Now THAT'S FUNNY!:biggrin: LOL I could just see that happening for sure.lol You got a flak jacket Donnie? Maybe you could do some duck hunting if you add some shot to the tail pipe. lol:biggrin:
Advancement of fuel delivery?
- Thread starter Alky V6
- Start date
Now THAT'S FUNNY!:biggrin: LOL I could just see that happening for sure.lol You got a flak jacket Donnie? Maybe you could do some duck hunting if you add some shot to the tail pipe. lol:biggrin:
The ECM has come back with the latest hardware and operating software upgrades. I've already converted the old version user (bin) file to be used with the new software version. There were a few settings that didn't make it through the conversion correctly and those have been adjusted.
A large difference is in the way the map sensor is interpreted in relation to an accurate real world pressure reading. The new software puts the reading much closer to real world. How close? Don't know that for sure yet, but it is closer. This has forced me to revamp the complete VE table. The map sensor reading resolution is greatly improved for more accurate fuel delivery.
The new software has some new tuning tools that has made it fun dialing the VE table back into shape.
So far, the VE table has been corrected to 4500 rpm / 98 kPa, off the nitrous.
A large difference is in the way the map sensor is interpreted in relation to an accurate real world pressure reading. The new software puts the reading much closer to real world. How close? Don't know that for sure yet, but it is closer. This has forced me to revamp the complete VE table. The map sensor reading resolution is greatly improved for more accurate fuel delivery.
The new software has some new tuning tools that has made it fun dialing the VE table back into shape.
So far, the VE table has been corrected to 4500 rpm / 98 kPa, off the nitrous.
Finished a test and tune session last night. Some notes.
T/C stall after .500 seconds on the nitrous and at the moment of transbrake release: 3660 rpm / 94 kPa. Rich condition was present at this point in the fuel table (maxed on the a/f meter). Most likely, stall will be higher when the mixture is corrected. RPM breakpoint in fuel table moved from 3800 to 3670 to pinpoint this stall mark.
100 kPa achieved by 4,000 rpm.
147 kPa achieved in 1.7 seconds from moment of launch. Down .3 seconds from past performance.
Off nitrous the fuel table was set to read back 10.9 to 11.2 throughout boost rise, up to the wall. When the nitrous was added, the a/f readout throughout the nitrous shot (4,000 rpm and on) was 14.64:1. Very interesting, considering I'm using a very, very rich nitrous pill tune, even for alcohol.
I richened the fuel table to get an ocillating a/f reading in the same nitrous region (4,000 rpm and on) between 12.96 to 13.67 with an increase in boost and rpm rise rate. The percentage of pw increase needed to do this was minimal. A sharp increase in pw was needed at the transition from 3800rpm/96 kPa to 4000 rpm/100 kPa. This is where the turbo is starting to spool.
Nitrous retard for these tests were at 18 degrees. The plan is to take away 2 degrees of retard at a time, after I've found the best performing a/f ratio for the nitrous. I have a feeling I will find that the richer I go with the nitrous, the lazier the hit will be. I think the lean mixture puts some heat into the process that allows a better burn of the total 300hp charge. A spectator said the tires lifted on one of the nitrous launches. That's with nitrous alone. Zero boost has built up by the time of the transbrake release.
The nitrous system is setup to timeout via a delay box. I also have a 16 psi pressure switch in series as a backup. The last time out with the car, nitrous was shutting down at around 136 kPa, or about 2 seconds from launch. This time out with the car, and the same 2 second shutoff point, the kPa reached 180 kPa. Needless to say, I don't need the nitrous on at that boost level. The tires quickly resorted to massive smokage, along with steering me into the other lane. I have an in-car vid of this pass. I'll try to get it posted. I cut back the delay timer to shut down the nitrous 1.7 seconds after leaving the line.
The feel of the launch, in general, feels smooth. Still some work to be done on the fuel map. Paricularly, 190 kPa on up. Way too rich. Pegging the a/f meter.
