Help me understand my engine map (1.9L ALH) (Or I intend to do stupid things)

robnitro · Aug 25, 2014

Target boost is the boost your ecu will try to get for x Iq driver wish and Y rpm.
Boost limit is for max safe turbo limits, including info for higher altutudes.
So if limit is 2200 and target asks 2300, you get 2200.
If you go up in alt, denver is around 850 mbar, you would get even less if your tune compensates for that.

See my post above for my settings on vnt17, and see how at altitude, the limits change, even the rpm shifts where max boost can be obtained (due to less mass flow- you dont hit the choke limit as fast).

[486] · Aug 25, 2014

robnitro said:
Target boost is the boost your ecu will try to get for x Iq driver wish and Y rpm.
Boost limit is for max safe turbo limits, including info for higher altutudes.
So if limit is 2200 and target asks 2300, you get 2200.
If you go up in alt, denver is around 850 mbar, you would get even less if your tune compensates for that.

See my post above for my settings on vnt17, and see how at altitude, the limits change, even the rpm shifts where max boost can be obtained (due to less mass flow- you dont hit the choke limit as fast).

yup, less boost as the p/r across the compressor goes up quick as the atmospheric goes down
I left my maps stock in the high altitude sections. This thing will live its entire life at 800 feet or so, so stock maps is just fine if it ends up in colorado once.

So if the target map is what is controlling commanded boost, I assume you have to mess with the N75 map as well to coincide, or does the computer just actuate the N75 solenoid to get the target boost, and the n75 map is just the maximum vacuum limit that the N75 can apply to the VNT can for that given throttle position and RPM?

robnitro · Aug 26, 2014

The n75 map is a base point the ecu aims for xx boost.
I think its followed only if boost is near requested (steady state).
Below a certain IQ, its always sticking to that table. So you might want 1100 mbar at 10iq but are getting 1600 mbar- that n75 table adjustment helps a lot there.

But there is a PID control of boost when transient.. when you mash the throttle

5 tables (some others I didnt include but nobody seems to mess with), all are 2 dimensional
P
I
D (these 3 are confusing axis in l/h?? and values in ??!?)
n75 min (table w mostly values of 500)
n75 max (table w values from 8000 to 5000 or so)
the min/max tables have rpm as X axis.

The n75 max is the only one I touched to reduce boost spikes around 2200-3000 rpm.
It was set to 7500 there abouts (25% if using what vcds reports) and I made it 7200 or so (28% vcds).
So when target doesnt meet request, that value is the max the vanes can close. Sometimes less is better for spool up too, less choking the engine by too much EMP at spool up.

Feinstaub_CH · Sep 2, 2014

Hi all

Thats how the passat goes with the SOI postet on earlier pages.
http://www.youtube.com/watch?v=gRbtjOrNuJs

Stock Turbo Map - no smoke - around 150ish horses.

Regards
Branislav

Feinstaub_CH · Sep 4, 2014

Hi all

Can you help me understand - my fuel consumption rises and rises, now I'm around 29.4 mpg us, which is for my understanding way to high.

I am driving normally, i do WOT to get to my speed then i'm changing to the highest gear, mostly i'm in the upper gears.

I did a chiptune to 160is horses, advancing SOI map "which should reduce fuel consumption"

Now comes my concern, car was standing 6 years without starting up the engine, is it possible that the pd-nozzles are worn out or somehow other defective?

Car is an AVF TDI, 4 motion, no comfort option exept of A/C.
-no visible smoke at WOT
-car is running very well

Regards
Feinstaub

dieseleux · Sep 4, 2014

Air leak between turbo and engine have big impact on comsumption, PD engine have some trouble with intake inlet tube.
Wheel pressure and Wheel alignment is also on check list to do.
Do this before chip modification.

Dieseleux

Feinstaub_CH · Sep 4, 2014

dieseleux said:
Air leak between turbo and engine have big impact on comsumption, PD engine have some trouble with intake inlet tube.
Wheel pressure and Wheel alignment is also on check list to do.
Do this before chip modification.

Dieseleux

Thanks Dieseleux

Will check for leaks

Tyrepressure and Wheel alignment are OK - checked them a couple of weeks ago.

