Home
What's new
Latest activity
Authors
Store
Latest reviews
Search products
Forums
New posts
Search forums
What's new
New posts
New listings
New products
New profile posts
Latest activity
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
Cart
Cart
Loading…
What's new
Search
Search
Search titles only
By:
New posts
Search forums
Search titles only
By:
Menu
Log in
Register
Navigation
Install the app
Install
More options
Change style
Contact us
Close Menu
Forums
SVTPerformance's Chain of Restaurants
Tuning À la carte
Is Your Car Tuned Correctly?
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Message
<blockquote data-quote="truckguy" data-source="post: 12525349" data-attributes="member: 99809"><p>I dont see how the initial post is helping the community at all. The main point seems to be that if it isnt done that way then it was done wrong. The issue that most of the tuners out there have with that statement is that it is simply not true. Both methods have margins of error in them and the tuner ultimately has to be the one to make sure that everything falls in line in the calibration. </p><p></p><p>The op and blackshelby have some very good points and I dont know any tuner that would disagree with these. For example:</p><p></p><p>1. The maf curve needs to be accurate so that load calculations are accurate</p><p>2. The load calculation needs to be accurate so that the spark calculation is accurate</p><p>3. The maf calculation needs to be correct so that the torque calculation is correct.</p><p>4. If the inferred boost guage in your GT500 is not reading after a tune, then your airflow model is not accurate</p><p>4. Just because the fueling is off doesnt mean the maf curve is off</p><p></p><p>All of those are 100% valid points and are accurate information.</p><p></p><p>Where the issue comes in is the statement that if it is not done that way, then the car was tuned wrong, the car will drive badly, and the motor will blow up. Reality is that you could get your maf curve from a flow bench and all of these statements could still apply. Why?</p><p></p><p>1. Maf sensors and cold air kits all have margins of error. If your particular intake and maf wasnt the one flowed, you would most likely have a margin of error in the maf curve. That margin of error would then makes its way into your load calculations, spark calculations, and torque calculations. All things the op and blackshelby are telling you that you need to do things their way to ensure those values are accurate....Granted you would have a small margin of error but there would be an error none the less. In the production world it is probably less of an issue because the manufacturers arent trying to squeeze every last hp out of the car. In the aftermarket world where you are trying to get that last bit of power, this needs to be accurate. </p><p></p><p>2. Mechanical variances can create issues as well. For example, simply moving the filter further onto the intake tube of a JLT 123mm intake for a GT500 or 5.0 Mustang can drastically affect fuel trims. Why is that? Simply because the filter placement had a direct affect on how the air was moving across the maf which affects the amount of air that gets reported to the pcm, which affects the load calculation and the torqe model... If the intake was assembled on the flow bench one way and installed on the car slightly different, then the airflow model would not be correct. </p><p></p><p>3. Things like ram air hoods, or poorly fitted hoods can have an impact on how air flows across the maf, especially at higher speeds. If the path of the air changes across the maf at all, then the data going into the pcm is skewed and load, spark, and torque calculations will all be off.</p><p></p><p>For those that say you cant derive the transfer function without a flow bench, think of it this way. Lets say you have a bone stock car. In theory, the airflow model is correct so your fueling on the car should match what is being requested by the pcm. Now lets say you change the intake. What happens? Your fueling is now off because the new intake changed how the maf reported airflow to the pcm. If your tuner adjusts the curve to get actual fueling back to what the pcm is requesting then everything else falls back in line 100%. This works because in order for the fueling to be correct the airflow has to be correct. This is the premise that tuners are using when doing the maf curves and if done that way, like Greg mentioned earlier, the values in the table would very, very close to values derived from a flow bench. Why? Because you are simply solving a 3 part equation where you know the other 2 parts. Its sort of like finding the third side of a triangle if you already know the first two. Math tells you that you dont have to measure it directly but that you can calculate it. Now with that being said, there are a few things that need to be in order for that method to work and for all of the calculations to come out properly:</p><p></p><p>1. Everything in the fuel system must be of known values. This means using fuel injectors from companies that supply good data (ie. ford racing, injector dynamics) and if you want to be even more picky about it, pony up and get a flow matched set so you know fueling is precise. If you dont have precise fueling information when back calculating the airflow model, then the airflow model will never be correct. </p><p></p><p>2. The equipment that your tuner is using MUST be top notch equipment. I personally use dual AFM-1000's (one in each bank) calibrated before each use and require they be mounted as close to the collector as possible