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Graham T

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Hungerford, Berks

Just a small offering at this point, but as I found a few minutes I thought I’d start a thread on the upcoming Tuning of my Turbo Engine.
Quick recap on basic Specs:
1312cc
GT1752 Turbo
Benross head
minispares clubman SC/CR gear set
X pin 2.95:1 diff
RTS clutch
Megasquirt II
875cc/min primary and secondary injectors (4x)

So, although I had the engine started a few years ago, I never got to actually drive it until a few weeks back, then only had a couple of runs on a very short (40M) “test track”.
The following week end I adjusted the wastegate actuator for a bit more boost and started up to have another test, but had no Oil pressure. Oil pressure was good when it was turned off after the last run, but next time it was started, absolutely none. That is still to be investigated, I decided to get on with finishing the paint work before the shite weather came in.
Now I am back to house renovation for a while, so all work has stopped on it yet again, but I just wanted to get general opinion on an issue I am seeing in the following log




The same sample, but in excel:



Obviously there is a fair bit of work to do on the fuelling side ( and AFR is the outers – strange timing values I am using at the moment) but my big concern at this point is the odd occurrence that can be seen around 9.5 seconds on the excel graph.
Although I do not believe the actual figures that I am getting from the MAF (I Know I need to calibrate), there is a definite rise in Mass air flow and a drop in Boost.
You can see a spike in PW2 at this point with MAP Decel, then it all instantly picked up again. There was also a 50 RPM drop in revs and from this point MAT can be seen to rise 6deg and slowly start to drop until I let of the pedal.
At around this time in the run, there was a soft pop which I have yet to identify the cause
I think the TP dip just after the MAF peak is my reaction to the “pop”
Initial thoughts were maybe a back fire, but I’m now wondering whether something like the DV opening or the DV signal pipe blowing off could cause the MAF to rise while pressure dropped?


I’m not in a position at the moment to look closer, but I thought I would ask the general opinion??

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


Paul S

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Backfire in my opinion.

How hot was the engine exhaust at this time. You could have had some unburnt fuel in the exhaust.

Backfire caused the turbo to stall cause boost to drop. Either some exhaust gas got into the inlet as a result of the 'pop' or the change of energy state cause the IAT to rise. In the short term, that upset the MAF sensor.

Just a theory.

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."


Brett

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Compressor surge?
Drop in map, upset maf, increase mat, inducing a slight misfire drop in power could explain the rpm dip
Just a thought
Edit: do the logs show sync loss and reason ? I had a similar log anomily and exhaust pops at a specific rpm turned out to be a vibration in the alternator belt whipping the crank sensor

Edited by Brett on 22nd Oct, 2014.

Yes i moved to the darkside *happy*

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Graham T

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Thanks for the input.

On 22nd Oct, 2014 Paul S said:


How hot was the engine exhaust at this time. You could have had some unburnt fuel in the exhaust.




I’d guess Very hot.
I said a couple of runs in my initial post, this was actually the fourth run.
On top of that a lot of stationary running while I messed around with the fuelling at idle and adjusting after the first 3 runs.
So not a lot of cooling going on at all.

On 22nd Oct, 2014 Brett said:


Edit: do the logs show sync loss and reason ? I had a similar log anomily and exhaust pops at a specific rpm turned out to be a vibration in the alternator belt whipping the crank sensor


No lost sync showing on the log.


On that note, the logging is still not good. Rod has already pointed out that there is lag in the readings. I was not sure at first how that could be, but now looking through it all in a bit more depth I can see what he means.
Possibly down to the version of firmware I am using on the MS2 and the fact that with the IOx and Rods Map carrier board (for the extra MAP, Air temp and MAF) connecting over CAN, I’m only seeing runtime data rates of 8 – 10 /sec.
So I may update the MS2 to the latest firmware for tuning, so that the runtime data rates are higher with CAN connected, then drop it back to the version I need for Traction control once I am sorted.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


Rod S

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As we've already discussed (off forum, by email) I'm not too worried about the slow data rate. I looks like about 12-14/s on excel.

