perfect air fuel ratio for a vq??
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Senior Member
Joined: Mar 2009
Posts: 546
From: STATEN ISLAND NY
perfect air fuel ratio for a vq??
got my wideband all buttoned up( was a ***** to run in my car lol) safc been up for months... now its time to tune
mods... block off plate...intake spacers...intake
.. headers/ypipe...testpipe...catback
surprisingly my car runs lean....in the 17s lean... from about 3k till redline... ill try to make a video for everyone... i got my rpm points set and i richend it out and 3k-3500 i got to about 14.9 and 4k-4500 is in the 15s and the rest i got down to the 16s... i do 4th gear pulls and i got more tuning to do....was just wondering what to aim for
it idle fine at 14.7... alot of people are saying sopmething is wrong and it shuld never have been that lean with any mods... i got no exhaust leaks or anything...no codes for sensors or nuthing... just thought id throw that in their lol... i have been richening it up and im getting the numbers down more and more each day...some say shoot for 13.1 and some say shoot for high 12's
mods... block off plate...intake spacers...intake
.. headers/ypipe...testpipe...catbacksurprisingly my car runs lean....in the 17s lean... from about 3k till redline... ill try to make a video for everyone... i got my rpm points set and i richend it out and 3k-3500 i got to about 14.9 and 4k-4500 is in the 15s and the rest i got down to the 16s... i do 4th gear pulls and i got more tuning to do....was just wondering what to aim for
it idle fine at 14.7... alot of people are saying sopmething is wrong and it shuld never have been that lean with any mods... i got no exhaust leaks or anything...no codes for sensors or nuthing... just thought id throw that in their lol... i have been richening it up and im getting the numbers down more and more each day...some say shoot for 13.1 and some say shoot for high 12's
I'd recomend you dind some dek/350z injectors so you dont have to add so much fuel via safc. You can accomplish the same thing by getting an adjustable fuel pressure regulator and upping the pressure slightly. I see plenty of cars idle around 14.7. As far as I know (which isnt much) that's perfect for idle. A friend of mine's car sits at around 17.1 when warmed up and sitting at idle. Although its a completely different car and setup, an experienced tuner told me this was fine.
What speed is redline in 4th gear with the 6 speed again? If it's anything like the 5 speed, i'd recomend tuning in 3rd for saftey's sake if street tuning. What wideband did you end up going with by the way?
What speed is redline in 4th gear with the 6 speed again? If it's anything like the 5 speed, i'd recomend tuning in 3rd for saftey's sake if street tuning. What wideband did you end up going with by the way?
But I'm wondering why it's so lean in the first place. That doesn't sound right.
FTR, mine idles @ 14.7 or so when my PCV is connected the way it should, w/o it connected, it goes off to the 17-18 area in gear, and then if put in park or neutral, it nearly dies at about 18.5 or so. This is due to my larger MAF + AT + PCV deal.
And in all honesty, every set-up is different, and I think you need to spend some dyno time or even track time to find your set-ups sweet spot. So, there is no perfect AFR for any given VQ.
As long as the AFR is flat, I think that's been proven and quantified, at least IMO.
IMO, the AFPR is kind of a PITA in the returnless arena.
But I'm wondering why it's so lean in the first place. That doesn't sound right.
FTR, mine idles @ 14.7 or so when my PCV is connected the way it should, w/o it connected, it goes off to the 17-18 area in gear, and then if put in park or neutral, it nearly dies at about 18.5 or so. This is due to my larger MAF + AT + PCV deal.
And in all honesty, every set-up is different, and I think you need to spend some dyno time or even track time to find your set-ups sweet spot. So, there is no perfect AFR for any given VQ.
As long as the AFR is flat, I think that's been proven and quantified, at least IMO.
But I'm wondering why it's so lean in the first place. That doesn't sound right.
FTR, mine idles @ 14.7 or so when my PCV is connected the way it should, w/o it connected, it goes off to the 17-18 area in gear, and then if put in park or neutral, it nearly dies at about 18.5 or so. This is due to my larger MAF + AT + PCV deal.
