Transport Delay /Transport Time Constant

[CCS86]

If you have a known calibration (Whipple) with known injectors (id1050x) can I use trims to adjust this? ie. keep tweaking until they are close to =-2-3 % in the important zones?

No.

There isn't a direct connection between fuel trim value and transport delay. The TD table does affect how the trims react, but only in their stability, not in the amount.

[superman07]

Lol, whipple told me the reason I was trimming -20 on each bank was the long tubes. Back to square one.

[txtailtorcher]

Alright I'm back with much testing about all of this since. Here is what I have noticed. The TD and MAF curve are related. The easiest example of this comes from a car with a PMAS and LT's ( I'll get into the longtubes later as I have noticed quite variable data across different brands of headers).

PMAS provides a maf curve that you can use to get the car running rather well and quick. What I do ( as im sure most of you do) is I take that curve, use it primarily. From there I created a table like CCS86 has and log TD total with some math applied. . Going into the headers. I've found that drive ability and throttle response (all feel based obviously) seem to feel much more linear. In fact almost stock if not a little smoother. Using this method I've seen my fuel trims become silky smooth but also very fast reacting during transient conditions.

Headers by Brand

Kooks- personally I do not like them, no matter how much I rinse and repeat I find that you still lose out some on these due to their size. I feel that they would work best for boost due to increased airmass. All the LT cars that I've had come in with these are N/A.

Stainless Works- Very nice! Great response to the changes made and they feel great driving around for the daily driver. I wouldn't recommend for racing as odd as that sounds but I feel like they don't quite have the air Velocity for high RPM's.

American Racing- 10/10 by far my favorite. Amazing low RPM and load throttle response. Great mid range response and by far flow the best up to about 7700rpm. These are the headers we have on our shop/test car. They seem especially happy when combined with E85. Very violent onset of power and it holds very well.

Conclusion:

TD seems to mainly affect drive-ability and feel. Looking at pure scanner data also reflects positive changes when TD has been calibrated properly. There is a noticeable difference when driving a car without TD dialed in and with TD dialed in. I have one other 'test car' that currently has stock headers. Unfortunately the last time I had it to log I was in the middle of dialing in other aspects of the car and as such I did not get a good polling rate on TD total. It is coming back soon so I will have a good opportunity to see how Fords stk TD table and mine compare. As a side note I have noticed that you must make sure you are getting a fast polling rate in TD total otherwise your data will not be smooth.

[CCS86]

Alright I'm back with much testing about all of this since. Here is what I have noticed. The TD and MAF curve are related. The easiest example of this comes from a car with a PMAS and LT's ( I'll get into the longtubes later as I have noticed quite variable data across different brands of headers).

PMAS provides a maf curve that you can use to get the car running rather well and quick. What I do ( as im sure most of you do) is I take that curve, use it primarily. From there I created a table like CCS86 has and log TD total with some math applied. . Going into the headers. I've found that drive ability and throttle response (all feel based obviously) seem to feel much more linear. In fact almost stock if not a little smoother. Using this method I've seen my fuel trims become silky smooth but also very fast reacting during transient conditions.

Headers by Brand

Kooks- personally I do not like them, no matter how much I rinse and repeat I find that you still lose out some on these due to their size. I feel that they would work best for boost due to increased airmass. All the LT cars that I've had come in with these are N/A.

Stainless Works- Very nice! Great response to the changes made and they feel great driving around for the daily driver. I wouldn't recommend for racing as odd as that sounds but I feel like they don't quite have the air Velocity for high RPM's.

American Racing- 10/10 by far my favorite. Amazing low RPM and load throttle response. Great mid range response and by far flow the best up to about 7700rpm. These are the headers we have on our shop/test car. They seem especially happy when combined with E85. Very violent onset of power and it holds very well.

Conclusion:

TD seems to mainly affect drive-ability and feel. Looking at pure scanner data also reflects positive changes when TD has been calibrated properly. There is a noticeable difference when driving a car without TD dialed in and with TD dialed in. I have one other 'test car' that currently has stock headers. Unfortunately the last time I had it to log I was in the middle of dialing in other aspects of the car and as such I did not get a good polling rate on TD total. It is coming back soon so I will have a good opportunity to see how Fords stk TD table and mine compare. As a side note I have noticed that you must make sure you are getting a fast polling rate in TD total otherwise your data will not be smooth.

I don't really understand this post.

