Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

8 Pages V < 1 2 3 4 5 > »   
Reply to this topicStart new topic
> Desperate for some Help With Microsquirt, Beyond Frustrated
mightyohm
post Aug 30 2017, 11:55 AM
Post #41


Advanced Member
****

Group: Benefactors
Posts: 2,277
Joined: 16-January 03
From: Seattle, WA
Member No.: 162
Region Association: Pacific Northwest



I haven't read the whole thread, but I've been running Megasquirt for many years and I never needed a fuel cut on decel. If you're seriously backfiring you most likely have an intake/exhaust leak or the mixture is grossly off. My car burbles and pops slightly on deceleration but it's not objectionable and i've attributed it to some small exhaust leaks near the head.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Aug 30 2017, 12:11 PM
Post #42


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(mightyohm @ Aug 30 2017, 09:55 AM) *

I haven't read the whole thread, but I've been running Megasquirt for many years and I never needed a fuel cut on decel. If you're seriously backfiring you most likely have an intake/exhaust leak or the mixture is grossly off. My car burbles and pops slightly on deceleration but it's not objectionable and i've attributed it to some small exhaust leaks near the head.


It is far from being set up to run well! Had a recent issue with a firmware problem so I am just in the beginning stages of tuning while running on 4-cylinders. Likely a bit soon to attribute issues to leaks.

Planning on working back through everything this afternoon.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mightyohm
post Aug 30 2017, 12:15 PM
Post #43


Advanced Member
****

Group: Benefactors
Posts: 2,277
Joined: 16-January 03
From: Seattle, WA
Member No.: 162
Region Association: Pacific Northwest



I guess my $0.02 would be - don't worry about stuff like fuel cuts until you get the base map sorted out. Those features just add complexity and aren't strictly necessary.

QUOTE(Mblizzard @ Aug 30 2017, 11:11 AM) *

QUOTE(mightyohm @ Aug 30 2017, 09:55 AM) *

I haven't read the whole thread, but I've been running Megasquirt for many years and I never needed a fuel cut on decel. If you're seriously backfiring you most likely have an intake/exhaust leak or the mixture is grossly off. My car burbles and pops slightly on deceleration but it's not objectionable and i've attributed it to some small exhaust leaks near the head.


It is far from being set up to run well! Had a recent issue with a firmware problem so I am just in the beginning stages of tuning while running on 4-cylinders. Likely a bit soon to attribute issues to leaks.

Planning on working back through everything this afternoon.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
McMark
post Aug 30 2017, 12:34 PM
Post #44


914 Freak!
***************

Group: Retired Admin
Posts: 20,177
Joined: 13-March 03
From: Grand Rapids, MI
Member No.: 419
Region Association: None



Somewhere in the menus you can pull up the 'Realtime Display' which shows all of the readings from the sensors. Actually, realtime display pulls up graphs, and then there's a button to see all the actual numeric values. Post a picture of that, with the key on, but not running. I've recently realized how vital understanding the 'non-running' readings of sensors is. For example, your MAP sensor should be reading around 100kpa while not-running (at sea level). It's pretty easy, once you know, to look at the gauges before you start the car and see if that looks right. Also, when the engine is cold, the CHT and Intake Air Temp sensors should read about the same. If they don't, one of them is configured wrong.


Also, have you used a timing light to confirm the timing displayed on the laptop matches what you see in real life?

Oh, and finally, I think it's prudent to turn off all closed-loop interaction while tuning. If you're trying to tune the VE table, and the AFR table is fiddling with things 'behind your back' then you're going to have a tough time because you'll make a change in the VE table, and then the AFR controls will put it back where it was (essentially). Tune the VE table open loop, then once it's running well turn on closed loop. This will make it run worse, until you tweak the AFR table so it runs back where it was. At the end of that process you have a tuned VE table and a tuned AFR table and everything is happy. (IMG:style_emoticons/default/wink.gif)
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Aug 30 2017, 12:38 PM
Post #45


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(McMark @ Aug 30 2017, 10:34 AM) *

Somewhere in the menus you can pull up the 'Realtime Display' which shows all of the readings from the sensors. Actually, realtime display pulls up graphs, and then there's a button to see all the actual numeric values. Post a picture of that, with the key on, but not running. I've recently realized how vital understanding the 'non-running' readings of sensors is. For example, your MAP sensor should be reading around 100kpa while not-running (at sea level). It's pretty easy, once you know, to look at the gauges before you start the car and see if that looks right. Also, when the engine is cold, the CHT and Intake Air Temp sensors should read about the same. If they don't, one of them is configured wrong.