I think the real issue in trying to understand it is the lack of RPM.

Your chosen gearset and FD meant you got totally bogged down on the start of that run and never made any real boost because of lack of RPM (and maybe the wastegate openned early too). (my equivilant test last year hit the rev limiter, and hit it in less time and hit at a higher terminal speed).

I agree with Paul not to worry too much about the apparent reading on MAF, nothing I've read suggests they are fast responding so could easily give a bad reading on a fast transient.

The other data does suggest something fast like a misfire.

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


Graham T

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Around the data rates I was more looking at correlation of Can1 data to MS2 data.
Example being the intake pressure traces.







It just does not look as I would have expected. Should the MAP be higher than previous points in the system?
I would have expected losses from Post intercooler to Plenum.
Also, looking at the graph, at around 9.4 seconds and on (after the “MAF Event”), the CAN1 Pressures are then higher than the MAP reading - This was my main reason for questioning the diagnoses of a back fire in the first place. If there was a signal pipe come off, could the MAP pressure now be lower than the rest of the system.
(I accept the backfire scenario - Just trying to understand the data)

Another point on the data rates is that Rod pointed out via one of our email exchanges that the AFR readings looked laggy and too smooth. The LC-1’s are connected to the IOx via their digital outputs and so AFR data to the MS2 from the IOx could now be compromised by the Can connectivity limiting data rate.
It is easy enough to test that theory by removing the CAN device from the MS2 project. That way the MS2 will just be using the remote ADC’s for AFR. In this configuration I get data rates of 55 – 60/sec.
Of course, it may just be down to the Sample pipes/ chambers – ie diameter, length of run from pre turbo to the sensors.








I think definitely that more data with longer runs is required, maybe get out of first gear, but that means getting the oil pressure sorted and getting an MOT. soon, one day...

Edited by Graham T on 23rd Oct, 2014.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


Paul S

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Your sample tubes are too long and too big a diameter from halfway in my opinion.

Looks like you have a dodgy MAP sensor too.

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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To speed up the data rate you don't have to remove the CAN device from the project but you can simply click the box in the project properties to disable the runtime data.

Also, make sure that your AFR lag factor on the MS2 is set to 100. That will have a huge impact on delay.

Edited by jbelanger on 23rd Oct, 2014.

http://www.jbperf.com/


Graham T

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On 23rd Oct, 2014 Paul S said:
Your sample tubes are too long and too big a diameter from halfway in my opinion.


Ok, thanks, taken on board.
The larger diameter pipe was supposed to be a way of reducing the Pressure and I imagine as a direct result, the gas velocity that the sensors see.
I forget the diameters now, but I THINK 4mm ID going to 8mm ID. I cannot find the receipts on any references to them though.

With length, I tried to keep the tubes for both outers and inners the same, hence the inner sample pipe having a few curves in it.
For the positioning of the actual sample chambers, it was difficult to locate them any further up the downpipe without their exit into the downpipe being exposed directly to gas coming out of the turbo. I was worried that it may have in some way have disrupted the gas flow exiting the sample chambers.


On 23rd Oct, 2014 Paul S said:
Looks like you have a dodgy MAP sensor too.


This is a distinct possibility. I have a spare, so can swap it out if necessary.
I’ll get some testing done on the Jimstim and see whether it reflects what is being seen in the above logs.
It could also explain why I am struggling to get the tick over as good as the first time I fired the engine up.





On 23rd Oct, 2014 jbelanger said:
To speed up the data rate you don't have to remove the CAN device from the project but you can simply click the box in the project properties to disable the runtime data.

