5.7 to 383 tuning question
"hrcslam", can you please explain to us all, how different people's cars can reference those VE tables differently than other's cars?
Also, how you can feel it when others can't?
Also, how you can feel it when others can't?
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If you live in Arizona I can show you this on my car first hand. I'll see if I can load a bad VE table and a good one, data log both and send you the files.
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If you want to learn the tuning process I suggest getting Greg Banish's video on GM tuning(beginner's video, not the advanced). It's not cheap, but if you want to tune yourself and do it right...start with that video. You will not regret the investment in the video if you are really serious about tuning.
The video is LSX centered, but the same processes apply to the LT1 as well. You just have to use different software to do it.
Be prepared to buy a wideband O2 as well.
As a general overview of the tuning process(once you have your injector data correct in the PCM).....
Couple of notes.....
All this done on a dyno with an eddy current feedback system. This will hold the car at a specific speed no matter what you do with the throttle.
Lambda error is anything other than your target Lambda. If you set the PCM to Lambda 1(in open loop mode) and the wideband reads 0.85 it's rich by 15%, if reads 1.15 then it's lean by 15%. Given the Lambda error, you can then adjust the cell value(up or down) by the percentage given by the fueling error .
For MAF calibration tuning....
For VE tuning......
Again, this is just a quick overview of how to tune steady state.
As noted in earlier posts, you can log your car in SD mode(closed loop) and use the LTFT's to adjust your VE table as well. Just be aware that the data will not be as accurate as on a dyno with a wideband and not being steady state can throw error into it as well. But it will help to get you into the ballpark(better than nothing).
The video is LSX centered, but the same processes apply to the LT1 as well. You just have to use different software to do it.
Be prepared to buy a wideband O2 as well.
As a general overview of the tuning process(once you have your injector data correct in the PCM).....
Couple of notes.....
All this done on a dyno with an eddy current feedback system. This will hold the car at a specific speed no matter what you do with the throttle.
Lambda error is anything other than your target Lambda. If you set the PCM to Lambda 1(in open loop mode) and the wideband reads 0.85 it's rich by 15%, if reads 1.15 then it's lean by 15%. Given the Lambda error, you can then adjust the cell value(up or down) by the percentage given by the fueling error .
For MAF calibration tuning....
- Lock the PCM into open loop mode(set the closed loop coolant temp as high as it can go).
- Set all fuel targets as lambda 1(14.7:1 AFR).
- Using a wideband, plot the Lambda error against the frequency of the MAF as you run through the RPM range of the engine on the dyno logging Lambda error against the MAF calibration table. To my knowledge, you can't log frequency on the LT1, but using g/s of the MAF you can correlate that to the MAF frequency.
- You hold in each cell for several seconds to get a steady state reading.
- You then use the Lambda error to adjust the MAF values for each frequency(using lamba makes this easy).
- Then keep repeating the process until the Lambda error is very small.
For VE tuning......
- Lock the PCM into open loop mode(set the closed loop coolant temp as high as it can go).
- Set all fuel targets to lambda 1(14.7:1 AFR).
- Disable or fail the MAF by making the PCM think it's bad(adjust the MAF high fail frequency to 0 and set the MAF high fail code DTC to set on 1st fail/1st trip).
- Copy high octane spark table to low octane spark table(don't leave it like this after the tuning process).
- Using a dyno to hold the car at a certain speed, you plot Lambda error(from your wideband O2 sensor) against RPM and MAP.
- You hold in each cell for several seconds to get a steady state reading.
- As you change MAP and RPM values, this builds you an error table(for each VE cell) of how much you need to adjust each VE value(cell by cell).
- Then you lather, rinse, repeat, until the Lambda error gets very small.
Again, this is just a quick overview of how to tune steady state.
As noted in earlier posts, you can log your car in SD mode(closed loop) and use the LTFT's to adjust your VE table as well. Just be aware that the data will not be as accurate as on a dyno with a wideband and not being steady state can throw error into it as well. But it will help to get you into the ballpark(better than nothing).
Last edited by ACE1252; Mar 18, 2015 at 09:46 PM.
If you want to put an LT1 PCM into Speed Density mode you simply, in Tunercat, go to the Switches, and select Speed Density. You don't have to screw with MAF settings, unplug anything, nothing. Won't set MAF codes like an LS1 either, which is actually a MAF failure mode. It is, with an LT PCM, an actual factory Speed Density mode.
Everybody that has hacked the calibrations know what I told you about the VE tables is accurate. Sometimes people succumb to the "placebo effect". It had to be proved to me as well.
Everybody that has hacked the calibrations know what I told you about the VE tables is accurate. Sometimes people succumb to the "placebo effect". It had to be proved to me as well.
