Maft=afc=?

[swing lo]

I didn't feel like searching but how many people are runiing both, and how many just use the maft to tune vs putting the maft on all zero's and tuning the car with the afc?

How good could you tune your car with just the maft?

 

[DamionGST]

Pretty good but not perfect.

 

[Mike Licht]

I disagree. I have cars that qre "perfect" using only a MAFT. I would like to see someone show me a car that was tuned properly with a MAFT and then retuned with a SAFC show me more than 5 HP I don't see it.
Mike

 

[ItsStockOfficer]

Originally posted by Mike Licht
I disagree. I have cars that qre "perfect" using only a MAFT. I would like to see someone show me a car that was tuned properly with a MAFT and then retuned with a SAFC show me more than 5 HP I don't see it.
Mike

Yeah, everyone here knows that optimal tuning always lands on a multiple of 5%, requires only 3 correction points, and that both low and high throttle require the same correction.

 

[brads]

Originally posted by ItsStockOfficer
Yeah, everyone here knows that optimal tuning always lands on a multiple of 5%, requires only 3 correction points, and that both low and high throttle require the same correction.

Didn't you use a 2G MAF to tune for 550s?

Brad

 

[Mike Licht]

Originally posted by ItsStockOfficer
Yeah, everyone here knows that optimal tuning always lands on a multiple of 5%, requires only 3 correction points, and that both low and high throttle require the same correction.

Those 5% airflow points = 2% fuel changes. More than good enough for good tuning. We also don't have 3 correction points our system does not work that way it does however have three ranges where the preprogrammed fuel curve in the ECM can be "bent" to your needs. Instead of a sarcastic remark when you don't know the facts I suggest you go to a dyno and prove me wrong. I will be happy to meet you somewhere.
Mike

 

[ItsStockOfficer]

Originally posted by Mike Licht
Those 5% airflow points = 2% fuel changes. More than good enough for good tuning. We also don't have 3 correction points our system does not work that way it does however have three ranges where the preprogrammed fuel curve in the ECM can be "bent" to your needs. Instead of a sarcastic remark when you don't know the facts I suggest you go to a dyno and prove me wrong. I will be happy to meet you somewhere.
Mike

And between those points it does what exactly? And how do you deal with the differeimg needs of a car on high and low throttle? Or do you just give it the same correction and let the fuel trims figure it out?

On an AFC does that mean that those 1% airflow changes are .4%fuel changes?

 

[kpt4321]

Originally posted by ItsStockOfficer
And between those points it does what exactly? And how do you deal with the differeimg needs of a car on high and low throttle? Or do you just give it the same correction and let the fuel trims figure it out?

On an AFC does that mean that those 1% airflow changes are .4%fuel changes?

1. STFU.

2. Between the points, it interpolates.

3. The MAFT has hi and low throttle adjustment just like the stupid SAFC. Just because they don't call it the same thing as you are used to, does not mean it's not there. As a matter of fact, the SAFC's throttle-dependant corrections are NOT a good way to do it, it should be based on load or airflow. The MAFT is based on airflow, that's why it has knobs for low, mid, and high.


I'm running a MAFT and a SAFC, and I have the car running as well as it can without touching the SAFC. I'm confident enough in the MAFT's abilities to sell the SAFC.

 

[kpt4321]

Originally posted by DamionGST
Pretty good but not perfect.

Just a note: You will never have a car tuned "perfectly" when you are using airflow corrections to modify the fuel AND timing.

However, a well tuned MAFT should be "just as good" as a SAFC.

 

[ItsStockOfficer]

Originally posted by kpt4321
1. STFU.

2. Between the points, it interpolates.

3. The MAFT has hi and low throttle adjustment just like the stupid SAFC. Just because they don't call it the same thing as you are used to, does not mean it's not there. As a matter of fact, the SAFC's throttle-dependant corrections are NOT a good way to do it, it should be based on load or airflow. The MAFT is based on airflow, that's why it has knobs for low, mid, and high.


I'm running a MAFT and a SAFC, and I have the car running as well as it can without touching the SAFC. I'm confident enough in the MAFT's abilities to sell the SAFC.

1. You can, and let me spell this out for you, shut the #### up. Maybe you should try not being a dick to someone who's car is over a second and 10 MPH faster then your own.

