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Rod S

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So this is just for info based on previous threads on multiple widebands and particularly the newer 4.9 LSUs vs the older 4.2s

There are only a few of us who have data on dual widebands (inners and outers measured seperately) and even less with three (one after the turbo as well).

We may not have posted much data because of the lack of interest in the AFR differences but this might be of interest particularly between the 4.2 LSUs and the newer 4.9s

For the last year I've been running some experimental stuff from Jean which, using the 14point7 controllers, gives me seperate digital displays of th AFRs and also monitors the internal temperatures of the LSUs themselves to see if they are working properly.

My test setup is very crude, I can only monitor the temperatures on the laptop, not the LED displays.

This was the early version I tested

http://forum.jbperf.com/viewtopic.php?f=9&...lit=rod+s#p6976

Latest test version looks a bit more like this



The hardware is all Jean's stuff this time, not my veroboard...

I'll show some more detailed pictures later, the cases are all 3D printing but the main interest really is the differnces between the 4.2 and 4.9 LSUs (as you can see on the photo).

The first two are 4.9 (the newer ones) that should run at 780C and the third a 4.2 (should run at 750C) but the AFRs should be pretty much the same.

Worst difference I've seen between the sample chambers and the 3rd one after the turbo is 0.5 - 1.0 when using just 4.2s.

Mine isn't road legal at he moment so this setup will shortly be on Graham T's (which is road legal) to see some more.

He also has 4.9s in the sample chambers and a 4.2 after the turbo.

Schrödinger's cat - so which one am I ???


PhilR

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Interresting - What do you think is the cause - do you intend to swap the position of the 4.2 to see what happens to the readings?


Rod S

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On 15th Sep, 2015 PhilR said:
Interresting - What do you think is the cause - do you intend to swap the position of the 4.2 to see what happens to the readings?


Not sure of the cause yet.

Paul had a theory that it was putting the sample tubes too close to the exhaust ports so got some exhaust gas not fully burnt.

Not convinced yet.

More interesting is the 4.2 vs 4.9 readings, never seen that much difference between pre-turbo and after turbo before with all 4.2s.

Yes, will probably swap the LSUs around, not entirely straightforward as the hardware needs changing (different jumpers for the two LSU types) which is a bit time consuming (solder jumpers not simple plug on ones).

But it's interesting stuff especially when you consider what the 4.9s are potentially capable of.

Schrödinger's cat - so which one am I ???


jbelanger

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Rod,

If you swap the sensors on the engine, you don't need to swap them on the SLC carrier which would avoid the need to change the solder jumper. The jumpers are already correct for the sensors. The display would then show the after turbo data in the first or second place instead of the third place (depending which 4.9 you swap the 4.2 for).

Jean

Edited by jbelanger on 15th Sep, 2015.

http://www.jbperf.com/


Rod S

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On 15th Sep, 2015 jbelanger said:
Rod,

If you swap the sensors on the engine, you don't need to swap them on the SLC carrier which would avoid the need to change the solder jumper. The jumpers are already correct for the sensors. The display would then show the after turbo data in the first or second place instead of the third place (depending which 4.9 you swap the 4.2 for).

Jean

True, I removed the jumpers on 3 and 4 so could just swap the cables and borrow a 4.2 SLC from my own setup to go in position 4

More testing for tommorow.

This stuff is really looking very good, and giving lots of interesting information (since I got the wiring problems sorted).

Really looking forwards to seeing the results on Graham's in the next few days (weather dependant).

I'm off to another beer festival over the weekend http://www.gcrailway.co.uk/special-events/...9-20-september/ so need to get it in the post before then..

Schrödinger's cat - so which one am I ???


robert

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uranus

so rod what does the 4.9 do that the 4.2 doesn't ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Rod S

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On 15th Sep, 2015 robert said:
so rod what does the 4.9 do that the 4.2 doesn't ?


