350z IM on fwd maxima
03-07-2006, 05:46 PM
#81
Guest
Posts: n/a
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback AT
control stops in order to maintain stabilized fuel combustion.
. Deceleration and acceleration
. High-load, high-speed operation AX
. Malfunction of heated oxygen sensor 1 or its circuit
. Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature SU
. High engine coolant temperature
. During warm-up
. After shifting from “N” to “D” BR
. When starting the engine
Mixture Ratio Self-learning Control ST
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxygen sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close
RS
to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as
originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., injector clogging) directly affect mixture ratio. BTAccordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
HA
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical SCvalue. The signal from the heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich,
and an increase in fuel volume if it is lean. EL“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment. IDX
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback AT
control stops in order to maintain stabilized fuel combustion.
. Deceleration and acceleration
. High-load, high-speed operation AX
. Malfunction of heated oxygen sensor 1 or its circuit
. Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature SU
. High engine coolant temperature
. During warm-up
. After shifting from “N” to “D” BR
. When starting the engine
Mixture Ratio Self-learning Control ST
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxygen sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close
RS
to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as
originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., injector clogging) directly affect mixture ratio. BTAccordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
HA
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical SCvalue. The signal from the heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich,
and an increase in fuel volume if it is lean. EL“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment. IDX
03-07-2006, 05:50 PM
#82
Guest
Posts: n/a
Originally Posted by chris'smax
It will compensate while in closed loop. When in open loop (above 40% throttle) that is where the SAFC is used to make fuel adjustments. And yes you will have to use the the 3.5L injectors or DEK injectors along with the 3.5 or DEK injector clips
03-07-2006, 05:52 PM
#83
Guest
Posts: n/a
Originally Posted by vsamoylov
open loop is when the throttle is wide open. how is 40% open loop? so you are saying i am driving in open loop all the time which means no feedback from o2 sensors?
03-07-2006, 06:02 PM
#85
Junior Member
Join Date: Feb 2006
Posts: 27
Cool project overall. I do have one question though? Using your logic about the ECU accomodating for the new larger injectors, how is it that EVERY other Nissan ECU needs a re-tune to run larger injectors? I mean really, what your saying makes no sense. It simply controls pulse time, in which case pulse time for a certain injector injects a certain amount of fuel, and the same pulse time on an injector that flows more will inject MORE fuel.
Your car WILL run richer as a result and will NEGATE some of the power you are trying to obtain by doing this mod. As previously stated, like shootng yourself in the foot. Just makes no sense to go through all that work to half *** that portion of the install.
Your car WILL run richer as a result and will NEGATE some of the power you are trying to obtain by doing this mod. As previously stated, like shootng yourself in the foot. Just makes no sense to go through all that work to half *** that portion of the install.
03-07-2006, 06:10 PM
#86
how about we let him get the kinks out of getting it to be everyday drivable and then we bug him about getting a dyno and a tune. sometimes support works wonders. all the old ****** on here tend to burn down someones dream if its different from the route they planned on going
03-07-2006, 06:11 PM
#87
Supporting Maxima.org Member
iTrader: (3)
Join Date: Oct 2002
Location: Ontario, Canada
Posts: 1,204
Originally Posted by vsamoylov
read my last posts and show me where open loop is above 40% throttle
Maybe you are not understanding because the 40% throttle opening is not explicitly written there. However terms like "acceleration" and "high speed operation" are.
I have spent many hours driving around data logging with an OBD-II scanner. One of the neat little features it has is that it tells you in realtime when you are in "O2 feedback" or "open loop drive" modes. I can honestly tell you that the only time the ecu is in closed loop is when you are idling, driving at a constant speed or very modestly accelerating. The rest of the time the ecu is in open loop.
Maybe you should invest or borrow a scanner. It provides a much more tangible insight into engine control than reading text from the fsm.
03-07-2006, 06:39 PM
#89
Hell i commend vsamylov for having the ***** to go ahead and do this. I have had thoughts of doing this but the hood issue has led me away from it. I am just trying to help the guy out. I am not the brightest crayon in the box, but i do know enough about fuel setups that i know he is going to run rich. I just want him to get the full potential from the work he has done.
03-07-2006, 06:48 PM
#92
I agree with ENG92....after I got my dyno tune, I immediately felt a difference in normal cruising around town....the low/mid-range is MUCH more powerful than it was before it got tuned....and if piggyback units only modify open loop....what could be this explaination then?
Well, if ENG92 monitered his OBDII percisely....and says that the car rarely goes into close loop anyway....then there goes the answer....
