Well I ran 3 times tonight...thanks to Matt (sr20den) for giving me his vafcii settings...Im currently using a PLX R300 as my wideband o2...my mods are intake/headers/test pipe/exhaust and vafcii....all 3 pulls were done in 3rd starting at around 2000 RPMs all the way to redline...just got a few questions though

1. In some areas below 4500 RPMs i'm in the high 13s and even a 14 AFR....is this okay? During the WOT pulls, i didn't feel any pinging....but can i squeeze more hp if I richen up the mixture a little bit by bringing it to 13.5?

2. My wideband o2 is located in my test pipe...I know I don't have any exhaust leaks since I checked before I ran....but what results will I expect if have an exhaust leak in the future? Lean or Rich mixture? Will it be detectable on the wideband?

3. To you wideband users, what AFR do you hang around at during normal daily driving....I'm usually hanging in the high 14s....I sometimes do see a mid 15 here and there....is this okay?

 

1)I'd aim for 13:1 until you get on a dyno and test what is best for your car, ie best torque.
2)An exhaust leak will add air, which will falsely read lean.
3)During light throttle/cruising, ie closed-loop 02 sensor feedback, the stock ECU targets 14.7:1, so 14-16:1 range is normal. Once you go WOT or make quick throttle changes to accelerate, you go open-loop and the ECU ignores 02s so you should see <14:1, however between 12.5-13.5:1 is best torque AFR supposedly.

 

Also, can you post some screen shots of your AFR logging? Or send the files?

I'd like to play around with the PLX logger software.

 

I wonder if you can datalog your ign timing w/ a OBDII scanner and see if there is any timing being pulled at those leaner a/f ratio rpm areas?

 

I have the files...but can you give it until tomorrow? I'm going out later tonight to do more pulls...

what e-mail addy do i send over the files too?

 

I wish i could...ignition timing adjustments would be nice for my vq35...or are they already advanced nicely from the factory?

 

bring those numbers at WOT down a bit. 13's are a good number to shoot for. 14's are asking for trouble. Good Luck and catch you on AIM.

 

hey justin...i'm trying to avoid 14s....its only very few areas that are actually in the 14s...majority of the "lean" spots are hanging in the 13.7 or 13.8....everytime i did a WOT pull, i couldn't feel my car physically knock....it means its running okay...but it doesn't mean i'm getting the most hp right? only a dyno will actually be able to tell if a leaner or richer mixture will actually help hp?

what AFR are you running during daily? kinda bad comparison since your turbocharged

 

its the inaudible knocks that kills motors over time, if you can hear a knock the damage may have be done already. You may actually get better numbers because of a leaner mixure but its border line unsafe when u see it being too lean. I would stay around mid 13's, I think thats a safe area and still get most outta your motor.

I'm running 11.5 wot all the way across mine, its much lower since I'm trying to fight detenation with fuel. Normal driving is still 14.7ish.

 

Gur! I can't wait to start tuning my V-AFC w/ my LC-1! But it hasn't arrived yet. Gurrr!

 

Damnit damnit damnit....i'm so angry tonight....I ran another 3 runs but came back with bad results...

alright my vafcii points are EVEN #s....for example....2200, 2400, 2600 and so forth...now heres my problem....everytime i go out and tune, i noticed there are spikes inbetween my points...for example, theres one at 2900 (inbetween 2800 and 3000)...its a pretty bad spike too...it jumps all the way to 14 while the 2800 and 3000 are more conservative 13.5....this isn't the only rpm either...theres one at 4300 which dips down to 12.7 AFR...and 4900 which spikes to 14.2 AFR.....how do i get rid of these stupid dips and spikes when my V-AFCII has EVEN number points

damn this is turning into a mess.....just last night i was starting to get everything perfect...after each run, i was correcting less and less...and even the first run tonight i only corrected like 3 points...it all started getting bad on the 2nd run....

tonight i had a friend come along to tune.....yesterday night i was tuning by myself...this won't change anything will it?

 

It shouldnt do that, the vafc/safc should compensate for the inbetween points hence u see 3 bars going up as u adjust the correction. On the safc if u push up or down (dont quite remember) it shrink the whole graph into one screen. I dunno if the vafc does that too.

 

nope, it doesn't do that...when you press UP or DOWN on the vafcii, it will switch over to the high points (12pts) or the low points (12pts)

damnit....u guys think i should just start over and erase everything? man this is a mess, forreals....