Also, have you used a timing light to confirm the timing displayed on the laptop matches what you see in real life?

Oh, and finally, I think it's prudent to turn off all closed-loop interaction while tuning. If you're trying to tune the VE table, and the AFR table is fiddling with things 'behind your back' then you're going to have a tough time because you'll make a change in the VE table, and then the AFR controls will put it back where it was (essentially). Tune the VE table open loop, then once it's running well turn on closed loop. This will make it run worse, until you tweak the AFR table so it runs back where it was. At the end of that process you have a tuned VE table and a tuned AFR table and everything is happy. (IMG:style_emoticons/default/wink.gif)



I think I got caught by the closed loop problem on my first attempt. Will see if I can find that display.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mightyohm
post Aug 30 2017, 12:44 PM
Post #46


Advanced Member
****

Group: Benefactors
Posts: 2,277
Joined: 16-January 03
From: Seattle, WA
Member No.: 162
Region Association: Pacific Northwest



The closed loop authority is typically pretty low, like 10 or 15%, so it will push things around but usually not in a way that prevents tuning. Some people like to disable it, though. I've tuned both ways - sometimes the closed loop correction helps because it sort of steers things in the right direction and your initial tune can be pretty rough but the car will still be drivable (assuming the AFR targets are reasonable).
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
McMark
post Aug 30 2017, 12:44 PM
Post #47


914 Freak!
***************

Group: Retired Admin
Posts: 20,177
Joined: 13-March 03
From: Grand Rapids, MI
Member No.: 419
Region Association: None



Had to look it up... (IMG:style_emoticons/default/biggrin.gif)

It's under Basic/Load Settings. Then click 'All Output Channels' at the bottom.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JamesM
post Sep 1 2017, 03:08 AM
Post #48


Senior Member
***

Group: Members
Posts: 1,872
Joined: 6-April 06
From: Kearns, UT
Member No.: 5,834
Region Association: Intermountain Region



I told myself I wasn't going to get involved in another Megasquirt troubleshooting sessions on the board, the amount of crazy uneducated bat:stromberg: advice i have seen around here over the years has really turned me off to discussing it.

That being said I have been having to much fun with it again lately so here we go...

First things first, dont make changes based on suggestions from anyone that isnt looking at 100% of your configuration, it will most likely mess you up more than you already are. This is a very complex system and its a lot more involved than turning a screw to lean it out, in reality there about about 1000 adjustable values here that interact with each other. There should be ZERO guesswork here as every variable is defined and should be set appropriately.

ok done with the rant and on to business:


1. First order of business, is the MSQ file you posted still current or have you fixed some things there? I see a few fundamental problems with the basic settings.

2. As Mark Henry stated earlier we really need full build details. The one detail I am most concerned with at the moment is are you controlling fuel and ignition or just fuel? If you are control spark you need to fix your advance table based on known advance curves for a type 4 you are way over advanced (assuming the physical timing is set correctly).

3. Your req_Fuel value needs to be set CORRECTLY. Yes technically you can set this to just about anything and then tweak your map around until the car runs but doing so will then render the values in your VE table meaningless. (seriously people tweaking the req_Fuel value around to "fix" a problem may be my #1 megasquirt pet peve) req_fuel is a constant that is set based on your injector setup NOT A TUNING VALUE. Specifically the number is a constant that represents a fuel pulse width at 100% VE based on your engine displacement and injector flow rate. Set this correctly and the numbers in your VE table will actually represent the volumetric efficiency for your engine at the given RPM/load bins. This then makes it a lot easier to roughly predict what those values should be. SCIENCE!!! NEAT! Given you had your injectors flow benched you are ahead of the game in that you know exactly what they flow (270cc/min@43psi) so the only question left is what fuel pressure are you running them at? The current req_fuel value you have set of 17.3 would only be correct if you were running at 24psi which i suspect is not the case. If you are running stock 914 fuel pressure 29psi those injectors calculate out at flowing ~220cc/min so your req fuel value would be 15.7 This is a calculated value, there is only one right answer so we need to know what your fuel pressure actually is. Lowering this value is going to lean out everything across the board so IF you have trouble starting after this change you will need to add fuel back by increasing values in the VE table.

