1.8T M3.8.3 tuning

[Thomas_20VT]

Hello,

As I have recently acquired a A3 AGU 1.8T 150hp and can't leave anything stock calibration-wise, I began to study Motronic M3.8.x that can be found in 1.8Ts AEB / AGU and AJL.
Those are basically all the 1.8Ts which are throttle cable driven (as opposed to DBW which are ME7.x)

I propose this thread as I will learn more about this ECU and tuning it so that everyone can benefit from it. As there seems to be professional tuners (companies) on the forum, please tell me if some infos are not well seen to be shared here.

First things first:
Those "old" Motronics are doing almost everything based on MAF info (pay attention to vacuum/boost leaks and that your MAF and O2 sensor are in good condition). All those infos are from some documentation found either through official documents or on the web.

What this software does is convert MAF into LOAD => Tl in milliseconds

Q: airflow | n: engine speed | Ki: injector constant
LOAD is the theoretical Injector Time needed to reach Lambda= 1 with the current injector setup

Injector opening time is then corrected (calculated) to take into account the varieties of engines (fuel trims...) and operating conditions by introducing MULTIPLICATIVE factors to correct the theoretical injector time to the ACTUAL time for injection (Ti) needed at that instant and an ADDITIVE factor (Tv) is added to compensate for the different injector latency time based on battery voltage (known as TVUB on ME7)

I can continue sharing some info on M3.8.x if this kind of old softwares are still interesting for some of you willing to understand what the ECU does or to tune their engine themselves

 

[<tuffty/>]

Nobody touches ME 3.8 these days so fill your boots dude... I am sure it will benefit some people but you may need to take a less technical approach to presenting your information as to make it a little easier to understand...

Not touched ME3.8 myself and not much in the way of decent knowledge out there... good luck

<tuffty/>

 

[<tuffty/>]

...oh one thing though... no open discussions over pirated software or links to anything deemed illegal...

<tuffty/>

 

[Thomas_20VT]

Thanks tuffty for the hints. I will wait for some other people to chime in as it takes quite some time to explain it. If useless, I will save the time...

Short comment: it's M3.8 and not ME3.8 where 'E' refers to electronic throttle (DBW)

 

[<tuffty/>]

Short comment: it's M3.8 and not ME3.8 where 'E' refers to electronic throttle (DBW)

See look... you are contributing already... everyday is a school day

I'll stick to ME7.5 I think...

<tuffty/>

 

[Thomas_20VT]

I would also stick with ME7.5 but I do think that people switch from M3.8 to ME7.x only because of lack of knowledge about those old ECUs.

From performance point of view, there is nothing that can't be done with M3.8 compared to ME7.x apart if you are deep into fancy tuning features which people seem to love for whatever reason nowadays such as launch control, anti-lag, no-lift shift and gargles

 

[tcg]

See look... you are contributing already... everyday is a school day

I think I've still got my old school slide rule in the loft,better go and dig it out after studying those equations

 

[badger5]

I would also stick with ME7.5 but I do think that people switch from M3.8 to ME7.x only because of lack of knowledge about those old ECUs.

From performance point of view, there is nothing that can't be done with M3.8 compared to ME7.x apart if you are deep into fancy tuning features which people seem to love for whatever reason nowadays such as launch control, anti-lag, no-lift shift and gargles

1000cc injectors 4" intake?, GT35 turbo, external wastegate, 2.5bar boost? - Would you try m3.8 on that?

 

[Thomas_20VT]

View attachment 144257

Don't be afraid, it's rather (very) simple. LOAD is injector opening time to reach lambda=1 and Tv compensates for injector latency (injector is supplied but does not inject). When you are in closed-loop lambda regulation with O2 sensor feedback, nothing else is taken into account. You see: simple!

Now, the tricky part, when load threshold for lambda control is overcome, ECU uses some multiplicative factors. 95% is given by the so-called Lambdakennfeld bei Teillast MAP which gives a factor that can be almost seen as an AFR target (example from my AGU below)

If there are some questions, feel free to ask as it could also help to gain some more knowledge

1000cc injectors 4" intake?, GT35 turbo, external wastegate, 2.5bar boost? - Would you try m3.8 on that?