I'm working the control pressure for the boost controller down. Max boost levels during these tests were 315 kPa, unintentionally. The car might like that at the end of the run, but it sure didn't like it much during the 1-2 shift. Although, the car was still controllable. Just a little skating through 2nd and part of 3rd.
T/C stall after .500 seconds on the nitrous and at the moment of transbrake release: 3660 rpm / 94 kPa. Rich condition was present at this point in the fuel table (maxed on the a/f meter). Most likely, stall will be higher when the mixture is corrected. RPM breakpoint in fuel table moved from 3800 to 3670 to pinpoint this stall mark.
100 kPa achieved by 4,000 rpm.
147 kPa achieved in 1.7 seconds from moment of launch. Down .3 seconds from past performance.
Off nitrous the fuel table was set to read back 10.9 to 11.2 throughout boost rise, up to the wall. When the nitrous was added, the a/f readout throughout the nitrous shot (4,000 rpm and on) was 14.64:1. Very interesting, considering I'm using a very, very rich nitrous pill tune, even for alcohol.
I richened the fuel table to get an ocillating a/f reading in the same nitrous region (4,000 rpm and on) between 12.96 to 13.67 with an increase in boost and rpm rise rate. The percentage of pw increase needed to do this was minimal. A sharp increase in pw was needed at the transition from 3800rpm/96 kPa to 4000 rpm/100 kPa. This is where the turbo is starting to spool.
Nitrous retard for these tests were at 18 degrees. The plan is to take away 2 degrees of retard at a time, after I've found the best performing a/f ratio for the nitrous. I have a feeling I will find that the richer I go with the nitrous, the lazier the hit will be. I think the lean mixture puts some heat into the process that allows a better burn of the total 300hp charge. A spectator said the tires lifted on one of the nitrous launches. That's with nitrous alone. Zero boost has built up by the time of the transbrake release.
The nitrous system is setup to timeout via a delay box. I also have a 16 psi pressure switch in series as a backup. The last time out with the car, nitrous was shutting down at around 136 kPa, or about 2 seconds from launch. This time out with the car, and the same 2 second shutoff point, the kPa reached 180 kPa. Needless to say, I don't need the nitrous on at that boost level. The tires quickly resorted to massive smokage, along with steering me into the other lane. I have an in-car vid of this pass. I'll try to get it posted. I cut back the delay timer to shut down the nitrous 1.7 seconds after leaving the line.
The feel of the launch, in general, feels smooth. Still some work to be done on the fuel map. Paricularly, 190 kPa on up. Way too rich. Pegging the a/f meter.
I'm working the control pressure for the boost controller down. Max boost levels during these tests were 315 kPa, unintentionally. The car might like that at the end of the run, but it sure didn't like it much during the 1-2 shift. Although, the car was still controllable. Just a little skating through 2nd and part of 3rd.
The pull was to the left. There were a few things that worked against me on that pass. Someone told me later that it looked like the right slick got warmed up more than the left. The right tire smoked during the burnout, while the left did not. He also told me that he thought I lined up pointing a little to the left to start with. I also didn't do enough to keep the car in the groove at the start of the run. By the time the boost hit like a sledge hammer, I was real close to the marbles. I'm sure the left lane car did his best to prepare for me coming across. Luckily, the car submitted.
Kinda sounded like what you had happen. Glad to hear you didn't have the same thing as Odell at BG. You need vids inside and out so you can correct things like this. Glad to hear you and the car are safe.:biggrin:
My first in-car video.
The cluster of four gauges in front of me include the boost gauge. It's at the upper left corner. The gauge just to the right of the tach is the fuel pressure, and the one to the right of that is the exhaust temp. The boost controller is in front of the shifter. Next time I do this, I need to remember to zoom in a little.
YouTube - Early Alky v3 2 20L video test
The cluster of four gauges in front of me include the boost gauge. It's at the upper left corner. The gauge just to the right of the tach is the fuel pressure, and the one to the right of that is the exhaust temp. The boost controller is in front of the shifter. Next time I do this, I need to remember to zoom in a little.