to ensure accurate readings. I would never trust air fuel readings from an off the shelf wideband or from a tail pipe sniffer for the purposes of tuning a car. Remember any errors in the reported fueling by those sensors is directly going to impact your airflow model. You wouldnt walk into a doctors office and expect to see him using equipment you saw at walmart. You need to expect the same from your tuner. </p><p></p><p>3.Talk to your tuner. Ask if they have used your particular intake before. The worst thing you could do is take a vehicle to a tuner with an intake they havent used before, using injectors that he doesnt have data for, and doing something aggressive like install a set of cams and expect the tune to be 100% spot on. That is asking for problems. </p><p></p><p>4. Make sure that your tuner is competent. Not every fueling error is a maf error. You need a tuner that can identify where the error is coming from so that correct fix can be applied. There are tuners out there that apply every fueling error to the maf and that is not the correct way to do things. Your tuner should be able to look at the big picture and ensure everything is in line. If he cannot do that or you are not comfortable with him, then find someone that can that you are comfortable with.</p><p></p><p>For those that say they want to help the community, the best way to do so would be to inform them with accurate information. The op and blackshelby certainly have some good information in the thread and they are correct that their are some tuners out there that have created problems by applying all of the corrections to the maf. Dumbing it down to where you simply input data from a flow bench is certainly helpful and has its place if you, the customer, are willing to spend the time and money to have your intake, maf, tb, etc. flowed. There is absolutely nothing wrong with that whatsoever. If you dont have the time or means to do so, then find a reputable tuner that uses sound principle and that can answer questions in a manner you can understand to tune your car. </p><p></p><p>For those that really want to help the community, how about some of these questions?</p><p></p><p>1. Is your tuner using lab grade equipment or is he using a $300 budget wideband?</p><p></p><p>2. Is the location your tuner is placing the wideband giving you accurate information? If its in the tailpipe, think about this. How many leaks are there in front of that wideband? Fueling is pretty much a time based thing. You have to tell the pcm when you move the o2 downstream with longtubes because there is a time shift present. What is the timeshift back to the sniffer? </p><p></p><p>3. If you have a dbw car, does your tuner actually have access to the dbw parameters and is he doing the etc properly? You would be absolutely astonished how many tuners do not have this access or knowlege and what is even scarier is what that means for you , the consumer....</p><p></p><p>Honestly, a little common sense goes along way. In my opinion, both methods of tuning the car work but both methods require a competent tuner on the other end. If either part of that equation is missing, well use your imagination....</p></blockquote><p></p>
[QUOTE="truckguy, post: 12525349, member: 99809"] I dont see how the initial post is helping the community at all. The main point seems to be that if it isnt done that way then it was done wrong. The issue that most of the tuners out there have with that statement is that it is simply not true. Both methods have margins of error in them and the tuner ultimately has to be the one to make sure that everything falls in line in the calibration. The op and blackshelby have some very good points and I dont know any tuner that would disagree with these. For example: 1. The maf curve needs to be accurate so that load calculations are accurate 2. The load calculation needs to be accurate so that the spark calculation is accurate 3. The maf calculation needs to be correct so that the torque calculation is correct. 4. If the inferred boost guage in your GT500 is not reading after a tune, then your airflow model is not accurate 4. Just because the fueling is off doesnt mean the maf curve is off All of those are 100% valid points and are accurate information. Where the issue comes in is the statement that if it is not done that way, then the car was tuned wrong, the car will drive badly, and the motor will blow up. Reality is that you could get your maf curve from a flow bench and all of these statements could still apply. Why? 1. Maf sensors and cold air kits all have margins of error. If your particular intake and maf wasnt the one flowed, you would most likely have a margin of error in the maf curve. That margin of error would then makes its way into your load calculations, spark calculations, and torque calculations. All things the op and blackshelby are telling you that you need to do things their way to ensure those values are accurate....Granted you would have a small margin of error but there would be an error none the less. In the production world it is probably less of an issue because the manufacturers arent trying to squeeze every last hp out of the car. In the aftermarket world where you are trying to get that last bit of power, this needs to be accurate. 2. Mechanical variances can create issues as well. For example, simply moving the filter further onto the intake tube of a JLT 123mm intake for a GT500 or 5.0 Mustang can drastically affect fuel trims. Why is that? Simply because the filter placement had a direct affect on how the air was moving across the maf which affects the amount of air that gets reported to the pcm, which affects the load calculation and the torqe model... If the intake was assembled on the flow bench one way and installed on the car slightly different, then the airflow model would not be correct. 