You claim that Time Delay and MAF curve are related, but then don't elaborate on how. They are not related. The MAF curve is the calibration for an instrument which measures the incoming air mass. It stands alone. The time delay describes the time it takes for a specific combustion event to reach the O2 sensor. This is a primary factor in how the ECU drives short term fueling corrections. When the TD table is wrong, STFT behavior is erratic and AFR error increases. This compromises feel.

You say Kooks "...still lose out some on these due to their size. I feel that they would work best for boost due to increased airmass." Loose out some what? How are you quantifying that? What do you mean increased airmass?

"... I feel like they don't quite have the air Velocity for high RPM's." This statement doesn't make sense either. Please explain.

"...by far flow the best up to about 7700rpm" Somehow I don't think you are flow testing these.

I don't understand how seat of the pants observations assigned to specific headers, most likely between different cars/builds/tunes, has anything to do with tuning time delay. Yes, each header type and size will require different tables values. That's the nature of this.

[txtailtorcher]

I don't really understand this post.

You claim that Time Delay and MAF curve are related, but then don't elaborate on how. They are not related. The MAF curve is the calibration for an instrument which measures the incoming air mass. It stands alone. The time delay describes the time it takes for a specific combustion event to reach the O2 sensor. This is a primary factor in how the ECU drives short term fueling corrections. When the TD table is wrong, STFT behavior is erratic and AFR error increases. This compromises feel.

You say Kooks "...still lose out some on these due to their size. I feel that they would work best for boost due to increased airmass." Loose out some what? How are you quantifying that? What do you mean increased airmass?

"... I feel like they don't quite have the air Velocity for high RPM's." This statement doesn't make sense either. Please explain.

"...by far flow the best up to about 7700rpm" Somehow I don't think you are flow testing these.

I don't understand how seat of the pants observations assigned to specific headers, most likely between different cars/builds/tunes, has anything to do with tuning time delay. Yes, each header type and size will require different tables values. That's the nature of this.

By related I mean that you can gain better control over Fuel Trims by making simultaneous adjustments to both the MAF curve and the TD table. You re-stated what I had originally said in your last sentence of the first paragraph. I'm not saying that the MAF affects TD or vice versa but that they rely on each other for fueling corrections (obviously there is a lot more to it than just that but that is what I have found.) As far as the Headers go; You are correct, I am not putting these on a bench (yet) but im measuring the rise rate of airflow vs rpm. Obviously this is affected by a number of factors but I am doing my best to get as equal car/car environment as possible. It is important to know I am using certain factors as "control" such as IVO and EVC for example. (intake manifolds fall into this category as well as CAI's and fuel type)

Kooks: I fee they lose out on the bottom end due to their size. They lack the structure to increase velocity with air mass. In short; I mean to say that they have too big of an inner diameter to keep the system pressurized. Exhaust scavenging is compromised and not enough vacuum is pulled at low RPM. However, at higher RPM when velocity is higher they have great scavenging properties thus pull exhaust much faster from the cylinder. You can see this by monitoring what I have in lower RPM ranges.

Stainless works: The opposite applies for your second 'question' I see that they have much better scavenging properties at low rpms but typically drop off at the higher ranges.

American racing: same thing as mentioned before.

I never said you could use the same values for any set of headers, that is nonsensical. What I am saying is that calibrating TD does have quite an impact on the feel of the car (obviously) but other changes are necessary for the same result across the different brands. I am using TD as a pivot point for my testing across exhaust design. I am eager to see how much it truly affects transients and if you can use it (TD) to maybe get an accurate guestimate at Manifold Volume and other Parameters that effect transients and other aspects of drive-ability.

[veeefour]

I have no problems with Kooks - have them installed on my personal car. We found that Kooks requires no Transport Delay changes...

We used Stainless Power in the last 2018 we tuned, we work with AM, BBK, Texas Speed any many other long tubes brands.
There's no difference between each long tubes tuning wise - none whatsoever.

[CCS86]

By related I mean that you can gain better control over Fuel Trims by making simultaneous adjustments to both the MAF curve and the TD table.

This is a terrible idea. Your TD table should be dialed in before touching the MAF curve (if you ever touch it that is). You are likely using logged STFTs to change the MAF curve. The problem is, with bad TD values, your STFTs will be erratic and contain a lot of bad data, as they chase AFR around. Using that data to alter the MAF curve is bad practice.

I'm not saying that the MAF affects TD or vice versa but that they rely on each other for fueling corrections

I don't agree. They don't "rely on each other". The ECU relies on both to get the most accurate fueling, but they both calibrate completely different things, which are not related to each other.