Fix these things first and get it idling and then ill go over tuning fundamentals/workflow


looking at your VE and advance tables its easy to see why it is running the way you say it is



User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mark Henry
post Sep 1 2017, 06:49 AM
Post #49


that's what I do!
***************

Group: Members
Posts: 20,065
Joined: 27-December 02
From: Port Hope, Ontario
Member No.: 26
Region Association: Canada



QUOTE(Mblizzard @ Aug 30 2017, 02:38 PM) *



I think I got caught by the closed loop problem on my first attempt. Will see if I can find that display.


Ahhhh! You have to tune in Open Loop! Always!
Closed loop is something you could try after tuning in open loop. Closed loop may always run too lean for our cars that like things a little rich side.

On the injectors 270cc is fine if they do that at 30-35 PSI. I totally hate increasing pressure to increase flow, to me it's a terrible way to compensate for incorrect injector sizing. I run at 35 psi.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Sep 1 2017, 07:29 AM
Post #50


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(JamesM @ Sep 1 2017, 01:08 AM) *

I told myself I wasn't going to get involved in another Megasquirt troubleshooting sessions on the board, the amount of crazy uneducated bat:stromberg: advice i have seen around here over the years has really turned me off to discussing it.

That being said I have been having to much fun with it again lately so here we go...

First things first, dont make changes based on suggestions from anyone that isnt looking at 100% of your configuration, it will most likely mess you up more than you already are. This is a very complex system and its a lot more involved than turning a screw to lean it out, in reality there about about 1000 adjustable values here that interact with each other. There should be ZERO guesswork here as every variable is defined and should be set appropriately.

ok done with the rant and on to business:


1. First order of business, is the MSQ file you posted still current or have you fixed some things there? I see a few fundamental problems with the basic settings.

2. As Mark Henry stated earlier we really need full build details. The one detail I am most concerned with at the moment is are you controlling fuel and ignition or just fuel? If you are control spark you need to fix your advance table based on known advance curves for a type 4 you are way over advanced (assuming the physical timing is set correctly).

3. Your req_Fuel value needs to be set CORRECTLY. Yes technically you can set this to just about anything and then tweak your map around until the car runs but doing so will then render the values in your VE table meaningless. (seriously people tweaking the req_Fuel value around to "fix" a problem may be my #1 megasquirt pet peve) req_fuel is a constant that is set based on your injector setup NOT A TUNING VALUE. Specifically the number is a constant that represents a fuel pulse width at 100% VE based on your engine displacement and injector flow rate. Set this correctly and the numbers in your VE table will actually represent the volumetric efficiency for your engine at the given RPM/load bins. This then makes it a lot easier to roughly predict what those values should be. SCIENCE!!! NEAT! Given you had your injectors flow benched you are ahead of the game in that you know exactly what they flow (270cc/min@43psi) so the only question left is what fuel pressure are you running them at? The current req_fuel value you have set of 17.3 would only be correct if you were running at 24psi which i suspect is not the case. If you are running stock 914 fuel pressure 29psi those injectors calculate out at flowing ~220cc/min so your req fuel value would be 15.7 This is a calculated value, there is only one right answer so we need to know what your fuel pressure actually is. Lowering this value is going to lean out everything across the board so IF you have trouble starting after this change you will need to add fuel back by increasing values in the VE table.

Fix these things first and get it idling and then ill go over tuning fundamentals/workflow


looking at your VE and advance tables its easy to see why it is running the way you say it is


Thanks for the help> It is a huge learning curve!

I am running right at 49lbs of fuel pressure which should put me right in the range of the rated injector flow. But what I wondered is if the max flow rate should be used or the 50% duty cycle? I changed to the 50% and as you said a number of adjustments to the VE table were required. If I should use the max flow it is an easy fix for the VE table if you look at the math!