Many thanks
Branislav

Enabled · Sep 25, 2014

Sbeghan said:
There are two limits on boost that I have found. The SVBL (Single value boost limiter) is a single value (1990 mbar). There is also the Boost Limit Map

I think that hitting the boost limit map will trigger limp mode. Note that there is an atmospheric pressure section in the chart. Yes, the engine would be ready for Mars or Venus if you could just transport it there. Except, that the maximum boost pressure in this chart is flat. a 2.15 ratio would be fine at 1 ATM, but it is unacceptable at higher elevations, easily pushing the turbo into grenade territory at low RPMs.

So I've been learning from this thread and other forums on how to tune my car.. (Which is going excellent at around 145-150hp, ~260ft lbs torque, all safely scrutinized for anything that looks bad)

Regarding the above map... I used to believe it was a mistake on VW's part as well, however... I found this map:

I'm not sure what it does, it's at 0566B8 (manual codebank) and 0766B8 (auto codebank).
This looks very suspicious to be a negative compensation for atmospheric conditions? No?

Anyone have more info?

Thanks.

[486] · Sep 25, 2014

Enabled said:
I'm not sure what it does, it's at 0566B8 (manual codebank) and 0766B8 (auto codebank).
This looks very suspicious to be a negative compensation for atmospheric conditions? No?

From the values I'd say that it cuts fueling at high altitudes to keep the turbocharger from spinning too fast.

There's an atmospheric boost limiter map as well, but you'd still get some bad boost spikes if the fueling wasn't reduced to suit.

JFettig · Sep 25, 2014

Smoke limiter maps take care of the fuel issue

[486] · Sep 25, 2014

JFettig said:
Smoke limiter maps take care of the fuel issue

That is relative to mass flow, though.
Sure, you get the same result as mass flow is limited by the reduced boost target values at high altitudes (in every stock map I've seen, it doesn't really do much until you hit 600mbar, iirc), but you'll still get spikes of high boost if the fueling rate is high.

Same as boost spikes on a little VNT15 turbo, the vanes can not react fast enough to deal with a huge change in fueling very effectively. Limiting the fueling makes it a little slower to build boost, so the vanes can keep up a little better.

A spike up to 25 PSI might not do much at sea level (14.7 psia), but at 600mbar (8.something psia) the pressure across the compressor wheel is a lot greater.

ETA: Oh! Did you mean the torque limiter maps? Those can be set up to cut fueling at higher altitudes as well, I don't remember seeing any significant reduction in fueling on them though.

robnitro · Sep 26, 2014

I used the torque limiter values for altitudes based on my ideal expected airflow for what boost at that alt in boost limiter map.
ex: 1.5 bar at 2000rpm at 800mbar, its ideally 480x1.5=720mg/s air. lets say smokemap says 42mg/s fuel... I'll put 46 there for leeway, to let the smokemap manage.

Enabled · Sep 26, 2014

In regards to my post at http://forums.tdiclub.com/showpost.php?p=4625613&postcount=338

Here is the atmospherical limiting map for the ASV, which accounts for pressure changes in that map:

And I have found no other maps in the ASV tune as in post #338, to potentially compensate for lower atmospheric pressures.

FrankTDI · Oct 15, 2014

Hi,

thanks for all the information in this topic, i'm also one that experiment with VAGEDCSuite.
So my question, is there any way to name/specify useful maps that i found by searching around in the 'unkown maps' in VAGEDCSuite ?

Enabled · Oct 15, 2014

FrankTDI said:
Hi,

thanks for all the information in this topic, i'm also one that experiment with VAGEDCSuite.
So my question, is there any way to name/specify useful maps that i found by searching around in the 'unkown maps' in VAGEDCSuite ?

I'd like to know this too, actually. There are some useful maps that should be named.

TDIJetta99 · Oct 18, 2014

unfortunately there's not a way to do it.. I'm pretty sure it was an open source program so I'm sure someone can edit it, but I don't even have the slightest idea where to start with that..

robnitro · Oct 19, 2014

It seems a bit tricky... I'm technical with computers but I have no idea on programming.
If you do, check source folder inside the vagedcsuite folder.

