So sealing the row makes no difference.
Also that steel sleeve is not moving at all.
This is the maf that comes with them

 

Clearly, the same sensor.
The ROW also don't have the same complicated overlap.

 

Ok now doing us boxes with sealing.
Went down from 26 to 6. It stays at 2,3 until coolant gets up in temps, then goes to 6.
I'm leaving us boxes on.

 

Seems that the row boxes are doing there jobs and getting more air into the motor.

Before you put the stock boxes on try a maf log on how much each setup flows.

Your tuning is just adding fuel to hit it's af target

 

In theory, the ECU should fuel according to how much air the MAF reads, then the O2 sensor determines what actually happened and if the motor is rich or lean, feeds that back and then the ECU trims or adjusts more or less fuel according to what the o2 sees post ignition. So that means either the ECU table doesn't have a high enough fueling value for the amount of air coming in, or more air is coming in than the MAF is reading.

Seems if all is sealed up good and no leaks past the MAF that maybe the stock US ecu tables can't handle the flow at idle. It does seem that the fuel trims are better at higher rpms. I have setup to log the actual MAF airflow readings, so going to compare that now and see if the rows really do flow that much better at idle.

 

Nice work.


That's the wrong way to think about it bro....just because they flow better, doesn't mean the fuel trims should be any different than US boxes. Even if that were true, I doubt there would be any difference in airflow at idle anyway...only up top.

By this rationale, the ROW boxes would show less peak airflow on a log...



It has nothing to do with fuelling via the ECU - the tunes will be the same. If it really does flow that much better at idle, then in order to maintain a low target idle rpm, the motor will be running lower ignition timing. From what I know, a stock, happy M156 will be sitting between 8-16 degrees of advance at idle, although the target (and general rule of thumb for most engines) is ~20. Cars with bigger TBs will run slightly lower timing because of the additional airflow which can't be physically restrained unless the ECU decides to close the butterfly plate 'backwards' by a degree or so to 12.5% opening when 'shut'.

 

Interesting
mine flows more one side than the other
are you guys getting similar readings from both sides or just one?

 

Mine used to be 8-10% on one of the banks and 4-7% on the other, so yeah mine was like yours too.

 

 

I was having something similar... I was getting around 6-7% on one side then 8-10% on the other. I went ahead and epoxied around the ROW boxes, let them cure for 24 hrs. and LTFT dropped for both. They're pretty even now, hovering around 3-4%. Just for s**ts and gigs I threw the stock airboxes back on and i noticed it was hovering between 6-8% on both banks. Really happy with that suggestion of epoxy-ing the gap around the boxes!

 

Gap around the boxes or the metal tube insert?

 

Sorry, should've clarified. The gaps around the metal tube insert... I got some Permatex Ultra Black silicone, sealed those small gaps around the ring and let it cure for 24 hrs. before I slapped em back on the car.

 

Nice, I'm going to give it a whirl. My LTFTs are in the 7-8% range on both sides.

 

Will be doing this tonight. My stop light LTFT's are in the 38-47% ranges and low throttle are in the 20's. Thanks guys!

 

Wow those make my 27% look low, everything I read says it should set a check engine light above 25% but mine never did and I am guessing yours doesn't so somehow the car is not deciding it is so bad it needs to set a code oddly.

I also have some permetex coming tomorrow to seal up my gaps and try.

 

ya...well i could see light past that metal deflector when i cut my boxes for ROW mod. will report back in a few days!

 

Barry, if you cut your boxes that my also explain your resulting fuel trims.

 

Interesting note about timing advance. I was looking at mine and it hovers in the high single digits to the low teens at idle. But I noticed it get up to the low 30's if I floor it. You guys getting something similar?

 

These are readings from OBD2 scanners. The scanners and all people know about how these codes work are in most cases from the "ancient" world of open-loop-closed-loop cars..
This is not such car anymore (except Decel, which can be ignored). Now it is true that the old school open loop fuel injection WAS in closed loop at idle.
However, the logic and functionality of our cars, from the stand point of how a tune works and in particular how trims work could be quite different.

I think that what the car reports to an OBD2 scanner and what it shows on a Xentry are two different things. Names of parameters, even values of readings.
It's almost like they send to the scanners values that don't make any sense (maybe because the car doesn't use those parameters and it only puts them out to comply to OBD regulation).

So, in the past I had a hard time sifting through what the car puts out for throttle position to a scanner vs what it puts out to Xentry.

Sunday I was taking some OBD2 logs of the temperature vs trims and RPM. I have 4 trims (OBD2 I think allows 6 or 8 trims out of which more than 4 have readings for our cars). So I was logging STFT1, LTFT1, STFT2, LTFT2.
I was logging ECT, commonly understood to mean Engine Coolant Temperature.

