VAFCII Questions + Tuning Advice
04-07-2006, 01:25 AM
#1
VAFCII Questions + Tuning Advice
All right, to start out, I have LVT-HVT crossover point set at 4,200RPMs, and the HVT-LVT crossover point set at 4,100RPMs (As per SR20DENs advice in his thread) My LVT RPM points (At WIDE THR) are 1200, 1600, 2000, 2400, 2600, 2800, 3000, 3200, 3400, 3600, 3800, 4000. My HVT RPM points (At WIDE THR) are 4200, 4400, 4600, 4800, 5000, 5200, 5400, 5600, 5800, 6000, 6200, 6400. Since I don't have my LC-1 yet, all of these points are at -/+0%. So no alterations to the hot-wire signal have been made.
FIRST QUESTION:
From reading in the manual, and what I have set on my VAFCII, I'm wondering what is the best THROTTLE OPENING SETTING. I have it at Narr. 10%, and WIDE 50%. How does this feature work? Does it basically mean it'll start running the WIDE THROTTLE FUEL MAP POINTS at +50% throttle? And the Narr. start running the NARROW THROTTLE FUEL MAP POINT anywhere over 10% [to below 50%]?
SECOND QUESTION:
Narrow throttle? Is that really nessecary to tune on a VQ with just I/H/E? I realize our ECU's basically run in a certain A/F ratio when not under WOT (Closed Loop, 14.7:1) When is this feature used? Would narrow throttle basically be manipulating the A/F ratio from 10%-49% throttle?
THIRD QUESTION:
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
Now onto the tuning questions. As mentioned earlier in this very looong post, I've purchased a LC-1 with datalogging capabilities and will be using that, along with my laptop and VAFCII to try and "street-tune" the VQ to a healthy 13-14.5 A/F ratio. The question is, depending upon RPM's, where is it bad to have the car running lean? I understand at higher-RPM's (4,500+) that the car is being placed under a lot more strain then say at.. 2,000RPMs, so woudn't that mean the I may not want to strain out the fuel in that high of an area? Another question I have is.. HOW DO I TUNE IT? Do I run off 3rd gear (4AT: 80-110MPH) Or can I do it from any gear, RPM, speed?
All right, I'm done.
Haha, thanks for listening and hopefully I can get some of my questions answered. Special thanks goes out to SR20DEN!
FIRST QUESTION:
From reading in the manual, and what I have set on my VAFCII, I'm wondering what is the best THROTTLE OPENING SETTING. I have it at Narr. 10%, and WIDE 50%. How does this feature work? Does it basically mean it'll start running the WIDE THROTTLE FUEL MAP POINTS at +50% throttle? And the Narr. start running the NARROW THROTTLE FUEL MAP POINT anywhere over 10% [to below 50%]?
SECOND QUESTION:
Narrow throttle? Is that really nessecary to tune on a VQ with just I/H/E? I realize our ECU's basically run in a certain A/F ratio when not under WOT (Closed Loop, 14.7:1) When is this feature used? Would narrow throttle basically be manipulating the A/F ratio from 10%-49% throttle?
THIRD QUESTION:
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
Now onto the tuning questions. As mentioned earlier in this very looong post, I've purchased a LC-1 with datalogging capabilities and will be using that, along with my laptop and VAFCII to try and "street-tune" the VQ to a healthy 13-14.5 A/F ratio. The question is, depending upon RPM's, where is it bad to have the car running lean? I understand at higher-RPM's (4,500+) that the car is being placed under a lot more strain then say at.. 2,000RPMs, so woudn't that mean the I may not want to strain out the fuel in that high of an area? Another question I have is.. HOW DO I TUNE IT? Do I run off 3rd gear (4AT: 80-110MPH) Or can I do it from any gear, RPM, speed?
All right, I'm done.
Haha, thanks for listening and hopefully I can get some of my questions answered. Special thanks goes out to SR20DEN!
04-07-2006, 05:29 AM
#2
Moderator who thinks he is better than us with his I30
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I have not used a V-AFC in particular, but I am sure the lingo is just about the same as the S-AFC.
