Whats your wideband solution?

[LittleBlueGT]

I meant more fuel required over and above what the MAF sensor sees.

 

How can a better IC magically make more air appear in the system that the MAF doesn't see? My evidence does not support THAT!

[NSFW]

How often do Mustang owners post up about blown motors?

 

I wonder if Subaru motors are more prone to failure. I've seen enough pictures of cracked ring lands to make me pretty paranoid about detonation.

 

I should clarify that to "motors blown by poor tuning." Failures due to other causes aren't relevant to the question.

[cryo]

I meant more fuel required over and above what the MAF sensor sees.

 

How can a better IC magically make more air appear in the system that the MAF doesn't see? My evidence does not support THAT!

 

How I always looked at it when working with other cars running small" fmic vs "big" fmic or upgraded sidemount/tmic situations.

 

No change at maf because of iat measurements taken pre-ic

assuming the same piping length

more temp drop across core theoretically *because of more efficient or larger core*

denser/colder charge at tb *albiet minor or major*

 

That is the theory I have always heard and have seen used. Fuel would need to be added because the maf has no way of seeing the increased density of the air post ic vs the previous "overworked tmic,smic etc" situation yet. The ecu would not see the change untill after the fuel trims show a lean condition. Now if the previous ic setup was not a big limiting factor under most driving conditions I could see the a/f learning not making much in the way of adjustments over the new setup other than maybe some slight WOT adjustments like you mentioned.

 

my .02 not that its even worth that.

 

Dave

[Boostin1657615274]

again it would be sweet to have another airflow sensor installed in blow-through right at the TB

[NSFW]

That is the theory I have always heard and have seen used. Fuel would need to be added because the maf has no way of seeing the increased density of the air post ic vs the previous "overworked tmic,smic etc" situation yet.

 

I got three words for you: conservation of mass.

 

Barring leaks, the mass that reaches the intake manifold is equal to the mass that went past the MAF sensor. Temperature changes don't affect that.

 

Or look at it this way: if 15,000 grams of air go past the MAF sensor over the course of one minute, and 15,100 go into the intake manifold, where do the extra 100 grams come from?

[LittleBlueGT]

I got three words for you: conservation of mass.

 

Barring leaks, the mass that reaches the intake manifold is equal to the mass that went past the MAF sensor. Temperature changes don't affect that.

 

Or look at it this way: if 15,000 grams of air go past the MAF sensor over the course of one minute, and 15,100 go into the intake manifold, where do the extra 100 grams come from?

 

Exactly.

[cryo]

I got three words for you: conservation of mass.

 

Barring leaks, the mass that reaches the intake manifold is equal to the mass that went past the MAF sensor. Temperature changes don't affect that.

Or look at it this way: if 15,000 grams of air go past the MAF sensor over the course of one minute, and 15,100 go into the intake manifold, where do the extra 100 grams come from?

 

I do agree that mass is mass regardless of temp but I dont see it as simple in this situation because of the variables. *ie engines reaction to different intake cylinder temps and the combustion event*

 

ex: If you are reducing post ic temps with no other changes you will have more combustable o2 into the cylinder thus more load and hopefully higher ve requiring more fuel do you not agree? I have seen tuning/hardware changes turn up less grams measured but quicker acceleration and more power which I dont fully understand. I just dont see how a maf could possibly measure for that type of change untill it is able to make corrections through a/f learning. I am in no way arguing but more interested in others opinions and experiences, I am always enlightened to learn I was wrong and learn from the experience.

 

Dave

[LittleBlueGT]

I do agree that mass is mass regardless of temp but I dont see it as simple in this situation because of the variables. *ie engines reaction to different intake cylinder temps and the combustion event*

 

ex: If you are reducing post ic temps with no other changes you will have more combustable o2 into the cylinder thus more load and hopefully higher ve requiring more fuel do you not agree? I have seen tuning/hardware changes turn up less grams measured but quicker acceleration and more power which I dont fully understand. I just dont see how a maf could possibly measure for that type of change untill it is able to make corrections through a/f learning. I am in no way arguing but more interested in others opinions and experiences, I am always enlightened to learn I was wrong and learn from the experience.

