SD tuning for bracket racing
09-28-2009, 01:17 PM
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SD tuning for bracket racing I'm sorry if this has already been answered, couldn't find it. But what is the best set up for bracketracing in regards to tuning. I run a maf tune and my car will be consistent for awhile and 3 or 4 runs in it will all of a sudden lose a tenth. I have to be available to track this to be ready for it. Any input would really help
09-29-2009, 05:20 PM
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Chances are it slows down because the IAT gets heatsoaked and causes the PCM to start pulling timing OR the weather changes are causing a loss in power.
Fact of the matter is, the car will make more power in cooler weather. You'll have better luck running a slower dial in and hitting the brakes at the line vs. trying to tune the car via the PCM to be consistent in all weather conditions.
Fact of the matter is, the car will make more power in cooler weather. You'll have better luck running a slower dial in and hitting the brakes at the line vs. trying to tune the car via the PCM to be consistent in all weather conditions.
09-30-2009, 09:59 AM
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Chances are it slows down because the IAT gets heatsoaked and causes the PCM to start pulling timing OR the weather changes are causing a loss in power.
Fact of the matter is, the car will make more power in cooler weather. You'll have better luck running a slower dial in and hitting the brakes at the line vs. trying to tune the car via the PCM to be consistent in all weather conditions.
Fact of the matter is, the car will make more power in cooler weather. You'll have better luck running a slower dial in and hitting the brakes at the line vs. trying to tune the car via the PCM to be consistent in all weather conditions.
09-30-2009, 11:11 AM
#5
A MAF is going to be more accurate for weather fluctuations than speed density will be, period. One is a measurement, one is "calculated". If/when the IAT heat soaks it's going to affect a speed density tune much more so than a MAF tune and throw the fueling/timing curves off a bit.
09-30-2009, 12:18 PM
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A MAF is going to be more accurate for weather fluctuations than speed density will be, period. One is a measurement, one is "calculated". If/when the IAT heat soaks it's going to affect a speed density tune much more so than a MAF tune and throw the fueling/timing curves off a bit.
09-30-2009, 12:44 PM
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09-30-2009, 01:00 PM
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I had the same issue with our dragster. Usually 3rd or 4th round it will pick up a tenth or more. My tune is very basic, most tables are zeroed out so nothing comes in to play. Just fuel and spark, keeping it real simple.
Last week I decided that I was running rich despite what my wide band O2 was telling me so from 5K to 7K I went from 12.90 AFR to 13.15. The predicted et's where within a few thousands during the heat of the day and the MPH did not move but later that night when it went from 7500DA to 6200DA it picked up exactly what the software predicted. This proved I was rich and when the air was better by the later rounds it loved the extra fuel. So by running it a little leaner it appears the et is more stable and predictable. That was our last race of the year so I wont be able to backup the claims....
Lee
Last week I decided that I was running rich despite what my wide band O2 was telling me so from 5K to 7K I went from 12.90 AFR to 13.15. The predicted et's where within a few thousands during the heat of the day and the MPH did not move but later that night when it went from 7500DA to 6200DA it picked up exactly what the software predicted. This proved I was rich and when the air was better by the later rounds it loved the extra fuel. So by running it a little leaner it appears the et is more stable and predictable. That was our last race of the year so I wont be able to backup the claims....
Lee
09-30-2009, 01:09 PM
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09-30-2009, 01:11 PM
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I had the same issue with our dragster. Usually 3rd or 4th round it will pick up a tenth or more. My tune is very basic, most tables are zeroed out so nothing comes in to play. Just fuel and spark, keeping it real simple.
Last week I decided that I was running rich despite what my wide band O2 was telling me so from 5K to 7K I went from 12.90 AFR to 13.15. The predicted et's where within a few thousands during the heat of the day and the MPH did not move but later that night when it went from 7500DA to 6200DA it picked up exactly what the software predicted. This proved I was rich and when the air was better by the later rounds it loved the extra fuel. So by running it a little leaner it appears the et is more stable and predictable. That was our last race of the year so I wont be able to backup the claims....
Lee
Last week I decided that I was running rich despite what my wide band O2 was telling me so from 5K to 7K I went from 12.90 AFR to 13.15. The predicted et's where within a few thousands during the heat of the day and the MPH did not move but later that night when it went from 7500DA to 6200DA it picked up exactly what the software predicted. This proved I was rich and when the air was better by the later rounds it loved the extra fuel. So by running it a little leaner it appears the et is more stable and predictable. That was our last race of the year so I wont be able to backup the claims....
Lee
09-30-2009, 03:59 PM
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09-30-2009, 04:27 PM
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09-30-2009, 04:42 PM
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09-30-2009, 04:42 PM
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My IATs (stock location) will drop around 10 degrees from start to finish of a 1/4 mile run. And you can just watch the wideband AFR going rich as the pass goes on. If you can get it to read outside air temp all the time fuel will be much closer during the run, so less chance of error based deviation from run to run.
http://speed-eng.com/store/exhaust-c...47b2e037b0bd34
There are 3 different length IAT extensions about 10 or so item down that page.
09-30-2009, 04:46 PM
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If it's reading real outside air temp all the time, then there will be less fluctuation down the track. And zero out any IAT timing in the normal operating range.
My IATs (stock location) will drop around 10 degrees from start to finish of a 1/4 mile run. And you can just watch the wideband AFR going rich as the pass goes on. If you can get it to read outside air temp all the time fuel will be much closer during the run, so less chance of error based deviation from run to run.
http://speed-eng.com/store/exhaust-c...47b2e037b0bd34
There are 3 different length IAT extensions about 10 or so item down that page.
My IATs (stock location) will drop around 10 degrees from start to finish of a 1/4 mile run. And you can just watch the wideband AFR going rich as the pass goes on. If you can get it to read outside air temp all the time fuel will be much closer during the run, so less chance of error based deviation from run to run.
http://speed-eng.com/store/exhaust-c...47b2e037b0bd34
There are 3 different length IAT extensions about 10 or so item down that page.
great thanks! looks like the 24" will be plenty