The LVT and HVT I am sure are your high and low throttle points. Don't worry about the low. Your only tuning the high, the low will be controlled by the o2 sensors in closed loop. I would set your HVT to 40%, meaning that at 40% throttle the changes you make with the VAFC in HVT will go into effect
At far as your rpm points, I would probably start at a little lower rpm. Like 3400, but you won't know for sure how you want it set up till you data log your AFR and see what the lowest rpm your gonna want to add/pull fuel.
you will be safe with an AFR between 13.5-13.8 through the entire power band. I wouldn't be concerned about going richer as the rpm's climb. Just keep it under 14:1 and you should be fine.
Your gonna want to tune it in a higher gear. Obviously you go through 1st and 2nd too fast. Your gonna want to start at the lowest rpm possible in the gear you choose. Being an auto it's a little harder to do. I tune in 4th (5spd) but that can bit a bit dangerous because of the speed. Just use your best judgement for the road your on. If you have a empty rural highway around use that and try and tune in the highest/longest gear possible (except over drive)
The LVT and HVT I am sure are your high and low throttle points. Don't worry about the low. Your only tuning the high, the low will be controlled by the o2 sensors in closed loop. I would set your HVT to 40%, meaning that at 40% throttle the changes you make with the VAFC in HVT will go into effect
At far as your rpm points, I would probably start at a little lower rpm. Like 3400, but you won't know for sure how you want it set up till you data log your AFR and see what the lowest rpm your gonna want to add/pull fuel.
you will be safe with an AFR between 13.5-13.8 through the entire power band. I wouldn't be concerned about going richer as the rpm's climb. Just keep it under 14:1 and you should be fine.
Your gonna want to tune it in a higher gear. Obviously you go through 1st and 2nd too fast. Your gonna want to start at the lowest rpm possible in the gear you choose. Being an auto it's a little harder to do. I tune in 4th (5spd) but that can bit a bit dangerous because of the speed. Just use your best judgement for the road your on. If you have a empty rural highway around use that and try and tune in the highest/longest gear possible (except over drive)
04-07-2006, 06:24 AM
#3
Originally Posted by 2002AltimaV6
Do I run off 3rd gear (4AT: 80-110MPH) Or can I do it from any gear, RPM, speed?
A couple of us autos here on the org tune in 2nd..
04-07-2006, 06:45 PM
#4
Originally Posted by 2002AltimateV6
FIRST QUESTION:
From reading in the manual, and what I have set on my VAFCII, I'm wondering what is the best THROTTLE OPENING SETTING. I have it at Narr. 10%, and WIDE 50%. How does this feature work? Does it basically mean it'll start running the WIDE THROTTLE FUEL MAP POINTS at +50% throttle? And the Narr. start running the NARROW THROTTLE FUEL MAP POINT anywhere over 10% [to below 50%]?
SECOND QUESTION:
Narrow throttle? Is that really nessecary to tune on a VQ with just I/H/E? I realize our ECU's basically run in a certain A/F ratio when not under WOT (Closed Loop, 14.7:1) When is this feature used? Would narrow throttle basically be manipulating the A/F ratio from 10%-49% throttle?
From reading in the manual, and what I have set on my VAFCII, I'm wondering what is the best THROTTLE OPENING SETTING. I have it at Narr. 10%, and WIDE 50%. How does this feature work? Does it basically mean it'll start running the WIDE THROTTLE FUEL MAP POINTS at +50% throttle? And the Narr. start running the NARROW THROTTLE FUEL MAP POINT anywhere over 10% [to below 50%]?
SECOND QUESTION:
Narrow throttle? Is that really nessecary to tune on a VQ with just I/H/E? I realize our ECU's basically run in a certain A/F ratio when not under WOT (Closed Loop, 14.7:1) When is this feature used? Would narrow throttle basically be manipulating the A/F ratio from 10%-49% throttle?
And you've pretty much figured out what the 50% setting means. Anything in between those two points is basically interpolated. Below 10% throttle the VAFC will only use the narrow throttle map you made. Above 50% it will run on the high throttle map.