Well, if ENG92 monitered his OBDII percisely....and says that the car rarely goes into close loop anyway....then there goes the answer....
03-07-2006, 07:15 PM
#93
I was just reading on my350z and they mention something about raising there hood when installing aftermarket plenums. Can the hood height be raised or do you have to use a spacer or something along those lines. Sorry if this is stupid but i am no body shop guy.
03-07-2006, 07:28 PM
#95
Originally Posted by vsamoylov
Open Loop Control
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion
. Deceleration and acceleration
. High-load, high-speed operation .
. Malfunction of heated oxygen sensor 1 or its circuit
. Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature SU
. High engine coolant temperature
. During warm-up
. After shifting from “N” to “D”
. When starting the engine
Mixture Ratio Self-learning Control
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxygen sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close
to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as
originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., injector clogging) directly affect mixture ratio. BTAccordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical SCvalue. The signal from the heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich,
and an increase in fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion
. Deceleration and acceleration
. High-load, high-speed operation .
. Malfunction of heated oxygen sensor 1 or its circuit
. Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature SU
. High engine coolant temperature
. During warm-up
. After shifting from “N” to “D”
. When starting the engine
Mixture Ratio Self-learning Control
The mixture ratio feedback control system monitors the mixture ratio signal transmitted from the heated oxygen sensor 1. This feedback signal is then sent to the ECM. The ECM controls the basic mixture ratio as close
to the theoretical mixture ratio as possible. However, the basic mixture ratio is not necessarily controlled as
originally designed. Both manufacturing differences (i.e., mass air flow sensor hot wire) and characteristic
changes during operation (i.e., injector clogging) directly affect mixture ratio. BTAccordingly, the difference between the basic and theoretical mixture ratios is monitored in this system. This
is then computed in terms of “injection pulse duration” to automatically compensate for the difference between
the two ratios.
“Fuel trim” refers to the feedback compensation value compared against the basic injection duration. Fuel trim
includes short term fuel trim and long term fuel trim.
“Short term fuel trim” is the short-term fuel compensation used to maintain the mixture ratio at its theoretical SCvalue. The signal from the heated oxygen sensor 1 indicates whether the mixture ratio is RICH or LEAN compared to the theoretical value. The signal then triggers a reduction in fuel volume if the mixture ratio is rich,
and an increase in fuel volume if it is lean.
“Long term fuel trim” is overall fuel compensation carried out long-term to compensate for continual deviation
of the short term fuel trim from the central value. Such deviation will occur due to individual engine differences,
wear over time and changes in the usage environment.
So I want to know how the ECU still knows to adjust the fuel trims during those conditions when it clearly states that the O2 sensors are taken out of the equation, essentually blinding the ECU.
03-07-2006, 10:37 PM
#102
Lol I can't believe all the hate. If everyone knows so much why hasn't everyone done something like this? I think its too easy to discredit people for their attempts at something new. So what if he breaks something or doesn't run 100% right away. I'm sure it will all be sorted out eventually. Just that it runs is a feat in itself guys. How many others have this set up running?
03-07-2006, 10:50 PM
#103
I think you are all confusing the 40% throttle is OPEN loop, with Hi and LO throttle adjustments on the AFC.
AFC is able to control how much more or less fuel goes in the engine at a GIVEN throttle input, so you could make it kick into "open loop like" enrichment with the AFC at 40%. ECU will still be in closed loop at 40% probably, but you can start to adjust your A/F tables at even 10% throttle. With lets say TP HI set at 40% on the AFC, it will start to dump a set amount of fuel more or less into the engine at over 40% throttle. At TP set LO it will do a similar thing. I liked tuning it by RPM on my G20, knowing that at WOT it would spool the turbo at XXXX RPM I could eighter add or subract fuel at that engine speed. I ran 370cc injectors with 240cc injector ECU program and S-AFCII for a long time with no issues, great gas mileage still.
There is no SET value as to WHEN it goes into open loop, its all based on engine load calculated by the MAF sensor. There are certain parameters that need to be meet in order for that to happen.
