Pages: [1] 2 3 4
Author Topic: Trouble tuning 2.0 TSI on E85 fuel  (Read 28553 times)
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« on: December 29, 2015, 03:51:22 PM »

Hi, I've been lurking on this forum for quite some time.
It has helped me tremendously with ECU tuning basics and I would like to thank everybody that contributes here.

I have a background in tuning diesels and old school carbureted petrol engines so I thought I could try to tinker with my daily driver a bit Smiley

Engine is 2.0 TSI 200 hp CCZA and it is completely stock

I have succesfully tackled "stage 1 tune" which resulted in 260hp 420Nm on 100 octane petrol.
Now I thought I could try to tune it on E85 and I have encoutered a broblem which I'm unable to solve by myself.

I dialled in KRKATE so that idle and partial trims are all within 1.5% and car runs great except for for WOT at 4500rpm onwards.
From idle to 4500 rpm everything is fine - requested lambda follows actual as well as rail pressure and engine pulls very strong.

But at 4500 rpm something weird starts to happen.

Rail pressure follows request as it is supposed to,but injector opening time suddenly goes up and actual lambda starts to lean out to an extent that I get a nasty torque intervention - boost cut and sometimes throttle cut.
Does anyone have any idea how is this possible?
How can mixture get leaner when fuel pressure is OK and injector stays open for longer?
I will be grateful for any suggestion Smiley

Log, original and tuned file attached.
Logged
S2evo1
Jr. Member
**

Karma: +0/-0
Offline Offline

Posts: 42


« Reply #1 on: December 30, 2015, 02:20:14 AM »

You are out off fuel, You need to work on HPFP and LPFP
Logged
daniel2345
Full Member
***

Karma: +11/-7
Offline Offline

Posts: 188


« Reply #2 on: December 30, 2015, 03:26:04 AM »

You need 30% more injected fuel mass for E85, when you squeeze it even more.

Consider that in your thoughts, just a fast switch to that fuel will not work well mostly. Many hours reading needed, sometimes one ore two new cylinder heads Wink
Logged
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« Reply #3 on: December 30, 2015, 03:46:31 AM »

So is it really a hardware issue? Nobody found something i screwed up in the software?
I read somewhere that stock HPFP and LPFP combo is good for ~350hp on petrol.
So, if i flow enough air for 260hp on petrol and want to use E85 which needs 30% more fuel to achieve same lambda, that should be equivalent of 340hp on petrol (260*1,3) and therefore stock HW should be fine, although pushed to the limit.

I would understand if problems started at higher rpm than 4500, or rail pressure would start to drop when actual lambda deviates from requested. That would indicate that i reached the limit of fuelling system but none of that seems to happen when lambda starts to go way off.

Am I missing something or have I been misinformed about the capability of stock fuel system and I really need to upgrade my pumps?
« Last Edit: December 30, 2015, 03:48:45 AM by bitmap » Logged
daniel2345
Full Member
***

Karma: +11/-7
Offline Offline

Posts: 188


« Reply #4 on: December 30, 2015, 04:07:47 AM »

I did not opened your file, i speak in general.

You forgot about eficency. Lambda and Ignition eficency. You can make rough estimations like that but no layout of systems.


If you squeeze the system to get 360 HP on pump gas, eficency is bad. You will probably need 1,4 times of fuel to get stable combustion without too high peak pressure. Watch lamiar flame front velocity  charts over lambda for alcohol fuels for that.

Maybe someone on sea level on a nice cold day managed to get 360 HP out of the pump, but how sure it is that ot is always possible under all conditions?


So calculate maybe 340 Hp as maximum with 100% pump gas duty cycle. Substract 40 percent and you are already below your current power output.



Remember: i speak in general, have no experience with that engine or specific ecu.
Logged
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« Reply #5 on: December 30, 2015, 04:25:18 AM »

Thank you for your reply, I didn't think of it like that.
Speaking of duty cycle - is it possible to increase pump's duty cycle?
Mine doesn't go over 80% so that might be something to try just to see if it does anything.
I have looked torough the file but didn't find anything that would resemble "pump duty cycle map".
Logged
Lost
Hero Member
*****

Karma: +21/-14
Offline Offline

Posts: 556


« Reply #6 on: December 30, 2015, 07:55:24 AM »

Yes, if you lower the FPR pressure.
Logged
ddillenger
Hero Member
*****

Karma: +637/-21
Offline Offline

Posts: 5640


« Reply #7 on: December 30, 2015, 07:56:57 AM »

Yes, if you lower the FPR pressure.

This is TSI.
Logged

Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!

Email/Google chat:
DDillenger84(at)gmail(dot)com

Email>PM
S2evo1
Jr. Member
**

Karma: +0/-0
Offline Offline

Posts: 42


« Reply #8 on: December 30, 2015, 08:01:07 AM »

I have not bin able to look on your file, but I'm doing 320-330whp with K04 turbo on stock fueling parts and 98 pump fuel.
So you should be able to run E85 with stock turbo. As I say before you need to look on LPFP and HPFP tuning.
Logged
S2evo1
Jr. Member
**

Karma: +0/-0
Offline Offline

Posts: 42


« Reply #9 on: December 30, 2015, 08:01:51 AM »

Yes, if you lower the FPR pressure.

