nitrorocket
August 21st, 2006, 04:27 AM
Some people have asked questions on how I have tuned my twin turbo 1000 hp stock cubed LS1with 96 lb. Injectors to run and idle on ONLY 93 octane.
I was completely new to LS1's and tuning with EFILIVE. I asked some pretty simple questions when I first started and had lot of difficulty first eliminating ALL torque management. Luckely I did not get banned for trying this on my own. I have now been answering PM's and emails on a regualr basis, so I thought I would share some info on commonly asked questions.
I am by no means an expert, but here is some ifo that might help you out.:D
Well, my setup is this:
Base fuel pressure is set at 45 psi and being that I have a streetcar, I wanted to have low fuel pressure to not overwork the pump. This has also greatly improved the overall flow rating of the pump by running such a "low" fuel pressure. I am over 800 rwhp with no fuel delivery problems.
I also do not use the boost reference on the fuel pressure regulator. A couple reasons for this is the ease of tuning, there are less fluctuations and inconsistencies in the tune with just a set static pressure. Also, again, being a streetcar with extreme amounts of boost, I do not want a mishap. I left the boost reference line off because if it were to ever fall off or fail under boost, fuel pressure would drop about 5 psi and the motor would BLOW UP! If the reference is connected, it taxes the pump harder, which lowers overall fuel delivery and heats up the fuel more then necessary. I did not need more flow from a 96lb injector anyway!
As far as the boost reference goes for idle, it makes NO difference. Idle AFR was almost not affected at all by the 5 psi decrease in fuel pressure.
There are 3 key things that affect idle tuning as far as getting consistent lean idle AFR.
IFR table can be tweaked (lowered) in the high vacuum ranges to trick the pcm into thinking the injectors are larger then they really are thus lowering PCM commanded pulse width at idle. This can be done at certain KPA(vacuum) levels that you need a smaller and faster pulse width.
SMALL PULSE ADJUST table can have “–“ numbers put in to actually subtract pulse width under the pcm commanded pulse width. This works well, up to about -.3 to -.4 where the injectors seem to not pulse at all and the car will want to die.
PULSE WIDTH VOLTAGE COMPENSATION table can be adjusted to not command as much additional pulse width by lessening the numbers in certain KPA(vacuum) levels that you need a smaller and faster pulse width.
Some of these mods can affect other parts of your tune INITALLY but can be corrected after data logging to see final changes. It took me a small combination of all these “tricks” to get the car idling correctly. These tricks also allowed me to have lean AFR on throttle deceleration where it normally wants to run rich due to the motor still spinning fast while the throttle blade is closed creating a really high vacuum pulling fuel from the injectors.
For boost tuning with the 3 bar,You simply set the 105 KPA on both the MAIN VE and the BOOST VE tables to match, from there you scale the boost ve table to about 50% richer(or whatever you feel comfortable with) to the last column. This will be way off but that doesn’t matter, you need a log first anyway.
Make a run into a small amount of boost while LOGGING and see how much richer the table is from 105 kpa on up. If it is getting richer by say 5% in each progressing column over what you want the AFR to be, then calculate the amount you need to lower the very last column and rescale the entire map from side to side and then top to bottom so the AFR does not progressively keep getting any richer or leaner. If you concentrate on making the map so the AFR is consistant, tuning will be easy. All you then do is richen or lean the entire map till you have the AFR you want, the whole chart will at least be consistant. This can be time consuming, but focus on this first a little at a time.
All this assumes you already somewhat know your way around the software pretty well. I hope this helps someone with a similar setup!
:)
I was completely new to LS1's and tuning with EFILIVE. I asked some pretty simple questions when I first started and had lot of difficulty first eliminating ALL torque management. Luckely I did not get banned for trying this on my own. I have now been answering PM's and emails on a regualr basis, so I thought I would share some info on commonly asked questions.
I am by no means an expert, but here is some ifo that might help you out.:D
Well, my setup is this:
Base fuel pressure is set at 45 psi and being that I have a streetcar, I wanted to have low fuel pressure to not overwork the pump. This has also greatly improved the overall flow rating of the pump by running such a "low" fuel pressure. I am over 800 rwhp with no fuel delivery problems.
I also do not use the boost reference on the fuel pressure regulator. A couple reasons for this is the ease of tuning, there are less fluctuations and inconsistencies in the tune with just a set static pressure. Also, again, being a streetcar with extreme amounts of boost, I do not want a mishap. I left the boost reference line off because if it were to ever fall off or fail under boost, fuel pressure would drop about 5 psi and the motor would BLOW UP! If the reference is connected, it taxes the pump harder, which lowers overall fuel delivery and heats up the fuel more then necessary. I did not need more flow from a 96lb injector anyway!
As far as the boost reference goes for idle, it makes NO difference. Idle AFR was almost not affected at all by the 5 psi decrease in fuel pressure.
There are 3 key things that affect idle tuning as far as getting consistent lean idle AFR.
IFR table can be tweaked (lowered) in the high vacuum ranges to trick the pcm into thinking the injectors are larger then they really are thus lowering PCM commanded pulse width at idle. This can be done at certain KPA(vacuum) levels that you need a smaller and faster pulse width.
SMALL PULSE ADJUST table can have “–“ numbers put in to actually subtract pulse width under the pcm commanded pulse width. This works well, up to about -.3 to -.4 where the injectors seem to not pulse at all and the car will want to die.
PULSE WIDTH VOLTAGE COMPENSATION table can be adjusted to not command as much additional pulse width by lessening the numbers in certain KPA(vacuum) levels that you need a smaller and faster pulse width.
Some of these mods can affect other parts of your tune INITALLY but can be corrected after data logging to see final changes. It took me a small combination of all these “tricks” to get the car idling correctly. These tricks also allowed me to have lean AFR on throttle deceleration where it normally wants to run rich due to the motor still spinning fast while the throttle blade is closed creating a really high vacuum pulling fuel from the injectors.
For boost tuning with the 3 bar,You simply set the 105 KPA on both the MAIN VE and the BOOST VE tables to match, from there you scale the boost ve table to about 50% richer(or whatever you feel comfortable with) to the last column. This will be way off but that doesn’t matter, you need a log first anyway.
Make a run into a small amount of boost while LOGGING and see how much richer the table is from 105 kpa on up. If it is getting richer by say 5% in each progressing column over what you want the AFR to be, then calculate the amount you need to lower the very last column and rescale the entire map from side to side and then top to bottom so the AFR does not progressively keep getting any richer or leaner. If you concentrate on making the map so the AFR is consistant, tuning will be easy. All you then do is richen or lean the entire map till you have the AFR you want, the whole chart will at least be consistant. This can be time consuming, but focus on this first a little at a time.
All this assumes you already somewhat know your way around the software pretty well. I hope this helps someone with a similar setup!
:)