It was dabated back end of last year in a few threads, this is just one

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=571621

Basically they were developed for lean burn engines so can toletate a higher exhaust gas temperature than the 4.2

As you see from the photo they are deliberately run hotter internally anyway.

But the other interesting difference is the datasheets (you'll find the links to them in that other thread) suggest they are nowhere near as suceptible to pressure variations skewing the reading as a 4.2 does.

Hence there is a possibility they may be OK pre-turbo wthout the sample chamber setup that myself, Graham and Paul (and maybe others we don't know about) are using.

That will be the next thing to test.

The important thing is they can't just be installed in place of a 4.2
Apart from the temperature there are other hardware and firmware differences required in the controller and not all of the aftermarket ones can deal with this.
And I'm only aware of one on the market that can actually display the temperatures as well.

This is something Jean is developing to fill that gap.

I'm not here to market it, that will be for Jean to do through his own routes, I'm simply helping with the testing and thought some of you might be interested.

I've had a trial version of this on my own Mini for best part of a year (I basically tested the initial code for Jean) but my hardware is very DIY and currently only configured for 4.2s

As soon as I've finished my basic testing of this and posted it to Graham for further testing, I'll do the hardware mods to my setup then there will be two of us able to continue experimemting with the 4.9s

Schrödinger's cat - so which one am I ???


PhilR

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On 16th Sep, 2015 Rod S said:
On 15th Sep, 2015 robert said:
so rod what does the 4.9 do that the 4.2 doesn't ?


It was dabated back end of last year in a few threads, this is just one

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=571621

...there is a possibility they may be OK pre-turbo wthout the sample chamber setup...

...That will be the next thing to test...



I'll also be running 2x 4.9 pre-turbo (no sample chambers) and a single 4.2 post-turbo. I have an Arduino pushing data into the MegaSquirt tables for the dashboard and logging, but there's still a number of things for me to do, both hardware and software, before I have any data myself. I really should get a move on!

Looking forward to data from your sample chamber setup, to see how they compare.


stevieturbo

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Are you saying those different readings are all taken from the exact same exhaust gas source ?

ie not different cylinders, pipes or locations in the exhaust ?

9.85 @ 145mph
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speed didn't kill me, but taxation probably will


robert

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uranus

thanks rod , i remember now !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Rod S

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Stevie,

Just to clarify, the readings in order are outer cylinders, inner cylinders, and after the turbo (down near the gearchange).

The inner/outer readings are from LSUs in a pair of sample chamber piped through some small bore tubing off the manifold which dumps into a large tube plumbed into the downpipe after the turbo.

It means the LSUs don't see extreme temperatures and don't see high pressures (pressure beng the largest factor in skewing the readings).

Getting the outer and inner cylinders the same has always been quite easy with the siamese MS-E code.

In fact the outers are slightly rich (ie, the holy grail of port injection is achieved) but the strange thing is the reading after the turbo is high.

It's always been about 0.5 - 1.0 above the average of the others but there seems to be a step change since swapping the pre-turbo ones to 4.9s

Previous theories have been air leaks, sample chambers too close to the head but this new data means more investigation.

Work in progress...

Schrödinger's cat - so which one am I ???


robert

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uranus

yup, i think ,(with no evidence to back me up) the gases have not settled after combustion to their final state that close to the head ?

i suppose a series of sensors down a downtube would let you know the place where the gas has finished its change of state ,and maybe give you a correction factor , if thats possible with the temp and velocity changing all the time through the rev range .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


jbelanger

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If the combustion is not finished, wouldn't that mean that you have more O2 in the gases and you would then read lean (like a misfire)? That's the opposite of what is happening here.

In any case, I look forward to see what the upcoming tests show.

http://www.jbperf.com/


Paul S

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It's worth having a watch of this video (previously posted by Jean):

https://www.youtube.com/watch?v=ueqDFWti47g

From 32 minutes onwards, particularly from 35 minutes.