And yes I can make you a perfect program on a EU for closed loop and open loop operation. S-AFC ? I tunned with those 3+ years ago... move on cave people <ducking>
AFC is able to control how much more or less fuel goes in the engine at a GIVEN throttle input, so you could make it kick into "open loop like" enrichment with the AFC at 40%. ECU will still be in closed loop at 40% probably, but you can start to adjust your A/F tables at even 10% throttle. With lets say TP HI set at 40% on the AFC, it will start to dump a set amount of fuel more or less into the engine at over 40% throttle. At TP set LO it will do a similar thing. I liked tuning it by RPM on my G20, knowing that at WOT it would spool the turbo at XXXX RPM I could eighter add or subract fuel at that engine speed. I ran 370cc injectors with 240cc injector ECU program and S-AFCII for a long time with no issues, great gas mileage still.
There is no SET value as to WHEN it goes into open loop, its all based on engine load calculated by the MAF sensor. There are certain parameters that need to be meet in order for that to happen.
And yes I can make you a perfect program on a EU for closed loop and open loop operation. S-AFC ? I tunned with those 3+ years ago... move on cave people <ducking>
03-07-2006, 11:25 PM
#105
Hey Mike Jez...you might be able to answer this one since I know you have an OBDII hooked on your car...
Does the car really stay in CLOSED loop that much? I mean according to the forums, they say it's 40% throttle and 3k+ rpms in order for the ecu to go into OPEN loop.....anything below that is CLOSED....now during daily driving, obviously this is kind of hard to reach...when I moniter my AFC, sure I can hit above 3k rpms, but i'm still hanging around 25-30% throttle....thats my daily driving style....
AFC modifys MAF signals....MAF = open loop only? Open loop = 40% & 3k RPMS....If thats the case, how come after i got my dyno tune, I can feel a very noticeable difference in the low-mid range just daily driving it? I know it's not my mind playing tricks, its real noticeable believe me....this leads me to believe that the car is barely even running closed loop...and majority of the time running open....
According to your scanner, when exactly does your car go from open-close and close-open? Under what conditions etc etc? Thanks !
Does the car really stay in CLOSED loop that much? I mean according to the forums, they say it's 40% throttle and 3k+ rpms in order for the ecu to go into OPEN loop.....anything below that is CLOSED....now during daily driving, obviously this is kind of hard to reach...when I moniter my AFC, sure I can hit above 3k rpms, but i'm still hanging around 25-30% throttle....thats my daily driving style....
AFC modifys MAF signals....MAF = open loop only? Open loop = 40% & 3k RPMS....If thats the case, how come after i got my dyno tune, I can feel a very noticeable difference in the low-mid range just daily driving it? I know it's not my mind playing tricks, its real noticeable believe me....this leads me to believe that the car is barely even running closed loop...and majority of the time running open....
According to your scanner, when exactly does your car go from open-close and close-open? Under what conditions etc etc? Thanks !
03-08-2006, 05:23 AM
#106
Originally Posted by zander
Lol I can't believe all the hate. If everyone knows so much why hasn't everyone done something like this? I think its too easy to discredit people for their attempts at something new. So what if he breaks something or doesn't run 100% right away. I'm sure it will all be sorted out eventually. Just that it runs is a feat in itself guys. How many others have this set up running?
03-08-2006, 05:36 AM
#108
Originally Posted by BlackBIRDVQ
I think you are all confusing the 40% throttle is OPEN loop, with Hi and LO throttle adjustments on the AFC.
AFC is able to control how much more or less fuel goes in the engine at a GIVEN throttle input, so you could make it kick into "open loop like" enrichment with the AFC at 40%. ECU will still be in closed loop at 40% probably, but you can start to adjust your A/F tables at even 10% throttle. With lets say TP HI set at 40% on the AFC, it will start to dump a set amount of fuel more or less into the engine at over 40% throttle. At TP set LO it will do a similar thing. I liked tuning it by RPM on my G20, knowing that at WOT it would spool the turbo at XXXX RPM I could eighter add or subract fuel at that engine speed. I ran 370cc injectors with 240cc injector ECU program and S-AFCII for a long time with no issues, great gas mileage still.
There is no SET value as to WHEN it goes into open loop, its all based on engine load calculated by the MAF sensor. There are certain parameters that need to be meet in order for that to happen.
And yes I can make you a perfect program on a EU for closed loop and open loop operation. S-AFC ? I tunned with those 3+ years ago... move on cave people <ducking>
AFC is able to control how much more or less fuel goes in the engine at a GIVEN throttle input, so you could make it kick into "open loop like" enrichment with the AFC at 40%. ECU will still be in closed loop at 40% probably, but you can start to adjust your A/F tables at even 10% throttle. With lets say TP HI set at 40% on the AFC, it will start to dump a set amount of fuel more or less into the engine at over 40% throttle. At TP set LO it will do a similar thing. I liked tuning it by RPM on my G20, knowing that at WOT it would spool the turbo at XXXX RPM I could eighter add or subract fuel at that engine speed. I ran 370cc injectors with 240cc injector ECU program and S-AFCII for a long time with no issues, great gas mileage still.