And in all honesty, every set-up is different, and I think you need to spend some dyno time or even track time to find your set-ups sweet spot. So, there is no perfect AFR for any given VQ.
As long as the AFR is flat, I think that's been proven and quantified, at least IMO.
That's a good question 
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
Last edited by NmexMAX; Feb 8, 2011 at 11:29 AM.
That's a good question
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
Thread Starter
Senior Member
Joined: Mar 2009
Posts: 546
From: STATEN ISLAND NY
That's a good question
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
1.) What are your IN/OUT settings?
2.) Where is the bung located at?
3.) How much did it require to get it to 14.9 from 17.x (%)
4.) How is your intake set-up (MAF/PCV/what intake do you have)
5.) What gears are you 'tuning' in? Typically the higher the gear, the leaner it gets, in my exp.
Out of curiosity:
6.) How did you get it in the cab and what WB set-up is it?
2. right after the ypipe in the test pipe
3. took alot to be honest...right now i got 3k-4k in the 13s and it took about 9percent
4. intake is maf with a berk intake
5. i tune in 4th gear pulls...was told by a good friend who had a street monster maxima and now is boosted lol
6. gauge is powerd by the cig lighter power... ran the wires threw the drivers side wheel well ..if u pull it bak ull see a gromet with the fuse box wires going to the cabin...just followed that..also its a aem uego
Last edited by maxima dude; Feb 8, 2011 at 01:15 PM.
keep it at 13.0-12.8 for the rest of the time to redline.
Here is my first dyno ever. just bop/ spacers/ intake /exhaust all stock with hks axleback . tuned with safc
13.1-13.0
Im looking for the retune with the 3" exhaust and race pipe. like 17 hp difference. i think the af went up to 13.2 ...
Here is my first dyno ever. just bop/ spacers/ intake /exhaust all stock with hks axleback . tuned with safc
13.1-13.0
Im looking for the retune with the 3" exhaust and race pipe. like 17 hp difference. i think the af went up to 13.2 ...
Last edited by NmexMAX; Feb 8, 2011 at 02:23 PM.
Thread Starter
Senior Member
Joined: Mar 2009
Posts: 546
From: STATEN ISLAND NY
well its taken alot of tuning to get my numbers down... some guy on another forum is sayen my car isnt running right? thing runs fine lol i kno every motor is different and i guess from not having a tune for so long with my mods that my car runs lean
What WB are you using, and does it have any way of calibrating it? Or at least getting a reliable baseline to compare to?
Do you think you might have any airleaks anywhere in the IM? Spacers are installed w/o any leaks I'm assuming? And you have a stock MAF is what I understand as well.
I would try and get some logs using 3rd gear. 4th is a bit much for the street IMO
In the meantime, 9% isn't that bad, I'd just add more fuel and see if it stays at the desired AFR and is repeatable.
I had to add +25-27% before SR20DEN coached me on the whole IN/OUT deal when I went to a larger MAF.
Do you think you might have any airleaks anywhere in the IM? Spacers are installed w/o any leaks I'm assuming? And you have a stock MAF is what I understand as well.
I would try and get some logs using 3rd gear. 4th is a bit much for the street IMO
In the meantime, 9% isn't that bad, I'd just add more fuel and see if it stays at the desired AFR and is repeatable.
I had to add +25-27% before SR20DEN coached me on the whole IN/OUT deal when I went to a larger MAF.
What WB are you using, and does it have any way of calibrating it? Or at least getting a reliable baseline to compare to?
Do you think you might have any airleaks anywhere in the IM? Spacers are installed w/o any leaks I'm assuming? And you have a stock MAF is what I understand as well.
I would try and get some logs using 3rd gear. 4th is a bit much for the street IMO
In the meantime, 9% isn't that bad, I'd just add more fuel and see if it stays at the desired AFR and is repeatable.
I had to add +25-27% before SR20DEN coached me on the whole IN/OUT deal when I went to a larger MAF.
Do you think you might have any airleaks anywhere in the IM? Spacers are installed w/o any leaks I'm assuming? And you have a stock MAF is what I understand as well.