Thanks Jean
To confirm:
Disabling the runtime for device CAN ID increases MS2 runtime data rate to ~55 – 60 /sec
At the same time, it stops the ability to log data from the IOx.
As I do not have the LC-1 daisy chain connected, so I cannot see for myself, will the Overwriting of ADC inputs with AFR data / MS2 EGO settings for using remote ports still continue to function?



On 23rd Oct, 2014 jbelanger said:
Also, make sure that your AFR lag factor on the MS2 is set to 100. That will have a huge impact on delay.


This is the Lambda Averaging lag factor?
Rod and I did discuss this – mine as set to what I believe is a default of 50.
I did read up on it:
“…The algorithm works like this: every sampling period, the new value of anything is computed as (((100 - lag factor) * previous value) + (lag factor * latest sample)) / 100. So if the lag factor is 100, the new value is always 100% of the sampled value. If the factor is 50, it's 50% of the sample + 50% of the old value. And so on... so when you set the lag to 10, the new value is 10% of the sample plus 90% of the previous value. That's pretty heavy averaging…”

I can’t remember where that excerpt came from, but I never got to test it out.
However, I’ll add this to the list of things to try.




’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


jbelanger

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The inter-device CAN traffic is not affect by disabling the runtime data; that is just so that TS stops polling the IOx. The MS2 will still get the data from the IOx.

And the lag factor (Lambda Averaging lag factor) is only needed if you expect noise on the analog signal. With a purely digital signal like in your setup, it only reduces accuracy and slows things down. And the LC-1 already does some noise reduction internally. So it is not recommended to use anything other than 100%.

Edited by jbelanger on 23rd Oct, 2014.

http://www.jbperf.com/


Graham T

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Thanks for the clarification Jean.

Lambda Averaging lag factor now set to 100

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


Rod S

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Although I'm pretty certain I must have seen the photo above some time ago, I either didn't look too closely or I simply missed the significance of the tube diameters, ie, I agree with Paul, that increase in diameter could well add a physical lag to the readings. If it is double the diameter, that's four times the CSA.

When we discussed the lag, I hadn't appreciated it was primarily for noise on analogue data but mine is also at the default of 50% and no lag in the data is visible - although the current low sampling rate could be hiding it.

From previous discussions with Jean (if I understood it right) I cannot disable polling if I want to see all my three (soon to be four) readings as only two ADCs can be overwritten (Jean, please correct me if I'm wrong).

However, with my arrangement there is certainly no evidence of the direct readings being sluggish (which I would expect if there was any real lag) in fact, since I've swapped to the 14point7 SLC-OEMs and have the dashboard displays running direct from the IOx, the second decimal place can sometimes just be a blur.

Re. the positioning of the sample chamber exhausts, yours are very little different to mine and have the same angle of entry (which I think also matches Paul's first one) so reversion up the tube is highly unlikely, the main difference is I have short sample tubes and long exits.

Most of my original photos got lost on photobucket about two years ago but recently I reloaded the sample tube ones because someonelse was asking (can't remember who) so they now all show again in this thread.
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=300943
I think Paul has just reposted some pictures too since his disappeared with an ISP change ?

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


jbelanger

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On 24th Oct, 2014 Rod S said:
From previous discussions with Jean (if I understood it right) I cannot disable polling if I want to see all my three (soon to be four) readings as only two ADCs can be overwritten (Jean, please correct me if I'm wrong).


You can overwrite all 8 ADCs if you want. The issue is that you will only have up to 2 AFR values and the other ones will be raw ADC values in the gpioadcX variables. You will need to add some calibration equations in the ini (or custom.ini) to see them as AFR values. But that is not complicated to do.

But there is also the issue of the other ADC values on the IOx that you lose when overwriting. You need to disable the overwritten channels so if you use more than 4 ADC channels that you also want to see on the MS2, there's a conflict.

http://www.jbperf.com/


Paul S

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Did you know that you can connect the 0-5v output from your wideband directly into the ECU ? *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."


jbelanger

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On 24th Oct, 2014 Paul S said:
Did you know that you can connect the 0-5v output from your wideband directly into the ECU ? *smiley*


And then you have to deal with noise from many sources, with ground offset and with a different 5V reference. Those are a lot more complex to deal with than whatever you need to set to get digital data over CAN.

