Questions regarding installation of my SAFC II
06-18-2004, 02:55 PM
#1
Donating Maxima.org Member
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Join Date: Apr 2001
Posts: 1,085
The official SAFC II thread for tuning.
I have been reading a lot of prior posts and can't come to any real conclusions. I know the hot wire setting on VQ30 Maxima's is 4 in and 4 out. I can't find what it would be for us VQ35 guys. Also, what is the ideal a/f ratio on a N/A Maxima? This says 14.7 is ideal: http://www.nissanperformancemag.com...project_qg18de/ I keep reading other places and past threads that say ~12 and others say ~13. Above 14.7 is lean and below it is rich. We need a good informative thread so others can find these answers as well. I want to make the most power, while still running safe. This website is full of good info, let's add to it.
06-18-2004, 03:32 PM
#2
VQ30 vs VQ35 MAFs are same type, so use the same "mode".
The best AFR varies engine/engine, so there isn't one exact AFR that's best and only a dyno will tell.
During cruise your AFR is ~14:1 because the ECU is using 02-sensor feedback to control it.
At WOT or during quick throttle changes the ECU switches to a different fuel map and no longer uses 02-sensors to control AFR. It's set at the factory based on RPM and your MAF sensor readings. You need to leave the "low" settings on the SAFC all at zero since the ECU will override them anyways according to what the 02-sensor feedback is saying. Just set the "high" settings with the threshold around 40% IIRC, so it kicks in at high load/throttle changes.
The best AFR varies engine/engine, so there isn't one exact AFR that's best and only a dyno will tell.
During cruise your AFR is ~14:1 because the ECU is using 02-sensor feedback to control it.
At WOT or during quick throttle changes the ECU switches to a different fuel map and no longer uses 02-sensors to control AFR. It's set at the factory based on RPM and your MAF sensor readings. You need to leave the "low" settings on the SAFC all at zero since the ECU will override them anyways according to what the 02-sensor feedback is saying. Just set the "high" settings with the threshold around 40% IIRC, so it kicks in at high load/throttle changes.
06-18-2004, 05:04 PM
#3
I don't have anything to add. Just wanted to subscribe because I'll be heading down this path soon. Also here's a link in case you need this info.
http://forums.maxima.org/showthread.php?t=318419
http://forums.maxima.org/showthread.php?t=318419
06-18-2004, 09:54 PM
#4
Donating Maxima.org Member
Thread Starter
Join Date: Apr 2001
Posts: 1,085
Originally Posted by IceY2K1
VQ30 vs VQ35 MAFs are same type, so use the same "mode".
The best AFR varies engine/engine, so there isn't one exact AFR that's best and only a dyno will tell.
During cruise your AFR is ~14:1 because the ECU is using 02-sensor feedback to control it.
At WOT or during quick throttle changes the ECU switches to a different fuel map and no longer uses 02-sensors to control AFR. It's set at the factory based on RPM and your MAF sensor readings. You need to leave the "low" settings on the SAFC all at zero since the ECU will override them anyways according to what the 02-sensor feedback is saying. Just set the "high" settings with the threshold around 40% IIRC, so it kicks in at high load/throttle changes.
The best AFR varies engine/engine, so there isn't one exact AFR that's best and only a dyno will tell.
During cruise your AFR is ~14:1 because the ECU is using 02-sensor feedback to control it.
At WOT or during quick throttle changes the ECU switches to a different fuel map and no longer uses 02-sensors to control AFR. It's set at the factory based on RPM and your MAF sensor readings. You need to leave the "low" settings on the SAFC all at zero since the ECU will override them anyways according to what the 02-sensor feedback is saying. Just set the "high" settings with the threshold around 40% IIRC, so it kicks in at high load/throttle changes.
06-19-2004, 04:19 PM
#6
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Join Date: Apr 2001
Posts: 1,085
A few more questions:
1. What do I set the number of cylinders to (I know I have a 6 cylinder)? The 350Z uses #1 setting.
2. During the "self learn the throttle opening sequence," do I take off my intake and manually hold the throttle valve open? Or is using the pedal with my foot fine even though it's drive by wire?