One little example I was looking at, but can't seem to figure out the way it works:
Its not even right for the GN 2003 ecu for example with the n146 pump voltage not detected....

public override void NameKnownMaps(byte[] allBytes, SymbolCollection newSymbols, List<CodeBlock> newCodeBlocks)
{
SymbolAxesTranslator st = new SymbolAxesTranslator();

foreach (SymbolHelper sh in newSymbols)
{
//sh.X_axis_descr = st.TranslateAxisID(sh.X_axis_ID);
//sh.Y_axis_descr = st.TranslateAxisID(sh.Y_axis_ID);
if (sh.Length == 544)
{
if (sh.X_axis_length == 16 && sh.Y_axis_length == 17)
{
if (sh.X_axis_ID / 256 == 0xE0 && sh.Y_axis_ID / 256 == 0xC2)
{
sh.Category = "Detected maps";
sh.Subcategory = "Fuel";
sh.Varname = "N146 Pump voltage map [" + DetermineNumberByFlashBank(sh.Flash_start_address, newCodeBlocks) + "]";
//sh.Correction = 0.001221001; // ?1.221001
//Todo: N146 correction factor EDC15C
sh.X_axis_correction = 0.01;
sh.Z_axis_descr = "Pump voltage (V)";
sh.X_axis_descr = "IQ (mg/stroke)";
sh.Y_axis_descr = "Engine speed (rpm)";
sh.YaxisUnits = "rpm";
sh.XaxisUnits = "mg/st";

Enabled · Oct 20, 2014

robnitro said:
It seems a bit tricky... I'm technical with computers but I have no idea on programming.
If you do, check source folder inside the vagedcsuite folder.

One little example I was looking at, but can't seem to figure out the way it works:
Its not even right for the GN 2003 ecu for example with the n146 pump voltage not detected....

If I have some time, I'd love to help build an XML for TunerPro, but that means doing all the work that the Suite has mostly done.

ausiaslp · Oct 25, 2014

Sbeghan said:
...
Of course we need to limit the boost and I'm sure you've seen this VNT15 compressor map image passed around here (its popular).

For simplicity's sake the Y axis is roughly ATMs or Bar. The X axis roughly corresponds to RPM / 500 (so 2000 RPM is about 4). Someone has drawn a line at 2.1 bar, I don't know why - the max on the boost target map and SVBL is 1.95 bar and the Boost Limiter Map is capped at 2150 (you'll see that soon).
The correction for the air flow (30C, .96 bar) puts the density of air at 1.104 g/L. At 2000 RPM and perfect flow at 0 boost we would flow 1900 L of air per minute or 2.097 kg/min. I think assuming at least a 5% inefficiency in air flow (for a safety margin) is being generous, so therefore, assume the bottom number is RPM/500.
...

I thought that there were something wrong with this numbers. But I did myself the calculation of flow and final figures are correct. it's only that seemed like you were taking 1.9L capacity by revolutions that is not in general the correct way.

According to this explanation max torque with max stock boost is in a non optimal zone and also with risk of overboost and turbo failure and max power figure is to the right far away the sweet spot, in the surge zone.
It doesn't feel right. ¿don't?

But it is very intersting your post and is very kind to share your guessing and doubts. I spent a lot of time doing my own R+D it is a pitty not knowing the existence of this post before.
I'll keep reading.

I have an european stock AHF (your ALH engine is an ASV 110 hp engine downrated, and ASV is an AHF engine with Euro 3 emissions instead of Euro 2).

Do you think is safe or possible to build up the boost to 2 bar at 1250 rpms or 1500rpm? or it will be very smokey exhaust if done.
I'm in the way to try that but my cars ECU can't be OBD flashed. I need to do more R+D.

thank you.

robnitro · Oct 25, 2014

Here's my calcs from a while back for VNT15 in absolute pressure, which the ecu uses.

Ideally, it can do 2.44 bar midrange, which is 21 psi gauge.
I know some people ran the vnt15 to around 20-21 psi fine... I had one that was spiking to 24 psi before I knew how to fix the actuator, lol.