If you want to start toying with these numbers it really helps to have a wideband that you can datalog with. And in my case I got more consistant A/F ratios by spreading those two points pretty far apart, but your setup isn't as far out as mine so you may not need to change them at all.
THIRD QUESTION:
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
Now onto the tuning questions. As mentioned earlier in this very looong post, I've purchased a LC-1 with datalogging capabilities and will be using that, along with my laptop and VAFCII to try and "street-tune" the VQ to a healthy 13-14.5 A/F ratio. The question is, depending upon RPM's, where is it bad to have the car running lean? I understand at higher-RPM's (4,500+) that the car is being placed under a lot more strain then say at.. 2,000RPMs, so woudn't that mean the I may not want to strain out the fuel in that high of an area? Another question I have is.. HOW DO I TUNE IT? Do I run off 3rd gear (4AT: 80-110MPH) Or can I do it from any gear, RPM, speed?
All right, I'm done.
Haha, thanks for listening and hopefully I can get some of my questions answered. Special thanks goes out to SR20DEN!
All right, I'm done.
Haha, thanks for listening and hopefully I can get some of my questions answered. Special thanks goes out to SR20DEN!
Also note that these recomendations that I made are for squeezing out more horsepower. They aren't exactly 100% safe when you start to go above 13.0:1 if you do more than some short runs or drag racing. If you intend to road race your car or go out and run it at WOT for tens or hundreds of miles you should use a more conservative fuel tune that really doesn't get any higher than 13.0:1.
Exhaust and EGT play a big part in this too, if you have the stock exhaust your EGTs are going to always be high and you won't be able to get away with those higher A/F ratios.
04-07-2006, 09:07 PM
#5
Awesome information man! I have intake, headers, and exhaust so the car is dumping in loads more fuel then needed, so w/ 94 octane (what I've been using now for the past 3-4 months) the car should be safe w/ 13.5:1-14.0:1? As for the wideband, I've got that on order. Well, it's backordered from Innovate, but I should have it in the next two weeks. Until then, I'll get my exhaust ready by having an extra O/2 bung installed.
At the moment, I'm running my car a little leaner (1-3%) across the board, and past 5,400RPM's, I'm keeping it inbetween +/-0 to +1, just to be safe with the extra load.
Again, thanks for all the information SR20DEN!
At the moment, I'm running my car a little leaner (1-3%) across the board, and past 5,400RPM's, I'm keeping it inbetween +/-0 to +1, just to be safe with the extra load.
Again, thanks for all the information SR20DEN!
04-08-2006, 09:49 AM
#6
Thanks for all the information in this thread it definitely help me and I have my vafc II wired and setup and will be tuning on Tuesday.
My dumb question is how to get the monitor setting to go from the line style real time graphing display to a analog or digital readout?
Everytime I go into this monitor 3 setting I pick out Cor, Thr, and Revs but I get the same stupid line display which is so freakin useless?
Any help on changing this setting would be appreciated.
My dumb question is how to get the monitor setting to go from the line style real time graphing display to a analog or digital readout?
Everytime I go into this monitor 3 setting I pick out Cor, Thr, and Revs but I get the same stupid line display which is so freakin useless?
Any help on changing this setting would be appreciated.
04-08-2006, 02:26 PM
#8
Thanks 2002AltimaV6.
After reading more on what Sr20den is saying about interpolation etc.
If the stock ecu is in open loop at <40% throttle and the primary O2s are doing the thing keeping everything stoich and efficient.
Wouldn't it make sense to set the VAFCII low throttle to say 41% and then the high throttle to say a 90% range and tune both areas? This way you could tune on the dyno or with a WBO2 for (midrange to high throttle in the 41%-90%) range and also tune for (WOT or 90%+ range)
For the 41%-90% low throttle range you could do multiple pulls and try to maintain say a 65% throttle opening, which is roughly half of this area and get your A/F to give good power and get the A/F nice and flat.
For the 90%+ high throttle range you would just do a normal WOT run and get the A/F in line etc.
