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Altitude Correction


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Hello All

            I think this what I did? with the numbers I posted that I found on a forum and the writer said it was not to critical(may be different for a race engine that is after every last bit of power?)

 

It seemed to work well enough for me(I wonder if I have enough suck to fool the second sensor in the garage and watch the laptop or AFR which should go lean I think?)

 

My understanding with BaroCorr is that it does not correct the PW by default.

The Baro curves are laid out to generate no correction out of the box.

The user has to adapt this curve, since each engine requires specific Baro correction.

 

I  could not see how it could work with only one MAP sensor and I know the TR6,s have trouble at high altitudes (I hear of nightmares of changing plugs on the tops of passes because they have fouled up and black smoke!)

 

I had non of these things!

 

I have managed to get an old 10" laptop to work and talk to Microsquirt(needs a new battery but found one on Fleabay for £8 delivered) so just need a 12v to 20v driver(cheap on Flea) and will leave the laptop in car as part of breakdown kit?

 

Roger

 

ps still have not finished porting the head! (No1 inlet looks good) just got to get the rest the same! still its a long winter? all others roughed out

            

 

 

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Yesterday I found time to play with the MS2 on the stim.

Instead of 2nd baro I fitted a poti. and had some pieces of paper at hand to note.

 

The fun starts with setting 2nd baro and JP5 in TS.

In the baro reading poti is set to 100 to simulate MSL

Stim was set to 3000 rpm and pulsewidth noted.

 

In the sensor calibration menue I set MPX4250 sensor for both

an MS sets at total vaccuum to 147

and rate to -47

 

1.) The correction works right out of the box

If I reduce outside pressure with the poti to 80

the fuel amount rises ca 20%

 

2.) If I set vac and rate to 0 the PW is fully out of range.

Engine will not run at all.

What I did was set outside pressure to 100 and note PW

with 147/-47

Now I set the vac to 20 and played with the rate to achieve

same PW as before. It was about 70.

So with 20/70 you get the same PW at MSL but only 5%

reduction at 80.

 

My conclusion is that baro correction works with 2nd baro when engaged.

In my case it did much to much when going to the alps.

Hopefully the amout of correction can be reduced with playing with

a pair of data.

 

As we need to keep the setup we found at home at MSL we must

ensure that we change data to fit on the hill and keep the setup of MSL

 

Best way from my view is to build suitable pairs at home with poti

that keep data at MSL and make different enrichments at 2000m altitude.

 

147/-47 ist the first pair

20/70 is the second pair.

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I  could not see how it could work with only one MAP sensor and I know the TR6,s have trouble at high altitudes (I hear of nightmares of changing plugs on the tops of passes because they have fouled up and black smoke!)

 

I had non of these things!

 

 

Roger

 

Hi ,

 

Well it should work the same way it works with 2 sensors, it's  just not continuously adapted to the correction curve, but only at startup.

When the engine starts to misbehave, as you climb the hill, you have to stop and restart the engine and move on until it misbehaves again... and so on. Is that the case for every 500m ascension, I don't know.

 

 

But I think your case and Andreas' case seem to show a bit how the FWs evolved in terms of altitude correction. It seems that the latest FW (3.4.x) is more intuitive to set up, as it worked rather straight forwardly  with Roger's set up.

 

Whereas Andreas' had to struggle around more to get things running.

 

P.S. nice planes in the pictures. The big one looks a bit like a mini Dakota. Is that, what you use to go to the  Goodwood revival?

 

Patrick

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In the sensor calibration menue I set MPX4250 sensor for both

an MS sets at total vaccuum to 147

and rate to -47

 

1.) The correction works right out of the box

If I reduce outside pressure with the poti to 80

the fuel amount rises ca 20%

 

2.) If I set vac and rate to 0 the PW is fully out of range.

Engine will not run at all.

What I did was set outside pressure to 100 and note PW

with 147/-47

Now I set the vac to 20 and played with the rate to achieve

same PW as before. It was about 70.

So with 20/70 you get the same PW at MSL but only 5%

reduction at 80.

 

My conclusion is that baro correction works with 2nd baro when engaged.

In my case it did much to much when going to the alps.

Hopefully the amout of correction can be reduced with playing with

a pair of data.

 

As we need to keep the setup we found at home at MSL we must

ensure that we change data to fit on the hill and keep the setup of MSL

 

Best way from my view is to build suitable pairs at home with poti

that keep data at MSL and make different enrichments at 2000m altitude.

 

147/-47 ist the first pair

20/70 is the second pair.

