Need some guidance tuning ls2 with heads and cam

[freaknbigpanda]

Hi There,

I am finishing up my ls2 build soon (ls2 with big cam and ls3 heads) and I am going to be starting tuning. I will have access to a dyno and a wideband AFR meter. This is my first ever tune and I wanted some input from veteran tuners on if the following steps look correct. I am planning on doing the following:

1. Increase idle speed across the board to 950
2. Increase idle percent max to around 3-4% to allow for the increased airflow
3. Retard timing by 5 degrees across the board to avoid knock
4. Try to start the car. If the car idles OK with AFR around 14.7 then continue
5. Disable closed loop operation and force the car to use MAF only
6. Use commanded AFR versus actual AFR as recorded by the wideband to calibrate the high and low MAF tables at partial to medium throttle with target AFR of 14
7. After the commanded AFR difference from actual is +/- 5% move onto speed density tuning
8. Keep closed loop operation disabled and force the car to use speed density only, disable MAF
9. Use commanded AFR versus actual to calibrate the speed density table at partial to medium throttle with target AFR of 14
10. Disable speed density again and go back to MAF but this time test and calibrate the MAF at WOT with a target AFR of 12.7
11. Disable MAF and then test and calibrate speed density to WOT with a target AFR of 12.7
12. Re-enable closed loop and make sure that the short and long term fuel trims are not adding or subtracting significant amounts of fuel, they should never be over +/- 5%
13. Drive home and hope nothing explodes

The first question I have is does this look generally correct to you? Am I missing any major steps? Also I had some general questions about hp tuners that I have listed below.

1. Do I need to adjust the "Idle Startup" Airflow table under the Idle->Airflow tab?
2. Do I need to adjust the Idle Spark Advance Base table under the Spark->Advance->Idle Spark Advance
3. Do I need to adjust the Power Enrichment table or settings? Why couldn't I just adjust the MAF or speed density tables to accomplish the same goal of adding more fuel in higher load situations?

Thanks in advance!!

[Lakegoat]

What kind of car and computer? What's a BIG cam?

[freaknbigpanda]

What kind of car and computer? What's a BIG cam?

It is a c6 z06 e38 ecu the ls2 has a dry sump ls3 crank cam and ls3 heads. I actually don?t know the exact specs of the cam I just know that according to the guy who sold the longblock to me it is a pretty big cam.

[freaknbigpanda]

Bump, can somebody help me out here? Don't want to damage my engine!

[LS ROB]

Hi There,

I am finishing up my ls2 build soon (ls2 with big cam and ls3 heads) and I am going to be starting tuning. I will have access to a dyno and a wideband AFR meter. This is my first ever tune and I wanted some input from veteran tuners on if the following steps look correct. I am planning on doing the following:

1. Increase idle speed across the board to 950
2. Increase idle percent max to around 3-4% to allow for the increased airflow
3. Retard timing by 5 degrees across the board to avoid knock
4. Try to start the car. If the car idles OK with AFR around 14.7 then continue
5. Disable closed loop operation and force the car to use MAF only
6. Use commanded AFR versus actual AFR as recorded by the wideband to calibrate the high and low MAF tables at partial to medium throttle with target AFR of 14
7. After the commanded AFR difference from actual is +/- 5% move onto speed density tuning
8. Keep closed loop operation disabled and force the car to use speed density only, disable MAF
9. Use commanded AFR versus actual to calibrate the speed density table at partial to medium throttle with target AFR of 14
10. Disable speed density again and go back to MAF but this time test and calibrate the MAF at WOT with a target AFR of 12.7
11. Disable MAF and then test and calibrate speed density to WOT with a target AFR of 12.7
12. Re-enable closed loop and make sure that the short and long term fuel trims are not adding or subtracting significant amounts of fuel, they should never be over +/- 5%
13. Drive home and hope nothing explodes

The first question I have is does this look generally correct to you? Am I missing any major steps? Also I had some general questions about hp tuners that I have listed below.