This would allow both sets of 24 NE points to be used and also let the ECU do its thing down at <40% throttle settings.
I guess my thoughts are if you just set the throttle values in the VAFCII to 39/40 you are limiting to only one set of 24 points for this entire range. If you can set it up like I mention above then you take advantage of the midrange area, ie over 41% and less than 90% and also the 90%+ for the WOT tune.
Is this a rational approach or am I missing something here?
Please chime in as I plan to tune with this theory in mind unless someone indentifies is as a bad idea.
Thanks.
After reading more on what Sr20den is saying about interpolation etc.
If the stock ecu is in open loop at <40% throttle and the primary O2s are doing the thing keeping everything stoich and efficient.
Wouldn't it make sense to set the VAFCII low throttle to say 41% and then the high throttle to say a 90% range and tune both areas? This way you could tune on the dyno or with a WBO2 for (midrange to high throttle in the 41%-90%) range and also tune for (WOT or 90%+ range)
For the 41%-90% low throttle range you could do multiple pulls and try to maintain say a 65% throttle opening, which is roughly half of this area and get your A/F to give good power and get the A/F nice and flat.
For the 90%+ high throttle range you would just do a normal WOT run and get the A/F in line etc.
This would allow both sets of 24 NE points to be used and also let the ECU do its thing down at <40% throttle settings.
I guess my thoughts are if you just set the throttle values in the VAFCII to 39/40 you are limiting to only one set of 24 points for this entire range. If you can set it up like I mention above then you take advantage of the midrange area, ie over 41% and less than 90% and also the 90%+ for the WOT tune.
Is this a rational approach or am I missing something here?
Please chime in as I plan to tune with this theory in mind unless someone indentifies is as a bad idea.
Thanks.
04-08-2006, 02:30 PM
#9
The 40% TPS closed loop hasn't ever been actually proven that I have seen. That is why I choose to ignore it now and do part throttle tuning from very low.
I can't say enough about the wideband O2 and OBD-II data loggers. You'll learn more in 20 mins by watching those than I could explain to you on here in a few days.
I can't say enough about the wideband O2 and OBD-II data loggers. You'll learn more in 20 mins by watching those than I could explain to you on here in a few days.
04-08-2006, 04:11 PM
#10
Wideband o2 sensors rock!
I have a PLX R300 wide band 02 sensor....kinda pricey at $420 a pop....includes all the hardware needed to get started though....all cables, USB, software, etc...this thing is awesome with its bright display and easy to use interface....datalogging is wonderful too!
you could also get away with a cheaper wideband like zeitronix...i believe its $275-ish without the display...then hook it up to a laptop for datalogging....save yourself a $150 versus the R300
I have a PLX R300 wide band 02 sensor....kinda pricey at $420 a pop....includes all the hardware needed to get started though....all cables, USB, software, etc...this thing is awesome with its bright display and easy to use interface....datalogging is wonderful too!
you could also get away with a cheaper wideband like zeitronix...i believe its $275-ish without the display...then hook it up to a laptop for datalogging....save yourself a $150 versus the R300
04-08-2006, 09:07 PM
#11
Originally Posted by SR20DEN
The 40% TPS closed loop hasn't ever been actually proven that I have seen. That is why I choose to ignore it now and do part throttle tuning from very low.
I can't say enough about the wideband O2 and OBD-II data loggers. You'll learn more in 20 mins by watching those than I could explain to you on here in a few days.
I can't say enough about the wideband O2 and OBD-II data loggers. You'll learn more in 20 mins by watching those than I could explain to you on here in a few days.
Or does the ECU see everything over ~40% throttle as closed loop and have one preset factory defaulted fuelmap for that. I have a hard time believing that but if so then I may as well just tune for WOT with 39/40 as the only low/high settings in my VAFCII ?
This sums things up for my basic tuning needs as I just have a 5.5gen with headers and catback. I do not want to go with a WBO2 and OBDII datalogger. I would just rather dynotune and be done knowing that the settings should work for the majority of my driving.
