Steve's Megasquirt/tunerstudio Help Thread

a91what

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I think you might misunderstand. The only difference from no-maf to maf is entering the maf curve for your maf & the VE table. Maf VE table is 100 in all cells. maf is only used for fuel; map is still used for spark table. You use the VE table only for trim to get a better idle.
Gotcha that seems very simple....
 
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Blown88GT

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You also have to change a couple settings in TS to tell it to use MAF.
General Settings---Primary Fuel Load = MAF
General Settings---EAE Curve Load = MAF
General Settings---MAF Settings---(should be clear what to change)
General Settings---MAF Flow Curve---(enter your calibration curve data)
Ford sensor is already 0-5V, no conversion or buffer needed.
Put a MAF Gauge on TS gauge cluster & then you'll know it's working.
 

a91what

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You also have to change a couple settings in TS to tell it to use MAF.
General Settings---Primary Fuel Load = MAF
General Settings---EAE Curve Load = MAF
General Settings---MAF Settings---(should be clear what to change)
General Settings---MAF Flow Curve---(enter your calibration curve data)
Ford sensor is already 0-5V, no conversion or buffer needed.
Put a MAF Gauge on TS gauge cluster & then you'll know it's working.
10-4 I'm pretty versed in this however I always welcome help. If you see something in a tune I missed or overlooked don't hesitate to say something.

Thanks for the info!
 

Blown88GT

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I'm one of the few that use the MAF. Only used when was able to obtain C&L flow curve data.
1. It was brand new when I converted to MS. Only had to add 2 wires to MS ECU.
2. Didn't want to lose compatibility with A9L.
3. MAF housing is larger than intercooler plumbing, so no loss there.
4. MAF was relocated to passenger side inner fender; not visible & only accessible by removing battery.
5. Added 2nd connector in engine compartment so it can be disconnected without removing battery.

Don't see your tune with MAF enabled. Only see tunes from 90sickfox.
What MAF do you intend to use?
 

a91what

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I'm one of the few that use the MAF. Only used when was able to obtain C&L flow curve data.
1. It was brand new when I converted to MS. Only had to add 2 wires to MS ECU.
2. Didn't want to lose compatibility with A9L.
3. MAF housing is larger than intercooler plumbing, so no loss there.
4. MAF was relocated to passenger side inner fender; not visible & only accessible by removing battery.
5. Added 2nd connector in engine compartment so it can be disconnected without removing battery.

Don't see your tune with MAF enabled. Only see tunes from 90sickfox.
What MAF do you intend to use?
:D unless I want to build a mixing circuit to average the input from 2 maf sensors...... I will be going speed density..... custom inlet manifold for my sbf m112 supercharger build, 2 TB one fed from each fender... My imagination got the better of me.
 
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Blown88GT

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:D unless I want to build a mixing circuit to average the input from 2 maf sensors...... I will be going speed density..... custom inlet manifold for my sbf m112 supercharger build, 2 TB one fed from each fender... My imagination got the better of me.
You said you wanted to use a MAF, now you say you need 2 MAFs. Put 1 MAF before the throttle body.. Don't tell me you need 2 throttle bodies!
 

a91what

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You said you wanted to use a MAF, now you say you need 2 MAFs. Put 1 MAF before the throttle body.. Don't tell me you need 2 throttle bodies!
Obviously you don't follow my crazy mad max style build thread...... I don't exactly follow the status quo. There is nothing bolt on in what I'm building so I went overboard and am feeding the blower with 2 65mm throttle bodies, one mounted on each side of the blower.
 

stanglx2002

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The file type is not currently on the approved list. I have detailed the instructions on how in my post, I have an updated picture of what I'm going to use that's a bit more aggressive than what's there.
@Noobz347 can you add (.msqpart) files to the approved list I know pita. :D
@a91what Thoughts?

I have been battling some issues with the AFR being out of whack when colder and hotter air temperatures. It looks as my MAT average temperatures are around 150*, and rise to around 175* at idle making the AFR go lean. It also does the opposite in the cold mornings with temps around 130* making it rich.

I was looking at tuning the MAT Air Density Table, but it looks like you are using the MAT/CLT Correction to make this correction to MAT.

What data points are you looking at to tune this table?
 
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a91what

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Basically the clt/mat table will blend the clt in at low airspeed
Airspeed is kpa×rpm
So you want to blend near 100 at idle this will help keep things in line at idle with the wandering mat.
Also proper dead time settings on the injector will play a role.

Use the file I posted on the tech thread for this it works in most situations.

