My adventure in to tuning! Tips and tricks before you try it yourself.
10-28-2015, 12:04 PM
#1
My adventure in to tuning! Tips and tricks before you try it yourself. I will predicate this with the following statement:
I am a novice tuner with my only experience coming from using Hptuners on my car. A 2000 Trans AM with the factory PCM. All comments and opinions come from tuning my car. The purpose of this post is to hopefully keep someone getting in to tuning from making the same mistakes as I did.
So my adventure began when I installed a medium sized cam on my SBE LS1. Knowing how often I like to change parts out for bigger and better, I decided I wanted to try and tune my own car and save $$$ doing it. Dyno tunes run 500-600$ in my area, and I was able to pick up a used Hptuners Standard VCM suite for 375$ with 6 credits left on it. I ordered books, read tutorials, browsed forums and watched videos until I thought I was knowledgeable enough to begin.
Mistake #1
Hptuners has a lot of things you can change, and one of the core problems is a lot of those things only have a brief description of what they are. A lot of the discussions online do not really explain what the effect is of changing them. I started tuning things that people said worked for them, without really knowing what it was going to accomplish.
Mistake 2#
A bad combination of parts or mechanical problems will cause you headache after headache. I started tuning my car after the cam install and didn't realize my fuel pump was going weak at WOT. I spent hours trying to get my car to run richer up top and really risked damaging my engine. MAKE SURE YOUR CAR IS IN GOOD MECHANICAL ORDER BEFORE TUNING. After installing a new pump every bit of fuel tuning I did was off. Days of tuning wasted.....
Mistake #3
Just because it worked well for someone else does not mean it is going to work well for you. I ended up jacking my idle spark tables up into the low 30 range because I read were other people had success smoothing out a cammed idle. What this did for me was essentially negated idle spark under and over speed, the car was already advancing the spark so much that the corrections the PCM tried to make really had no effect. Took my idle advance down into the 20 degree range and car idled rock steady at 800 RPM.
Mistake #4
Understanding cause and effect..... Fixing one problem through tuning can easily cause a problem somewhere else. It is about finding a happy median.
Mistake #5
Being realistic with what can be accomplished through tuning. So after fighting and fighting and not really getting anywhere I decided I didn't want to try anymore. I called Frost and wanted to schedule an appointment to have him do it instead. Long story short, he told me he wouldn't do it. Trying to clean up the mess from a hobby tuner was entirely too much time and wouldn't be worth it for him. He was absolutely right. He did spend more time then he had to spare telling some things to try, and telling me some things that were just going to be inherent in driving a car around with a big cam. His advice helped tremendously and I was finally able to solve about 90% of the problems I had.
Mistake #6
Fueling, Fueling, Fueling....... If your fueling isn't right, tuning anything else is a waste of time.
If I had to do it over again this is how I would proceed.
#1 - Convert to the Hptuners Speed Density OS. Tuning VE tables is much, much, much easier. You can real time alter your VE tables and see the cause and effect of your changes without flashing over and over. Another perk is being able to street tune without being in limp mode. Also, you're only dealing with one VE table instead of 2. After I had my VE tables dialed in I was able to copy those change back over to my MAF tune.
#2 - Start with LTFT tuning before moving on to Wideband. I had much greater success using LTFT's to begin with then jumping straight to wideband and here is why. Wideband open loop tuning right out the gate has you dealing with fueling that is all over the place. Starting out with LTFT gets you in to the general vicinity of where you need to be and has the added bonus of keeping your fueling at a safe AFR. I would drive to work in speed density mode every day for a week (25 mins) and reset trims before every drive AFTER the car was warmed up. When I got to work i would copy my LTFT scan and paste special 1/2 % into my VE table. Making half changes seemed to keep me from overcorrecting. After 4-5 days doing this back and forth all my LTFT's were -1 to +1.
#3 - While its nice to have a VE table scan with all low error percentages, my car ran better concentrating more on smooth transitions. If you are going to go back to running closed loop, you want to have your table dialed in to the point were your PCM can make the necessary corrections.
#4 - Spark tables need to also have smooth transitions. Going from 40 degrees to 20 degrees all of a sudden is not good. You have to look at where you are shifting. If your first to second shift transitions you from one extreme to the other, it makes for a rough shift.