Don't get me wrong, I would still go with ME7.5 with 5120 hack as it's more up-to-date (and documented) to do so but I don't think it's impossible with M3.8. But, time consuming that's for sure!

 

[Stuart B]

I'm certainly only a beginner but... isn't it cheaper and simpler in the long run to install a standalone ECU as Prawn has done? - or just buy a bigger car? I thought a wideband ECU exposed the additional data required for mapping experts.

 

[Thomas_20VT]

A bit off-topic but I will try to answer with my personal view:
- cheaper: No. How could it be ?
- simpler: Yes, for sure! (if you don't want to lose your time in understanding how your original software works)
- weaker: Yes also. Standalone ECU are not offering as many features for monitoring ,safety, driveability, environmental compensations as OEM ones unless you go with MOTEC or those really expensive aftermarket ECUs

Still, ME7.5 is the way to go but if you're on the cheap, you can get same results with M3.8 and tune it yourself. Fairly easy, all you need is vagcom, a wide-band lambda controller and optional (but recommended) an EGT gauge (pre-turbine)

 

[Stuart B]

you will make some good business in this assistance as many tuners stopped supporting the M3.8 ECU - even nefmoto has very few M3.8 threads about 9 in total

ME7.5 is 17 pages

it's crazy really as people have been remapping cars for years, I'm surprised VAG made it so difficult on the early versions. best of luck, there are occasional requests for tuners of these, I think someone changed their whole car because they couldn't find anyone to help them.

 

[Thomas_20VT]

I know those ECUs are not supported and I am not against a little bit of challenge

BUT I don't plan to do any business in tuning those old motronics. My aim was more to help people willing to do their own remaps on M3.8 and gain some more knowledge from this forum as there are quite a lot of 1.8t gurus here!

 

[antwan64og]

As there are no official documents available on how the maps interact with each other there is some disagreement on what is what.

2 things I have not found,
is there a switch for turning the O2 feedback off for tuning or is it hard coded?
Is there a directory so that blank parts of the chip can have larger maps written in, like they do on old bmw motronic to change map resolution.

Most of the professional tunes I have seen obviously have no clue, they do not rescale anything. They raise limiters and massage KFLF and KFZW so it works but never quite right.

 

[antwan64og]

KHFM - MAF/Injector constant

KFMLDMX - MAF limit im Kg/HR

FGATO - injector constant

TLST - start fuel ms

TEMIN - min injection time

TVUB - injector voltage correction

MLHFM - rescale for new kg/h 0-5v

KFTLWS - base fuel from TPS, pre injection, in ms for 1 Lambda

KFLFLAV - map for setting 1 lambda

KFLF - adjust fuel 0-1.99

KFLDS - Boost control ; ms

KFLDTV - boost/load start to prevent overshoot

KFLUL - load/boost limit ; measured in ms - 12.75ms max

LDSMXN - Load max ; measured in ms

KFZW - Base Ignition timing


NMAXDV - soft cut limiter

NMAX - Hard cut limit


Fuelling calculated by (KFTLWS x KFLFLAV) x KFLF = fuel injected ms


Iginition and fuelling corrections also for IAT, coolant temp, barometric

 

[mogsalie0010]

Hi. I would like to know how to tune my m3.8... cable throttle and can it be done via obd

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[mogsalie0010]

Im not to keen on doing the equations...lol.

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[mogsalie0010]

Im the type who like to know a bit of everything.,,,at the mo im busy rebuilding my engine. I went oversize pistons, ported my head, abf fly,vr6 clutch and ko3s turbo.,, so now I would like to know how to remap.,,

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[mogsalie0010]

Oh yes injectors I changed too.,,,

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[antwan64og]

Some M3.8.3 can be mapped via OBD.
Those cars that have a wire going from pin 43 on the ecu to pin 13 on the OBD can be flashed through the port.
This seems to be present on AGU MK4 Golfs but not on all AGU A3’s which means you have to bench flash the ECU.

I use MPPS to flash the ecu and tunerpro to edit the file, MTX provide a Checksum for Tunerpro.
Some people prefer Winols.

 

[Prawn]

I seem to recall when mine was on 3.8 that Niki ran a hot wire from the battery to pin 43 when flashing maps onto it.