1. What do I set the number of cylinders to (I know I have a 6 cylinder)? The 350Z uses #1 setting.
2. During the "self learn the throttle opening sequence," do I take off my intake and manually hold the throttle valve open? Or is using the pedal with my foot fine even though it's drive by wire?
06-19-2004, 04:27 PM
#7
I run a S-AFCII on my Turbo G20. I have alot of experience with the little black box. Ok there are diff A/Fs U wanna run for boosted, nos-ed or NA cars. On a Turbo car U wanna be little on the rich side, same with NOS, yet with NA U are able to get away with leaner A/F and not worry bout detonation as U would with a turbo or NOS where there is alot more pressures inside the cylinder. I would go -10% across the board on the low and high setting and work from that on the dyno. Also the low MAP is for up to 40% throttle, anything over 40% throttle is on the Hi side. I been messing around with Emanage alot lately on SR20s- building guys maps for their engines corresponding for mods. And I am gonna install Emanage in my Maxima to see how much power is there to be gained. Cause because I can fine tune the map alot better on the Emanage than I would on the S-AFC. Emanage gives U ability to tune by RPM and throttle application. S-AFC gives lets you lean out or richen only at low and hi throttle setting by RPM- so the car is not as smooth with power delivery.
06-19-2004, 04:35 PM
#8
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Originally Posted by BlackBIRDVQ
I run a S-AFCII on my Turbo G20. I have alot of experience with the little black box. Ok there are diff A/Fs U wanna run for boosted, nos-ed or NA cars. On a Turbo car U wanna be little on the rich side, same with NOS, yet with NA U are able to get away with leaner A/F and not worry bout detonation as U would with a turbo or NOS where there is alot more pressures inside the cylinder. I would go -10% across the board on the low and high setting and work from that on the dyno. Also the low MAP is for up to 40% throttle, anything over 40% throttle is on the Hi side. I been messing around with Emanage alot lately on SR20s- building guys maps for their engines corresponding for mods. And I am gonna install Emanage in my Maxima to see how much power is there to be gained. Cause because I can fine tune the map alot better on the Emanage than I would on the S-AFC. Emanage gives U ability to tune by RPM and throttle application. S-AFC gives lets you lean out or richen only at low and hi throttle setting by RPM- so the car is not as smooth with power delivery.
ex:14.7:1
06-19-2004, 04:53 PM
#9
there is no set procentage to A/F ratio equation really untill U dyno you car with everything set to 0 on the AFC. When U dyno make sure to have a good A/F machine hooked up in the exhaust right before the main cat. It will be just a wide band 02 sensor bolted in there. The TAIL PIPE kind of A/F readers suck for tuning. Then watch the BASE line run A/F reading and remove or add fuel as needed
till U have a pretty good map with lots of added power. Don't keep on leaning the **** out of it cause it will start to detonate and acutally it will probably stop making power and blow up
I can't tell U how I tune my G20 cause it will make no sense here. This car don't use stock injectors so I need to compensate with less or more fuel - tricking the computer to think I have stock injectors still. I run that much HP as in the sig line with a stock ECU Why pay more for JWT.
till U have a pretty good map with lots of added power. Don't keep on leaning the **** out of it cause it will start to detonate and acutally it will probably stop making power and blow up
I can't tell U how I tune my G20 cause it will make no sense here. This car don't use stock injectors so I need to compensate with less or more fuel - tricking the computer to think I have stock injectors still. I run that much HP as in the sig line with a stock ECU Why pay more for JWT.
06-20-2004, 09:14 AM
#10
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Thread Starter
Join Date: Apr 2001
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1. What do I set the number of cylinders to (I know I have a 6 cylinder)? The 350Z uses #1 setting.
2. During the "self learn the throttle opening sequence," do I take off my intake and manually hold the throttle valve open? Or is using the pedal with my foot fine even though it's drive by wire?
2. During the "self learn the throttle opening sequence," do I take off my intake and manually hold the throttle valve open? Or is using the pedal with my foot fine even though it's drive by wire?
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