If someone can confirm these two theoretical settings I have mentioned at 40% low and 90% high, and if what I have said should work then please let me know. Thanks in Advance.
04-08-2006, 09:24 PM
#12
Basically, for low throttle, I have mine set 10%. Anything below 10% throttle, the ECU is reading it's normal closed loop settings and keeping the A/F ratio at 14.7:1, I believe. After 10%, the VAFCII will begin to use the modifications that you've done to the fuel. Really, for anyone w/o larger injectors, or a massive 4" intake (with 4" MAF to boot) tuning the low-throttle wont net you much since the car will still be in closed-loop. For me, after 50%, it goes into high-throttle and that's where I've gotten it tuned, so right after 50% is when it will start reading. So from 10%-49%, it's in low-throttle tuning. So with someone tunning from 40% to 90%, from 40% to 89%, you'll be in low-throttle. Anything below 40%, and you'll be running closed-loop ECU settings. And why tune in mid-range? Haha, you need WOT for racing. 
Trust me when I say that having a WBO2 or Datalogger will SAVE you tons of money. What first started this thread was that I had gone to a shop and wasted $132 for a measly 227WHP and 225WTQ. You know why those numbers are incorrect? The tuner ADDED in more fuel all around the range instead of taking it off, since the car was already running pig-rich to all hell with the headers.
One more question I have is, even in closed loop, will the ECU adjust the ratio at which it keeps the car at? Or is it always the same, no matter what modification you add on? Unless it's larger injectors, or a large MAF in SR20DEN's case. But say with just I/H/E, wont the ECU try and add in more fuel even at closed loop?
One more final thing, I love the VAFCII, it's so easy to use and so easy to tune with. Just get the LC-1, or whatever otehr WBO2 w/ datalogging capabilities, and you can easily and efficently street-tune your vehicle. Thank you APEX'i! And again, another BIG thanks to SR20DEN!
Trust me when I say that having a WBO2 or Datalogger will SAVE you tons of money. What first started this thread was that I had gone to a shop and wasted $132 for a measly 227WHP and 225WTQ. You know why those numbers are incorrect? The tuner ADDED in more fuel all around the range instead of taking it off, since the car was already running pig-rich to all hell with the headers.
One more question I have is, even in closed loop, will the ECU adjust the ratio at which it keeps the car at? Or is it always the same, no matter what modification you add on? Unless it's larger injectors, or a large MAF in SR20DEN's case. But say with just I/H/E, wont the ECU try and add in more fuel even at closed loop?
One more final thing, I love the VAFCII, it's so easy to use and so easy to tune with. Just get the LC-1, or whatever otehr WBO2 w/ datalogging capabilities, and you can easily and efficently street-tune your vehicle.
Thank you APEX'i! And again, another BIG thanks to SR20DEN!
04-08-2006, 09:41 PM
#14
If you only want to tune WOT then you can get away with 39%,40% and tune the Wide Throttle map only. That is what most people do anyway.
The setting of 10% for low throttle doesn't mean that the VAFC doesn't correct below 10%. That only means that below 10% your narrow throttle map has complete control of the corrections. At 10% or above is when the VAFC starts to interpolate between the narrow and high throttle maps.
Page 40 of the VAFC manual can describe this in far more detail.
http://www.apexi-usa.com/pdfInstallation/25.pdf
My EB (Emanage Basic) came in Friday so I'll be mostly working on it from now on. And from what I have seen so far, this thing can do quite a bit more than I have seen anyone here do. It's even given me some possible insight to more unturned stones of the SAFC-II/VAFC-II, concerning different MAFs.
The setting of 10% for low throttle doesn't mean that the VAFC doesn't correct below 10%. That only means that below 10% your narrow throttle map has complete control of the corrections. At 10% or above is when the VAFC starts to interpolate between the narrow and high throttle maps.
Page 40 of the VAFC manual can describe this in far more detail.
http://www.apexi-usa.com/pdfInstallation/25.pdf
My EB (Emanage Basic) came in Friday so I'll be mostly working on it from now on. And from what I have seen so far, this thing can do quite a bit more than I have seen anyone here do. It's even given me some possible insight to more unturned stones of the SAFC-II/VAFC-II, concerning different MAFs.
