I had technosquare do the full-spec and they nailed it right on 12.9-13.1.
But i noticed something. my car after cams lost the trq from stop. so basically if i push the pedal all the way from a stop, it doesn't burn the tires. the car bogs down and feels like is flooding but my wideband tells me is at 13.0. middle rande and up top is more than perfect. the problem is from a stop.
I have the safc2. should i lean the mixture quite a bit from 1000 to 3000 rpms?
I know how it should be middle range and up top. but have no idea how lean it should be from a dead stop. i noticed that when you are going less than 40% throttle the car usually oscillates from 14.5-15.0. should i lean it that high on hi throttle? the only gear that is going to be at that range of rpms is first gear.

 

what? im having problems understanding most of your posts..

Anyways, anything under 40% throttle and under 3000 rpm do not attempt to tune that, your o2 sensors should be doing the job there...

You have an auto right?

EDIT: You are using a wideband right?

Your target AFR for a N/A car is 13.0-13.5 at WOT/3K+

Do not lean it out to 14-15:1 thats just asking for trouble.

 

what do you mean? at idle it should try and run a 14.7:1 so that is fine, id be scared if at WOT your at 15:1. It should run a 14.7:1 when running off 02 sensors and then when you gun it 13-13.5:1. this is N/A im sure for FI id look to be more rich even. What you do want to live in a perfect world?

 

lol sorry but my native language is spanish.
the safc2 has the option to tune above let's say 40% throttle right? so if i'm taking off at 100% throttle from a complete stop, my car bogs down as if too much fuel is passing thru. i tried leaning it out from 1000 rpms at 13.5 to 3000 rpms at 13.1. yesterday and the car is working much better. I want to know how lean can i go at 1000 - 3000 rpms area? of course after 3000 i'm going to keep it between 12.9-13.1.
you refer that I don't need to tune below 3000 rpms. why is that?
closed loop conditions are less than 40% throttle if i'm not mistaken.

 

Hey Virg,

are you by any chance tuning with a WB02, or using just the SAFC graphs to measure your tune? Also, are you on Southfloridamaximas.com?

 

closed loop is less than 40% throttle AND under 3K RPM.

 

i have an lm1 with the xd gauge.
you got that right. 40% throttle AND 3k rpms. either of these parameters break then is open loop.
above 40% throttle is open loop even under 3000 rpms.

 

hey virgilio, that's not the case. the ECU only goes into Open Loop
A- during initial start up
and
B- >40% throttle AND >3000RPM

In other words, even if you go 100% throttle at idle, the ECU will still trim the fuel off the oxygen sensors' signals and try to maintain the 14.7-14.9 AFR ... UNTIL.... the RPMs get over 3000, then it switches to open loop and THIS is when the settings from your SAFC affect the car.

This is why we're telling you that trying to tune anything under 3k rpm is useless, because the computer will use the oxygen sensors anyways.

 

hmmm. i wonder if either my wideband is bad or 02+ ecu is different from previous years.
my car doesn't show that a/f between 1000 and 3000.
shows 13.0-13.1

 

Well if the wideband is in fact good, and its telling you you're runing 13.0-13.1:1 AFR, I'd replace the oxygen sensors just to rule that out as a variable in this. For sure, messing with the settings on the SAFC wont do anything at idle/ bottom end area of the powerband. So you have to look at what actually affects that area.

Also, if the oxygen sensors are bad, that would explain why your car feels so sluggish on the bottom end, you're runing extremely rich! It should be bouncing back and forth between 14.7-14.9 for closed loop mode.

 

when youre below 3k, the a/f should still be pretty close to 14.7:1. youre probly flooding it. with the original ECU it will be pretty close to 14.7:1 below 3k even at 100% throttle. When i had my car dynoed, all the way to 3k it was really close to 14.7:1. maybe you should try adjusting it to there somehow.

 

that is what i'm getting too. I think my car is flooding when i press the gas all the way from a dead stop. not even all the way, above 40 % which is ridiculous when you are trying to take off at the track.
I removed about 8 points on the safc2 at 1k and substracted about 3 points at 3k and now i can chirp the tires. lol i'm about 14.0 at 1k and it goes smooth down to 13.5 at 3k and from there to the end 12.9-13.0 area.
i'm going to leave it like that to see if the a/f changes at those rpms.
you know what i find funny?
some dynos on this site from a manual tranny, showed 13.0-14.0 a/f between 1k-3k

 

Where have you seen a dyno that starts at 1k 4th gear and 1K RPM do not mix IIRC...

 

there o2 sensors are probably bad

anyways, do whatever works for you

 

my car runs perfect on closed loop. 14.5-15.2 all the time. so that tells me the a/f sensors are working right.
the only issue is when pressing the gas above 40% from a dead stop. seems to flood between 1k-3k and then starts to take off.
I'm pushing 260+ to the wheels so not been able the take off is driving me insane. I can really do it if i press the gas below 40% and then at 2500 rpms press it all the way.
but that's not the idea of having a faster car lol

 

Open Loop Control
NFEC0014S05
The open loop system condition refers to when the ECM detects any of the following conditions. Feedback
control stops in order to maintain stabilized fuel combustion.
Deceleration and acceleration
High-load, high-speed operation
Malfunction of heated oxygen sensor 1 or its circuit
Insufficient activation of heated oxygen sensor 1 at low engine coolant temperature
High engine coolant temperature
During warm-up
After shifting from “N” to “D”
When starting the engine


From the FSM...

