AFR tuning?
01-13-2007, 11:23 PM
#1
AFR tuning?
Does anyone know of a good resource for information regarding AFR and how it interacts with the engine. I know lots of people run 12.5-13 but why? I want to learn the theories and really get an indepth understanding of it before I set out to tune my car.
01-13-2007, 11:30 PM
#2
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Posts: n/a
really most people are shooting for 13.5, the reason is that that seems to be the right place for power in the maxima. you want a straight line because the balance there results in more power. 14.7 is perfect, but under a load the engine wants more gas so that it can get a more powerful burn, but going richer than 13.5 by much results in a poor burn which also sucks power from the engine
01-14-2007, 06:46 AM
#3
01-14-2007, 11:36 AM
#4
Originally Posted by Nietzsche
Does anyone know of a good resource for information regarding AFR and how it interacts with the engine. I know lots of people run 12.5-13 but why? I want to learn the theories and really get an indepth understanding of it before I set out to tune my car.
More fuel = cooler EGT's. Less fuel = higher EGT's.
EGT's semi related to AFR.
01-15-2007, 06:57 AM
#5
Off-topic but still related, I installed a S-afc2 in my 97 gxe and THE only problem we still have is the RPM read by the controller. It reads 160 RPM idle when it runs 650 idle hot in reality. It reads 1002 RPM at 6600 RPM WOT. maybe wrong wire but related to jime's diagram, i"m ok. THE wire tapped is yellow/red stripe with the GREEN wire from the S-AFC2. Since it doesn't read the correct RPM, it won't correct fuel since it don't read the actual RPM!!
ANY SOLUTITONS ANYBODY!!!
ANY SOLUTITONS ANYBODY!!!
01-15-2007, 08:21 AM
#6
think the RPM signal wire from the ECU is a Green/White stripped wire....double check your wiring again......and the reason for tuning is like NmexMax said....under Open Loop conditions stock ECUs tend to be fairly rich for longevity and saftey procautions.....13.5 is about the sweet spot to be safe and still get some power increase...plus if u bump fuel pressure and tune u can get some timing as well
01-15-2007, 01:59 PM
#7
Originally Posted by Kevlo911
01-16-2007, 12:01 PM
#8
Is there any info on how to tune a s-afc2 right, direct me please, it would be very appreciated!!! By right, i mean to extract powwer out of it. Actually i run -8% from 3000 to 6600 rpm.
01-16-2007, 12:07 PM
#9
Originally Posted by VQ'ed
Is there any info on how to tune a s-afc2 right, direct me please, it would be very appreciated!!! By right, i mean to extract powwer out of it. Actually i run -8% from 3000 to 6600 rpm.
01-16-2007, 12:44 PM
#10
Originally Posted by jmeister
Did you dyno tune it? How are you monitoring your air/fuel ratio?
01-16-2007, 01:27 PM
#11
Originally Posted by VQ'ed
Is there any info on how to tune a s-afc2 right, direct me please, it would be very appreciated!!! By right, i mean to extract powwer out of it. Actually i run -8% from 3000 to 6600 rpm.
01-16-2007, 06:53 PM
#13
Originally Posted by MaximaSE96
^^^^^^^ -8 is alot with not using a wideband is risky.....and if ur using an air/fuel gauge hooked to stock o2 sensors its useless...so yea what monitoring devices are u using
01-16-2007, 07:08 PM
#15
Originally Posted by Nietzsche
My 06 uses widebands so how exactly is it useless.
http://www.innovatemotorsports.com/products/xd16.php
then you are ok...but then again u would need 2 or a special module to read both banks at the same time
01-17-2007, 06:48 AM
#16
Get a Cipher from UpRev. You can monitor wb readings.
He wasn't replying to you, IIRC, it was meant in reply to this post.
sure do.
Originally Posted by Nietzsche
My 06 uses widebands so how exactly is it useless
Originally Posted by VQ'ed
Is there any info on how to tune a s-afc2 right, direct me please, it would be very appreciated!!! By right, i mean to extract powwer out of it. Actually i run -8% from 3000 to 6600 rpm.
Originally Posted by MaximaSE96
also i wasnt aware teh 06 had widebands stock
sure do.
01-17-2007, 07:59 AM
#17
I'm about to swap my injectors for DE-K ones. I don't have any ways to moniter the a/f ratio, i assumed the knock sensor would be a good tool. I called a dyno shop and i have an appointment saturday to get the a/f right and a run to display power. Thanks you guys for the fast reply and confirm my worries about the crude setup (-8%). Gonna get the dyno technician to setup my car.
Is there any way to tune the closed loop for better fuel economy in city use? I never go over 2500RPM in town and get crappy mileage (113mi for 5gallons/ 180km for 20liters is good or not???) When i drive highway, i get 60miles for 3gallons!!!!!! or 100km for 12liters). Any answers would be appreciated...
