Lets Talk Torque Modelling / Virtual Torque

[hjtrbo]

Hub dyno for the win. Like I said, I haven't dived into how it all works. I just posted all that as an example of some of the stuff the ECM is working with. The transmission has it's own torque model and is even looking at vehicle drag. Pretty insane. Gen 5 must be off it's head.

[07GTS]

If you pick a cell and plot it for each spark point you will see it has a curve to it. My thoughts whether right or wrong are keep the curve a similar shape whilst tweaking it.


Here are 2 curves, the blue 1 is OEM and the orange one is the lowest airmass cell x 0.8 then vertical interpolate with link selections turned on. You can see the curve stays similar but about 10Nm has been added. Added benefit is when clicking the calculate button the changes stick, it plays nice with the coefficient generator. Ignore the high values, I just picked a random cell for this example. This so far has been working well for idle. I have a different method for WOT.

nice thanks, hopefully can get it going for the weekend do some testing

[Allen Vos]

I'm getting lost, you're doing that 'post to many times' thing again

The row axis on the airmass tables are in mg of 'cylinder airmass'. I checked your log, you're logging it.


It was, until you added that cam shaft. That has shifted your idle vacuum which means the torque model is no longer valid in that region. In your case we need to get the oem idle torque numbers shifted into your new idle region.


Auto & manual use the same torque tables.
For auto tunes we can increase the torque values as needed which causes the transmission to apply more pressure. There is no science behind the changes, just a blatant number fudge although we want the numbers to be realistic. On mild to big builds or when adding forced induction it's very important to check the reported torque and adjust the torque tables as required.

All of us have different ways to correct the numbers, but we are all aiming to achieve the same outcome.

Sorry man, just have a lot of questions. This stuff is pretty advanced for me and I do want to understand it but I will try my best to keep things simple.


On the idle MAP based torque tables I need to shift my torque values from 30 KPA to 57KPA to match my cam, and also do I need to only do it to the Spark -10 table as my base spark is at 18 degrees?

I know you said I am logging cylinder air mass but that is in Grams. The torque tables for airmass are clearly stated in MG.

It takes 1000 MG to equal 1 Gram. In my mind that math does not work at all as 800 mg which is the highest value on the torque table converts to .8 Grams.

The car idles at 9-10 gram/second.

I had asked this in my previous post , maybe just did not word it correctly.



As far as adjusting the torque tables goes, what is the best way to do this?

Can I log torque or delivered torque along with MAP or AIRFLOW and plug those values right back into the torque tables?

[LS ROB]

Honestly, I wouldn't try to mess with the torque tables this early in the calibrating stages. If you haven't driven the car yet and are making all of these changes, then its going to be real tough to chase down issues that may or may not come up when you do actually get to log a drive.

[hjtrbo]

I know you said I am logging cylinder air mass but that is in Grams. The torque tables for airmass are clearly stated in MG.

It takes 1000 MG to equal 1 Gram. In my mind that math does not work at all as 800 mg which is the highest value on the torque table converts to .8 Grams.

The car idles at 9-10 gram/second.

I had asked this in my previous post , maybe just did not word it correctly.

I'm sure you're smart enough to handle the conversion between grams and mg in your head without to much trouble

The 9-10g/s is your 'mass airflow'
The 800mg is 'cylinder air mass'

Cylinder air mass = MAF x 15 / rpm

[hjtrbo]

Leave your map table alone for now.

Attached is what I would do with your air mass for the first round of testing. I grabbed the tune from one of your last posts in your idle thread.

[GHuggins]

Honestly, I wouldn't try to mess with the torque tables this early in the calibrating stages. If you haven't driven the car yet and are making all of these changes, then its going to be real tough to chase down issues that may or may not come up when you do actually get to log a drive.

This, before you trip and fall into the hole. Fuel has to be right before even considering the torque model.

[hjtrbo]

Can I log torque or delivered torque along with MAP or AIRFLOW and plug those values right back into the torque tables?

