Project: RS2 ABY

[A80Avant]

Looks a bit rich, but depends also where the WBO2 is located...

Sorry Dmitri, this is the first time I have heard that the location of the wideband has anything to do with the measurement of the richness or leanness of the fuel mixture. People run widebands from the very top of the downpipe up to all the way down to the end of the exhaust and the mixture reading is always the same. Unless there is a hole in the exhaust before the wideband that allows gasses to evaporate that way and mess their reading somehow, I cannot see how the location of the wideband would show anything different than the right value.

If you were to move the widebands on your rs4 to another location would you get a different reading? I don't think so...

[prj]

Sorry Dmitri, this is the first time I have heard that the location of the wideband has anything to do with the measurement of the richness or leanness of the fuel mixture. People run widebands from the very top of the downpipe up to all the way down to the end of the exhaust and the mixture reading is always the same.

Clearly you have never put more than one wideband on a car whereas I have.
I've put a WBO2 at the exhaust, and after the turbo, and the readings varied 0.3-0.5.
I guess you've learned something new then.

If you were to move the widebands on your rs4 to another location would you get a different reading? I don't think so...

RS4 ECU is narrowband. But even so, ME7 has a model for modeling exhaust parameters and WBO2 location on the cars that do have wideband.
RS4 is a nice car to test this on though, remove stock narrowbands and fit widebands in S1 and S2 positions.

[A80Avant]

Clearly you have never put more than one wideband on a car whereas I have.
I've put a WBO2 at the exhaust, and after the turbo, and the readings varied 0.3-0.5.
I guess you've learned something new then.


RS4 ECU is narrowband. But even so, ME7 has a model for modeling exhaust parameters and WBO2 location on the cars that do have wideband.
RS4 is a nice car to test this on though, remove stock narrowbands and fit widebands in S1 and S2 positions.

I see. Then 0.3-0.5 if you want me to accept I will, assuming that your tests were done with properly calibrated sensors.
In that case the mixture is too rich still as 10.6 is nowhere near 12.2 in ideal situations even with your 0.5 difference. That is why I asked where the egt sensor is to understand if the mixture is that way due to high egt or its because its just not running right

[prj]

In that case the mixture is too rich still as 10.6 is nowhere near 12.2 in ideal situations even with your 0.5 difference.

12.2 in ideal solutions? Yeah, there is no "perfect AFR", I would say 12.2 is not optimal at all on this engine.

10.X is too rich, but did you intentionally overlook the part where I explained why this is?

[A80Avant]

No not intentionally. Just didn't see the post.!

[prj]

Usually when the mixture does this - good on first pull but getting really rich on gear change it means that the dump valve is not big enough to vent the air.
And in this case it's especially bad because there is no dump valve...

This always happens when you push air through the MAF backwards, and this should never happen with a properly set up dump valve.

[A80Avant]

Its interesting though that it doesn't clear all the way to the end of the pull. Is that normal? Gear change with the maf reading sounds plausible, but why is it staying low at 6500rpm when the pull is at its end?

[Sonic]

Well it feels awful to drive, it's not predictable at all.

Sometimes it it boosts aggressively as you'd expect, other times it slowly builds boost, taking a long time, other times it just shoots up suddenly anywhere between 3.5 and 5krpm, and sometimes it tails off.

Very odd, but i shall refit the dv and re-log in the meantime.

[prj]

Its interesting though that it doesn't clear all the way to the end of the pull. Is that normal? Gear change with the maf reading sounds plausible, but why is it staying low at 6500rpm when the pull is at its end?

If you actually look at the graphs you will see that it only goes as low as 10.6 when he lifts the throttle...
Rest of the time it's about 0.3-0.4 too rich in higher gears. And this is exactly how it's going to behave when air is bouncing around.

What is your point? I am pretty certain it was not like that when mapping it, so clearly something has happened since then.
The boost didn't do this when mapping it either. Not a single time.

[Sonic]

The boost didn't do this when mapping it either. Not a single time.

Nope not at all, it was absolutely fine.

The first time i can remember having boost issues was in August at the 'ring, and that was just failing to come back on boost after shifting...

Also it's worth mentioning that i've sent dmitri a copy of the ZDL log files rather than just the images above, so he can see every datapoint not just the ones ive marked above, although i've tried to make them as useful as possible!

[A80Avant]

If you actually look at the graphs you will see that it only goes as low as 10.6 when he lifts the throttle...
Rest of the time it's about 0.3-0.4 too rich in higher gears. And this is exactly how it's going to behave when air is bouncing around.

What is your point? I am pretty certain it was not like that when mapping it, so clearly something has happened since then.
The boost didn't do this when mapping it either. Not a single time.

No particular point, just trying to make sense of the AFR and understand it.

so your AFR (requested) is at 11.0 or thereabouts on high boost during the run? That is why i ask where the EGT sensor is, is it knock limitation that you need to go to those lengths or high EGTs?

Andy, by the sounds of it, i have to admit, ECU is coping for a mechanical fault of some sort though. Its definitely not behaving right!

[Sonic]

[prj]

so your AFR (requested) is at 11.0 or thereabouts on high boost during the run? That is why i ask where the EGT sensor is, is it knock limitation that you need to go to those lengths or high EGTs?

It's not. Request will only go down that low if there is knock.
I think request is fine, it's actual that's not.

[A80Avant]

so what is the requested lamda then? what have you tuned it to be? 11.5?

Andy, is the 800+ figures on the logs from runs of higher gears?

looking at run 5/2 which seems to be a decent pull, its looking like with 10.4 lamda, its reaching 800C, which is around or close to 900 on the collector, which is not bad. I see now what Dmitri means about the engine paramaters and the lamda values. Do you remember which gear that was done in?

[Sonic]

5-2 was started from 4th IIRC and you can see shifts into 5th and then 6th.. so yes all higher gears.

The lowest AFR value was 10.2 at 6900rpm, right before shifting into 5th.