So I will try to attach them here, but even as I was sitting in the car watching the engine coolant temperature on the dashboard stable at 197F, the ECT was being logged at 228 at the same time and it didn't seem to have stopped increasing at 228.
So I don't think what was being put out to the scanner as ECT at 228 is realistic as coolant temperature.

At the same time, since these trims have bothered me for a long time now, during the duration when I was reading in the high 20% trims and having no code, I went to scan the trims with Xentry.
Well, Xentry does not call them trims and they were normal.
I took a picture of them and posted them somewhere here.
Let me try to find them and link here.

In sum, the high trims would be good to address but their exact value in a scanner should be taken with a grain of salt, because of all the reasons above.

 

I found it, Xentry (and Mercedes) call these "Mixtrure formation percentages" and while my crazy high 20's LTFT's were happening in the OBD2, Xentry was "relaxing" with these:

https://mbworld.org/forums/c63-amg-w...ercentage.html

 

That's normal and expected. Different levels of load/driving behaviour implied on the engine, so comparing the two has no relevance

High single digits to low teens at idle is good. You're on V7, right? Low 30's if you floor it....are we talking full throttle flooring it and what rpm range?

I love your posts man. Always insightful

 

thanks.

 

Vladds, thanks for the excellent post -I am on board with OBD2 scanners being all over the place, I tried 2 scanners and 3 apps before I found on that accurately could show the monitors which is supposed to be standard data, but my cheap scanner that works find on my BMW reports incorrect data on the MB and actually changes everytime you refresh the data randomly. So if that is inaccurate, the rest of the non standard OBD data may be a bit all over the place also. Here is a little more history on why I specifically noticed my issue and it was a DMV computer that initially indicated the high trims. I live in MA and on October 1st they changed their inspection system which was a disaster like anything the RMV/DMV does. I went in late September to avoid the issues, but forgot I had my battery disconnected the week before and failed due to not having readiness (and then determined V7 beta had O2's disabled and I would never get readiness, but that was another story). So I flashed back to stock, drove around for like 6 weeks since you have 2 months to get reinspected, go back and the registry system will not even perform an inspection. Many attempts phone calls and weeks later I give up and go to the special place for criminals that modify their cars. They go over everything with a fine tooth comb, hook it up to their system and log it for a while and come back with you ltft's are abnormally high, that indicates you have a tune, you need to get it flashed back to stock, I don't argue a lot and go on my way. I call Jerry and he says ltft's with the flash should look normal after 50 miles of adaptation and he says to check my intake gaskets as that is normally the culprit of high fuel trims if it is leaking. I check it all and no leaks, but while in there decide to switch back to stock airboxes as it is literally the only thing on the car that is not stock at this point. Drive around and all good. I go back to the special place and they take a look and they say I am all good and still think I had a tune and flashed back to stock, but whatever makes them happy.

I now am good, go get inspected and nothing works - turns out when they switched systems my car data didn't come over correctly due to being failed in the old system, there was a flag that was hidden in the new system preventing the inspection. So they fixed and all was good, still not sure if they would flag the car on the new system if they see high fuel trims, but they indicated that was something they look for to find tunes, and they also look for any OBD2 channels that are disabled that normally should not be (like O2's) so in MA for sure, flash back to stock now - it used to be fine to have O2's disabled as we could have one not ready, but now they indicate they flag that and the ROW airboxes if throwing high ltft's may also be a flagging event.

Rob

 

I freaking told you guys ma can see if your tuned now and you can see why I went through 3 sets of cats and 5 o2 sensors and sent months in mode 6 data to get my car with headers to look normal.

there new system knows what each car should look like in mode 6 with stock ECU tune.

your are the 4th car now that I heard about getting flagged.

right now I'm close with headers to pass even though I'm not having any pending codes and all monitors passed.

I have a few mode 6 things that are like 3 points away from sending a code and my cat numbers are off on each side.stock car wants to see 5500 on each bank and I'm 6100 and 4700 bank 1 and 2

take a look at my post cat o2 .its so close to pending a rich stuck sensor code.

I have row boxes with pro drys and see around 6-10 ltft on each side and they bounced around a ot
And it depends on weather conditions and how I drive the car before going to a stop and looking at them.

if stock boxes makes them go down to normal you guys just helped us a lot With headers.ill just throw my old boxes on instead of trying to get the rows to look normal.

 

For sure try your stock boxes, I see a lot of difference and they are definitely looking at higher than normal fuel trims as an indicator you have been under the hood doing stuff - let us know how you make out - MA may be making CA look like an easy state for inspections - guy told me if it ain't carb approved you won't get through MA emissions anymore - it isn't quite that bad but is close for sure - need to move to NH soon or at least figure out how to register my car there.