There is no SET value as to WHEN it goes into open loop, its all based on engine load calculated by the MAF sensor. There are certain parameters that need to be meet in order for that to happen.
And yes I can make you a perfect program on a EU for closed loop and open loop operation. S-AFC ? I tunned with those 3+ years ago... move on cave people <ducking>
03-08-2006, 05:58 AM
#109
Originally Posted by nismology
Did you ever ask yourself why people have been tuning their S-AFC's at >40% throttle? Because the ECU won't try to correct it back to stoich. Numerous people with wideband o2's and/or OBD dataloggers have confirmed that 40% throttle and up is the condition for open-loop operation.
03-08-2006, 07:52 AM
#110
Loss won't be "that much", however search for the SAE doc SteVTEC posted on how Nissan spent effort optimizing the intake duct. The straightest path possible provides the lowest resistance, however without changing the throttle-body angle/neck inlet, there isn't much you can do about that.
I wouldn't worry about it until you tune it and see how well it does the way you have it now.
We're not attacking what you have done, we know what you do, we are just slapping your brothers inflated ego back where it belongs.
Until you guys put down more then SR20DENs what 265whp?, you might listen to what he says about optimal tuning...at least with the FWD VQ35 injectors/ECU there isn't anyone here that has dyno tested more.
I wouldn't worry about it until you tune it and see how well it does the way you have it now.
We're not attacking what you have done, we know what you do, we are just slapping your brothers inflated ego back where it belongs.
Until you guys put down more then SR20DENs what 265whp?, you might listen to what he says about optimal tuning...at least with the FWD VQ35 injectors/ECU there isn't anyone here that has dyno tested more.
Originally Posted by maxS
the other thing, if someone can prove that a few 45 deg bends on 3" piping create that much of a restriction, i WILL rework the setup.
03-08-2006, 08:46 AM
#112
Fluid mechanics will dictate that any time you have a bend you will have a small loss. Any restriction, or flow blockage you also have a loss. The longer the pipe, the more loss, and the rougher the surface walls, the more loss. There is also an optimal diameter for the airflow velocity you want to achieve, which will vary depending on what rpm you are trying to tune for. (There's also an optimal intake path length based on resonance tuning but that's a whole other topic).
Some of these losses can be minimized but they are still there. Also, running an intake pipe across the front of a hot cylinder head and/or radiator is not the best configuration IMO as the pipe can heat soak and raise air temps.
ANyways, I'm sure many of you are well aware of these things so I won't go on. Just re-iterating what's been said.
Vasily and MaxS, I do think you need to add a tuning solution. But I give you credit for doing this and would like to see pics of the hood now with the scoop on it please...
Man all these VQ35 swap threads are making me itch to get on with mine. I have had several interesting ideas kicking around in my head about it for a long time, a few of which involve a couple of different Z manifolds. However I have to hold off for a bit due to financial pressures. In the meantime I have a couple goals for my little ol' 3L. (Can't just do nothing.. I'd be bored. lol)
Some of these losses can be minimized but they are still there. Also, running an intake pipe across the front of a hot cylinder head and/or radiator is not the best configuration IMO as the pipe can heat soak and raise air temps.
ANyways, I'm sure many of you are well aware of these things so I won't go on. Just re-iterating what's been said.
Vasily and MaxS, I do think you need to add a tuning solution. But I give you credit for doing this and would like to see pics of the hood now with the scoop on it please...
Man all these VQ35 swap threads are making me itch to get on with mine. I have had several interesting ideas kicking around in my head about it for a long time, a few of which involve a couple of different Z manifolds. However I have to hold off for a bit due to financial pressures. In the meantime I have a couple goals for my little ol' 3L. (Can't just do nothing.. I'd be bored. lol)
03-08-2006, 08:54 AM
#114
Guest
Posts: n/a
like i said if anybody can prove that the bends are restrictive the piping will be reworked and about the heat issue, you are forgetting about the sc guys that have the piping running in the same place. Also the piping is no longer then the stupid injen and all the other intakes that are out there for the maxima. IMO this one beats all the ones that are produced by companys and are sold for a high price amount.
hood wont be repainted cause the scoop is carbon fiber. there is one thign left and this project is done.
hood wont be repainted cause the scoop is carbon fiber. there is one thign left and this project is done.