BTW, even the stock ecu tune is not right with the surge line- they ask too much boost down low- and the boost limiter doesn't limit it either there. The TDICLUB faq even explains you don't want more than 7 psi at 1500 rpm (which is 0.5 bar gauge or 1.5 bar map).

TDIJetta99 · Oct 26, 2014

^ Go ahead and tune a stock hardware ALH boostmap like that and see how bad it runs at low rpm at the top of a normal hill LOL.

Also, if you sustain 21psi from 3250-4500 for any length of time you'll be unpleasantly surprised when it spits parts out.. It'll take that for a little while but failure is inevitable..

[486] · Oct 26, 2014

TDIJetta99 said:
Also, if you sustain 21psi from 3250-4500 for any length of time you'll be unpleasantly surprised when it spits parts out.. It'll take that for a little while but failure is inevitable..

Think feeding 5-8 PSI into the VNT-15'll remedy that issue a bit?

Could see it doing nothing, as the air's more dense and therefore the load on the shaft would be more or less the same...

TDIJetta99 · Oct 27, 2014

I don't think it's worth the trouble when there are other turbos that work so much better.. The 17/22 can make as much boost down low as a VNT15 and is almost as responsive when set up properly. Good for a LOT more power, and it's more durable..

Enabled · Oct 27, 2014

TDIJetta99 said:
I don't think it's worth the trouble when there are other turbos that work so much better.. The 17/22 can make as much boost down low as a VNT15 and is almost as responsive when set up properly. Good for a LOT more power, and it's more durable..

So *IF* (knock on wood) my VNT 15 ever goes out, I should skip the VNT17, and go to the 17/22? Cost difference? What about these newer generation turbos? I realize that this conversation appears all over these forums, but since you brought it up...

TDIJetta99 · Oct 27, 2014

The newer generation turbos all require a custom manifold and custom pipework.. the 17/22 is a bolt on replacement for a vnt15 and is more responsive than a VNT17 when set up properly.. I've put them in otherwise stock ALH cars and you can't tell the difference other than the sound.. Some nozzles and a tune and you'll have a solid 150hp and more reliable than stock..

TDIJetta99 · Oct 27, 2014

If cost is an issue just put a new VNT15 on it.. they are stronger than the original ones and there's no guesswork at all..

Enabled · Oct 27, 2014

Thanks for the info. I think I already have about maximum fueling I can get from my pump pushing through the PP520's. I set up my fueling for 50mg of fuel, unless it can give more (stock 10mm pump and PP520 nozzles)? I'm not thoroughly sure about that.

Knowing what is reliable and will work similar to this turbo, or slight upgrade is good to keep in mind if ever the need.
It is my daily beater car.
I've put 40,000 miles on it in the past year since I bought it. I want it to be as reliable as possible.

robnitro · Oct 27, 2014

TDIJetta99 said:
^ Go ahead and tune a stock hardware ALH boostmap like that and see how bad it runs at low rpm at the top of a normal hill LOL.

Also, if you sustain 21psi from 3250-4500 for any length of time you'll be unpleasantly surprised when it spits parts out.. It'll take that for a little while but failure is inevitable..

You know the tdifaq says no more than 7 or 8 psi at 1500 rpm, because of surge?
The 21 psi limit is from the wheel speed. In my sig you see even the vnt 17 can do more than "24" psi. Not just the calcs show it, but majesty78 in europe confirmed it.
Wheel speed or crazy spooling spikes kill turbos. Thats why its not a good idea to try to get full boost below 2k. But its always put on the driver, as if them mashing the peda is something that the ecu tune cant protect from.l

Problem is that most tunes Ive seen in the past dont really use the altitude (boost limit) map. So go to 5k feet, and even 18 psi on a vnt15 is too much!

And at altitude the surge limit stinks more... lasts more into the mid 2k rpm.

octy900 · Oct 27, 2014

Mate can I give you advice.take your msp and post it on ecuconnections.com under rate my tune.
Guys on here are ok but thats thee place for rating/sorting your map. No offence guys

JFettig · Oct 27, 2014

robnitro said:

The units on this thing are WAY off. There is no way you'll get 24lb/min out of a vnt15. The GT1749VC is around 22-24lb/min.

Help me understand my engine map (1.9L ALH) (Or I intend to do stupid things)

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