The idea is that at low airspeed the manifold air is the same temp as the clt
 

stanglx2002

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I will load those settings in, and run a datalog this afternoon on my way home from work to see how it works.

What will this do to hot-starts? Does this correct that issue as well?
 
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stanglx2002

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what are the normal MAT temps you are seeing in datalogs? Mine on avg are 150*

Doesn't that make the MAT Air Density Table curve wrong? That means there is always a correction factor being applied, which would reduce the fuel by as much as 15% all the time right?
 
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a91what

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what are the normal MAT temps you are seeing in datalogs? Mine on avg are 150*

Doesn't that make the MAT Air Density Table curve wrong? That means there is always a correction factor being applied, which would reduce the fuel by as much as 15% all the time right?
No. The mat air density table is based off of the ideal gas law. The issue is that at low air speeds latent heat is transferred to the air before it enters the chamber. Hot air carries less oxygen.

Watch in a datalog when you go WOT the mat temps will fall rapidly, this is because the heat transfer cannot have as much of an effect on fast moving air.

The table is not wrong you must find a method of correction (just like the oem do) to compensate for the latent heat absorption. Some have good luck moving the mat sensor before the TB. Some use the mat in the maf sensor. However the clt/mat correction table is needed in all instances to cure the AFR drift at idle.

Good luck and if you find a method that works better than mine please share it I will add it to the tech notes.
 
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stanglx2002

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No. The mat air density table is based off of the ideal gas law. The issue is that at low air speeds latent heat is transferred to the air before it enters the chamber. Hot air carries less oxygen.

Watch in a datalog when you go WOT the mat temps will fall rapidly, this is because the heat transfer cannot have as much of an effect on fast moving air.

The table is not wrong you must find a method of correction (just like the oem do) to compensate for the latent heat absorption. Some have good luck moving the mat sensor before the TB. Some use the mat in the maf sensor. However the clt/mat correction table is needed in all instances to cure the AFR drift at idle.

Good luck and if you find a method that works better than mine please share it I will add it to the tech notes.
Im sorry in the terms of the words that I used, and would like to clarify...

You are correct in that the MAT Air Density Table is based on the "ideal gas law", but the issue is that it is based on physics not the real world. From my research and viewing of numerous of my own datalog's over the past 6 months, I have noticed that this is something that most of us ignore thinking we don't need to tune it or don't know much about, so I wanted to give back to everyone my findings to gain others feedback on the subject.

What I have found out is that the "ideal gas law" is based on an air temperature of 70* to be 100%, and then as a correction% adds fuel when colder than 70* and removes fuel above 70*. The curve is set by default assuming that the MAT/IAT sensor is reading ambient temperature (or close to) as being the intake of air into the engine. In our case of our sensors being located in the lower intake manifold these numbers will be increased due to the heat of the engine. This is very different from "heat soak", so we can not confuse the two. If you review your datalogs for the field "Fuel: Air Cor" you will notice a %, which if less than 100% it is removing fuel and above 100% it is adding fuel. I noticed in my datalogs that my average MAT temperature was around 150* during normal driving/cruising at 70* ambient temperature, which means that the correction% factor was around 82% based on the default curve which is removing 17% fuel.

From what I can tell the curve needs to be shifted to your average MAT Temperature at 70* ambient temperature, but I am not sure if this is correct. Other turners also seem to think the curve maybe to aggressive as well, but this can be confirmed at different MAT temperatures and your EGO Correction% as long as you have a good VE Table to work with or you would be chasing your tail. I wanted to put this out there to everyone for there feedback on the subject.

@a91what what are your thoughts as I respect your feedback.
 

a91what

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Im sorry in the terms of the words that I used, and would like to clarify...

You are correct in that the MAT Air Density Table is based on the "ideal gas law", but the issue is that it is based on physics not the real world. From my research and viewing of numerous of my own datalog's over the past 6 months, I have noticed that this is something that most of us ignore thinking we don't need to tune it or don't know much about, so I wanted to give back to everyone my findings to gain others feedback on the subject.

What I have found out is that the "ideal gas law" is based on an air temperature of 70* to be 100%, and then as a correction% adds fuel when colder than 70* and removes fuel above 70*. The curve is set by default assuming that the MAT/IAT sensor is reading ambient temperature (or close to) as being the intake of air into the engine. In our case of our sensors being located in the lower intake manifold these numbers will be increased due to the heat of the engine. This is very different from "heat soak", so we can not confuse the two. If you review your datalogs for the field "Fuel: Air Cor" you will notice a %, which if less than 100% it is removing fuel and above 100% it is adding fuel. I noticed in my datalogs that my average MAT temperature was around 150* during normal driving/cruising at 70* ambient temperature, which means that the correction% factor was around 82% based on the default curve which is removing 17% fuel.

