LS1 to LS2 motor change

[billiardcue]

Changing the head and cam LS1 in my 04 Vette to an LS2 408 h/c motor.
What do I need to change in my tune to make the car driveable until it gets to the dyno tuner?
Changing 30# ford injectors to 42# Bosch injectors, LS2 90mm intake and throttle body, increasing cam duration by about 10*.
I increased the injector flow rate B4001 by 40% and the cylinder volume B0104 to 51.1.

[Redline Motorsports]

If you are using a LS2 block the knock sensors and the cam sensor are different for starters. You can buy a conversion harness from Casper Electronics http://www.casperselectronics.com/

The IFR rate should be correctly changed. I would not add 40 %. Use one of the Excel spreadsheets to figure it out. Its a constant value that should not be touched after it is recalculated.

I have had very good luck in getting the 90mm TB's to work by changing B4349 to .0157 to tell the PCM the effective throttle area has changed.

Set the coolant fans as well and you should be OK to get it moving!

Howard

[ringram]

My Fast90/90 worked fine, just did a RAF log and paste.
IAC counts were down to 30 counts from the stock 40 probably due to the extra air around the blade. No need to touch any other tables.

[billiardcue]

If you are using a LS2 block the knock sensors and the cam sensor are different for starters. You can buy a conversion harness from Casper Electronics http://www.casperselectronics.com/
done


The IFR rate should be correctly changed. I would not add 40 %. Use one of the Excel spreadsheets to figure it out. Its a constant value that should not be touched after it is recalculated.
Do I create a spreadsheet or are they available online?


I have had very good luck in getting the 90mm TB's to work by changing B4349 to .0157 to tell the PCM the effective throttle area has changed.
I will make this change.


Set the coolant fans as well and you should be OK to get it moving!
done

Thanks

[billiardcue]

My Fast90/90 worked fine, just did a RAF log and paste.
IAC counts were down to 30 counts from the stock 40 probably due to the extra air around the blade. No need to touch any other tables.
What is an RAF log?
What are IAC counts?

Thanks

[TAQuickness]

This is the spreadsheet you want for scaling injectors.

http://www.allmod.net/hpt/injectors.xls

Be sure to click the EFILive tab.

[Bruce Melton]

I did this by starting with a 6 liter truck VE and RHS scale for the 42s. It was closer than you would guess. From there I did AutoVE and it was pretty easy other than the 42s were a bit big so I went back to 36s for now.
If I can help let me know-
Bruce

[Redline Motorsports]

What is an RAF log?
What are IAC counts?

Thanks

The IAC counts are a bit misleading with the ETC (electronic throttle control) cars. The non-etc cars have a IAC motor. Basically it is a computer controlled vacuum leak which is used control idle in a variety of situations. IAC counts are the steps that the IAC is moved being zero as fully closed. If the IAC is not in a reasonable range the PCM will have a hard time adapting to the different conditions fast enough to control idle. This means that if you have a IAC count of zero and the car is still idling well, additional air is entering and you have no control on the back side of idle. If you have a high count, lets say 140-160 it means the IAC is opened quite a bit indicating that the engine is looking for more air.

Most agree that 60-80 puts the IAC in a position that allows more or less air to be provided with good PCM control.

The ETC cars don't have a IAC which is why it gets confusing. It is actually quite amazing that the throttle blade is the IAC and the "air valve" at the same time. You also can't play with the throttle blade as well as you can the non-etc motors. Logging the RAF (Running Air Flow) is a way to see what kind of air is moving into the engine as the engine warms up.

What Ring is refering to is make a map of the RAF table. Start the car cold and log until is fully warmed up. Then paste the value into the tune file and reflash it. These are also called the desired airflow if I'm not mistaken.

I have learned that don't make too many changes, especially with the ETC cars! Keep it simple!

Howard

[driver456]

Wouldn't you have to change {B0104} Cylinder Volume also?Would that be 51?...........Paul

[billiardcue]

Wouldn't you have to change {B0104} Cylinder Volume also?Would that be 51?...........Paul
Done - see first post.

[billiardcue]

The IFR rate should be correctly changed. I would not add 40 %. Use one of the Excel spreadsheets to figure it out. Its a constant value that should not be touched after it is recalculated.

TAQuickness posted this Excel spreadsheet and my 40% increase settings are real close to these numbers. I just did the math and 42 is 40% larger than 30.

I assume the larger the number = the shorter the dwell time of the injector and as the manifold vacuum decreases (WOT) the lesser injector flow number actually richens the afr.
Or am I thinking backwards?
[quote=Redline Motorsports]I have had very good luck in getting the 90mm TB's to work by changing B4349 to .0157 to tell the PCM the effective throttle area has changed.
My B4349 is now 0.025497, is that a correct number for the stock throttle body?

The table B3618 - what settings would you start with?

[TAQuickness]

Make sure your IFR table is correct and not just "close enough". The IFR table serves as the one known costant in your tune. A discrepancy as little as 1-2% in the IFR table is enough to skew an entire tune.

[billiardcue]

Make sure your IFR table is correct and not just "close enough". The IFR table serves as the one known costant in your tune. A discrepancy as little as 1-2% in the IFR table is enough to skew an entire tune.
Thanks for the Excel IFR tables.
My tables have been skewed by different tuners. If I use the values in the spreadsheet should I be correct?

[TAQuickness]

If you use your actual fuel pressure, the IFR table will be very accurate and serve as the base for the rest of your tune.

[Tordne]

If you use your actual fuel pressure, the IFR table will be very accurate and serve as the base for the rest of your tune.

You already know TA, but my VE table has changed shape along with the IFR table slope as a result of the fuel pressure stuff... I don't view VE in % but it is not more realistic values in that table in both high and low areas :)

[PladdPezzPunk]

If you are using a LS2 block the knock sensors and the cam sensor are different for starters. You can buy a conversion harness from Casper Electronics http://www.casperselectronics.com/

The IFR rate should be correctly changed. I would not add 40 %. Use one of the Excel spreadsheets to figure it out. Its a constant value that should not be touched after it is recalculated.

I have had very good luck in getting the 90mm TB's to work by changing B4349 to .0157 to tell the PCM the effective throttle area has changed.

Set the coolant fans as well and you should be OK to get it moving!

Howard

when you did this on ETC cars, were you able to see the throttle blade open to 100% @WOT. Also when you ran a log, at idle, were you shoing between 0 and 10% throttle. On mine, I have the LS2 90 MM throttle body and 02's tac module to command it. and have had the ongoing problem that the blade only opens physically about 85-90% but says 100% in the computer, also at idle, i stay at about 16-24%. (I also noticed my fuel trim numbers going nuts with the throttle position for some reason, but i think that is another problem)

[Redline Motorsports]

when you did this on ETC cars, were you able to see the throttle blade open to 100% @WOT. Also when you ran a log, at idle, were you shoing between 0 and 10% throttle. On mine, I have the LS2 90 MM throttle body and 02's tac module to command it. and have had the ongoing problem that the blade only opens physically about 85-90% but says 100% in the computer, also at idle, i stay at about 16-24%. (I also noticed my fuel trim numbers going nuts with the throttle position for some reason, but i think that is another problem)

That is 100 % normal to see log values of 0-10% at idle. I believe that they self adjust upon startup to know that its at idle. How are you confirming that the throttle is at 100%?? I always thought the car had to be running to obtain full control of the blade......

What is the actual problem that is causing you to look into this? Sounds normal to me with a ETC.

The trims sound like they are just responding to air changes when you move the throttle...