 

[Thomas_20VT]

I am glad you came up in this thread antwan640g! Thanks for sharing the info!

KFTLWS - base fuel from TPS, pre injection, in ms for 1 Lambda => IMO, this is more a MAP in case of defective MAF where the ECU will go to Alpha-N for safety measure with running fairly rich but enables to keep a driveable vehicle.

2 things I have not found,
is there a switch for turning the O2 feedback off for tuning or is it hard coded?

There is a curve that determines based on engine speed at which load threshold, lambda feedback is deactivated. In my opinion, you could fill this curve with very low values (0?) to disable 02 feedback

Is there a directory so that blank parts of the chip can have larger maps written in, like they do on old bmw motronic to change map resolution.

There is a MAP Look-up table with the indexes of all the MAPs (some kind of library) and you could ask for pointing to another address with free space and make the MAP the size you want if willing to get a 32x32 KFLF MAP or else. Not tried though, only theory here...

Most of the professional tunes I have seen obviously have no clue, they do not rescale anything. They raise limiters and massage KFLF and KFZW so it works but never quite right.

Because they are 'professional' tunerswho don't even take the time to open the files they are receiving from extenal companies that tuned it for them... (I'm talking for what I know so valid for France at least)

I will prepare a post about BOOST control with M3.8.x

By the way, M3.8.2 can't be flashed because the processor doesn't enable this feature but all M3.8.3 CAN be flashed. Then, as mentioned by antwan64og, in some vehicles, wire from ECU PIN43 to OBD port pin 13 is missing and can either be flashed on bench or by adding the missing wire

 

[antwan64og]

KFWTL is the limp fuel map for a defective/unplugged MAF sensor.

As stated the old AGU engines running M3.8.2 have a 28F200 chip and can’t be flashed, M3.8.3 have the 29F200 eprom which is writable.

Interested to read your strategy on tuning this ecu

 

[Thomas_20VT]

BOOST chapter

Let's start with boost control, as said, M3.8.x are not equipped with MAP sensor so everything is based on Load which is a representation of cylinder filling based on MAF sensor. To cut things short: boost is regulated thanks to MAF feedback !

Boost request (load request) is based on throttle angle and engine speed with the following map and asks for a load in milliseconds

After that, there is also a curve defining the maximum load accepted which will cap out load request. (This is comparable to LDRXN for people familiar with ME7.x and later)

Additionnally, there is another limitation based on atmospheric pressure (altitude) which in my understanding could be comparable to KFLDHBN on ME7.x and later

That's more or less the basis.

I will prepare an update for boost regulation and monitoring

 

[mogsalie0010]

Thanks a mill.,,, y not post a map file with values that you change as an example.,,,

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[mogsalie0010]

This guy Thomas is great,, and very helpfull if only there were more ppl like willing to help each other out,,all of us car fanatics,cars would be driving out in harmony making the best swoosh and woosh sounds as we go by.,,,lol.. bt on a serious super post guy.,,,@Thomas

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[Broken Byzan]

If only definition files and offsets were properly available. I see no point in tuning a narrow band, dumb as a box of rocks ECU that is at best flashable via obd by powering it up on pin 43 as Prawn has already stated. The maf stops reading as does the the 02 sensor, you are tuning for it to run off scale and hope for the best. The ECU would have no idea what to do if stuff went wrong as it would not even know.

Re scaling is not an option either from what i have read

 

[Thomas_20VT]

My goal is not to show how I tune it but more to make people understand how it works so that they can benefit from it and tune it by themselves.

Later on, I would be able to propose a short comparison between AGU 150hp and AJL 180hp (supposed to be 180hp because in reality, it appears they are dynoed closer to 163hp and map file suggests around 161hp worth of airflow...)

 

[Broken Byzan]

different cars and setups. A4 v a3, not fair comparison IMHO Longitudinal v transverse setups feature different sized turbo's, inlets, exhaust setups and even different fuelling setups $ bar v 3bar


I have not come across an TQS A4 that didn't make almost 180 in std form, no idea what ones you have seen make only 163, poor mistreated cars

 

[Thomas_20VT]

If only definition files and offsets were properly available. I see no point in tuning a narrow band, dumb as a box of rocks ECU that is at best flashable via obd by powering it up on pin 43 as Prawn has already stated. The maf stops reading as does the the 02 sensor, you are tuning for it to run off scale and hope for the best. The ECU would have no idea what to do if stuff went wrong as it would not even know.
Re scaling is not an option either from what i have read

I don't get the meaning of this comment. I understand that some people are against the idea of spending a lot of time in understanding the logic of this ECU for which information is not readily available on the internet though.