I'm all for picking the low hanging fruit myself *smiley*

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


Paul S

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On 16th Sep, 2015 jbelanger said:
If the combustion is not finished, wouldn't that mean that you have more O2 in the gases and you would then read lean (like a misfire)? That's the opposite of what is happening here.

In any case, I look forward to see what the upcoming tests show.


Conversely, the unburnt hydro-carbons will give a rich reading.

I actually think that it is far more complex and that sampling at the head flange is actually sniffing at a flame.

I'm now sampling 500mm from the exhaust valve plus downstream of the turbo with identical sensors and controllers. That should eliminate some of the variables.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


jbelanger

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On 16th Sep, 2015 Paul S said:
Conversely, the unburnt hydro-carbons will give a rich reading.

But a misfire also has the unburnt hydro-carbons and it definitely reads lean. So the excess O2 is the leading factor in how it reads.

http://www.jbperf.com/


Paul S

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But a misfire and partial combustion are two totally different situations.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


jbelanger

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On 16th Sep, 2015 Paul S said:
But a misfire and partial combustion are two totally different situations.

Agreed.

http://www.jbperf.com/


Paul S

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I agree that the leading factor is the presence of O2, but just because combustion is incomplete does not mean that O2 is present or in a state that can be detected by the sensor.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


jbelanger

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Yes, it's definitely not a static situation as opposed to a misfire where you have an effectively inert mixture of gases.

I'm still not fully convinced that this is the issue but I don't have anything concrete against it or any alternative explanation. So I'll wait for more test results (which I can't perform myself unfortunately).

http://www.jbperf.com/


Rod S

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Let's not get too bent out of shape over this (like happened last year).

I've not really posted any results yet, just a quick photo of the displays.

If we can all take this seriously, there are only a very few of us who can actually provide real data.

So let's stop bickering (did I spell that right ?) and agree a way forward where we are all happy to do the testing and publish the results.

Enough said for the moment.

Schrödinger's cat - so which one am I ???


robert

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uranus




On 16th Sep, 2015 Paul S said:



I'm now sampling 500mm from the exhaust valve plus downstream of the turbo with identical sensors and controllers. That should eliminate some of the variables.




that should be fascinating to compare with your earlier closer to the port logging paul.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM


Paul S

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Not sure that we will be able to make a comparison with the earlier engine as this is a different engine and injection setup in many ways.

However, I have drilled and tapped the manifold at the head flange so that, once set up, I can transfer a sample tube so that I'm effectively monitoring at the head, 500mm from the head, before the "Y" piece and turbo, plus downstream of the turbo.

That should give us the answers we need.

We've not seen this problem in a real world situation on the road yet, so Graham's data will confirm, or otherwise, if there is an issue.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."


PhilR

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Perhaps the original thread linked above should be resurrected for general discussion and theory, to help keep this thread uncluttered?

Rod, will the data from my setup (above) be of interest, or is this too far off track?


Rod S

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On 17th Sep, 2015 PhilR said:
Rod, will the data from my setup (above) be of interest, or is this too far off track?

Most certainly will be of interest. The more scenarios we explore the better IMO

On 17th Sep, 2015 PhilR said:
Perhaps the original thread linked above should be resurrected for general discussion and theory, to help keep this thread uncluttered?

Perhaps start a new one once we have more meaningfull data (and just keep links back to the previous ones).
I'm just trying to get my old thermocouples up and running on Jean's new stuff (it does EGTs as well as the AFRs and temperatures) but I'm having a bit of a blond moment with my ini files...

Graham has installed thermocouples and pressure transmitters in his sample chambers which should show what the sample chambers actually achieve and then we can compare to straight off the manifold.

We're just waiting on a PCB to set this all up and the package arrived from Shenzhen a few minutes ago.

However I have a beer festival to go to tommorow and all weekend so there will be a short delay at my end.

Schrödinger's cat - so which one am I ???

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