2. My point was that it interpolates, like any tuning tool, and that often 3 points is not enough. a 2% change in fuel can be significan't, especially on a larger injector. My SAFC changes throttle settings based on boost, another easy thing to setup, but doing it based of throttle position is easy and effective.

3. Tell me how.

 

[kpt4321]

Originally posted by ItsStockOfficer
1. You can, and let me spell this out for you, shut the #### up. Maybe you should try not being a dick to someone who's car is over a second and 10 MPH faster then your own.

First of all, how fast your car is is irrelevant.

How fast did you go on a 14b, with stock injectors and all stock intake and intercooler piping? If you want to get into a pissing match, that can be done. I'd suggest we don't though.

2. My point was that it interpolates, like any tuning tool, and that often 3 points is not enough. a 2% change in fuel can be significan't, especially on a larger injector. My SAFC changes throttle settings based on boost, another easy thing to setup, but doing it based of throttle position is easy and effective.

My SAFC was set up that way as well, because basing it on throttle position is NOT accurate.

2% is 2%, no matter what size injector you are running.

If you need more precision than that, then the MAFT alone is not for you. However, my arguement is that 95% of the people using the MAFT couldn't tune to 5% accuracy if their lives depended on it, so 2% precision is fine for them.

3. Tell me how.

Tell you how WHAT?

 

[ItsStockOfficer]

2% is 2 % is crap, a larger injector sprays more fuel per unit of time its open. The larger the injector, the finer resolution you need in order to tune properly.

Mike is saying his 5% airflow correction is equal to 2% of fuel correction.

Does that mean that 1% on the SAFC is .4% fuel change, because I can tell how my car runs diffrently changing it 1-2% (.4-.8)easily. I would Like Mike to make a statement on this because Im not sure I have this correctly.


And how does it switch between your high throttle and low throttle maps, assuming it has them like you like to claim. Some cars like to have a richer high throttle map then low throttle map, some are the opposite, its often depends on the style injector. I would like to know how such things are controlled.

Also, many people find significant spool gains and timing gains throughtout the rpms band by having fine control of 3000-4000 RPM, how can i create bell shaped curves specifically within that RPM range no related to the interpolation among the rest of the map.

 

[kpt4321]

Originally posted by ItsStockOfficer
2% is 2 % is crap, a larger injector sprays more fuel per unit of time its open. The larger the injector, the finer resolution you need in order to tune properly.

I didn't say the mass was the same, I said that the percentage was the same. Whether or not you need finer resolution is debatable...

If you need more accuracy with larger injectors (and more airflow), do you need to more accurately monitor the A/F ratio too? Because, 2% fuel changes will correlate to a certain percentage of A/F ratio change, regardless. Injector size does not effect this.

And how does it switch between your high throttle and low throttle maps, assuming it has them like you like to claim. Some cars like to have a richer high throttle map then low throttle map, some are the opposite, its often depends on the style injector. I would like to know how such things are controlled.

I explained this already, it does not have throttle based tuning, because throttle based tuning is dumb and ineffective.

What you need to do, is you need to stop concentrating on how your SAFC works, and start concentrating on general tuning techniques.

The reason the SAFC uses throttle position based corrections, is because when they added a second map, they needed something to index it by. With two 2 dimensional maps and interpolation, such as the SAFC has, you really end up with one 3D map, where you set certain points, and the SAFC figures out the rest. However, a 3D map requires that 3 axes be defined. 2 of those are already defined, they are correction and engine speed (rpm). Apex-i knew that the third axis needs to be load, but load can be all kinds of things. The DSM ECU uses airflow for its load reference, Hondas use manifold absolute pressure, and the SAFC uses throttle position. Why? Because it's easy.

Throttle position based load approximations are fairly effective on a non-turbo car, because the load is fairly dependant on the cross-sectional flow area of the throttle body (ie: throttle position). However, this is NOT true on a turbo car! On a turbo car, the load can vary quite a bit for the same throttle position, and the throttle position can vary quite a bit for the same load. That means that the use of throttle position as an index for anything engine management related is not a good idea.

That is why people (like you and I) have replaced the throttle based load reference with a MAP based load reference, because it is a MUCH better representation of the load on the motor.

