NefMoto

Is it possible to disable EGT for part protection correction? Atleast temporary to test some things...
If possible which maps should I look at?

Thanks

you want to disable BTS ?
set tabgbts to 1250°C and it will never be active .

Yes, thank you

BTW: Could someone explain me why my EGT skyrockets after I've disconnected aftercat o2 sensor?? Does EGT model takes some variables from post cat o2 sensor??
I have no cat, no postcat o2 sensor and no sai. They're coded out (with the help of s4wiki) and no DTC are stored, but my EGT model goes out of it's mind!

Please see attached log in EcuXPlot software or excel ;)

And this is with E85 and stock tune (except for KRTKE and TVUB)!

Are you sure you're not running lean?

Do you have wideband?

Are we talking about BTS or ATR?

I wouldn't be so quick to disable BTS.

I'm not an expert but E85 burns slower than gasoline. If you have stock timming then the combustion is too retarded, so fuel is burning in your exhaust. Just add advance.

A few thoughts.

You need to log tats_w (the actual EGT from the EGT sensor). Is it functional on your car? All I am seeing in your log are three modeled temperatures and EGT for component protection. mrfa_w would have been useful too and rl_w so we can get a handle on the engine load.

That said, when you get to high engine speeds, your EGT for component protection is hitting high 870˚C which doesn't seem unreasonable to me. You don't seem to be running especially lean either with AFR down to 0.75 (rich best torque rule-of-thumb). Have a look at my log here and see how it compares.

http://nefariousmotorsports.com/forum/index.php?topic=1296.msg12400#msg12400

The variables shaded in yellow are the bare minimum I would be logging on a routine basis. I measure EGT up to 930˚C region on extended high load pulls so I wouldn't be overly concerned about 870˚C.

I can only echo phila_dot's caution about disabling LAMBTS because you'll have no protection then given that you already have no pre and post-cat O2 sensors active.

TTQS

Surely a stock tune will cope with E85? I haven't heard of anyone requiring a remap because they have started using high ethanol fuel. I haven't studied it myself, but I understand that ethanol burns cooler than gasoline so that shouldn't be the cause of high EGTs. I don't see why it should be burning in the exhaust either.

TTQS

In my ME7.5 1.8T Passat there are no EGT sensors, everything is based on model... I have wideband precat o2 though... :) Now car is hitting 870C with only 0.5 bar of boost. Normally my stock KO3 would boost 0.7-0.8bar and that is what I have to sort out before going to the kmirl/iop/l....

I can log about 20 variables with me7logger at 20 samples per second. Could you tell me what 20 variables are most important to test what is limiting my boost?

• gangi
• nmot_w
• lamfa_w
• lamsbg_w
• lamsoni_w
• lambts_w
• mshfm_w
• plsol_w
• pvdkds_w
• ldtv
• wped_w
• mrfa_w
• rlsol_w
• rl_w
• rlmax_w
• tats_w  
• tabgbts_w
• zwgru
• zwopt
• zwist
• dwkrz_0
• dwkrz_1
• dwkrz_2
• dwkrz_3
• tans
• pu_w

BTW: If you're going to E85 you'll have to open your injectors for 30% more time than normal fuel

Why is that? I am confused as to how fuel retailers can sell E85 when engines require changes to use it.

I can't really shed any light on the boost issues, sorry.

The stoich afr of e85 is 9,x (i don't know exactly) instead of 14,7, because e85 contains more oxygen. This is why you should increase 30% of fuel or you would go lean.
You can use e10 with stock tune because the ecu can adapt this little percent, but if you use e85 the ecu will throw a lean error.

Yes, you are right

TTQS, I logged data with every variable that was in your file yellow. Could you take a look?

As you see my engine load is lower than requested and boost is cut off

Yes, of course. I should beat myself with birch sticks. Being an ex-chemist, I should have known that!  ::) Possibly I was reading E85 and thinking E15. The premium 99 RON fuel I use regularly at the supermarket is up to 15% bioethanol. The stoichiometric ratio is 9 exactly for ethanol going by the table of page 14 of Engine Management: Advanced Tuning by Greg Banish, so weighting for 85% ethanol and 15% gasoline would probably give a stoichiometric ratio of 9.855 for E85 fuel assuming it's a linear scale...

Some more info was posted here by rob.mwpropane:

http://nefariousmotorsports.com/forum/index.php?topic=1185.msg12763#msg12763

Can I just check what you modified your KRKTE value to?

I presume your calculation went something like this:

For gasoline
KRKTE = (50.2624 x Vhcyl)/Qstat

where 50.2624 approximately equals 1.23/(1.05 x 14.7 x 1.67E-5) where

1.293 g/dm3 = air density at 0°C and 1013 mbar)
1.05 = injector correction factor for gasoline (i.e ratio of gasoline density 0.7135 g/cm3 to n-heptane density 0.6795 g/cm3)
14.7 = Stoichiometric air quantity at lambda = 1.0 and
1.67E-5 conversion factor minutes to milliseconds.

I get 50.1621 instead of the 50.2624 quoted in the funktionsrahmen, a difference of 0.2%.

For E85 (85% ethanol)
KRKTE = (67.7104 x Vhcyl)/Qstat

where 67.7104 approximately equals 1.23/(1.1626 x 9.855 x 1.67E-5) where

1.293 g/dm3 = air density at 0°C and 1013 mbar)
1.1626 = injector correction factor for ethanol (i.e ratio of E85 density 0.79 g/cm3 to n-heptane density 0.6795 g/cm3)
9.855 = Stoichiometric air quantity at lambda = 1.0 and
1.67E-5 conversion factor minutes to milliseconds.
with the 0.2% corretion applied

So I make that an overall change of +34.7%.

TTQS

First I caclulated KRTKE for new injectors and then added 30% and then corrected it depending on idle trims ;)

O.k. Please would you post up the calculation you did with details of old and new injector Qstat values and idle fuel trim corrector factor, etc. Apparently the level of ethanol content can vary according to time of year. Just another possible factor to consider...

I am probably misunderstanding your hardware configuration again, but if you don't have any lambda sensors, how does the ECU calculate the required fuel trim?

Thanks.

TTQS

TTQS, I have precat wideband sensor :)

original krtke: 0.10478 ; new injectors with e85: 0.10567. Since new injectors could spray about 30% more fuel in the end my KRTKE almost didn't changed. At idle my fuel trims are -0.8.

With wideband it's actually very easy to fix idle fueling, because you have very big range of triming field (-+30%) ;)

Actually I'm beginning to think that my problem of limp is asociated to this: http://nefariousmotorsports.com/forum/index.php?topic=524.0 (http://nefariousmotorsports.com/forum/index.php?topic=524.0) Because I started getting limp only after I disconnected postcat o2 sensor..

Hi master_j.

Sorry. Yet again, I misread your earlier post.

I had a look at phila_dot's thread that you linked to. I was already working on a translation of the large module LRS 15.40 (Continuous Lambda Regulation) to better understand the basics of lambda control. However, I have started work on LRSHK 9.80 (Continuous Post-Catalyst Lambda Regulation) so we can get a handle on how the post-cat control affects pre-cat control. The following statement early on in the module is of concern:

"Regulation with the post-catalyst probe is superimposed on the pre-cat lambda control."

Hopefully this will shed some more light on continuous lambda control which should be basic knowledge for us.

TTQS