Andreas,

 

Does MSL stand for Meeres Spiegel Luftdruck, the ambient pressure at altiude 0m?

 

I'm astonished  that you only seem to play around with the 147/-47 settings and never mention the curve  under:

Basic / Load settings

 --> Barrometric Correction

 

This curve should, as a default, be flat at 0% over the whole Barometer range ( if the settings in Calibrate Map/Baro are 147/-47).

I thought you had to adapt this flat curve to your engines need for altitude.

How does this curve look like in your case?

 

You write:

"1.) The correction works right out of the box

If I reduce outside pressure with the poti to 80

the fuel amount rises ca 20%"

 

Does that mean, that if you have 80KPa ambient pressure,

your MAP sensor will also measure about 20% less MAP than it would at sea level

--> and your SD algo will command a VE  that is about 20% lower and thus a lower PW.

 

--> this lower PW is then risen by your Baro correction by 20% ?  Did I get that right?

 

Patrick

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Hello Patrick

                  P.S. nice planes in the pictures. The big one looks a bit like a mini Dakota. Is that, what you use to go to the  Goodwood revival?

 

I wish the twin engine one is an Avro Anson and the biplane a Bücker Bü 133 Jungmeister (Young master)

 

https://en.wikipedia.org/wiki/B%C3%BCcker_B%C3%BC_133

 

I think I must have been very lucky with my Baro correction set up judging by all the trouble others are having?

 

Roger

 

 

ps perhaps my lack of knowledge of EFI is a good thing? and Microsquirt and software is better sorted now? all most plug and play!

 

 

 

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Hello All

             Now I am confused!

 

I connected a piece of hose to the 2nd baro sensor and had a look a the laptop as I sucked and I recon I can suck to 10,000ft

 

So I stared the engine and let it warm up completely then sucked to about 75/70 baro which is 84/80 on my settings and the AFR went richer?

 

So I thought I must have the correction curve the wrong way so I altered the 2 points to about 110/115 and tried again and it went richer?

 

So does that mean its not working or the 1st MAP sensor is still at sea level?

 

But it worked at 5,000ft?

 

Roger

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Does MSL stand for Meeres Spiegel Luftdruck, the ambient pressure at altiude 0m?

Yes

 

I'm astonished  that you only seem to play around with the 147/-47 settings and never mention the curve  under:

Basic / Load settings

 --> Barrometric Correction

That does nearly nothing, compared to what happens if you play with the curve.

If you are wrong you can not get it right with these data.

 

This curve should, as a default, be flat at 0% over the whole Barometer range ( if the settings in Calibrate Map/Baro are 147/-47).

I thought you had to adapt this flat curve to your engines need for altitude.

How does this curve look like in your case?

It is 0 all around

 

You write:

"1.) The correction works right out of the box

If I reduce outside pressure with the poti to 80

the fuel amount rises ca 20%"

 

Does that mean, that if you have 80KPa ambient pressure,

your MAP sensor will also measure about 20% less MAP than it would at sea level

--> and your SD algo will command a VE  that is about 20% lower and thus a lower PW.

It is not perfect because I am cheating

The MAP sees still the pressure here.

So only the second baro is set to 80 the first sees the 100 we have here

 

--> this lower PW is then risen by your Baro correction by 20% ?  Did I get that right?

Under these conditions I got 20% more that is right and I am interested to see what

that will do on the hill with first MAP also reduced.

But what I can say is that going with o at baro correction and 147/-47 at vac and rate

the engine runs much to rich at Timmelsjoch in Austria.

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Hello All

             Now I am confused!

 

I connected a piece of hose to the 2nd baro sensor and had a look a the laptop as I sucked and I recon I can suck to 10,000ft

 

So I stared the engine and let it warm up completely then sucked to about 75/70 baro which is 84/80 on my settings and the AFR went richer?

 

So I thought I must have the correction curve the wrong way so I altered the 2 points to about 110/115 and tried again and it went richer?

 

So does that mean its not working or the 1st MAP sensor is still at sea level?

 

But it worked at 5,000ft?

 

Roger

That is the way to go.

A fuel injected car goes leaner at high altitude

not richer like a carb engine.

 

Without my car leaned unaceptable

with 2nd baro it went too rich on the hill.

I am searching for the middle.........

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Hello V8

 

That is the way to go.

A fuel injected car goes leaner at high altitude

not richer like a carb engine.

 

Without my car leaned unaceptable

with 2nd baro it went too rich on the hill.

I am searching for the middle.........