But that's my very biased opinion :)

http://www.jbperf.com/


Paul S

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You seem to be introducing more sources of error instead.

Given that the wideband reading itself will vary depending on the distance of the sensor from the valve, you seem to be trying to deal with potential issues (of which I've never had a problem with thousands of miles of actual road use) rather than the real problems.

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 24th Oct, 2014 Paul S said:
You seem to be introducing more sources of error instead.

Given that the wideband reading itself will vary depending on the distance of the sensor from the valve, you seem to be trying to deal with potential issues (of which I've never had a problem with thousands of miles of actual road use) rather than the real problems.

I don't see how there is any error being introduced. The digital value that the controller is computing internally is read directly and transferred to the MS, again digitally. There is no digital to analog conversion with a signal put on a wire exposed to a very nasty environment followed by an analog to digital conversion. All of those will add noise, offset and translation artifacts.

And those are real problems for a lot of people. Not having to deal with those makes dealing with the physical constraint much more straightforward.

Also, have you checked that you get the exact same value under all circumstances in your MS that you get from the Innovate software with the controller connected to the PC. If not, you don't know if you have an offset and/or voltage reference issue. And are you using any lag on your MS? If so, that's a very crude filtering that does create its own artifacts.

http://www.jbperf.com/


Paul S

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On 24th Oct, 2014 jbelanger said:

I don't see how there is any error being introduced. The digital value that the controller is computing internally is read directly and transferred to the MS, again digitally. There is no digital to analog conversion with a signal put on a wire exposed to a very nasty environment followed by an analog to digital conversion. All of those will add noise, offset and translation artifacts.

And those are real problems for a lot of people. Not having to deal with those makes dealing with the physical constraint much more straightforward.

Also, have you checked that you get the exact same value under all circumstances in your MS that you get from the Innovate software with the controller connected to the PC. If not, you don't know if you have an offset and/or voltage reference issue. And are you using any lag on your MS? If so, that's a very crude filtering that does create its own artifacts.


I don't disagree if you want the most accurate reading.

The main issue is that a few of us on this forum promote fuel injection and the use of dual widebands. Anyone reading those last few posts ^^^ will get an impression that it's very complicated, you need to learn a different language and will be put off.

Two widebands directly connected to the ECU is far better than just a singe one downstream of the turbo, even though it may not be as accurate as using serial data via CAN.

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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I see your point. I was answering in the context of the setup discussed in this thread.

Even with very standard non-siamese port setups, some people do have issues with their AFR values. So I agree with not wanting to discourage people and I may not be doing the best job at this. But I also don't think that all discussions on the subject need to be concerned about this if discussing a very specific setup.

I do understand now that this is what you wanted to do, and I agree with the intention and the content, but the smiley was the only indication to me that this was not a technical discussion but rather a message at large intended to reassure some potential lurkers.

http://www.jbperf.com/


Rod S

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Paul,

You have complained numerous times in the past that anything technical has been dissed by people saying anything is good enough when it comes to charge robbing.

In this case I think getting the AFR data digitally instead of just 0-5V is the same step forwards as actually adding the sample chamber arrangement.

Do you want the discussion to be technical or not ???

Graham's initial post was about how he was using the digital data, not last millenium's 0-5V

If you want to stay with 0-5V that's fine, just accept it will be inaccurate.

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


Paul S

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Where does this perception that the 0-5v signal is inaccurate come from?

I can't find anything to suggest that there is a problem. Only people who do not install and connect the instruments properly.

I'm happy with the numbers that I get as I'm sure are the other 99.9% of wideband users. Doesn't mean that they are perfect, but you have to use your judgement and decide for yourself, based on the available data if you trust the device for it's intended use.