#5 - Idle tuning has no magic bullet. There isn't one table that is going to fix an erratic idle. Poor tuning of fuel and spark is going to make every mistake show up when you try to tune idle. There are more settings to getting good idle quality then anything else.
#6 - WOT tuning without a wideband is dangerous and a waste. On a stock tune, closed loop is disabled and your fuel calculations are done from the MAF. If your MAF curve is off, it is really hard to get accurate readings without a wideband. This can make the difference between a melted piston and running rich to the point where you are losing 30+ horsepower. To put it in to perspective I made 5 passes at the dragstrip running 15:1 afr before I installed my wideband, I didn't suffer any damage thankfully.
I have ran out of time, and if anyone wants to point out errors I will gladly edit my post. Open and kind discussion is appreciated.
I am a novice tuner with my only experience coming from using Hptuners on my car. A 2000 Trans AM with the factory PCM. All comments and opinions come from tuning my car. The purpose of this post is to hopefully keep someone getting in to tuning from making the same mistakes as I did.
So my adventure began when I installed a medium sized cam on my SBE LS1. Knowing how often I like to change parts out for bigger and better, I decided I wanted to try and tune my own car and save $$$ doing it. Dyno tunes run 500-600$ in my area, and I was able to pick up a used Hptuners Standard VCM suite for 375$ with 6 credits left on it. I ordered books, read tutorials, browsed forums and watched videos until I thought I was knowledgeable enough to begin.
Mistake #1
Hptuners has a lot of things you can change, and one of the core problems is a lot of those things only have a brief description of what they are. A lot of the discussions online do not really explain what the effect is of changing them. I started tuning things that people said worked for them, without really knowing what it was going to accomplish.
Mistake 2#
A bad combination of parts or mechanical problems will cause you headache after headache. I started tuning my car after the cam install and didn't realize my fuel pump was going weak at WOT. I spent hours trying to get my car to run richer up top and really risked damaging my engine. MAKE SURE YOUR CAR IS IN GOOD MECHANICAL ORDER BEFORE TUNING. After installing a new pump every bit of fuel tuning I did was off. Days of tuning wasted.....
Mistake #3
Just because it worked well for someone else does not mean it is going to work well for you. I ended up jacking my idle spark tables up into the low 30 range because I read were other people had success smoothing out a cammed idle. What this did for me was essentially negated idle spark under and over speed, the car was already advancing the spark so much that the corrections the PCM tried to make really had no effect. Took my idle advance down into the 20 degree range and car idled rock steady at 800 RPM.
Mistake #4
Understanding cause and effect..... Fixing one problem through tuning can easily cause a problem somewhere else. It is about finding a happy median.
Mistake #5
Being realistic with what can be accomplished through tuning. So after fighting and fighting and not really getting anywhere I decided I didn't want to try anymore. I called Frost and wanted to schedule an appointment to have him do it instead. Long story short, he told me he wouldn't do it. Trying to clean up the mess from a hobby tuner was entirely too much time and wouldn't be worth it for him. He was absolutely right. He did spend more time then he had to spare telling some things to try, and telling me some things that were just going to be inherent in driving a car around with a big cam. His advice helped tremendously and I was finally able to solve about 90% of the problems I had.
Mistake #6
Fueling, Fueling, Fueling....... If your fueling isn't right, tuning anything else is a waste of time.
If I had to do it over again this is how I would proceed.
#1 - Convert to the Hptuners Speed Density OS. Tuning VE tables is much, much, much easier. You can real time alter your VE tables and see the cause and effect of your changes without flashing over and over. Another perk is being able to street tune without being in limp mode. Also, you're only dealing with one VE table instead of 2. After I had my VE tables dialed in I was able to copy those change back over to my MAF tune.
#2 - Start with LTFT tuning before moving on to Wideband. I had much greater success using LTFT's to begin with then jumping straight to wideband and here is why. Wideband open loop tuning right out the gate has you dealing with fueling that is all over the place. Starting out with LTFT gets you in to the general vicinity of where you need to be and has the added bonus of keeping your fueling at a safe AFR. I would drive to work in speed density mode every day for a week (25 mins) and reset trims before every drive AFTER the car was warmed up. When I got to work i would copy my LTFT scan and paste special 1/2 % into my VE table. Making half changes seemed to keep me from overcorrecting. After 4-5 days doing this back and forth all my LTFT's were -1 to +1.