04-09-2006, 12:19 PM
#17
Originally Posted by 2002AltimateV6
Yes. Darn 15 character limit.
now I have the PLX R300 wideband and I couldn't be anymore happier...this thing rocks! oh did u get an external gauge for your LC-1, or your just planning to go datalogging and nothing else? I also believe u need an RPM converter too?
04-09-2006, 09:15 PM
#18
Just using the LC-1 and having it datalog onto my laptop. And I have no idea about wether or not I'll need the RPM converter? I've never heard about needed that from the NissanClub guys that have it. Meh, I'll see what happens once I get it.
04-09-2006, 09:49 PM
#20
Originally Posted by SR20DEN
Que ?
04-09-2006, 10:03 PM
#21
When does the ECU & oxygen sensors start to change the AFR? Only with larger injectors and big maf? I mean headers is a pretty big mod for our vq35s....I would think the AFR would get thrown off from stock 14.7
04-10-2006, 02:39 AM
#22
[QUOTE=2002AltimateV6]THIRD QUESTION:
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?QUOTE]
I believe this setting is for activating vtec according to throttle opening...like if u want vtec to activate at 50% thr, then it will...for us, it isn't vtec...but actually the high Hvt map that we created....i'm guessing this setting is exactly the same as Lvt-Hvt & Hvt-Lvt, except its based on thr...not rpm...I haven't touched this setting btw...I don't see why anyone should either
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?QUOTE]
I believe this setting is for activating vtec according to throttle opening...like if u want vtec to activate at 50% thr, then it will...for us, it isn't vtec...but actually the high Hvt map that we created....i'm guessing this setting is exactly the same as Lvt-Hvt & Hvt-Lvt, except its based on thr...not rpm...I haven't touched this setting btw...I don't see why anyone should either
04-10-2006, 02:45 AM
#23
Matt, you say 13-13.5 is a good AFR...and you even say that u can get away with higher than 13.5 AFR below 5k....do you recommend this to cali 91 octane? I only put the best in my car, Chevron with techron 91....I haven't experienced any pinging since I bought this car....my question is
If you were in my shoes (cali gas)...would u tune for high 13s AFR below 5k...then bring it to 13.5 above 5k? I don't do much racing and when I do, its short drag racing....I don't do any high RPM freeway racing...and most of my daily spirited driving is in the city...I usually don't get past 60mph....what do ya think?
If you were in my shoes (cali gas)...would u tune for high 13s AFR below 5k...then bring it to 13.5 above 5k? I don't do much racing and when I do, its short drag racing....I don't do any high RPM freeway racing...and most of my daily spirited driving is in the city...I usually don't get past 60mph....what do ya think?
04-10-2006, 08:38 AM
#24
You guys are making me have doubts on going to a dyno place. Can't I tune it myself at the dyno place or is it mandatory that they do it. Also, once I get the list of A/F ratios throughout the powerband can't I just go ahead tune it home to get to my prefered ratios.
04-10-2006, 10:46 AM
#25
Originally Posted by speed racer
You guys are making me have doubts on going to a dyno place. Can't I tune it myself at the dyno place or is it mandatory that they do it. Also, once I get the list of A/F ratios throughout the powerband can't I just go ahead tune it home to get to my prefered ratios.
04-10-2006, 11:55 AM
#26
Originally Posted by speed racer
You guys are making me have doubts on going to a dyno place. Can't I tune it myself at the dyno place or is it mandatory that they do it. Also, once I get the list of A/F ratios throughout the powerband can't I just go ahead tune it home to get to my prefered ratios.
08-30-2006, 09:47 PM
#29
Originally Posted by 2002AltimateV6
THIRD QUESTION:
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
V/T Unmt? Will using this feature affect anything? And is using this nessecary for our cars? Or is it just for VTEC? And if it is required, what's the best setting for it?
Originally Posted by SR20DEN
I'll have to take a look at one this weekend if I can. I don't quite remember what that setting is.
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