What!.?
Logged
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« Reply #10 on: December 30, 2015, 08:14:03 AM »

I have not bin able to look on your file, but I'm doing 320-330whp with K04 turbo on stock fueling parts and 98 pump fuel.
So you should be able to run E85 with stock turbo. As I say before you need to look on LPFP and HPFP tuning.
Could you be more specific, please?
What maps did you alter in your file that enabled you to safely run 330whp which is surely over 360hp at the crank.

I'm very new to tuning MED ECUs so only thing I was able to do was alter KRKATE and slightly increase rail pressure in part load.
I was unable to increase pressure at full load, although I modified all seven fuel rail maps and everything that even resembled a limiter, but rail pressure stayed at stock value of 150 bar no matter what I did.

I also tried decreasing rail pressure but problem remained the same only thing different was longer injector opening time, but lambda leaned out exactly the same.

Logged
S2evo1
Jr. Member
**

Karma: +0/-0
Offline Offline

Posts: 42


« Reply #11 on: December 30, 2015, 08:49:56 AM »

Could you be more specific, please?
What maps did you alter in your file that enabled you to safely run 330whp which is surely over 360hp at the crank.

I'm very new to tuning MED ECUs so only thing I was able to do was alter KRKATE and slightly increase rail pressure in part load.
I was unable to increase pressure at full load, although I modified all seven fuel rail maps and everything that even resembled a limiter, but rail pressure stayed at stock value of 150 bar no matter what I did.

I also tried decreasing rail pressure but problem remained the same only thing different was longer injector opening time, but lambda leaned out exactly the same.






Sorry I'm home so don't have my winols her, I'm back at work on monday then I can take a look on your file.
A note is that you can't have long injection times, you should stay under maximum 9ms. Also you should log your low fuel pressure with a external gauge.
« Last Edit: December 30, 2015, 08:55:31 AM by S2evo1 » Logged
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« Reply #12 on: January 02, 2016, 09:42:55 AM »

So, I've had couple of sleepless nights over this, but I can now proudly say that I solved the issue Grin

Problem indeed was in HPFP and LPFP calibration.
Firstly I increased LPFP duty cycle but that has helped only slightly. (Note: in VCDS - Advanced measuring values there is a "group" with Rail press spec., Rail press actual and fuel pump duty cycle. Spec and actual are values for high pressure fuel but said duty cycle is low pressure pump duty cycle. Maybe this is common knowledge but it sure had confused me at first.)

Then I tried to increase Rail pressure but it never went over stock 150 Bar no matter what was specified in the map. I increased every limiter I could find but none of it had any effect.
Then I found out that "main" temperature dependent fuel pressure limiter was somehow screwed up in the damos so I altered it directly in hex code and now I finally had 170 Bar of rail pressure which fixed my fuel delivery Issue.

Now, (apart from slight dip in rail pressure around 3000 rpm) I have stable fuel delivery throughout the rev range with reasonable injector timing so it seems that it really is possible to support equivalent of 350 hp on stock hardware Smiley
« Last Edit: January 02, 2016, 09:46:34 AM by bitmap » Logged
bitmap
Jr. Member
**

Karma: +2/-2
Offline Offline

Posts: 28


« Reply #13 on: January 02, 2016, 12:53:07 PM »

It appears I celebrated prematurely.
Apparently rail pressure request or some kind of limiter is gear dependent or something like that, because in 4th, 5th and 6th gear everything is fine, but in 1st, 2nd and 3rd gear rail pressure request stays at 150 Bar up to 5000 rpm and only after that rises to the 170, although map requests 170 Bar from 4000 rpm.
Has anyone experienced this?
I looked through the file for some kind selector but didn't find anything, although I dont' know if I can trust my definition file after that mistake with rail pressure limiter.

« Last Edit: January 02, 2016, 12:55:06 PM by bitmap » Logged
dream3R
Hero Member
*****

Karma: +18/-8
Offline Offline

Posts: 1194


« Reply #14 on: January 02, 2016, 06:09:40 PM »

You need 30% more injected fuel mass for E85, when you squeeze it even more.

Consider that in your thoughts, just a fast switch to that fuel will not work well mostly. Many hours reading needed, sometimes one ore two new cylinder heads Wink

Sounds painful!
Logged



How to work out values from an A2L Smiley

http://nefariousmotorsports.com/forum/index.php?topic=5525.msg52371#msg52371


Starting Rev's http://nefariousmotorsports.com/forum/index.php?topic=5397.msg51169#msg51169

noobs read this before asking http://nefariousmotorsports.com/forum/index.php?topic=9014.0title=


ORGORIGINAL 05 5120 creator for Volvo
ORIGINAL Datalogger (Freeware) Author
ORGINAL finder of the 'extra' torque' limits
I don't have ME7.01 A2L I just use ID
Pages: [1] 2 3 4
  Print  
 
Jump to:  

Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Page created in 0.024 seconds with 16 queries. (Pretty URLs adds 0s, 0q)