#3 - While its nice to have a VE table scan with all low error percentages, my car ran better concentrating more on smooth transitions. If you are going to go back to running closed loop, you want to have your table dialed in to the point were your PCM can make the necessary corrections.
#4 - Spark tables need to also have smooth transitions. Going from 40 degrees to 20 degrees all of a sudden is not good. You have to look at where you are shifting. If your first to second shift transitions you from one extreme to the other, it makes for a rough shift.
#5 - Idle tuning has no magic bullet. There isn't one table that is going to fix an erratic idle. Poor tuning of fuel and spark is going to make every mistake show up when you try to tune idle. There are more settings to getting good idle quality then anything else.
#6 - WOT tuning without a wideband is dangerous and a waste. On a stock tune, closed loop is disabled and your fuel calculations are done from the MAF. If your MAF curve is off, it is really hard to get accurate readings without a wideband. This can make the difference between a melted piston and running rich to the point where you are losing 30+ horsepower. To put it in to perspective I made 5 passes at the dragstrip running 15:1 afr before I installed my wideband, I didn't suffer any damage thankfully.
I have ran out of time, and if anyone wants to point out errors I will gladly edit my post. Open and kind discussion is appreciated.
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cino (02-16-2020)
10-28-2015, 12:33 PM
#2
Very good post. The mistakes you made are very common when learning to tune. The problem I see all the time is people just copy and paste what someone posts on a forum and it gets repeated several times and then people swear thats the way. If your going to tune and get better at out you have to do what you did and put in the time and learn what does what and what changes cause what result.
10-28-2015, 02:37 PM
#3
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Agreed a desire to learn how to do it is a big key. Good working order is a big thing too a simple issue can drive you crazy when you are trying to chase it in the tune and its mechanical.
11-02-2015, 10:23 AM
#6
Good info here for the novice.
I would add another common mistake is going too large in Injector.
Injectors that are too large are a pain to tune idle & low speed drivability. If it is a race car then it is no big deal, but for a daily driver you need just big enough to make the power but small enough to offer good spray pattern & control at lower duty cycles. You can spend months getting something right while it changes from day to day, especially in SD tunes, as weather conditions change. I have had some tell me over the years to have inj. Run no more then 85% duty cycle. I don't agree here. I try to find a size that will run 97-98% DC at your max HP number. I've ran some to over 100% as long as it is for short periods or at the top of the rev range. Injector life will suffer but it will save you a lot of headaches tuning & the mileage difference over a number of years will pay for new ones if one starts to go down.
I would add another common mistake is going too large in Injector.
Injectors that are too large are a pain to tune idle & low speed drivability. If it is a race car then it is no big deal, but for a daily driver you need just big enough to make the power but small enough to offer good spray pattern & control at lower duty cycles. You can spend months getting something right while it changes from day to day, especially in SD tunes, as weather conditions change. I have had some tell me over the years to have inj. Run no more then 85% duty cycle. I don't agree here. I try to find a size that will run 97-98% DC at your max HP number. I've ran some to over 100% as long as it is for short periods or at the top of the rev range. Injector life will suffer but it will save you a lot of headaches tuning & the mileage difference over a number of years will pay for new ones if one starts to go down.
11-03-2015, 01:36 PM
#7
The biggest things people underestimate are good injector characteristics, and not having the car steady state while tuning. What I mean is that they will sweep through cells and only get a few counts and assume the data is right. There is a reason the OE's take so much time and usually do it in such a way to keep the engine in steady state conditions first.
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11-07-2015, 09:42 AM
#9
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I liked your point about making multiple drives and resetting trims. Something similar I did on my suburban was to log it to and from work a couple days in a row, then use excel to average the trims from each log into one big paste. Then did the multiply by percent. After a couple of those, it was pretty well nailed. Once my LTFT were close to zero, I disabled them and used STFT only. Quicker for fine tune adjusting.
11-10-2015, 12:04 PM
#11
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Can someone point me in the right direction for resource material? I need to start getting my head into tuning and I don't really know jack about it. I will probably end up with holley efi or dominator unless there is something out there that is more preferable. Thank!
11-10-2015, 02:51 PM
#12
Can someone point me in the right direction for resource material? I need to start getting my head into tuning and I don't really know jack about it. I will probably end up with holley efi or dominator unless there is something out there that is more preferable. Thank!
The basis would be knowing how the EFI in your application works before trying to tune it.