1. Do I need to adjust the "Idle Startup" Airflow table under the Idle->Airflow tab?
2. Do I need to adjust the Idle Spark Advance Base table under the Spark->Advance->Idle Spark Advance
3. Do I need to adjust the Power Enrichment table or settings? Why couldn't I just adjust the MAF or speed density tables to accomplish the same goal of adding more fuel in higher load situations?

Thanks in advance!!

Not real sure on any of that. You will want to post the tune, so others may have an idea of what you are working with. Myself, I did not have to adjust the Idle Startup table. As for the Idle Spark Advance, yes; you will need to adjust that accordingly. PE can be adjusted to whatever you wish the AFR to be at WOT. If you hover over the PE table, look at the bottom of the page and it will give you an idea of how the numbers work. Lets say you want an AFR of 12.7 @ WOT. You take Stoich and divide it by your multiplier. 14.67/1.155= 12.7. Hope this helps.

[freaknbigpanda]

Definitely helps! Thanks! I?m going to try to start it tomorrow. Fingers crossed everything goes according to plan!

[Dave_In_VA]

Hi There,

I am finishing up my ls2 build soon (ls2 with big cam and ls3 heads) and I am going to be starting tuning. I will have access to a dyno and a wideband AFR meter. This is my first ever tune and I wanted some input from veteran tuners on if the following steps look correct. I am planning on doing the following:

1. Increase idle speed across the board to 950
2. Increase idle percent max to around 3-4% to allow for the increased airflow
3. Retard timing by 5 degrees across the board to avoid knock
4. Try to start the car. If the car idles OK with AFR around 14.7 then continue
5. Disable closed loop operation and force the car to use MAF only
6. Use commanded AFR versus actual AFR as recorded by the wideband to calibrate the high and low MAF tables at partial to medium throttle with target AFR of 14
7. After the commanded AFR difference from actual is +/- 5% move onto speed density tuning
8. Keep closed loop operation disabled and force the car to use speed density only, disable MAF
9. Use commanded AFR versus actual to calibrate the speed density table at partial to medium throttle with target AFR of 14
10. Disable speed density again and go back to MAF but this time test and calibrate the MAF at WOT with a target AFR of 12.7
11. Disable MAF and then test and calibrate speed density to WOT with a target AFR of 12.7
12. Re-enable closed loop and make sure that the short and long term fuel trims are not adding or subtracting significant amounts of fuel, they should never be over +/- 5%
13. Drive home and hope nothing explodes

The first question I have is does this look generally correct to you? Am I missing any major steps? Also I had some general questions about hp tuners that I have listed below.

1. Do I need to adjust the "Idle Startup" Airflow table under the Idle->Airflow tab?
2. Do I need to adjust the Idle Spark Advance Base table under the Spark->Advance->Idle Spark Advance
3. Do I need to adjust the Power Enrichment table or settings? Why couldn't I just adjust the MAF or speed density tables to accomplish the same goal of adding more fuel in higher load situations?

Thanks in advance!!

@freaknbigpanda, See my signature below. Just to confirm, you have a LS2 shortblock and not a LS7 shortblock.

I have a 2005, M6, E38 ECU H/C/I/E car. LS2 shortblock with LS3 top-end. Seems similar to yours. Dryslump oiling should not make a difference.

My cam is more moderate, but I'm using 1.8 rockers which make it a little bigger.

Please confirm you are using a LS7/LS3 style MAF sensor and not the LS2 MAF sensor which is part of a housing. If you're using the OEM style LS2 MAF Sensor then the MAF tables from my tune would need to be changed.

Attached is my final tune from the dyno. I should be a good starting point. My cam has about 2 or 3 degrees overlap. If yours has a lot more than some of the changes Rob suggested would be good. This has MAF starting at 2800 RPM, good low speed drivability on using VE tables.

Dave

[freaknbigpanda]

Awesome thanks a ton! This helps a lot. And yes I am using ls7 maf not ls2. I?ll load this tune in and see how it goes today.

[freaknbigpanda]

@freaknbigpanda, See my signature below. Just to confirm, you have a LS2 shortblock and not a LS7 shortblock.