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
McMark
post Sep 1 2017, 08:37 AM
Post #51


914 Freak!
***************

Group: Retired Admin
Posts: 20,177
Joined: 13-March 03
From: Grand Rapids, MI
Member No.: 419
Region Association: None



Max flow. The idea is to know what the max those injectors are capable of. Everything in the software calculations is scaling down. So if you put in a lower number (50% duty cycle) then the scaling gets done twice, once by you and once by the software.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Sep 1 2017, 08:40 AM
Post #52


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(McMark @ Sep 1 2017, 06:37 AM) *

Max flow. The idea is to know what the max those injectors are capable of. Everything in the software calculations is scaling down. So if you put in a lower number (50% duty cycle) then the scaling gets done twice, once by you and once by the software.


That seems to make sense but it is not well documented in the setup information I have. It is likely the one of those things that should be apparent but I missed it somehow.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JamesM
post Sep 1 2017, 10:29 AM
Post #53


Senior Member
***

Group: Members
Posts: 1,872
Joined: 6-April 06
From: Kearns, UT
Member No.: 5,834
Region Association: Intermountain Region



QUOTE(Mblizzard @ Sep 1 2017, 05:29 AM) *


Thanks for the help> It is a huge learning curve!

I am running right at 49lbs of fuel pressure which should put me right in the range of the rated injector flow. But what I wondered is if the max flow rate should be used or the 50% duty cycle? I changed to the 50% and as you said a number of adjustments to the VE table were required. If I should use the max flow it is an easy fix for the VE table if you look at the math!



Injector static flow rate is the value you are looking for.

What is the reason for running the pressure so high? Given you know the exact flow rate at 43.5 PSI and 270cc/min should support up to ~160hp at an 80% duty cycle. I would recommend setting the fuel pressure there (43.5 PSI) unless you are expecting more than 150-160 hp out of your 2056. Also 3 bar is where most injectors are designed to run, go to high or low from there and you can have unexpected fuel delivery problems. So...

Set fuel pressure to 43.5
Injector size=270cc/min
Req_fuel=12.8

If for some reason you cant adjust the pressure and you have to run it at 49psi than injector size=295cc/min and req_fuel=11.7, but i would adjust the fuel pressure down if at all possible.

I wouldn't tweak your VE table yet unless its required to get the car started after the change. It still needs to be tuned anyways.

Let us know when its idling after the adjustments...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Sep 1 2017, 10:34 AM
Post #54


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(JamesM @ Sep 1 2017, 08:29 AM) *

QUOTE(Mblizzard @ Sep 1 2017, 05:29 AM) *


Thanks for the help> It is a huge learning curve!

I am running right at 49lbs of fuel pressure which should put me right in the range of the rated injector flow. But what I wondered is if the max flow rate should be used or the 50% duty cycle? I changed to the 50% and as you said a number of adjustments to the VE table were required. If I should use the max flow it is an easy fix for the VE table if you look at the math!



Injector static flow rate is the value you are looking for.

What is the reason for running the pressure so high? Given you know the exact flow rate at 43.5 PSI and 270cc/min should support up to ~160hp at an 80% duty cycle. I would recommend setting the fuel pressure there (43.5 PSI) unless you are expecting more than 150-160 hp out of your 2056. Also 3 bar is where most injectors are designed to run, go to high or low from there and you can have unexpected fuel delivery problems. So...

Set fuel pressure to 43.5
Injector size=270cc/min
Req_fuel=12.8

If for some reason you cant adjust the pressure and you have to run it at 49psi than injector size=295cc/min and req_fuel=11.7, but i would adjust the fuel pressure down if at all possible.

I wouldn't tweak your VE table yet unless its required to get the car started after the change. It still needs to be tuned anyways.

Let us know when its idling after the adjustments...



Sorry typo. I am right at 40 PSI. 9 is too close to the 0!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JamesM
post Sep 1 2017, 10:41 AM
Post #55


Senior Member
***

Group: Members
Posts: 1,872
Joined: 6-April 06
From: Kearns, UT
Member No.: 5,834
Region Association: Intermountain Region



QUOTE(Mark Henry @ Sep 1 2017, 04:49 AM) *

QUOTE(Mblizzard @ Aug 30 2017, 02:38 PM) *



I think I got caught by the closed loop problem on my first attempt. Will see if I can find that display.


Ahhhh! You have to tune in Open Loop! Always!
Closed loop is something you could try after tuning in open loop. Closed loop may always run too lean for our cars that like things a little rich side.