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Joined: Dec 2010
Posts: 2,610
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From: Maricopa, AZ
If you want to learn the tuning process I suggest getting Greg Banish's video on GM tuning(beginner's video, not the advanced). It's not cheap, but if you want to tune yourself and do it right...start with that video. You will not regret the investment in the video if you are really serious about tuning.
The video is LSX centered, but the same processes apply to the LT1 as well. You just have to use different software to do it.
Be prepared to buy a wideband O2 as well.
As a general overview of the tuning process(once you have your injector data correct in the PCM).....
Couple of notes.....
All this done on a dyno with an eddy current feedback system. This will hold the car at a specific speed no matter what you do with the throttle.
Lambda error is anything other than your target Lambda. If you set the PCM to Lambda 1(in open loop mode) and the wideband reads 0.85 it's rich by 15%, if reads 1.15 then it's lean by 15%. Given the Lambda error, you can then adjust the cell value(up or down) by the percentage given by the fueling error .
For MAF calibration tuning....
For VE tuning......
Again, this is just a quick overview of how to tune steady state.
As noted in earlier posts, you can log your car in SD mode(closed loop) and use the LTFT's to adjust your VE table as well. Just be aware that the data will not be as accurate as on a dyno with a wideband and not being steady state can throw error into it as well. But it will help to get you into the ballpark(better than nothing).
The video is LSX centered, but the same processes apply to the LT1 as well. You just have to use different software to do it.
Be prepared to buy a wideband O2 as well.
As a general overview of the tuning process(once you have your injector data correct in the PCM).....
Couple of notes.....
All this done on a dyno with an eddy current feedback system. This will hold the car at a specific speed no matter what you do with the throttle.
Lambda error is anything other than your target Lambda. If you set the PCM to Lambda 1(in open loop mode) and the wideband reads 0.85 it's rich by 15%, if reads 1.15 then it's lean by 15%. Given the Lambda error, you can then adjust the cell value(up or down) by the percentage given by the fueling error .
For MAF calibration tuning....
- Lock the PCM into open loop mode(set the closed loop coolant temp as high as it can go).
- Set all fuel targets as lambda 1(14.7:1 AFR).
- Using a wideband, plot the Lambda error against the frequency of the MAF as you run through the RPM range of the engine on the dyno logging Lambda error against the MAF calibration table.
- You hold in each cell for several seconds to get a steady state reading.
- You then use the Lambda error to adjust the MAF values for each frequency(using lamba makes this easy).
- Then keep repeating the process until the Lambda error is very small.
For VE tuning......
- Lock the PCM into open loop mode(set the closed loop coolant temp as high as it can go).
- Set all fuel targets to lambda 1(14.7:1 AFR).
- Disable or fail the MAF by making the PCM think it's bad(adjust the MAF high fail frequency to 0 and set the MAF high fail code DTC to set on 1st fail/1st trip).
- Copy high octane spark table to low octane spark table(don't leave it like this after the tuning process).
- Using a dyno to hold the car at a certain speed, you plot Lambda error(from your wideband O2 sensor) against RPM and MAP.
- You hold in each cell for several seconds to get a steady state reading.
- As you change MAP and RPM values, this builds you an error table(for each VE cell) of how much you need to adjust each VE value(cell by cell).
- Then you lather, rinse, repeat, until the Lambda error gets very small.
Again, this is just a quick overview of how to tune steady state.
As noted in earlier posts, you can log your car in SD mode(closed loop) and use the LTFT's to adjust your VE table as well. Just be aware that the data will not be as accurate as on a dyno with a wideband and not being steady state can throw error into it as well. But it will help to get you into the ballpark(better than nothing).
Substitute LTFT for LT BLMs and lambda 1 for BLM 128. So instead of .85 or 1.15 you'll see 108 or 147 respectively.
Also worth noting that the injector voltage offset is injector specific, but it can be further adjusted to your cam exhaust valve closing event. So once you have the correct injector voltage offset in the tune (should already be there if you are using the same injectors and previous tune) and you change your cam you don't have to change this setting, but it can help with fuel efficiency (less fresh fuel going straight through the cc to the exhaust).
Last edited by hrcslam; Mar 18, 2015 at 09:48 PM.
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If I'm not mistaken, SD can operate in either closed loop or open loop....and if he is using LTFT of the car's O2's to make his corrections then it must be logged in closed loop. That why I put that in ().
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Please elaborate? Serious question. And I don't use it for injector closing. I use it to time injector opening. I gained 3+ mpgs doing this.
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The voltage offset effects the length of the injector cycle as it's an adder to the total injection pulse to counter varying voltage levels, but does not shift the starting point or ratherly the ending point of injection...just before the intake opens.