3. Things like ram air hoods, or poorly fitted hoods can have an impact on how air flows across the maf, especially at higher speeds. If the path of the air changes across the maf at all, then the data going into the pcm is skewed and load, spark, and torque calculations will all be off. For those that say you cant derive the transfer function without a flow bench, think of it this way. Lets say you have a bone stock car. In theory, the airflow model is correct so your fueling on the car should match what is being requested by the pcm. Now lets say you change the intake. What happens? Your fueling is now off because the new intake changed how the maf reported airflow to the pcm. If your tuner adjusts the curve to get actual fueling back to what the pcm is requesting then everything else falls back in line 100%. This works because in order for the fueling to be correct the airflow has to be correct. This is the premise that tuners are using when doing the maf curves and if done that way, like Greg mentioned earlier, the values in the table would very, very close to values derived from a flow bench. Why? Because you are simply solving a 3 part equation where you know the other 2 parts. Its sort of like finding the third side of a triangle if you already know the first two. Math tells you that you dont have to measure it directly but that you can calculate it. Now with that being said, there are a few things that need to be in order for that method to work and for all of the calculations to come out properly: 1. Everything in the fuel system must be of known values. This means using fuel injectors from companies that supply good data (ie. ford racing, injector dynamics) and if you want to be even more picky about it, pony up and get a flow matched set so you know fueling is precise. If you dont have precise fueling information when back calculating the airflow model, then the airflow model will never be correct. 2. The equipment that your tuner is using MUST be top notch equipment. I personally use dual AFM-1000's (one in each bank) calibrated before each use and require they be mounted as close to the collector as possible to ensure accurate readings. I would never trust air fuel readings from an off the shelf wideband or from a tail pipe sniffer for the purposes of tuning a car. Remember any errors in the reported fueling by those sensors is directly going to impact your airflow model. You wouldnt walk into a doctors office and expect to see him using equipment you saw at walmart. You need to expect the same from your tuner. 3.Talk to your tuner. Ask if they have used your particular intake before. The worst thing you could do is take a vehicle to a tuner with an intake they havent used before, using injectors that he doesnt have data for, and doing something aggressive like install a set of cams and expect the tune to be 100% spot on. That is asking for problems. 4. Make sure that your tuner is competent. Not every fueling error is a maf error. You need a tuner that can identify where the error is coming from so that correct fix can be applied. There are tuners out there that apply every fueling error to the maf and that is not the correct way to do things. Your tuner should be able to look at the big picture and ensure everything is in line. If he cannot do that or you are not comfortable with him, then find someone that can that you are comfortable with. For those that say they want to help the community, the best way to do so would be to inform them with accurate information. The op and blackshelby certainly have some good information in the thread and they are correct that their are some tuners out there that have created problems by applying all of the corrections to the maf. Dumbing it down to where you simply input data from a flow bench is certainly helpful and has its place if you, the customer, are willing to spend the time and money to have your intake, maf, tb, etc. flowed. There is absolutely nothing wrong with that whatsoever. If you dont have the time or means to do so, then find a reputable tuner that uses sound principle and that can answer questions in a manner you can understand to tune your car. For those that really want to help the community, how about some of these questions? 1. Is your tuner using lab grade equipment or is he using a $300 budget wideband? 2. Is the location your tuner is placing the wideband giving you accurate information? If its in the tailpipe, think about this. How many leaks are there in front of that wideband? Fueling is pretty much a time based thing. You have to tell the pcm when you move the o2 downstream with longtubes because there is a time shift present. What is the timeshift back to the sniffer? 3. If you have a dbw car, does your tuner actually have access to the dbw parameters and is he doing the etc properly? You would be absolutely astonished how many tuners do not have this access or knowlege and what is even scarier is what that means for you , the consumer.... Honestly, a little common sense goes along way. In my opinion, both methods of tuning the car work but both methods require a competent tuner on the other end. If either part of that equation is missing, well use your imagination.... [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
SVTPerformance's Chain of Restaurants
Tuning À la carte
Is Your Car Tuned Correctly?
Top