On the injectors 270cc is fine if they do that at 30-35 PSI. I totally hate increasing pressure to increase flow, to me it's a terrible way to compensate for incorrect injector sizing. I run at 35 psi.



Not always, it depends on how you are tuning. If you are tweaking things manually than closed loop will probably make things difficult you. If you are tuning your VE table via log analysis though having closed loop on while you are collecting your data will actually give the analyzer more data points to work with and speed up the process.

Doing things manually is a royal PITA given the number of data points we are working with. The autotune feature available in the paid version of Tunerstudio is worth WAY more than what they charge for it as is the log analyzer in MegaLogViewer. You will turn weeks of tuning into hours and get things a hell of a lot more accurate in the end. again SCIENCE!! If you are only going to pay for one get the registered version of Tunerstudio for the autotune feature. I like having both because i nerd out on data.

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
JamesM
post Sep 1 2017, 10:47 AM
Post #56


Senior Member
***

Group: Members
Posts: 1,872
Joined: 6-April 06
From: Kearns, UT
Member No.: 5,834
Region Association: Intermountain Region



QUOTE(Mblizzard @ Sep 1 2017, 08:34 AM) *

QUOTE(JamesM @ Sep 1 2017, 08:29 AM) *

QUOTE(Mblizzard @ Sep 1 2017, 05:29 AM) *


Thanks for the help> It is a huge learning curve!

I am running right at 49lbs of fuel pressure which should put me right in the range of the rated injector flow. But what I wondered is if the max flow rate should be used or the 50% duty cycle? I changed to the 50% and as you said a number of adjustments to the VE table were required. If I should use the max flow it is an easy fix for the VE table if you look at the math!



Injector static flow rate is the value you are looking for.

What is the reason for running the pressure so high? Given you know the exact flow rate at 43.5 PSI and 270cc/min should support up to ~160hp at an 80% duty cycle. I would recommend setting the fuel pressure there (43.5 PSI) unless you are expecting more than 150-160 hp out of your 2056. Also 3 bar is where most injectors are designed to run, go to high or low from there and you can have unexpected fuel delivery problems. So...

Set fuel pressure to 43.5
Injector size=270cc/min
Req_fuel=12.8

If for some reason you cant adjust the pressure and you have to run it at 49psi than injector size=295cc/min and req_fuel=11.7, but i would adjust the fuel pressure down if at all possible.

I wouldn't tweak your VE table yet unless its required to get the car started after the change. It still needs to be tuned anyways.

Let us know when its idling after the adjustments...



Sorry typo. I am right at 40 PSI. 9 is too close to the 0!



At 40PSI the calculated flow rate would be 259cc/min so req_fuel=13.3. Flow rate calculations are not 100% exact though. If you are obsessive like me and want to be exact run at 43.5 given you have the bench testing at that pressure.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Sep 1 2017, 10:47 AM
Post #57


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(JamesM @ Sep 1 2017, 08:41 AM) *

QUOTE(Mark Henry @ Sep 1 2017, 04:49 AM) *

QUOTE(Mblizzard @ Aug 30 2017, 02:38 PM) *



I think I got caught by the closed loop problem on my first attempt. Will see if I can find that display.


Ahhhh! You have to tune in Open Loop! Always!
Closed loop is something you could try after tuning in open loop. Closed loop may always run too lean for our cars that like things a little rich side.

On the injectors 270cc is fine if they do that at 30-35 PSI. I totally hate increasing pressure to increase flow, to me it's a terrible way to compensate for incorrect injector sizing. I run at 35 psi.



Not always, it depends on how you are tuning. If you are tweaking things manually than closed loop will probably make things difficult you. If you are tuning your VE table via log analysis though having closed loop on while you are collecting your data will actually give the analyzer more data points to work with and speed up the process.

Doing things manually is a royal PITA given the number of data points we are working with. The autotune feature available in the paid version of Tunerstudio is worth WAY more than what they charge for it as is the log analyzer in MegaLogViewer. You will turn weeks of tuning into hours and get things a hell of a lot more accurate in the end. again SCIENCE!! If you are only going to pay for one get the registered version of Tunerstudio for the autotune feature. I like having both because i nerd out on data.