YouTube - Early Alky v3 2 20L video test
You almost bought a chevy on that pass
I'm not sure how close beside me he was, but I'm sure he had a good view of the fun.
That was the first pass going back on the nitrous, since the ECM hardware/software upgrading, and fiddling with the fuel map to get things back in line. Like I stated a few posts back, from 4,000 rpm to the shut off of the nitrous, the a/f readout on this pass was a flatline 14.64:1. The fuel table off-nitrous was plenty rich, and the nitrous tune was very rich.
Very strange... a perfect burn? Or maybe, some of the methanol that made it through the combustion process had dissassociated by the time it got to the ego sensor and the sensor picked up the disassociated oxygen molecules from the fuel. Wow. That throws a monkey wrench into my tuning procedure.
Looks like the EGT maxed out at 1,050 F on that run. Very good. That's a minimum target.
I can't tell what the max fuel pressure was. Base setting is at 45 psi and the gauge reads 40, 60, 80. It doesn't seem that it dropped on the top end, anyway.
The boost gauge reads 18-19 psi at the 12 o'clock position and is 30 psi at the 3 o'clock position. I can't tell what the max reading was, but I could see in the video that it at least got to 25 psi.
The boost gauge reads 18-19 psi at the 12 o'clock position. Note the attitude of the car with the gauge needle before the 12 o'clock position.
Shut off before the midtrack cone and still did a 7.xx ET.
I can't tell what the max fuel pressure was. Base setting is at 45 psi and the gauge reads 40, 60, 80. It doesn't seem that it dropped on the top end, anyway.
The boost gauge reads 18-19 psi at the 12 o'clock position and is 30 psi at the 3 o'clock position. I can't tell what the max reading was, but I could see in the video that it at least got to 25 psi.
The boost gauge reads 18-19 psi at the 12 o'clock position. Note the attitude of the car with the gauge needle before the 12 o'clock position.
Shut off before the midtrack cone and still did a 7.xx ET.
Peculiar thing happening at the stall rpm on the nitrous (3,650 rpm). The a/f reading goes max rich. Then by 4,000 rpm, the reading goes max lean. I run into the same type of tuning issue at converter stall rpm off the nitrous (2,440 rpm).
The engine basically has two converter stall speeds, and the two different stall rpm points need to be treated identically when it comes to the fuel table. When I get the fueling at this transition point squared away, the engine should run through that zone much better.
After the fueling in that zone is fixed, I may engage the nitrous with more time before transbrake release. Now it is at .480 second before transbrake release. I have up to .920 second to play with.
The engine basically has two converter stall speeds, and the two different stall rpm points need to be treated identically when it comes to the fuel table. When I get the fueling at this transition point squared away, the engine should run through that zone much better.
After the fueling in that zone is fixed, I may engage the nitrous with more time before transbrake release. Now it is at .480 second before transbrake release. I have up to .920 second to play with.
If it was a fuel supply volume problem, the reading wouldn't richen when I increase the injector pw. It would just stay lean. Besides, after the nitrous shuts down, the reading goes back to rich. Even after the aux fueling system turns on, which demands more fuel volume than the nitrous system, it stays rich.
Here's one. With the last test run, there was a short moment when all systems overlapped. The E injectors + 'the wall', the nitrous system and the aux system were all on at the same time. I can tell when the nitrous system is still on by the ignition retard level, and I know the aux system turns on at 8 psi (147 kPa). On this run the nitrous retard stayed on until 183 kPa and the a/f ratio started heading rich at 159 kPa (The tail end of 'the wall'). 'The wall' is a large extra injection of fuel that I turn on at 147 kPa and turn off at 161 kPa, to cover the turning on of the aux fuel system and the resulting air purge from the aux fuel system.
That brings up another note. This time out I shortened the duration of 'the wall' from 165 kPa to 160 kPa. Before 'the wall' would turn on at 147 kPa and stay on until the boost had risen to 165 kPa where it would drop. The turn off point for 'the wall' now comes sooner by 160 kPa, and may soon be changed to 159 kPa. So the upgraded aux fuel plumbing did help a little.