No Wideband data is going to be 100% accurate, serial or analogue, particularly if you are not sampling in the right place.

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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There has been dozens of post on the msextra forum on this. And not all the issues can be solved by simply wiring things better. This is especially true for some controllers such as the AEM but all the controllers I'm aware of have been reported to have issues on some units.

The DAC and the voltage reference issues are relatively common and no amount of fiddling with the installation/wiring will do anything. Also, there is an intrinsic introduction of noise and systematic error from a DAC-ADC chain with different voltage references.

The fact that the default lag factor is 50 % is an indication (it could be debated if it is a strong or weak one) that there is an expectation of noise since this is a very aggressive filtering (with some implementation shortcomings). And it does introduce more inaccuracies that will vary depending on the speed of any AFR change and the response speed of the controller/sensor as well as any filtering done in the controller.

So you can get acceptable data from using the analog signal but you will get less error with digital data, assuming that the controller does its job.

Regardless of that, the physical installation of the sensor (position, sampling chamber, ...) needs to be done correctly to get useful data. And I agree that this is the most critical point.

If you're happy with using what you have and want to recommend the same thing, fine. But if you say you haven't seen people having issues and seem to claim that this is done uselessly and blindly, then I have an issue. There are obvious and tested advantages to this approach.

http://www.jbperf.com/


Graham T

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On 24th Oct, 2014 Rod S said:
Although I'm pretty certain I must have seen the photo above some time ago, I either didn't look too closely or I simply missed the significance of the tube diameters, ie, I agree with Paul, that increase in diameter could well add a physical lag to the readings. If it is double the diameter, that's four times the CSA.

Ok, thanks. Again, taken on board.

I found a receipt for some of the pipe and it was 6mm OD with 1mm wall and 8mmOD with 1mm wall, although the picture does seem to suggest a bigger difference than this on the OD’s. I’ll measure when I next get near the car.

On 24th Oct, 2014 Rod S said:
Re. the positioning of the sample chamber exhausts, yours are very little different to mine and have the same angle of entry (which I think also matches Paul's first one) so reversion up the tube is highly unlikely, the main difference is I have short sample tubes and long exits.


The biggest problem I came up against was packaging.





Because I initially thought the car was going to need to go through a BIVA, I wanted to keep most of the brake system as it was in the original car (just to mitigate any nit picking from an examiner). Therefore the Servo was to stay in place, meaning I had to get the Lambda sensors in, but well below the servo, hence the short exit tubes.
But since finally finding out from DVLA that I do not need to do the BIVA , but only need to supply pictures of the finished car to get the logbook changed from Saloon to “coupe” (DVLA’s take on the new “style”, not mine!), I decided that the servo can go.
It’s next to useless on My Dad’s Turbo mini and I know a good majority of you all do not use them, so I have no issue with this.


However, with the work involved in changing all the sample chamber pipework now, I’m going to stay with what I have, at least unless I have to pull the engine out to sort out the oil Pressure problems – Even then it may just be a 3rd “common” wideband in the downpipe to start with.


The data presented above is obviously only a very small amount and as it was the first time the engine was run in anger, with all the sensors and electronics coupled up (and the IOx project included with runtime data) there’s more work/ testing/tweaking to do before I entertain any significant changes.


I just can’t handle the thought of pulling this apart again at this moment. I’d rather get an MOT and some miles on it so I have more data.


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Edited by Graham T on 25th Oct, 2014.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675


apbellamy

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The 'Coupe' conversion turned out nicely. A considerable inprovement over a lot of attempts I've seen in the past.

On 11th Feb, 2015 robert said:
i tried putting soap on it , and heating it to brown , then slathered my new lube on it

*hehe!*


Paul S

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Yep, very nice.

I think we need to do some testing to verify the potential wideband issues.

I'll start a new thread rather than clutter this one up.

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."

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