Yes I agree. I have both full versions. Like you said there is just too much data too manage for the new person. While you can grasp the interrelation of the varies data points and the impacts your changes are suppose to have. I just find it frustrating when because of your own lack of knowledge you don't get the expected change. the end it is your fault because you had a setting incorrect but I guess that is just part of it all!

Hope I don't have weeks required to complete. Have to drive this to Okteenerfest!
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Mblizzard
post Sep 1 2017, 11:11 AM
Post #58


Advanced Member
****

Group: Members
Posts: 3,033
Joined: 28-January 13
From: Knoxville Tn
Member No.: 15,438
Region Association: South East States



QUOTE(JamesM @ Sep 1 2017, 08:47 AM) *

QUOTE(Mblizzard @ Sep 1 2017, 08:34 AM) *

QUOTE(JamesM @ Sep 1 2017, 08:29 AM) *

QUOTE(Mblizzard @ Sep 1 2017, 05:29 AM) *


Thanks for the help> It is a huge learning curve!

I am running right at 49lbs of fuel pressure which should put me right in the range of the rated injector flow. But what I wondered is if the max flow rate should be used or the 50% duty cycle? I changed to the 50% and as you said a number of adjustments to the VE table were required. If I should use the max flow it is an easy fix for the VE table if you look at the math!



Injector static flow rate is the value you are looking for.

What is the reason for running the pressure so high? Given you know the exact flow rate at 43.5 PSI and 270cc/min should support up to ~160hp at an 80% duty cycle. I would recommend setting the fuel pressure there (43.5 PSI) unless you are expecting more than 150-160 hp out of your 2056. Also 3 bar is where most injectors are designed to run, go to high or low from there and you can have unexpected fuel delivery problems. So...

Set fuel pressure to 43.5
Injector size=270cc/min
Req_fuel=12.8

If for some reason you cant adjust the pressure and you have to run it at 49psi than injector size=295cc/min and req_fuel=11.7, but i would adjust the fuel pressure down if at all possible.

I wouldn't tweak your VE table yet unless its required to get the car started after the change. It still needs to be tuned anyways.

Let us know when its idling after the adjustments...



Sorry typo. I am right at 40 PSI. 9 is too close to the 0!



At 40PSI the calculated flow rate would be 259cc/min so req_fuel=13.3. Flow rate calculations are not 100% exact though. If you are obsessive like me and want to be exact run at 43.5 given you have the bench testing at that pressure.


I think the resolution is capable of adjusting to that. Will revise.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mightyohm
post Sep 1 2017, 12:37 PM
Post #59


Advanced Member
****

Group: Benefactors
Posts: 2,277
Joined: 16-January 03
From: Seattle, WA
Member No.: 162
Region Association: Pacific Northwest



QUOTE(Mark Henry @ Sep 1 2017, 05:49 AM) *


Ahhhh! You have to tune in Open Loop! Always!
Closed loop is something you could try after tuning in open loop. Closed loop may always run too lean for our cars that like things a little rich side.



As long as you set the AFR targets correctly I don't see why this would be the case.

I agree that tuning open loop is usually a better approach (particularly if the AFR targets aren't configured correctly) but I've done it both ways. The key is to understand what is happening, you can usually see the influence of the closed loop control and decide if it's helping or hurting the tune.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
McMark
post Sep 1 2017, 12:48 PM
Post #60


914 Freak!
***************

Group: Retired Admin
Posts: 20,177
Joined: 13-March 03
From: Grand Rapids, MI
Member No.: 419
Region Association: None



I can see the logic of both approaches: focusing on the VE table first vs. the AFR table first.

If you're tuning the VE table, it seems to me, you should be open-loop. You then tune via whatever feedback you have available to you (WBO2, dyno, etc) to bring the VE table to 'perfection'. Then you can enable closed-loop, after populating the AFR table with the values you see while running your final tune.

--OR--

If you're tuning via the AFR table, you run closed-loop from the start and then tune via whatever feedback you have available to you (WBO2, dyno, etc) to bring the AFR table to 'perfection'. Then populate the VE table with the values you see while running your final tune.

But I feel like, from the other responses, that I might be missing something from the picture. James? Jeff? Can you correct or add to my understanding?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

8 Pages V < 1 2 3 4 5 > » 
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 28th March 2024 - 06:01 PM