Is there any way to tune the closed loop for better fuel economy in city use? I never go over 2500RPM in town and get crappy mileage (113mi for 5gallons/ 180km for 20liters is good or not???) When i drive highway, i get 60miles for 3gallons!!!!!! or 100km for 12liters). Any answers would be appreciated...
01-17-2007, 08:15 AM
#18
to get around closed loop i think you have to use e-manage or EU to tune around it but I am not sure....there really is no way to get around close loop with a norman s-afc...atleast i dont know anyway....and judging by ur milage it might be time for a new knock sensor if ur gettin that bad of milage or other maintenance items...there has also been discussion when exactily open and close switch over.....most say 40% throttle and above 3k...but then there was someone i forget who has a scanner that was monitoring his o2s and he said pretty much any acceleration cause open loop....there are others with mor knowledge than me that will chime in
01-17-2007, 02:54 PM
#20
Originally Posted by VQ'ed
I'm about to swap my injectors for DE-K ones. I don't have any ways to moniter the a/f ratio,
Originally Posted by VQ'ed
i assumed the knock sensor would be a good tool.
WB is the best.
Originally Posted by VQ'ed
I called a dyno shop and i have an appointment Saturday to get the a/f right and a run to display power.
Originally Posted by VQ'ed
Gonna get the dyno technician to setup my car.
Originally Posted by VQ'ed
Is there any way to tune the closed loop for better fuel economy in city use? I never go over 2500RPM in town and get crappy mileage (113mi for 5gallons/ 180km for 20liters is good or not???) When i drive highway, i get 60miles for 3gallons!!!!!! or 100km for 12liters). Any answers would be appreciated...
Here's a good link. http://forums.maxima.org/showpost.ph...7&postcount=87
01-17-2007, 04:23 PM
#21
Originally Posted by VQ'ed
I'm about to swap my injectors for DE-K ones.
I don't have any ways to moniter the a/f ratio, i assumed the knock sensor would be a good tool.
Is there any way to tune the closed loop for better fuel economy in city use?
01-17-2007, 04:51 PM
#22
Originally Posted by jmeister
Doing a VI swap? If not how or why you changing injectors?
Originally Posted by nismology
You can't. DE = side feed and DE-K = top feed.
Need the whole fuel rail for a 00vi swap.
01-17-2007, 05:46 PM
#23
I plan one using either cipher or autoenginuity for datalogging. I still haven't decided. From what I've seen autoenginuity can do everything cipher can, plus I can use it on non-nissan vehicles.
01-18-2007, 06:33 AM
#24
Originally Posted by Nietzsche
I plan one using either cipher or autoenginuity for datalogging. I still haven't decided. From what I've seen autoenginuity can do everything cipher can, plus I can use it on non-nissan vehicles.
I was in the same situation and spoke to a couple of members that had experience with both and taht was the only reason they cjhose the AE.
I have 2 Nissan vehicles, and in the future plan on getting another so, for me it was a no brainer, Cipher it was.
01-18-2007, 08:07 AM
#25
First, i purchased a DE-K with crank problem and planning to take all the components such as the reworked heads, fuel rails, VI, injectors. Bolting all those components on my current DE, I was looking to upgrade my injectors to get more fuel in the top end to accord with the VI top end performance, a better spray pattern and better combustion up top. Big story short, update te DE with what i already have. I'm also not equipped with a chain block and a lift to do the job on replacing the whole engine and don't want to (he's healty). The dyno technician uses a dynojet 248 and before he tunes, he changes the front manifold o2 sensor for a WB02 to monitor, make changes on the s-afc2 and re-run the car with the new setup. 90$ can for a baseline run and a setup run.
01-18-2007, 08:41 AM
#26
Originally Posted by VQ'ed
First, i purchased a DE-K with crank problem and planning to take all the components such as the reworked heads, fuel rails, VI, injectors.
Bolting all those components on my current DE, I was looking to upgrade my injectors to get more fuel in the top end to accord with the VI top end performance, a better spray pattern and better combustion up top.
The dyno technician uses a dynojet 248 and before he tunes, he changes the front manifold o2 sensor for a WB02 to monitor, make changes on the s-afc2 and re-run the car with the new setup. 90$ can for a baseline run and a setup run.
Sorry for going OT. This will be the last of it.
01-18-2007, 10:16 AM
#27
So, your telling me that the cam specs from 97-99 and 2000-2001 are the same also? I read of better cooling from the later heads. Of course better spray pattern because mine have never been cleaned thoroughly inside and out (i planned to get them to the injectors specialists over here. I thought about that setup because i had the parts laying around for a while and wanted to update my VQ30DE. I assumed there was advantages somewhere in the process of swapping the whole 2000-2001 upper engine assembly like the VI, fuel rails, injectors, adjustable FPR and pathy 70mm throttle over my existing mods!!! tell what you guys think about this.
01-18-2007, 10:28 AM
#29
Originally Posted by VQ'ed
So, your telling me that the cam specs from 97-99 and 2000-2001 are the same also?