From what I can tell the curve needs to be shifted to your average MAT Temperature at 70* ambient temperature, but I am not sure if this is correct. Other turners also seem to think the curve maybe to aggressive as well, but this can be confirmed at different MAT temperatures and your EGO Correction% as long as you have a good VE Table to work with or you would be chasing your tail. I wanted to put this out there to everyone for there feedback on the subject.

@a91what what are your thoughts as I respect your feedback.
I agree and disagree.
- the table does function and does so correctly. Your assumption that refining the curve to your average mat temps may work for the most part. However I have seen in my own logs under boost on a 90* ambient day my mat temps go from 170* at cruise all the way down to ambient (or just above)of 95* after a long 4th gear pull. My AFR was spot on the entire pull I do not use ego correction under boost...
If I had adjusted the curve as you have suggested then the fuel in that much lower temp range would have been much richer.

-simply moving the mat sensor before the TB will alleviate the mat correction issue you are experiencing. Quite a few people do this and then the mat/clt correction table works to keep the AFR creep under control.

I would like to see an adjusted air density table used year round and see the effects. Much cooler air is going to be ingested by the engine I wonder if this would have a negative impact on the tune after the adjustment.

I tuned my car untill the issue you are experiencing was gone, this was done with the clt/mat correction table and a mat sensor in the intercooler piping. I have not attempted to change the density table myself I have however reloaded a correct table to tunes that other have adjusted the table in to correct erroneous errors during high temperature boost.

If you want to tune your own density table and are willing to be a guinne pig....this is how I would go about it. Zero the table out at 100% across the temp range. Then run the car and disable ego correction.... take a drive and datalog.
Using the AFR vs target AFR vs mat temp in the table generator(hopefully you can use all of these fields there) in megalog viewer you will be able to see the needed correction by temp some math will be involved using the fueling equation but I believe this will let you get what you are looking for. It will be time consuming for sure if you need help I am willing to entertain the idea, if it is successful it will make a great writeup.

Edit: I forgot to mention any adjustment to the density table will heavily affect the tune an entire 've table adjustment may be necessary.
 

stanglx2002

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Thank you for your feedback on the subject as I do really appreciate it.

I agree with your comments as well on the subject. I would be curious to know now that's its getting colder does your AFR stay spot at that same cruise you were at 170* or do they become richer than target?

The thing I have been noticing is the curve is most effected by the summer and winter months when the temperatures are quite different.
 

a91what

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Thank you for your feedback on the subject as I do really appreciate it.

I agree with your comments as well on the subject. I would be curious to know now that's its getting colder does your AFR stay spot at that same cruise you were at 170* or do they become richer than target?

The thing I have been noticing is the curve is most effected by the summer and winter months when the temperatures are quite different.
I tuned my engine in the winter months of Florida, I noticed no appreciable difference in AFR during the summer months. This may be due to the fact that I do use the mat/clt blend table so no matter the ambient temp I assume air temp is the same as clt temp at low airspeed.

My new blower install has the iat sensor under the blower in the manifold. So if I do have an issue using my current method I will detail how I deal the issue once I'm in the tuning stage.
 

stanglx2002

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I was doing more reading on your injector deadtime, and are unsure how you come up with the numbers for the deadtime and battery Voltage Correction? Can you explain more on how to use the two links/tables to come up with those values for stock cobra 24lb injectors?
 

a91what

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How to get the proper dead time information will require we jump on the hyperlink bus......
http://www.efidynotuning.com/injdata.htm

We will then select the injector in question.
93-95 Cobra 24LB injectors Blue(Stock)
then hit load.....
Capture.PNG Injector dead time.png

In TunerStudio only 2 parameters matter, Deadtime and voltage correction. Dead time is based off of 13.2v so a bit of math is involved.......
13v-.59
14v-.50

.59-.50=.09 .09/10=.009 .009*2=.018 .59-.018=.572

So at 13.2v we have a dead time of .572

For the correction voltage it is ms/v so to do this we will take a mean correction from 12-14v

.81-.59=.22 .59-.50=.09 .22+.09=.31 .31/2=.155

This method of correction is not perfect of course because older style injectors are not as linear as the newer ones are. so the mean method will give you the lowest error. If you do not have heavy electrical loads you may be able to get away with using only positive correction numbers for the voltage correction.
In this instance i would go with a correction of .100


I hope this carifies things.
 
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