As far as the Headers go; You are correct, I am not putting these on a bench (yet) but im measuring the rise rate of airflow vs rpm. Obviously this is affected by a number of factors but I am doing my best to get as equal car/car environment as possible. It is important to know I am using certain factors as "control" such as IVO and EVC for example. (intake manifolds fall into this category as well as CAI's and fuel type)

Just "doing your best" to control for variations doesn't mean you are succeeding. Before you start throwing around conclusions you have made, you need to give more information. Are you testing these on the same cars? If not, you are likely talking about different mods and different tunes. There's no way to control for all that and derive conclusions. If you want to make conclusions, do an actual test with the same car and same tune, different headers. Then make a new thread for that, because this isn't the "which header is best" thread.

Kooks makes 1-3/4", 1-7/8", and 2" headers for Coyotes. How can you fail to acknowledge this, then say they "lose out on bottom end due to their size"? Which size are they? Have you measured the inside diameters of the primaries to compare between the brands, or are you just making assumptions?

How are you "measuring" scavenging? You "...see that they have much better scavenging properties at low rpms but typically drop off at the higher ranges", but how?

I'm not trying to be a dick, but it sounds like you are comparing apples to oranges, without any real scientific method,throwing around terms you don't completely grasp, then forming conclusions and posting them here as fact. I have studied all the things governing flow through a header at a top ranked engineering school and don't see how you conclude any of this.

[txtailtorcher]

This is a terrible idea. Your TD table should be dialed in before touching the MAF curve (if you ever touch it that is). You are likely using logged STFTs to change the MAF curve. The problem is, with bad TD values, your STFTs will be erratic and contain a lot of bad data, as they chase AFR around. Using that data to alter the MAF curve is bad practice.








I don't agree. They don't "rely on each other". The ECU relies on both to get the most accurate fueling, but they both calibrate completely different things, which are not related to each other.






Just "doing your best" to control for variations doesn't mean you are succeeding. Before you start throwing around conclusions you have made, you need to give more information. Are you testing these on the same cars? If not, you are likely talking about different mods and different tunes. There's no way to control for all that and derive conclusions. If you want to make conclusions, do an actual test with the same car and same tune, different headers. Then make a new thread for that, because this isn't the "which header is best" thread.

Kooks makes 1-3/4", 1-7/8", and 2" headers for Coyotes. How can you fail to acknowledge this, then say they "lose out on bottom end due to their size"? Which size are they? Have you measured the inside diameters of the primaries to compare between the brands, or are you just making assumptions?

How are you "measuring" scavenging? You "...see that they have much better scavenging properties at low rpms but typically drop off at the higher ranges", but how?

I'm not trying to be a dick, but it sounds like you are comparing apples to oranges, without any real scientific method,throwing around terms you don't completely grasp, then forming conclusions and posting them here as fact. I have studied all the things governing flow through a header at a top ranked engineering school and don't see how you conclude any of this.

For starters I am not using STFT to dial in MAF, secondly you again, repeated what I had already said in your second statement and you also somehow arrived at "this is the best header"? I'm not sure where you got this from as I only stated my personal opinion of what I noticed from each brand. All diameters are the same (across the kooks) as I don't see why it would even be resonable to test different diameters and A) not expect different data or B) even be comparable? It sounds to me you're trying to disprove my findings even though I never said anything concrete? This thread isn't about header brands either so I'm not sure why you felt that I was trying to determine which is best.... My main point was to show what I noticed about TD and MAF having effects on STFT's. Again I'm not sure why you assumed I would be using STFT to correct fueling. Using that process in this situation doesn't make any sense to me.

[MRRPMBRP]

I like when guys describe parts that handle air by how they "feel" like they would work, or not work. I always thought women worked off of feelings.

Or think any part is happy.

Or talk about how the part "flows", yet haven't flowed said part.

Or use other emotional words to describe parts or behavior. Some guys have violent onsets of power, while being outran by someone else, this leads to the question of what they would describe the other guys obviously more powerful onset of power as.

[txtailtorcher]

I have no problems with Kooks - have them installed on my personal car. We found that Kooks requires no Transport Delay changes...

We used Stainless Power in the last 2018 we tuned, we work with AM, BBK, Texas Speed any many other long tubes brands.
There's no difference between each long tubes tuning wise - none whatsoever.

It's odd you say that. With the logging I've done I have seen quite different sets of data per brand (obviously different size and designs) . What I was referring to in Kooks isn't a "problem" per say but more so that even though I fill out the TD table completely it does not change driver feel/pedal response nor the STFT's as much as the others do when the table is filled. I have been trying to figure out if this an error in the process that I use or if it just the way it is. This process has worked wonderfully for all other sets of headers except Kooks.