Originally Posted by nismology
The DE-K heads are EXACTLY the same as the DE heads. Same part number and all.
Originally Posted by VQ'ed
I assumed there was advantages somewhere in the process of swapping the whole 2000-2001 upper engine assembly like the VI, fuel rails, injectors, adjustable FPR and pathy 70mm throttle over my existing mods
01-19-2007, 01:09 PM
#30
Originally Posted by NmexMAX
This is the ONLY reason why you should get the AE over the Cipher.
I was in the same situation and spoke to a couple of members that had experience with both and taht was the only reason they cjhose the AE.
I have 2 Nissan vehicles, and in the future plan on getting another so, for me it was a no brainer, Cipher it was.
I was in the same situation and spoke to a couple of members that had experience with both and taht was the only reason they cjhose the AE.
I have 2 Nissan vehicles, and in the future plan on getting another so, for me it was a no brainer, Cipher it was.
01-20-2007, 11:23 PM
#33
From an EXTREMELY knowledgeable member.
AUTERRA (Palm version)
I bought the Auterra about 2 years ago which was long before I had contemplated doing a 3.5 swap. I already had a Palm Tungsten at the time so the software and cable were a relatively cheap investment. I have only used the Palm version so I cannot comment on the one for Windows. It is a good basic unit for reading/clearing codes and logging data from basic ec related sensors.
I have 2 complaints:
1) data sampling is limited to the rate at which the ecu updates using the standard OBD-II interface. It works out to be about 0.25 sec per sample per sensor.
2) no time stamping of data. This may change in a later version of the software.
AUTOENGINUITY (w/ NISSAN enhanced)
I bought this unit a few months ago mainly for the ability to log other engine operating parameters that are not required in the OBD-II standard.
It gives you access to a whole lot of extra parameters and tests but it is still hampered with "slow" data logging because it communicates with the ecu using the OBD-II interface.
UPREV CIPHER
From the data logs that I have seen, this unit must communicate with the ecu using the Nissan Consult-II
interface. The data sampling rates are probably four or more times faster than what you get through OBD-II.
I bought the Auterra about 2 years ago which was long before I had contemplated doing a 3.5 swap. I already had a Palm Tungsten at the time so the software and cable were a relatively cheap investment. I have only used the Palm version so I cannot comment on the one for Windows. It is a good basic unit for reading/clearing codes and logging data from basic ec related sensors.
I have 2 complaints:
1) data sampling is limited to the rate at which the ecu updates using the standard OBD-II interface. It works out to be about 0.25 sec per sample per sensor.
2) no time stamping of data. This may change in a later version of the software.
AUTOENGINUITY (w/ NISSAN enhanced)
I bought this unit a few months ago mainly for the ability to log other engine operating parameters that are not required in the OBD-II standard.
It gives you access to a whole lot of extra parameters and tests but it is still hampered with "slow" data logging because it communicates with the ecu using the OBD-II interface.
UPREV CIPHER
From the data logs that I have seen, this unit must communicate with the ecu using the Nissan Consult-II
interface. The data sampling rates are probably four or more times faster than what you get through OBD-II.
01-21-2007, 02:50 PM
#34
Originally Posted by NmexMAX
From an EXTREMELY knowledgeable member.
Do you know if OBDII is fast enough, or would I be missing to much data?
01-21-2007, 05:02 PM
#36
Basically I'm looking for something to datalog my wideband O2's, RPM, Throttle position, timing, and knock. I will use the data to fine tune the vehicle with a SAFCII most likely.
01-21-2007, 05:30 PM
#38
I'll use which ever I can get cheaply. This is a stopgap until go with headers/exhaust and go with a more complex system.
I know with the VAFC I can use 24 points of correction with the vtec switchover but I can have two different maps of 12 with the SAFC. I could go either way and be happy.
I know with the VAFC I can use 24 points of correction with the vtec switchover but I can have two different maps of 12 with the SAFC. I could go either way and be happy.
01-21-2007, 08:22 PM
#39
dont meen to butt into this thread but...im not knoledgeable about this type of stuff.
currently i have an intake and catback on my 3.5.
bought a sfacII at a decent price and want want to do some tunning b/c with the extra flow im prolly not running the optimal A/F ratio.
plan is to get a base line dyno run then tune with safcII.
my ?'s...im assuming im on the right track here (the above)...tell me if im not.
do i need to be giving the dyno tech any information that wont be available after a base line run?
what a/f ratio am i trying to acheive? town and highway driving
anyone else running this simple set up and what gains are possible?
currently i have an intake and catback on my 3.5.
bought a sfacII at a decent price and want want to do some tunning b/c with the extra flow im prolly not running the optimal A/F ratio.
plan is to get a base line dyno run then tune with safcII.
my ?'s...im assuming im on the right track here (the above)...tell me if im not.
do i need to be giving the dyno tech any information that wont be available after a base line run?
what a/f ratio am i trying to acheive? town and highway driving
anyone else running this simple set up and what gains are possible?
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