is what your looking for.

Let me say this however, WOT needs to be dead on dont trust VEAL to tune this area do this by hand.

 

[wiseguyk]

Normal is probably still fine for megalog viewer analysis. I don't typically like smoothing a full table. When you run the analyzer, you'll see the cells that are being changed and the ones that aren't. You don't want to pull the good cells out of adjustment by smoothing the whole table. I like to look at the areas of the table that are changing the most, go to the 3D map, then smooth the edges that transition into those areas. I think this more quickly and closely shapes the table to where it needs to be.

Ah ok that makes sense, smooth out the areas where it was tweaked by VEAL so there aren't big jumps between them or between them and the "unmodified" cells around them.

I haven't used the 3D feature yet other than just turning it on, going "ooooh pretty", and turning it back off haha. I'll take another look now that I'm a little more familiar with the VE tuning process, I can imagine it makes spotting the rough transitions much easier.

I had been using the hard setting when using MLVHD to VE analyze on my logs as recommended by @a91what. Is normal, or even easy ok to use while actually driving and running VEAL? I know setting to easy will allow it to make more drastic changes so just curious since I'm in such early stages of driveability tuning if that might get me dialed in quicker or just do more driving with set to normal?

Thanks for your help!

 

[a91what]

Ah ok that makes sense, smooth out the areas where it was tweaked by VEAL so there aren't big jumps between them or between them and the "unmodified" cells around them.

I haven't used the 3D feature yet other than just turning it on, going "ooooh pretty", and turning it back off haha. I'll take another look now that I'm a little more familiar with the VE tuning process, I can imagine it makes spotting the rough transitions much easier.

I had been using the hard setting when using MLVHD to VE analyze on my logs as recommended by @a91what. Is normal, or even easy ok to use while actually driving and running VEAL? I know setting to easy will allow it to make more drastic changes so just curious since I'm in such early stages of driveability tuning if that might get me dialed in quicker or just do more driving with set to normal?

Thanks for your help!

Large fuel changes I like to tune by hand... using a datalog pick 4 points and write down the target afr, actual afr, and the point it exists in the ve table.
let's do some quick math shall we....
Have÷want= actual afr÷target afr
13÷14= .928%

What this mean is at this point in the map we are 7.2% rich, by multiplying this ve point by .928 we will correct the fuel error.
Do this in a few spots then blend into the table, this will get you to target faster.

I dont suggest using the easy or normal setting for the self tuning for a beginner because typically they don't know how to sanity check the fuel changes. In your case you have a basic grasp on things so get at it.

 

[wiseguyk]

I have mixed feelings about VEAL the ms3 works well with it but it almost killed my first engine (albeit I was just learning to tune) always wanted to pull to much fuel.

I really love VE analyzer and using datalogs, I can filter what I dont want to use (transient events) that throw off VEAL.

Smoothing should be done by hand once you start getting past the basics (which you are congrats! Your learning fast) as Thunder said just feather things in at this point.
Now if you ask me what's more important, hitting target afr perfectly OR having a smooth map..... smooth the map you will never notice the table being .1 or .2 off of target but you WILL notice sharp transitional changes during low load cruise... that's just my .02
Let ego do its job from there, if it is setup correctly you will stay within .2 of target which is what your looking for.

Let me say this however, WOT needs to be dead on dont trust VEAL to tune this area do this by hand.

Oops, sorry I didn't see your reply until I submitted my last message!

I guess my main question then is if I don't use VEAL, and do all my adjustments afterwards using MLVHD VE analyzer won't I run the risk of being too lean in spots while driving? I feel like I'm close to a eureka moment with this, but struggling to know when it's "normal" to see high AFR numbers.

For example, here's a snippet of my log from the drive yesterday. It's at 17.4 AFR at this point but the target is 14.5. It's tough to watch the AFR while I'm doing these short drives, but I do see it spike up

Here's one more snippet a little later in the drive. It spikes up to 19.9 here, but I'm not sure if that's because I downshifted or what...

Are there any guidelines you can give me on what I can expect to see from the wideband, that way I'll know when to be worried? I just really don't want to mess up this brand new motor

 

[wiseguyk]

Large fuel changes I like to tune by hand... using a datalog pick 4 points and write down the target afr, actual afr, and the point it exists in the ve table.

Would points like the two I posted screenshots of be what you're talking about for this? Thanks for the formula, I think I can do that as long as I know what suitable points in my log files are for adjustment

 

[a91what]

Oops, sorry I didn't see your reply until I submitted my last message!

I guess my main question then is if I don't use VEAL, and do all my adjustments afterwards using MLVHD VE analyzer won't I run the risk of being too lean in spots while driving? I feel like I'm close to a eureka moment with this, but struggling to know when it's "normal" to see high AFR numbers.

