MAF or speed density
05-16-2010, 10:49 AM
#63
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Can you recommend any places to do more research on this?
I am looking at a future FI build with 370 & F1A as street car that sees limited track time. Seems like having ability to use MAF for DD status and having it flop over to SD when under load would be ideal.
I am looking at a future FI build with 370 & F1A as street car that sees limited track time. Seems like having ability to use MAF for DD status and having it flop over to SD when under load would be ideal.
05-16-2010, 01:36 PM
#64
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If you are doing a MAF tune the PE vs RPM table is what you use to add or remove fuel once the MAF is maxed out. It is a lot simpler than a SD tune which you will find out is very time consuming to get all the little issues that will come up ironed out. You can usually see a blip on the dyno chart on a MAF car where the MAF has maxed out and it is now using the PE table.
05-16-2010, 04:51 PM
#65
If you are doing a MAF tune the PE vs RPM table is what you use to add or remove fuel once the MAF is maxed out. It is a lot simpler than a SD tune which you will find out is very time consuming to get all the little issues that will come up ironed out. You can usually see a blip on the dyno chart on a MAF car where the MAF has maxed out and it is now using the PE table.
05-16-2010, 04:58 PM
#66
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Depends on the tuner but usually, no. Most tuners will put you in open loop when going to speed density. You will likely need a wideband and should have one regardless IMO.
PE table is used in both SD and MAF tuning and does not work the way that you stated above. The Power Enrichment table is a divider value to define the commanded AFR at WOT. Tunning the MAF and/or VE table is done by comparing the commanded AFR vs the actual AFR readings and getting them as close to each other as possible. If you go to a shop that is just working with the PE table in order to dial in fueling at WOT, they are doing wrong.
PE table is used in both SD and MAF tuning and does not work the way that you stated above. The Power Enrichment table is a divider value to define the commanded AFR at WOT. Tunning the MAF and/or VE table is done by comparing the commanded AFR vs the actual AFR readings and getting them as close to each other as possible. If you go to a shop that is just working with the PE table in order to dial in fueling at WOT, they are doing wrong.
05-17-2010, 01:25 PM
#69
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I bought my 2002 SS used and the previous owner had it SD tuned. It ran great. It
felt strong from a launch. I bought it in August, well after a few months the night time temps dropped below 50 degrees and the car wouldn't start. I had to hold the pedal down a little to keep it from stalling out. Once the motor warmed up a little it surged until it was almost fully warmed up then it idled fine. If temp doesn't effect SD tuning then what was going on with my car? The next morning it did the same thing, so i pulled the IAT sensor out of the lid and warmed it up in the house and i was rolling the sensor in my hands. Then i reinstalled it back in the air lid and the car surged some but it did idle better and i didn't need to hold the pedal down. After that i just had a stock file flash in my PCM and it's been fine ever since. But i still think the car ran better with the SD tuning once it warmed up.
felt strong from a launch. I bought it in August, well after a few months the night time temps dropped below 50 degrees and the car wouldn't start. I had to hold the pedal down a little to keep it from stalling out. Once the motor warmed up a little it surged until it was almost fully warmed up then it idled fine. If temp doesn't effect SD tuning then what was going on with my car? The next morning it did the same thing, so i pulled the IAT sensor out of the lid and warmed it up in the house and i was rolling the sensor in my hands. Then i reinstalled it back in the air lid and the car surged some but it did idle better and i didn't need to hold the pedal down. After that i just had a stock file flash in my PCM and it's been fine ever since. But i still think the car ran better with the SD tuning once it warmed up.
05-17-2010, 02:27 PM
#70
Right on. In EFILive custom os there's a open loop VE multiplier based off of ECT so you can give more fuel when it's cold. In 50 degree weather mine needs about 20% more fuel than at normal operating temp. Previous owner probably didn't tune startup for colder weather. Funny thing, is that until it actually gets cold it's impossible to tune for it because it ain't just a matter of scaling it down to predict for it.
