NefMoto

Hi,

I've a question about EGT limits if there is no EGT sensor at the engine(motorcode AUQ). If I know well at this case only modelled EGT available. I set the TABGSS to 1000 celsius but the enrichment comes at 980. The TABGBTS is set to 680 celsius. Which is the limit for the enrichment when there is no EGT sensor, and how can I set the limit upper? Or try to config the EGT modell with some parameters?

Thanks

What do you mean by limit upper?

You mean when BTS is enabled based on modeled EGT? You kind of already answered your own question :)

The current problem is that the modelled EGT reaches the 980 celsius and fuel will be rich. I want to set the 980 celsius limit upper. I set TABGSS to 1000 but there is no influence to the enrichment limit. I know the best would be if wet put an EGT sensor into the system and try to adapt the ECU EGT model to the real EGT.

Hint:

I've attached the log. My problem is that I cannot set the 980 celsius limit upper.  Until that point the software is running from LAMFA. KFFDLBTS is set to 0.

What is TABGBTS set to? BTS is triggering well below 980

What do you think KFFDLBTS=0 does if KFLBTS isn't 1?

Also, you are out of wgdc, pull back boost req up top or you might eventually throw a pos deviation code.

You have the modelled EGT in KFTATM relative to load and rpm.  But on a tuned car the model doesn't fit any more. You have to adapt the model to your tuned engine.  First I would measure your real egt and calibrate KFTATM better. Do also change ZATMATL to fit your real MAF flow better.
TABGBTS will trigger the BTS enrichment based on the calculated KFTATM which is also corrected further (see funktionsrahmen)

I hope this helps you
Andreas

TABBGTS is set to 680 celsius
What I can see at the log the lambts_w is 1 until 940 celsius. lamsbg_w is 0,812(this is my lamfa value) until 985 celsius. So I cannot see when the KFLBTS table is used.

For the boost I don't have deviation code. My turbo is very slow at lower RPM and it cannot reach the required pressure. I hope it will change with a turbo repair.

Thanks. I will check these variables how to set.

flbts_w may also be delaying activation of BTS.

It can't reach required pressure at high rpm either.

By and large, you should not let boost deviation happen, code or no code. That way if something goes wrong, it will be reflected in deviation.

With FBSTABGM 0 the entire BTS function is disabled.

I don't see a good reason for him to do this, since he can just adjust the BTS tables to do what he wants.

The question is why the onset is delayed so far above TABGBTS

FWIW, I just zero out the factor table and model KFLBTS to mirror LAMFA It's not exact, but my AFR's always seem to be right where I want them to be when I do it that way.

That approach melts the engine on a bad tank of fuel, no thanks.

But it is no different than

Hence both are a horrible idea.

What could be the problem when it's not reach the required boost? Is it better when the required boost under the current?

My mechanicher wanted to run from lamfa  not from bts. That's why we would like to use bts only what the EGT is too high.

BTS should almost always be always in use, but tuned so that it only kicks in with bad fuel or indeed when EGT is high.
Killing the entire thing until a certain temperature is a really bad idea, because by then it will be far too late. BTS is there to stabilize before it gets out of hand.

I accept this. The problem is that the tabgbts is 730 celsius from the beginning. So I will always run from the BTS table with full throttle. I will check the EGT modell parameters. I don't know what could be the difference between the current model and the real EGT.

Set TABGBTS to 980 , then BTS will trigger when modelled EGT is above that value
there is also TKATBTS , set this to the same.  BTS will also trigger to protect the cat.

Modelled EGT comes from  KFTATM, so  put in lower values .
But KFTATM is for lambda = 1 at optimal iginition angle, there is corrections for richer lambda in  KFATMLA (so lower by 50-100 degrees for richer lambda) and other corrections for  non optimal ignition angles (KFATMZW)

Then there are several time constants that defining the transfer of heat to exhaust pipes / cat. Those dipend mostly on the gas flow.

Best is to measure EGT and put in measured values  into KFTATM to have a proper starting point.

Good luck

980C is way too late. You realistically never want to exceed 1000C pre-turbo.

730C is not on all the time, it will be on from only longer WOT runs where you need it... log your actual tabgm and so on.

There's a lot of basics missing here, a lot of suggestions without EVER asking "why?" or "how?".

An engine's ability to heat it's cylinders is directly proportional to the amount of flow through the engine. Until you get to very rich mixtures that help to cool.
That means that at 3500 RPM you are almost never going to actually have EGT problems vs. for example 7000 RPM. This is because the engine cylinders have twice as much time to cool between two power strokes, and there is also (very roughly, depends on curve) half as much fuel burned. So literally, as your RPM's go up your EGT gain increases very quickly, and as RPM's are lower it decreases quickly.

The same idea should be applied to BTS tuning. Tune it so that at lower RPM's it only actually kicks in if there is a bunch of timing retard. This can be controlled with the base delta and KFFDLBTS.
Other than that with normal fuel lambts should be very close to output from LAMFA throughout the range. Actually as EGT heats up, backpressure of exhaust gas also increases and there is more timing pull, so having KFFDLBTS at reasonable values will richen up your mixture as the engine gets hotter.
If you want some additional safety you can set FBSTABGM to be a little more aggressive after a certain temperature. For example 1.01-1.02 at 900C calculated and 1.0 below that.