 

this is one
http://forums.maxima.org/showpost.ph...06&postcount=9

 

thank you for giving more info. i already read the one that i have and says the same thing. it doesn't specify above or below 3000 rpms. and it doesn't say above 40% throttle either. i found it is +-40% cause as soon as i pass 40% my a/f changes right away.
so this means open loop is also under 3000 rpms?

 

1800RPM

Anyways, im pretty sure the ECU goes to a preset map(openloop) when you floor it from a stop. I am sure that is considered "high speed operation" or "high acceleration"

 

thanks. i'm sharing the same opinion. or maybe is considered high load?

 

I kinda doubt that 40% throttle and 3000 rpm are exactly the parameters the ECU uses to determine whether to use closed loop or open loop. It is more likely just determined by a region of cells on the fuel map (that correspond to a certain minimum engine loading or greater). However datalogging seems to indicate that the transition from the closed loop region to open loop region tends to occur at engine loads that begin to be seen around those 40%, 3000 rpm points.

 

And I believe eng92 stated once that he found from datalogging that the ECU is really only in closed loop at idle, constant speed driving or very light acceleration. It is open loop most all other times.

 

so I should blame it on technosquare now lol.

 

No, you should blame it on your cams...

You are worried about nothing. The loss in power at low RPM with your cams has nothing to do with your air fuel ratio. It is a result of how high lift high duration cams work, low end suffers. Changing your air fuel won't change that fact. People are putting too much emphasis on the "perfect" air fuel ratio. Altering your air fuel ratio a little bit (or even a bunch) at that low of RPM will gain you virtually nothing. You are trying to change one variable that has nothing to do with the power loss you are experiencing. The power loss at low RPM is a result of your cams and your air fuel ratio has nothing to do with it.

 

OH cams.. sheesh I shoulda gone back up and read more carefully. I agree with Neal. I don't know which ones you got (how aggressive) but yeah low end will suffer. You could try richening it up a bit and bumping timing but it wouldn't do a whole lot at that low of an rpm. If you need to accelerate from a stop quickly you just gotta launch it from a higher rpm.

 

I don't think you are completely right. you have a good point where i should lose some power bottom end. but the fact that i don't burn out tires, don't even chirp them it's something else. i eventually leaned out the mixture and know i feel that is taking off with a little chirp on the tires.
I went to the track and it was lagging so bad on first gear that i ended up doing a 2.3 60' without tire spin. hell i even did a 14.5 which i should be more on high 13s.

 

I have an auto, tried to break trq and it was worse. it takes off fine on closed loop. open loop seems to be the ****.

 

Oh auto huh, ok.

Well the only other thing you might want to do if you're convinced it's more than the cam effect is get some good datalogs off the TS ECU so you know exactly what it's doing. Do it without SAFC corrections so you can see what the basic TS flash settings are for timing and AFR.

 

If you want to KNOW, you've got to get it on a dyno and start datalogging various changes. Right now you are shooting in the dark. I've given you the most likely culprit, high lift high duration cams will cause a low RPM power loss, if it's not that it's either something you haven't thought about yet, or it's in your head. Let us know what you find once you dyno and datalog, until you've got some hard data it's all just conjecture. Saying "oh noes I can't chirp the tires anymore therefor I know my car is making less power than it was before" is a ridiculous way to gauge how much power you are putting down. Get it on a dyno and start making some changes with the SAFC and see what happens. Personally my money is on cams and imagination.

 

lol. i'm not a retard that imagine things. if you were here in south florida I can problably show you. chirp tires was just an addition to the problem so you can understand further more and help me out. but you are right on the datalog that is why i'm going to take a couple of samples and see what is going on further down.
I was asking about the a/f trying to figure out whats wrong.

 

its been extremely hot this past week or so down here... so maybe its the heat, and your imagination...

 

Hmm skipped over the cams part. They are right about that being the reason for a low end loss.


Ever think you have sticky tires?

 

I cant squeel my fusion ZR1s launching at 3k... Let me put my sawblades back on with the crappy Kumho touring tires, they squeel like a pig!

 

We just retuned sloppymax's car last night, from a stop, with my zt2 wideband. I aimed his A/F at 14.0:1 across the board @WOT. I guess we'll see how the 2001 AE Auto ECU holds out over time with those low end throttle settings. But even with the PV removed his car has no trouble at all spinning the tires from a stop, even with a passenger in the front.

 

i am the least to talk here since i have the least knowledge, but in my experience my auto lags the same from the line. lately iv been trying to find what is the best way to launch either from instant WOT or part throttle then go to WOT as rpms rise. in my experience it has to do alot with weather and also "maybe" the intake setup you may have, with the stock mid pipe my car has less of the lag and i can spin the tires. with the entire CAI setup i get more lag. So far i get better results off the line going part throttle instead of an instant WOT. I tap it quickly and as the car takes off and chrips i take it to WOT.

 

OK. I am bringing the thread back as I am about to purchase these cams to put in a 3.5 with a 3.0 JWT ECU in a 4th gen. Do any of you guys think that I will notice a big difference in the low end going from a stock VQ30 to a VQ35 with cams? I really want to get that additional torque out of the VQ35 everyone talks about but it seems like the low end is suffering a lot from these cams even though they've been proven to give 20 hp up top. But if I could at least feel the same low end from the VQ35 with cams as I do now with my vq30 I would be satisfied seeing that my top end will be crazy. Additionally, I haven't heard anyone running these cams with a valve spring and shim kit. I know the basis of this is so you can rev the vq35 over 7000 rpm's safely but do you think the $240 for the JWT valve spring and shim kit is worth being able to go up to 7500 RPM's? Any thoughts would be appreciated.

Mike