 

Now I am confused I thought the air gets thinner so the fuel gets richer?

 

I need a simple explanation please? my old brain is struggling

 

I think my Brain memory chip needs an upgrade!(I think it is still on Windows 98 but the rest of the world is on Windows 10) can I get it done on the NHS?

 

Roger

 

ps there are not many high passes in Northern Ireland but Andorra will be different next year!

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The Triumph PI cars certainly go rich. 

Less oxygen per volume of air, but same fuel is injected?

 

This may be different if a map sensor is used, maybe more like a carb car?

 

I did read somewhere that a second map sensor, wired the opposite way round and connected to the plenium one, was a good solution. Sort of makes sense.

 

Anyway, I got brave and switched my wideband controller on (having calibrated it. Usefully the LD one toggles 10/20 afr for a few seconds when switched on)

 

On 10% authority it was still running a tad rich at idle. Think I may tweek the base map a little. Again.

I also spoke to the ecu maker. He suggested I really needed a map sensor for baro correction, and closed loop was not a proper solution but would help. His suggestion was taking the lappy and altering the "injector size" setting! great minds etc on this. 

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The Triumph PI cars certainly go rich. 

Less oxygen per volume of air, but same fuel is injected?

 

This may be different if a map sensor is used, maybe more like a carb car?

 

I did read somewhere that a second map sensor, wired the opposite way round and connected to the plenium one, was a good solution. Sort of makes sense.

 

Anyway, I got brave and switched my wideband controller on (having calibrated it. Usefully the LD one toggles 10/20 afr for a few seconds when switched on)

 

On 10% authority it was still running a tad rich at idle. Think I may tweek the base map a little. Again.

I also spoke to the ecu maker. He suggested I really needed a map sensor for baro correction, and closed loop was not a proper solution but would help. His suggestion was taking the lappy and altering the "injector size" setting! great minds etc on this. 

Hello

       That,s what I thought!

 

So if I sucked on the pipe and it was reading 70kpa(10,000ft) the multiplier is 80% so it should reduce the fuel by 20%?

 

Well that,s how I understand it to be? (and it must have been working at 5,000ft = 85kpa = 90% in my settings or she would have been rich and it was hot day so would have made it worse?)

 

So I still do not know why it went rich! unless it was because at tick over the closed loop is on and was correcting it? but that does not make sense to me either!

 

Or I suppose the 1st MAP sensor is still at sea level although reading engine MAP so I assume giving conflicting readings?

 

Roger

 

ps It could just be MAGIC?

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Hello V8

 

Now I am confused I thought the air gets thinner so the fuel gets richer?

 

I need a simple explanation please? my old brain is struggling

 

It is simply what I could see in the Alps.

That is one reson and the other one is

that the working altitude compensation enrichens ...

 

So what I learned must be correct.

Do not care about the details.

It is like the whole MS thing.

I do not understand all and fully but want to understand

completely what is necessary to adjust MS for my car.

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Hello Patrick

                  No I have it set to new method and the MAP sample setting is set to event average

 

Roger

 

Hi Roger,

 

That's weird

so the PW is ok and then it goes rich, when you suck into the barometer sensor, whether you use factor >100% or <100%?

 

slightly off-topic

Since you're using FW 3.4.1. find this quote, which might be of interst for you, if you're using EDIS.

Re: MS2/Extra firmware 3.4.1 released - use this

icon_post_target.gifby jsmcortina » Sat Apr 09, 2016 1:31 pm

9th April 2016: Critical EDIS bug discovered in 3.4.1.

Please revert to 3.4.0 or use pre-3.4.2 beta 2 or later.

 

James

 

Patrick

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As a post-10CR followup, I can report the approach of giving the wideband 20% correction, plus bodging the injector size by 5% meant we never ran rich even at 2750m.

 

On top of that I am beginning to understand a bit more about all this malarky.  I fully intend fitting a map sensor to give me altitude correction. But that will be sometime over the winter...

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After some more extended testing (8 or 9 passes over 2000m on Thursday / Friday) I can say with some certainty that mine works fairly well and runs fine under power right up to the top of Stelvio (2750m ish).  It doesn't idle though, and although matters can be improved by winding the throttle stop in a bit, it still tends to drown and will only restart in flood clear mode (throttle right down).  Also pops and bangs a lot more on the over-run at higher altitudes.

 

Certainly works a whole lot better than PI though as we had a number of cars on the run that really struggled over 1500m and a couple could not get over 2000m passes.  To be fair I think both were running rich even at sea level from what the owners were saying about mpg.

 

Nick

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