I remember reading about people doing this. NO. Why is beyond me. Another example where 'ol mates AI bot would have sucked up absolute shit.

]As far as adjusting the torque tables goes, what is the best way to do this?

I loosely outlined it a few posts above. Before you can run you must crawl apparently, or something like that anyway. Ignore the map table for now.
Have you got your scanner charts sorted for virtual torque?
Does air mass flow and air mass per cylinder gel now?

[hjtrbo]

This, before you trip and fall into the hole. Fuel has to be right before even considering the torque model.

NSFW Aussie language alert

Ah fuck it Greg, just hit the cunt in the nuts and drag his feet into the fire. He'll be circling around with his tune anyway. Let him play in the sandbox with his toys will yah!

[hjtrbo]

NSFW

Volume up lads
Aussie Road Rage (youtube.com)

[edcmat-l1]

OK I'm here to poop on everybody's parade. I've tuned literally thousands of GEN4s, E38s and E67s. All kinds of ridiculous combos. I've made 1000 RWHP on a bone stock LS3. Made close to 700 rwhp on a couple ridiculous NA LS7s. I've tuned magazine cars, race winning cars, etc. Big injectors, big throttle bodies, huge cams, NA, turbo, blower, etc. I've never even considered tuning the virtual torque in a GEN4. A few years ago it wasn't even available in these. I can make ridiculous combos drive incredibly well. I built my reputation on "drives like stock". I was speed density tuning the E38 before HPT had the ability. I can honestly say I've never run into a scenario, a problem, a driveability issue where I said to myself "Ya know, maybe if I dial in the VTT it'll fix that".

I'm a pretty good math guy and I like everything to make mathematical sense and I can understand dialing in the VTT from that standpoint. To make it all make sense. But to say that it's a necessity or even that it will make a significant difference in the way that the vehicle runs, I'd have to argue that. I've done way too many cars in my career. In the GEN4s it's don't flippin matter.

[hjtrbo]

I'm a pretty good math guy and I like everything to make mathematical sense and I can understand dialing in the VTT from that standpoint. To make it all make sense. But to say that it's a necessity or even that it will make a significant difference in the way that the vehicle runs, I'd have to argue that. I've done way too many cars in my career. In the GEN4s it's don't flippin matter.

What can I say, some of us have too much time on our hands.

I would like you to try the baro tables on your next big cam tight converter car though if you could spare the extra hour.

[edcmat-l1]

What can I say, some of us have too much time on our hands.

I would like you to try the baro tables on your next big cam tight converter car though if you could spare the extra hour.

Oh there's no doubt I'll be spending some time on this just to get a yay or nay feeling for it. But from sheer experience I'm telling you I don't know where there's going to be significant improvement. Just speaking from a point of volume I've probably tuned a couple thousand of these dating back to when they first came out.

[LS ROB]

Lol Nathan

[GHuggins]

If you can figure out how to do it Ed, it'll make a world of difference - even on the gen 4's. I'm known for drivability too. Near stock on 1000whp cars. Magazine cars and blah blah too Even had some cars that do the drive around to each track and then race thing. I do it by dialing in everything that I can... Have I tuned "thousands" - no, for me it's not numbers, it's getting them right... I've only tuned maybe over or around 1200 or so? Don't know, don't keep count.

I look at the torque model like this - it's the icing on the cake for a gen 4, but you kinda gotta bake the cake first. In other words one of the last things. Then any final cleanup to fueling after that as it will change fueling a small amount.

[GHuggins]

NSFW

Volume up lads
Aussie Road Rage (youtube.com)

Guess it's good that doesn't happen in the US "much". That would have been a fist fight by about 10 secs into it

[hjtrbo]

I look at the torque model like this - it's the icing on the cake for a gen 4, but you kinda gotta bake the cake first. In other words one of the last things. Then any final cleanup to fueling after that as it will change fueling a small amount.

Never heard it explained any better. This quote will be re-used.

Oh there's no doubt I'll be spending some time on this just to get a yay or nay feeling for it. But from sheer experience I'm telling you I don't know where there's going to be significant improvement. Just speaking from a point of volume I've probably tuned a couple thousand of these dating back to when they first came out.