For example, here's a snippet of my log from the drive yesterday. It's at 17.4 AFR at this point but the target is 14.5. It's tough to watch the AFR while I'm doing these short drives, but I do see it spike up

Here's one more snippet a little later in the drive. It spikes up to 19.9 here, but I'm not sure if that's because I downshifted or what...

Are there any guidelines you can give me on what I can expect to see from the wideband, that way I'll know when to be worried? I just really don't want to mess up this brand new motor

Notice the spikes are happening on a lifted throttle or gear change at very low load, this is not going to cause a meltdown. Some settings need to be looked at, is overrun fuel cut enabled?
Have we done any acceleration enrichment tuning?

 

[stanglx2002]

Another trick for you is when you are driving datalogging you can hit the space bar. This will put a red line a the bottom of the time lapse. This helps when you are trying to pin point certain events.

 

[a91what]

Would points like the two I posted screenshots of be what you're talking about for this? Thanks for the formula, I think I can do that as long as I know what suitable points in my log files are for adjustment

"Solid" points, dont pick any transitional fuel points, the tps needs to be stable and it cant be at any up/down shifts.

 

[wiseguyk]

Notice the spikes are happening on a lifted throttle or gear change at very low load, this is not going to cause a meltdown.

Ok exactly the info I was looking for. So spikes while I'm on the throttle are the ones to worry about.

Some settings need to be looked at, is overrun fuel cut enabled?

Yes it appears to be on.

Have we done any acceleration enrichment tuning?

No we haven't.

Think maybe you can take a look at my latest tune and give it a onceover just to make sure there's nothing crazy set?

 

[a91what]

You can also add acceleration enrichment to the datalog so you can see when that fuel adder happens.

You should probably smooth the datastream as well, if you click on the data tag in the graph (top right in the graph ie. The afr tag) you can select 'smooth' do a small number like 2-3 this makes the graph less scary lol. You are looking at 100% raw data it is hard to interpret smooth the graph slightly.

 

[a91what]

Ok exactly the info I was looking for. So spikes while I'm on the throttle are the ones to worry about.

Yes it appears to be on.

No we haven't.

Think maybe you can take a look at my latest tune and give it a onceover just to make sure there's nothing crazy set?

Turn off overrun for now, it's a fuel saving feature. Turn it back on when your done tuning
AE can be tuned in the driveway. Lol not kidding, call me for this one hard to explain in text.

 

[stanglx2002]

Defiantly need to disable Over-Run Fuel at this point you are in right now. That is going to throw off your numbers for sure.

I do things probably a little different than others but I typically disable: Over-run fuel, EGO Control, and Accel Enrichment. I do this so there isnt anything adding/subtracting fuel while dialing in my initial VE Table. I personally do like VEAL, but just make sure you are not doing quick throttle changes. Slowly get on the throttle (25%ish), since Accel Enrichment is disabled this will make sure you dont have lean spikes. It is best to do this on an LONG open highway or street, so you can go from a stop and roll slowly up the RPM's to say 5k then shift gears and do the same thing again. Just like @a91what said you want to keep at a steady set point as long as possible. Once I get the the end of the highway or street, I pull over smooth out the VE Table, and then drive it back with VEAL on again. It typically only takes 2 trips to get an initial VE Table ironed out.

If you ever put your mouse of a VE cell when you are in VEAL a pop-up will come up displaying Hit Count and Hit Weighting. The more you are in the cells the more VEAL can accurately adjust the numbers. If you are on and off the throttle a lot it will skew the numbers, which goes to the same point of doing the math for fuel error.

You will not hurt your engine in part/low throttle. It is WOT you have to be more careful.

 

[wiseguyk]

You can also add acceleration enrichment to the datalog so you can see when that fuel adder happens.

Ah, I didn't even see it at first but then found it under the "Fuel" group.

You should probably smooth the datastream as well, if you click on the data tag in the graph (top right in the graph ie. The afr tag) you can select 'smooth' do a small number like 2-3 this makes the graph less scary lol. You are looking at 100% raw data it is hard to interpret smooth the graph slightly.

Wow dude, I would have had NO idea that was a feature! Very cool though and yeah it makes it less radical for sure. Thanks for that tip

Turn off overrun for now, it's a fuel saving feature. Turn it back on when your done tuning
AE can be tuned in the driveway. Lol not kidding, call me for this one hard to explain in text.

I've turned it off. Yeah, I was just looking at the AE settings and a bit confused. I'll read up on the MS docs about it so I'm better informed before we chat

Thanks so much!!! Progress!