06-24-2010, 12:01 PM
#71
PE table is used in both SD and MAF tuning and does not work the way that you stated above. The Power Enrichment table is a divider value to define the commanded AFR at WOT. Tunning the MAF and/or VE table is done by comparing the commanded AFR vs the actual AFR readings and getting them as close to each other as possible. If you go to a shop that is just working with the PE table in order to dial in fueling at WOT, they are doing wrong.
Since RPM exists in the PE EQ table, you can adjust a belt driven boost based on a slope to make up the difference from the last (max) air mass reading vs what is actually going in the motor. The problem is no elevation change takes this calc into consideration.
If you dont agree, I would like to know what alternate method there is while keeping a MAF enabled tune (not using the VE table) ?
06-24-2010, 01:27 PM
#72
[QUOTE=elias_799;13274523]what i have been told is that our computer does not read the maf past 500whp, so i after the 500whp it is a guessing game QUOTE]
Not if you have all of your parameters covered, I run a stock maf on a LT1, made 722 rwhp with a D1 and my fueling was spot on everywhere, everytime. I put it on the dyno in different cities, temps and my fueling was always flat lined.
Not if you have all of your parameters covered, I run a stock maf on a LT1, made 722 rwhp with a D1 and my fueling was spot on everywhere, everytime. I put it on the dyno in different cities, temps and my fueling was always flat lined.
11-16-2010, 09:50 PM
#73
So from after reading all of 4 pages, I came up with this little checklist for my tuner when he tunes my D1SC: SD tune, delete all 02 sensors, adjust for different temp's and different elevations.
You guys know in the Midwest we have 90 deg summers and below 0 deg Fahrenheit winters! I want to able to drive this baby anytime of and anywhere I want.
You guys know in the Midwest we have 90 deg summers and below 0 deg Fahrenheit winters! I want to able to drive this baby anytime of and anywhere I want.
12-11-2012, 03:05 PM
#75
To all those worried about a SD tune and temp or elevation changes, do you not realize how many cars come from the factory running SD? They don't need to be retuned just because the temp or elevation changes. Even F-bodies were SD from the factory from 90-93. If temp or elevation causes problems then something is wrong.
07-28-2013, 10:00 PM
#76
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Ok, so this may be a dumb question, but here goes...
I'm getting ready to put a Procharger on my SS and my tuner said they will be gong with the 2 Bar SD tune. From reading this thread, that sounds like the way to go!
Now my question is: Since the MAF won't be used anymore, should I just remove the whole unit from my intake piping for better airflow?
I'm getting ready to put a Procharger on my SS and my tuner said they will be gong with the 2 Bar SD tune. From reading this thread, that sounds like the way to go!
Now my question is: Since the MAF won't be used anymore, should I just remove the whole unit from my intake piping for better airflow?
07-29-2013, 09:39 AM
#77
Ok, so this may be a dumb question, but here goes...
I'm getting ready to put a Procharger on my SS and my tuner said they will be gong with the 2 Bar SD tune. From reading this thread, that sounds like the way to go!
Now my question is: Since the MAF won't be used anymore, should I just remove the whole unit from my intake piping for better airflow?
I'm getting ready to put a Procharger on my SS and my tuner said they will be gong with the 2 Bar SD tune. From reading this thread, that sounds like the way to go!
Now my question is: Since the MAF won't be used anymore, should I just remove the whole unit from my intake piping for better airflow?
07-29-2013, 02:59 PM
#78
I have 2 questions, i'm kind of learning in this topic so sorry if they are stupid questions!
1-can i use efi live to make a SD tune?
2-if i use the 100mm MAF can i still usind it above 500HP rage and i still going to have the ability to have good results with my tuning?
1-can i use efi live to make a SD tune?
2-if i use the 100mm MAF can i still usind it above 500HP rage and i still going to have the ability to have good results with my tuning?
07-30-2013, 05:57 AM
#80
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Another for Speed Density. If the car is tuned correctly it will run good all the time.
Plenty of cars have come from the factory using speed Density.
Plus on a FI car pushing any good amount of boost its really the only option.
Go read the HP tuners forum. Read read read and read some more.
Plenty of cars have come from the factory using speed Density.
Plus on a FI car pushing any good amount of boost its really the only option.
Go read the HP tuners forum. Read read read and read some more.