[CCS86]

For starters I am not using STFT to dial in MAF, secondly you again, repeated what I had already said in your second statement and you also somehow arrived at "this is the best header"? I'm not sure where you got this from as I only stated my personal opinion of what I noticed from each brand. All diameters are the same (across the kooks) as I don't see why it would even be resonable to test different diameters and A) not expect different data or B) even be comparable? It sounds to me you're trying to disprove my findings even though I never said anything concrete? This thread isn't about header brands either so I'm not sure why you felt that I was trying to determine which is best.... My main point was to show what I noticed about TD and MAF having effects on STFT's. Again I'm not sure why you assumed I would be using STFT to correct fueling. Using that process in this situation doesn't make any sense to me.

What are you using to "dial in" the MAF curve then?

How is this confusing? You injected a bunch of "feelings", rating headers against one another and drawing conclusions. Not only is this "off topic", but your methods are flawed/non-existent. Just because you also made false claims about TD, doesn't make everything else admissible too.

I like when guys describe parts that handle air by how they "feel" like they would work, or not work. I always thought women worked off of feelings.

Or think any part is happy.

Or talk about how the part "flows", yet haven't flowed said part.

Or use other emotional words to describe parts or behavior. Some guys have violent onsets of power, while being outran by someone else, this leads to the question of what they would describe the other guys obviously more powerful onset of power as.

Seriously. I feel like I'm arguing with my wife.

Headers don't cause a "violent onset of power". Poorly tuned driver demand / torque tables do. Who would want that anyway? I have a spend a bunch of time tuning driver demand to get a linear throttle with a PD blower and its instant boost.

[txtailtorcher]

Sorry, what 'false claims' did I make about TD? You seem rather combative than willing to inform. You also cannot seem to wrap your head around the fact that again it was my personal opinion, not fact.

[CCS86]

Sorry, what 'false claims' did I make about TD? You seem rather combative than willing to inform. You also cannot seem to wrap your head around the fact that again it was my personal opinion, not fact.

This one.

The TD and MAF curve are related.

In case you missed it: What are you using to "dial in" the MAF curve, if not STFTs?

[txtailtorcher]

Again, I explained what I meant by that in a later response after you questioned it the first time. You also didn't answer my question as to what false claims I made.

[CCS86]

Again, I explained what I meant by that in a later response after you questioned it the first time. You also didn't answer my question as to what false claims I made.

I have answered you multiple times. Read it or don't. Just because you stepped away from the claim, doesn't mean that you didn't make it. People generally believe what they read on here, so it's important to identify false claims right away.

For some reason, you are refusing to answer the question I asked though.

[txtailtorcher]

I haven't stepped away, I clarified my intentions. As well I'm using commanded vs actual AFR (lambda) to make my corrections.

[CCS86]

I haven't stepped away, I clarified my intentions. As well I'm using commanded vs actual AFR (lambda) to make my corrections.

Call it what you want. You made a claim, which read in plain english is false. If you meant something else and misspoke, fine. What you wrote is still false.

As well I'm using commanded vs actual AFR (lambda) to make my corrections.

IMO, that is a bad idea.

Think about it: the whole concept of time delay, is to acknowledge that whatever I command to happen right now, can't be measured for some varying amount of time. Time delay quantifies this and allows the fast acting STFTs to make the proper corrections.

When you try to calculate your own AFR error, you ignore this entirely. You are associating all the current operating conditions (rpm, MAF rate, spark, MP weight, pedal position, etc) with a "historical" signal: measured EQR/AFR. This is inherently flawed and introduces error in your "corrections".

[veeefour]

Girls...

[CCS86]

Girls...

Contribute something useful or move on.

There is nothing "girly" about this. If the forum members don't self police, we end up with a bunch of bad information being referenced as truth.

[txtailtorcher]

Call it what you want. You made a claim, which read in plain english is false. If you meant something else and misspoke, fine. What you wrote is still false.





IMO, that is a bad idea.

Think about it: the whole concept of time delay, is to acknowledge that whatever I command to happen right now, can't be measured for some varying amount of time. Time delay quantifies this and allows the fast acting STFTs to make the proper corrections.

When you try to calculate your own AFR error, you ignore this entirely. You are associating all the current operating conditions (rpm, MAF rate, spark, MP weight, pedal position, etc) with a "historical" signal: measured EQR/AFR. This is inherently flawed and introduces error in your "corrections".

So what would you do to make changes to the maf curve reliable?