I would try and get some logs using 3rd gear. 4th is a bit much for the street IMO
In the meantime, 9% isn't that bad, I'd just add more fuel and see if it stays at the desired AFR and is repeatable.
I had to add +25-27% before SR20DEN coached me on the whole IN/OUT deal when I went to a larger MAF.
I think I am at 22%
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For the OP: You want 14.7ish at idle and low load conditions. For WOT, 13.5ish @ 3000, gradually richening out to the 12.8-13.0 area from 4500 and up has given me the best results. This may vary for other cars, but a vast majority of VQ35DEs seem to like the 13.0ish range at torque peak and up. edit: also, did you calibrate your wideband sensor? Most have a clean air calibration that must be done before installing it in the pipe.
Last edited by sparks03max; Feb 8, 2011 at 02:58 PM.
If you are getting 17-18 AFRs at idle with the PCV disconnected, then I am going to assume that you have only disconnected the PCV from the intake pipe and not from the rear of the intake manifold as well. The lean idle is because it is effectively a vacuum leak, pulling in unmetered air instead of air from the intake behind the MAF. If you just cap off the PCV on the rear of the manifold and fully vent it to atmosphere, you will no longer get that lean idle condition. I had the same problem as you for 6+ months until I figured out that my partially disconnected PCV system was the culprit. Have had 14.5-14.7 AFRs at idle ever since.
For the OP: You want 14.7ish at idle and low load conditions. For WOT, 13.5ish @ 3000, gradually richening out to the 12.8-13.0 area from 4500 and up has given me the best results. This may vary for other cars, but a vast majority of VQ35DEs seem to like the 13.0ish range at torque peak and up. edit: also, did you calibrate your wideband sensor? Most have a clean air calibration that must be done before installing it in the pipe.
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Next time my valve covers are off, I'll be drilling out the PCV (on the rear valve cover) and the restrictor on the intake side of the PCV breather (on the front valve cover) to better support a vent to atmosphere setup and also fitting a small catch can that is vented to atmosphere on each of them so I don't have oil dripping in my engine bay any more.
If anybody is curious, this is how our PCV system works. Notice at low load conditions when the engine is still pulling vacuum, it pulls air from the intake behind the MAF into the front valve cover, goes through the engine block, and gets sucked back out via the actual PCV valve on the rear valve cover into the rear of the intake manifold (the 3/8" hose on the passenger side of the elbow to be exact). It explains why just removing the hose on the front valve cover and allowing the PCV to pull unmetered air causes the lean idle condition. It is also why the port on the front valve cover has such a tiny hole to restrict too much air from bypassing the TB through the engine and screwing up the idle. By drilling out both the PCV valve on the back and that restrictor on the front valve covers, it should allow proper flow of blowby pressure without the assistance of engine vacuum. At least that is how the Z guys who vent to atmosphere tend to do it.
If anybody is curious, this is how our PCV system works. Notice at low load conditions when the engine is still pulling vacuum, it pulls air from the intake behind the MAF into the front valve cover, goes through the engine block, and gets sucked back out via the actual PCV valve on the rear valve cover into the rear of the intake manifold (the 3/8" hose on the passenger side of the elbow to be exact). It explains why just removing the hose on the front valve cover and allowing the PCV to pull unmetered air causes the lean idle condition. It is also why the port on the front valve cover has such a tiny hole to restrict too much air from bypassing the TB through the engine and screwing up the idle. By drilling out both the PCV valve on the back and that restrictor on the front valve covers, it should allow proper flow of blowby pressure without the assistance of engine vacuum. At least that is how the Z guys who vent to atmosphere tend to do it.
Last edited by sparks03max; Feb 8, 2011 at 08:12 PM.
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From: Greensboro, NC
DO NOT DO BUSINESS WITH THIS MEMBER - OWES PEOPLE MONEY
iTrader: (7)
Joined: Jan 2008
Posts: 3,468
From: Greensboro, NC
DO NOT DO BUSINESS WITH THIS MEMBER - OWES PEOPLE MONEY
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From: Greensboro, NC
I am saying you will get used to it. At least that's usually how it works. Every time I do something to gain power, it feels fast for a few weeks then the novelty wears off and it needs to be faster again.
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