Not using BTS at all or not using KFFDLBTS is a great way to melt the engine on part throttle on the autobahn when you are going fast, but you are not triggering LAMFA and running lambda 1 with a bunch of boost. Or if you get some bad fuel.

To do these things correctly at least some knowledge about the internal combustion engine process is required. I've seen outright ridiculous "advice" posted in this thread, which really makes me scratch my head...

Thank you a lot for this summary. What is the diff between tabgm and tabgbts? I've just realized now that I'm log only the tabgbts value currently. Which is the trigger value for BTS table?

Hi,

What is the difference between the tabgm and tabgbts? I've logged these and there is 150-200 celsius difference. Which is the input for BTS tables?

Thanks

I kept telling you this over and over again.

Not sure why you ignored me.

https://s4wiki.com/wiki/Tuning#LAMBTS

Thanks. So tabgbts_w is the input. But what is the difference compare to tabgm_w? I don't have EGT sensor at my car but tabgbts values are very high. I've checked tabgm and it shows more realistic values.

Your question really should be what is the difference between tabgm_w and tabgkrm_w, since SYTURBO and CWLAMBTS.2 select which one ends up in tabgbts_w

I don't know what the difference between the two EGT models are. The FR has more details but I've not looked more closely.

Looks like kr stands for "Krümmer". No clue what elbow that is referring to.

TABGKRM_W ATM AUS Abgastemperatur im Krümmer aus Modell
TABGM ATM AUS Abgastemperatur vor Kat aus Modell

Hi,

I've tried to find a lot about BTS tables. proj said that FBSTABGM 0 disable the BTS. I've checked my original software and FBSTABGM is 0 at 920 celsius. Does it mean that until 920 celsius the BTS is disabled?

Yes

Btw krummer means exhaust manifold(abgaskrummer). One means modelled temp in exhaust manifold ,one is modelled temp at kat.

Huh I'm a little bit confused. So the BTS is disabled until 920 celsius, but we have a limit in TABGBTS around 400 celsius. Maybe my map is wrong or the original software working with that values? Sorry if this a stupid question but I don't really see the point when TABGBTS has any influence.

The function is active and running, but enrichment happens after 920C. Nothing special there.

Ok but the enrichment is what we need to cool down the engine. So until 920C I cannot melt the engine?

The FR illustrates the difference between TABGBTS and FBSTABGM perfectly. You really ought to take a look, because we're just running around in circles here.

I switched back FBSTABGM to the original version. I made a log and the problem is that from 5200 rmp the bts is enabled. I made only this WOT, and before that I run with 90kph. I uploaded the log. What can I do? I have k03s turbocharger with 60mm downpipe and cat. Does the EGT values look good or I should change the EGT model parameters? I know that I have overboost, I will change the duty cycle of N75 valve.

Thanks for the help

If modeled EGT gets to 900C you probably want BTS to activate.

You can lean out BTS if you want, but increasing the BTS threshold is likely not a great idea.

You really want it activating even if LAMFA isn't asking for fuel.

Yes I want to protect the parts. The question is that the model is still good and I have more than 900C before the cat or I should change the model parameters to get more realistic value. From the log what I can see is that before the cat the temperature is over 900C but in the exhaust manifold maximum is 800C.

Absolutely doable but ideally you'd want to wire in a real pre-cat EGT sensor before messing with the model.

Yesterday I made a log from my friend's car. AUQ motorcode with a software modification and with a fmic. He has this software since 2010. He does not have BTS and the engine is still ok. 80000km with this kind of software.

I'm assuming the enrich in that log is from LAMFA and not BTS.

12 (.82) isn't bad, my own bts doesn't go below 11 AFR (.75)

BTS is for long distance autobahn part throttle cruising at high speed where LAMFA is requesting 1.0

Just because somebody else's car is "fine" doesn't mean you dont need BTS.

I know that if something is working in one car it does not mean that it is good for the others. Just it was strange for me that car can run since 2010 without any issue, and there was not used for cruisin.

I'm saying that high speed part throttle cruising with LAMFA 1.0 and no BTS is going to cause very high EGTs.

Something your typical driver may not see, and something a track car will NEVER see.

Side note: what the hell is that requested boost pressure line..

Seriously. LOL @ trusting that dipshit yahoo.

I don't undestand that software. It requests the maximum boost, but it is running lambda 1 until 3000rpm WOT

Who even made that soft...

Anyway what is the "point" of this thread. As explained pretty well, BTS is used for EGT temp control or can be used as boost fueling , or it can be used as both in conjunction with lamfa(s4wiki) etc. Do you want to use it or not then?

Currently I'm using BTS for EGT enrichment. A little problem is that at WOT my calculated EGT reach 920C@5200RPM and my lambda goes down to 0.75 beacuse of the enrichment.

Nothing wrong with .75

change it to .8 if you like.

I know that it is not wrong. Just a little bit less power and my injectors are running full capacity at high rpm with 0.75 lambda.

Hi,

why is bts triggered in my case at ~710?
TABGBTS is set to 820
FBSTABGM is 0 at 700, 0 at 820, 1 at 860, 1 at 900
KFTATM is stock
TABGSS is set to max value of 1229
i'm on e85 so egt is under 800

shouldnt be related to my dying egt probe