 

Dave

 

The lower your temps are going into the cylinder the less psi you will actually be running, all things being equal. If you run the same psi (as measured at the intake manifold) and you have a denser air charge going in, then you are ingesting more air, which will show itself in the MAF reading.

 

Power and MAF are not interchangeable. If you are making more power at the same airflow, then you are just running things more efficiently.

[NSFW]

The lower your temps are going into the cylinder the less psi you will actually be running, all things being equal.

 

Yes. See also: http://en.wikipedia.org/wiki/Gay-Lussac%27s_law

[LittleBlueGT]

Yes. See also: http://en.wikipedia.org/wiki/Gay-Lussac%27s_law

 

I know!

[NSFW]

I know you know, but who knows what they know?

[LittleBlueGT]

I know you know, but who knows what they know?

 

I know that you know that I know.

 

But I don't know if they know that I know, or that you know, or that I know that you know.

 

[NSFW]

Truly, you have a dizzying intellect.

[Boostin1657615274]

I got three words for you: conservation of mass.

 

Barring leaks, the mass that reaches the intake manifold is equal to the mass that went past the MAF sensor. Temperature changes don't affect that.

 

Or look at it this way: if 15,000 grams of air go past the MAF sensor over the course of one minute, and 15,100 go into the intake manifold, where do the extra 100 grams come from?

 

Custom MAF scaling complicates all this, and we'd really have to have the expensive modeling software that the OEM's have to get a better handle on this issue. But yes, 15,000 total grams of grams in the total intake tract past the MAF is 15,000 grams. The issue here is the distribution of that air, or how much of that air is actually ending up in the cylinders at any given time.

 

There's stuff going on inside the engine that the MAF can't see. With a more efficient intercooler the same mass of air may be in the totality of the intake piping, but that doesn't mean the same mass of air is entering the cylinders during a given intake stroke event. The cooler air from lower temperatures may be more effectively compressed during the dynamic supercharging that takes places as the valves open and close (Helmholtz effects). This effect isn't seen by the MAF.

 

http://legacygt.com/forums/attachment.php?attachmentid=82206&stc=1&d=1269235000

 

Once the valve (assume a single intake valve for simplicity's sake) completely closes, the air hits a wall and a pressure wave reverberates back into the intake plenum. When the pressure wave reaches the plenum it is like compressing a spring. The spring force is then released and this helps cram more air into the next cylinder once that valve is mostly open. That's the intake inertia effect, and it is dependent on runner length, plenum volume, Reynolds numbers, and other stuff.

 

http://legacygt.com/forums/attachment.php?attachmentid=82207&stc=1&d=1269235000

 

During conditions of valve overlap, the intake valve for a cylinder will begin to crack open while the exhaust valve is still open (overlap). There will be high exhaust pressure in the cylinder which creates a pressure difference and another pressure wave in the intake manifold. Depending on plenum volume and runner length, that pressure wave (through similar velocity and spring-like effects) will help cram more air into another cylinder just as its valve is closing. That's the exhaust obstruction effect.

[LittleBlueGT]

Blah blah blah.

 

Like the graphs though, and always interesting reading.

 

I don't care what the air does once it is past the MAF, but unless there is a leak, the only way out is through the cylinders.

 

I wouldn't be so stubborn on this, but I have gone through 4 sets of headers, and 3 different ICs, and none of them changed the AFRs of the motor.

[Infamous1]

As remedial as it may sound...who cares, whats the argument? It can all be tuned out. If there is no change great, if there is dial it in. I have seen it both ways. I have no explanation for it, but it can be accounted for. This has nothing to do with the topic..come on guys

[Boostin1657615274]

As remedial as it may sound...who cares, whats the argument?

 

yeah I guess it's all academic. Again, in my case the car needed more fuel (according to the factory front O2 sensor) so I changed the fuel tables and that was it.

[LittleBlueGT]

yeah I guess it's all academic. Again, in my case the car needed more fuel (according to the factory front O2 sensor) so I changed the fuel tables and that was it.