I know the EOI(End Of Injection) table in the LS1 pcm's can do this(move the injection timing), but I don't know of a table that can do this in LT1 PCM.
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I think that is right.
The voltage offset effects the length of the injector cycle as it's an adder to the total injection pulse to counter varying voltage levels, but does not shift the starting point or ratherly the ending point of injection...just before the intake opens.
I know the EOI(End Of Injection) table in the LS1 pcm's can do this(move the injection timing), but I don't know of a table that can do this in LT1 PCM.
The voltage offset effects the length of the injector cycle as it's an adder to the total injection pulse to counter varying voltage levels, but does not shift the starting point or ratherly the ending point of injection...just before the intake opens.
I know the EOI(End Of Injection) table in the LS1 pcm's can do this(move the injection timing), but I don't know of a table that can do this in LT1 PCM.
My understanding is this has to do with how long it takes for the injector to open after it receives a certain voltage. The pulse width is determined by the pcm.
Last edited by hrcslam; Mar 18, 2015 at 10:15 PM.
The only way the voltage offset changes could effect your fuel economy would be correcting fuel trims.
Are you sober? :-)
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The LS tables have vacuum in them as well because there is no vacuum compensation for the fuel pressure regulator on an LS1. It's accomplished with the injectors themselves.
The injector voltage offset is a flat time adder to the pulse width of the injector.
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VE tables were adjusted at the same time. But less than 2%. Not enough to account going from 17mpg to 20mpg in the same driving conditions and routes. The only other change I made was shortening the injector offset (from the chart I got from the manufacturer). At idle the fumes are significantly reduced.
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The tables are in uS for the LT1.
The LS tables have vacuum in them as well because there is no vacuum compensation for the fuel pressure regulator on an LS1. It's accomplished with the injectors themselves.
The injector voltage offset is a flat time adder to the pulse width of the injector.
The LS tables have vacuum in them as well because there is no vacuum compensation for the fuel pressure regulator on an LS1. It's accomplished with the injectors themselves.
The injector voltage offset is a flat time adder to the pulse width of the injector.
Ahh ok. Makes sense now. Basically I leaned it out by shortening the offset. Got it. And yes I meant usec.
So how do I move the injector timing?
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No.
Injector voltage offsets are flat time adders to compensate for varying voltage levels as the engine runs. Injectors take longer to open as voltage lowers, less to open as voltage rises. They apply all the time.....during every aspect of engine operation.
Short pulse adders are a flat time adder to injector pulse widths up to 2mS in the LT1. They are needed during the non-linear flow region of an injector. The larger your injector, the more critical this value is....as more time may be spent operating under 2mS...especially at idle. For my 30# FMS injectors, they don't get below 2mS most of the time even at idle...I'm almost always operating in the linear flow range.
Both of the above affect injector pulse width, but neither have the effect of moving end of injection timing relative to the intake valve opening.
The injector will start opening sooner, but where it ends always stays the same.
At least, that is how I understand it.
Injector voltage offsets are flat time adders to compensate for varying voltage levels as the engine runs. Injectors take longer to open as voltage lowers, less to open as voltage rises. They apply all the time.....during every aspect of engine operation.
Short pulse adders are a flat time adder to injector pulse widths up to 2mS in the LT1. They are needed during the non-linear flow region of an injector. The larger your injector, the more critical this value is....as more time may be spent operating under 2mS...especially at idle. For my 30# FMS injectors, they don't get below 2mS most of the time even at idle...I'm almost always operating in the linear flow range.
Both of the above affect injector pulse width, but neither have the effect of moving end of injection timing relative to the intake valve opening.
The injector will start opening sooner, but where it ends always stays the same.
At least, that is how I understand it.
Last edited by ACE1252; Mar 18, 2015 at 10:42 PM.
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From: Maricopa, AZ
No.
Injector voltage offsets are flat time adders to compensate for varying voltage levels as the engine runs. They apply all the time.....during every aspect of engine operation.
Short pulse adders are a flat time adder to injector pulse widths up to 2mS in the LT1. They are needed during the non-linear flow region of an injector. The larger your injector, the more critical this value is....
Both of the above affect injector pulse width, but neither have the effect of moving end of injection timing relative to the intake valve opening.
The injector will start opening sooner, but where it ends always stays the same.
At least, that is how I understand it.
Injector voltage offsets are flat time adders to compensate for varying voltage levels as the engine runs. They apply all the time.....during every aspect of engine operation.
Short pulse adders are a flat time adder to injector pulse widths up to 2mS in the LT1. They are needed during the non-linear flow region of an injector. The larger your injector, the more critical this value is....
Both of the above affect injector pulse width, but neither have the effect of moving end of injection timing relative to the intake valve opening.
The injector will start opening sooner, but where it ends always stays the same.
At least, that is how I understand it.