Gotta be mid to big cam (3/4 race cam) tight converter car to notice any decent change for your first dive into it. Small cam or loose converter I don't reckon you'll notice any noteworthy improvement. A good VE table and fuel data straightens things out on those cars. Greg could disagree with me here. When I adjusted them on my car it was just so much nicer to drive around car parks. There was nothing wrong with the before, but after it was like my Nana's Mazda 3, just crispy az bro.

Guess it's good that doesn't happen in the US "much". That would have been a fist fight by about 10 secs into it

You guys have guns. If I was on holiday in the US I'd be treading very carefully lol. Think I wouldn't last long in some states if I carried on like I do over here

[GHuggins]

Ehhh. Just cause we got guns don't mean the people got guts enough to use them. I have quite a few personally, but doesn't mean I'm going to wave one around. Even with my busted shoulder I think I would clock some dumbass in the jaw first - granted I would probably go and cry or pass out from the pain, but still. It's just those who have gone over the deep end and have nothing to lose that go to the guns first and a lot seems to drive you that way here...

I dial the torque models in even on stock cam engines as long as they have had blowers or other significant power adders done, although it honestly won't change that much as the stock model is close other than in the higher rpms in those situations.

I only adjust the baro tables when a different tb is involved as they are part of the throttle model. Most of my reasons come from playing with and finding out bad things can happen in "certain" circumstances and I want a car to have near stock safeties even if they make a 1000hp. I actually wrecked a shop car back in the day because of those baro tables not being touched!!! Was doing drivability on an 1100ish hp car lugging it in 5th gear at about 1200 rpms when it started drizzling rain. Well I learned 2 things that day. Drag tires release oil when they get wet and when a big tb with a blower pulling air through it is under a lug and you let off and the tires break loose, well that don't mean the throttle will immediately return to idle if the baro tables aren't right, especially with a 108mm tb and a PD blower...... Car actually revved up a touch and it was like I was on ice as I lost all traction and because I was heading up a hill, the front of the car stopped and the rear came around. Happened in a split second but caused me to hit the guard rail even going somewhat as slow as I was. The sonic airflow or throttle air flow equation was completely skewed at that point.

A lot of mine also comes from me doing primarily complete torque controlled platforms now and while going through the ringer working out every possible problem an underlying system may influence, so I understand more and more how the torque model plays into the control of a torque controlled platform. A gen 4 isn't a "complete torque controlled" system, but it's close enough that I find it to be important to dial in. You can screw up just as much as you can help, so I recommend if you don't know what you're doing and what you're currently doing is good enough, then probably best to leave it alone. At least until the tools done and tested

[Allen Vos]

Honestly, I wouldn't try to mess with the torque tables this early in the calibrating stages. If you haven't driven the car yet and are making all of these changes, then its going to be real tough to chase down issues that may or may not come up when you do actually get to log a drive.

Oh I'm not planning on it. lol In my state of Hibernation (Canadian Winter) I'm actually trying to learn about Virtual torque before I set anything.

I played with it a bit to reduce the idle blip I was fighting but that's about it. It stays put for now. lol

[Allen Vos]

I'm sure you're smart enough to handle the conversion between grams and mg in your head without to much trouble

The 9-10g/s is your 'mass airflow'
The 800mg is 'cylinder air mass'

Cylinder air mass = MAF x 15 / rpm

Ha Ha might be hard to do this morning lol.

I'm definitely crawling on this Virtual Torque thing, but it makes a lot more sense having the Cylinder air mass formula now and how it relates to Mass air flow.

I haven't even done anything in the scanner with regards to Virtual torque.

Just trying to take all this in and not get confused lol

Thanks for modding those air mass tables for me. I noticed from 1000 rpm and lower was changed from 0 mg to 800 mg

Did you just multiply all 3 columns by .8 as you were saying earlier?

And leave that poor AI Bot alone, he's gonna be playing with me in the sandbox LMFAO!!