Here is what I determined is my fuel supply problem with my system as it stands now.
The aux fueling is supplied by mechanical injector nozzles. They are at constant flow. As rpm increases fuel demand increases, but the nozzles are supplying a fixed volume no matter what the rpm is.
The e injectors can be programmed to increase fuel volume with rpm increase, to the point of max duty cycle.
I'm cutting back the e injectors when the aux fuel comes in at 8 psi. The amount of cutback at 8 psi is all that the ECM will allow. I'm at the limit of how much I can cut back the e injectors at 8 psi.
By max rpm and 30 psi boost, the e injectors are back up to 85% duty cycle.
The problem isn't the pump not being able to supply the fuel. It's the size of the e injectors being maxed out and the size of the mechanical nozzles at a fixed volume/constant flow being maxed out also.
Now I could raise the base fuel pressure, but that presents some problems. When it comes time to cut back the e injectors, I would need to cut them back further since the mechanical nozzles are now supplying more fuel at 8 psi, and the e injectors are supplying more fuel at 8 psi. Since, at the present base fuel pressure that I'm using, I'm already maxing out the amount of e injector cutback that the ECM allows me, you can see the problem.
Here is the easiest fix for my problem with the present system.
Everything is working real well up to 280 kPa. After 280 kPa you start to see some leaning out. That's with the e injectors at 85%. I'm not interested in running more than 85%.
If a FMU could be used that inflated fuel rail pressure only after 280 kPa, that would be the ticket!
The aux fueling is supplied by mechanical injector nozzles. They are at constant flow. As rpm increases fuel demand increases, but the nozzles are supplying a fixed volume no matter what the rpm is.
The e injectors can be programmed to increase fuel volume with rpm increase, to the point of max duty cycle.
I'm cutting back the e injectors when the aux fuel comes in at 8 psi. The amount of cutback at 8 psi is all that the ECM will allow. I'm at the limit of how much I can cut back the e injectors at 8 psi.
By max rpm and 30 psi boost, the e injectors are back up to 85% duty cycle.
The problem isn't the pump not being able to supply the fuel. It's the size of the e injectors being maxed out and the size of the mechanical nozzles at a fixed volume/constant flow being maxed out also.
Now I could raise the base fuel pressure, but that presents some problems. When it comes time to cut back the e injectors, I would need to cut them back further since the mechanical nozzles are now supplying more fuel at 8 psi, and the e injectors are supplying more fuel at 8 psi. Since, at the present base fuel pressure that I'm using, I'm already maxing out the amount of e injector cutback that the ECM allows me, you can see the problem.
Here is the easiest fix for my problem with the present system.
Everything is working real well up to 280 kPa. After 280 kPa you start to see some leaning out. That's with the e injectors at 85%. I'm not interested in running more than 85%.
If a FMU could be used that inflated fuel rail pressure only after 280 kPa, that would be the ticket!
I don't know if it would work or if someone has come up with it yet, but I have an idea for you Donnie. Is there any way to have 2 different circuits to the mechanical injetors pump that would allow for a reduction in power to it and them jump it to a higher power? I'm refering to electricity not pump action. If you had 1 circuit that had say 10 volts and then jumped to 12-14 volts this would increase the amount of fuel to the injectors and get rid of the lean issue. Like I said it may not be feasable but it might do what you want without to much hassle.
I haven't added the other fuel pump yet.
I do have a voltage booster on the single pump that increases voltage by 50% when 5 psi boost is reached. 12V to 18V. It does help, but the problem is not a shortage of supply volume. After 280 kPa, it is a shortage of fuel, but it's not the pumps fault. The mechanical injection nozzles, and the e injectors are supplying all the fuel they can at the fuel pressure that's being used. What I need is a boost in fuel pressure after 280 kPa so that the nozzles and e injectors can supply more fuel. The increase in fuel pressure needs to ramp upwards after 280 kPa. A step up in pressure will not work. If the ramp up of pressure could be adjustable, that would be best.
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