I have a 2005, M6, E38 ECU H/C/I/E car. LS2 shortblock with LS3 top-end. Seems similar to yours. Dryslump oiling should not make a difference.

My cam is more moderate, but I'm using 1.8 rockers which make it a little bigger.

Please confirm you are using a LS7/LS3 style MAF sensor and not the LS2 MAF sensor which is part of a housing. If you're using the OEM style LS2 MAF Sensor then the MAF tables from my tune would need to be changed.

Attached is my final tune from the dyno. I should be a good starting point. My cam has about 2 or 3 degrees overlap. If yours has a lot more than some of the changes Rob suggested would be good. This has MAF starting at 2800 RPM, good low speed drivability on using VE tables.

Dave

Just loaded this tune but unfortunately the car doesn't idle, just fires up for a second and then dies. Interesting enough if I load a stock c6 corvette grandsport tune it does idle but only if I give it a lot of gas. Any idea where I should start to fix this?

[freaknbigpanda]

I noticed in the vcm scanner app the MAP sensor was reading 7 kpa in accessory mode which seems completely wrong. Seems like the sensor is bad, I?ve ordered another hopefully it will read around 102 and fix my issues.

[LS ROB]

I noticed in the vcm scanner app the MAP sensor was reading 7 kpa in accessory mode which seems completely wrong. Seems like the sensor is bad, I?ve ordered another hopefully it will read around 102 and fix my issues.

Is your OFFSET and LINEAR set correctly?

[eXo3901]

Just loaded this tune but unfortunately the car doesn't idle, just fires up for a second and then dies. Interesting enough if I load a stock c6 corvette grandsport tune it does idle but only if I give it a lot of gas. Any idea where I should start to fix this?

Doesn't work because the tune you tried to load is for an E40 and you said you were using an E38. Don't blindly load random files. Compare them to stock versions of the same OS and study the changes. If you cannot understand why something was changed, ask.

[freaknbigpanda]

Doesn't work because the tune you tried to load is for an E40 and you said you were using an E38. Don't blindly load random files. Compare them to stock versions of the same OS and study the changes. If you cannot understand why something was changed, ask.

I didn't flash that exact tune, I copied the differences to my stock ls7 tune using the comparison log window. But yeah I do see that it is an E40 tune which is odd because Dave_In_VA mentioned that he was using an E38. I wonder if he posted the wrong tune file or something. I also noticed in that tune that the cylinder size was set to ~.71 for a ~5.7L engine. I am guessing this should be .75L for LS2 right?

Is your OFFSET and LINEAR set correctly?

I didn't check that but I am using a stock c6 grandsport tune so shouldn't it work just fine with the stock ls3 MAP that I have?

EDIT: Just double checked the tune values and I am using 128.13 kpa for the linear and -0.31 kpa for offset which is what the stock ls3 tune was using

[LS ROB]

I didn't flash that exact tune, I copied the differences to my stock ls7 tune using the comparison log window. But yeah I do see that it is an E40 tune which is odd because Dave_In_VA mentioned that he was using an E38. I wonder if he posted the wrong tune file or something. I also noticed in that tune that the cylinder size was set to ~.71 for a ~5.7L engine. I am guessing this should be .75L for LS2 right?



I didn't check that but I am using a stock c6 grandsport tune so shouldn't it work just fine with the stock ls3 MAP that I have?

EDIT: Just double checked the tune values and I am using 128.13 kpa for the linear and -0.31 kpa for offset which is what the stock ls3 tune was using

MAP sensors are not a strong suite of mine but correct me if im wrong here eXo3901, the MAP offset and linear have to be set up for your elevation and you have to make sure you have the right MAP sensor as well. Naturally Asperated vehicles normally run 1bar MAP sensor. 2 & 3 bar are for Forced Induction setups.

[eXo3901]

MAP is like injector data, it is static. You match the data to the physical sensor. Best to just use OEM GM sensors since the data is easy to find. If it is correct your KOEO MAP reading in the scanner should be close to your local STATION pressure.

[broncjones]

Could you attach tube again