Since you have this mod done, why do you even keep inquiring about how the MAFT bases its corrections on throttle position? Your SAFC isn't basing its corrections on the throttle position because you didn't want it to do so, so why would you want the MAFT to do this?

The MAFT bases its corrections in airflow, which, like MAP, is a MUCH better way to do it. I could debate that basing corrections on airflow is the best way to do it, but the fact of the matter is that the difference between airflow and MAP load reference is small enough that it's not going to make a huge difference either way. However, keep in mind that the stock ECU uses airflow, so that says something in itself.

Cliffnotes: Stop referring to "throttle" based corrections, they are useless and dumb. The MAFT bases corrections on airflow, which is one of several better ways to do it.

Also, many people find significant spool gains and timing gains throughtout the rpms band by having fine control of 3000-4000 RPM, how can i create bell shaped curves specifically within that RPM range no related to the interpolation among the rest of the map.

If you think about it, they are not getting these gains from modifying the A/F curve between 3k and 4k rpm, so much as they are seeing the gains from modifying the tuning as the boost comes on and the airflow ramps up. If someone had a turbo that spooled at 6k rpm, then changing the settings at 3k and 4k wouldn't do jack for their spool time and timing.

So, what we need is fine control when the turbo is spooling, and when airflow is coming on. Whoop, the MAFT does this. The MAFT's mid knob applies when the airflow is greater than it normally is under cruise, before it reaches the kind of airflow it reaches in the higher rpm's at full boost. That means that at mid boost, and right when full boost hits but the motor is still not spinning very quickly, the mid knob is taking care of things. There is your adjustment under spool.

It's also important to note that there is a newer version of the translator in the works with finer adjustment. I will not elaborate on this any more, Mike can if he wishes.

I'd also like to hear what he has to say about this 5%=2% thing, because I don't understand it.

 

[ItsStockOfficer]

Different motors have highly different flow rates, I can;t imagine the mid knob can accurately compensate for all of them with any degree of accuracy. You still need to be able to have decnt control of what RPM and load you are making corrections at for fine tuning.

You honestly cannot achieve any better results with a better fuel tuning device then you can with the MAFT?

 

[kpt4321]

Originally posted by ItsStockOfficer
Different motors have highly different flow rates, I can;t imagine the mid knob can accurately compensate for all of them with any degree of accuracy. You still need to be able to have decnt control of what RPM and load you are making corrections at for fine tuning.

Arrgh.

A 4G63 is a 4G63, you would be surprised how close flow rates are when you're talking about lower rpm's and less than full boost.

The DSMLink guys who aren't logging boost use airflow to approximate spool points when measuring boost threshold.

When we're talking about the airflow of a motor at 3k rpm under partial boost, the difference between different intake manifolds or cams isn't going to make as much of a difference as you would expect. Products that have large VE gains usually only do so at higher RPMs.

The mid knob has a large enough range to take care of all this, and the way it slopes the settings up to the WOT setting is perfect for what it is.

Once again, I have to explain this. THE LOAD IS TAKEN CARE OF BY AIRFLOW. If you are at 300Hz and a certain rpm, then you're damned accurate in terms of load and rpm. RPM is irrelevant anyway when talking about spool, since turbos spool at different RPM's, you better off NOT making it RPM dependant. Also, what happens if you downshift, and then get on it? You're no longer spooling at 3-4k rpm, you're spooling at 5k. The RPM is totally different, but the ramping airflow is exactly the same as it would be at any RPM.

Also, it is interesting to note that the MAFT, or anything with airflow and rpm inputs, can approximate boost level fairly well.

You honestly cannot achieve any better results with a better fuel tuning device then you can with the MAFT?

I didn't say that. If it's a better device, then of course it will be able to achieve better results.

The problem is, the SAFC really isn't a much better device.

 

[Kevin Jewer]

I agree with kyle that most poeple wont need better than the 5%. But I will tell you right now that at 25 psi on pump gas, 5% one way or the other is a massive difference. I couldnt get by with that kind of resolution. But at the same time, and I use DSMlink, I couldnt live without the MAFt for its other functions. Namely letting me use my SARD BOV (that will NOT leak) and I have maxed out the 2g MAS occassionally. So I get the best of both worlds. For most poeple, the MAFt and a simple logger will work.