But what's the point in saying it's SH*T without knowing it?

Why would the MAF and O2 stop reading ? MAF can read with stock AGU housing and also recalibrated for some bigger diameter MAF housings and O2 feedback is disabled in full load but O2 sensor value is still recorded. Anyway, as with every narrow band ECU, you should use a wideband lambda gauge to make sure everything is fine when tuning.

Also, why re-sclaing would not be an option ?

Those ECUs are suffering so much hate but are not so dumb actually. If this thread is not interesting, I would stop sharing what I have understood so far and use my time to do something more useful then

 

[Thomas_20VT]

I was not expecting this kind of "hater's reaction" on this forum especially coming from a moderator as I understand...

It appears that I may be a fool to be spending some time working on such a dumb ECU according to Broken Byzan so let's close the thread I suppose

 

[badger5]

I was not expecting this kind of "hater's reaction" on this forum especially coming from a moderator as I understand...

It appears that I may be a fool to be spending some time working on such a dumb ECU according to Broken Byzan so let's close the thread I suppose

calm down and carry on
its interesting to read.
(I'm not a fan of this ecu either, replacing them for standalones when possible) but reading your info is interesting to me at least. every days a school day

please continue

 

[badger5]

Also, why re-sclaing would not be an option ?

MLHFM equivalent in the M3.8?

 

[Broken Byzan]

I was not expecting this kind of "hater's reaction" on this forum especially coming from a moderator as I understand...

It appears that I may be a fool to be spending some time working on such a dumb ECU according to Broken Byzan so let's close the thread I suppose

I hate the ECU from a personal level with a passion, nothing stopping you tinkering. I am expressing years worth of frustration with this ECU. Nothing is available, they don't do this, they don't do that. I was asking questions. Trying to work out what your aims were was all

 

[antwan64og]

MLHFM equivalent in the M3.8?

MLHFM is just the fairly linear MAF table with volts against kg/hr of Air.

M3.8 isn’t really comparable in anyway to ME7.
Since M3.8 is a physically based system, (that’s how Bosch describe it) how it works is wholly dependent on the sensor readings it gets.
ME7 being torque based has theoretically calculated what everything should be from the throttle angle/rpm/altitude/injector size etc so it knows as soon as anything is wrong.

M3.8 doesn’t seem to precalculate much beyond being hardcoded to achieve lambda 1 when criteria is met. So if the hardware goes wrong/leaks/sensor starts fails you have a tough time tracking it down with M3.8

 

[mogsalie0010]

Each and everybody has the own opinion and point of views.,,, bt why attack the person trying to shed some light on something that others find a problem.,, im not saying change ur beliefs but try to keep an open mind to the fact that Thomas is going out of his way and spending alot of his time trying to teach others for the good

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[Stuart B]

With Thomas knowledge he would have more traction and positive feedback from
http://nefariousmotorsports.com/forum/index.php that's a tuning forum, full of hobby tuners and experts?

Do you know Thomas? People have complianed about the ECU not the posters interest in it.

 

[mogsalie0010]

No I dont know him.,, but I know that his few points his made helped me alot.,, and made me understand my ecu alot better

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[mogsalie0010]

What would you recommend,, would it be better to just have a standalone ecu fitted?

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[Broken Byzan]

Each and everybody has the own opinion and point of views.,,, bt why attack the person trying to shed some light on something that others find a problem.,, im not saying change ur beliefs but try to keep an open mind to the fact that Thomas is going out of his way and spending alot of his time trying to teach others for the good

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Sigh, Internet gone wrong. I wasn't attacking anyone i was asking questions and stating what i had heard/found myself. I will gladly be educated by superior knowledge, but at the same time I do not want mis information spread or shared that could cause more harm than good. As you were. Knowledge is power