 

According to the OEM O2 sensor? What? It is in the OEM location too, right?

 

How much more is the better TMIC gonna cool the charge at less then 80 g/s? I even thing it will cool it less, as the end-tanks are aluminum, and the OEM TMIC actually is very efficient at cooling small airflow, I think probably better then the Perrin unit.

 

I am talking about AFR changes at WOT, like 200-350 g/s.

 

FWIW here is my LV before and after my FMIC:

 

http://i248.photobucket.com/albums/gg194/littlebluegt/LearningView_SS_12-18-200961428AM.jpg

 

http://i248.photobucket.com/albums/gg194/littlebluegt/LearningView_SS_12-27-2009115701PM.jpg

 

http://i248.photobucket.com/albums/gg194/littlebluegt/LearningView_SS_2-28-2010115115PM.jpg

 

http://i248.photobucket.com/albums/gg194/littlebluegt/LearningView_SS_3-3-2010112034PM.jpg

 

W/o looking at the date, which is before and which is after? (obviously A fluctuates a bit due to heat-soak)

 

Infamous1: some of us like to talk about such trivial things. There are reasons for differences, whether or not someone cares is up to them.

[Boostin1657615274]

According to the OEM O2 sensor? What? It is in the OEM location too, right?

no, it's been relocated behind the turbo.

 

I don't try to put too much thought into MAF stuff because MAF's are a pain in the ass once you get past stage 2 style setups. There are too many things that we can't understand without expensive modeling software and proprietary information. I just fiddle with whatever tables I need to fiddle with it until I see the results I like. It's the same deal with adjust IAT correction on speed density cars with standalones.

[LittleBlueGT]

no, it's been relocated behind the turbo.

 

I must have forgotten that you did that.

 

Did you have any troubles with AFR oscillation at steady state cruise? I did and had to rescale my sensor.

[NSFW]

W/o looking at the date, which is before and which is after? (obviously A fluctuates a bit due to heat-soak)

I don't think it's heat-soak actually. There's something very non-linear going on with fuel delivery around idle. Ever notice that the per-injector compensations all add a bit of pulse width around idle? I think it's related to the way the stock AF Learning boundaries are at 5 g/s and 10 g/s, creating a B trim that's almost impossible to reach. But I can't quite figure it out. I tried removing the per-injector comps in that corner, and compensation with extra latency, but it just made my car idle poorly. Only made two attempts though, I need to take another crack at it some time.

[LittleBlueGT]

I don't think it's heat-soak actually. There's something very non-linear going on with fuel delivery around idle. Ever notice that the per-injector compensations all add a bit of pulse width around idle? I think it's related to the way the stock AF Learning boundaries are at 5 g/s and 10 g/s, creating a B trim that's almost impossible to reach. But I can't quite figure it out. I tried removing the per-injector comps in that corner, and compensation with extra latency, but it just made my car idle poorly. Only made two attempts though, I need to take another crack at it some time.

 

I disagree (never been afraid of saying that) and here is why:

 

My AFRs (and others I have tuned) change with IAT. it is easy for the MAF to get heat-soaked to 140+F when you are stopped. I find that my learning "A" moves with IAT only. And it makes sense. IAT affects how the MAF works, but at low speed the whole aluminum unit heatsoaks, along with the sensor, but the actual temp of the air is not really 140F when it enters the system.

 

Also, I can hit learning "B" very easily, it is called fast idle when the car is cold.

[NSFW]

Interesting... I'll have to watch IAT in this scenario. I have to admit I haven't looked at it at all for a long time.

[LittleBlueGT]

Interesting... I'll have to watch IAT in this scenario. I have to admit I haven't looked at it at all for a long time.

 

Go 100 mph, then put the car in neutral and watch the trims change as the car idles away at normal IAT.

 

Then sit in traffic idling and watch it change the other way.

[McDowell Performance Tunin]

I see you can use the LM-1 with RomRaider. Anyone running the LM-2 through it? I've heard yes and no. Even if you can, the display is pretty sweet looking