can someone explain to me what the correct percentage is on the vafc. on my car it reads at about -15% at idle and on the low cam it will get up to about -3 under high throttle. then as soon as the cams switch lobes, the % jumps to about +10% and then under WOT will gradually go down to about 0% or even -1%.

is this the percentage away from stoich or something? the instruction manual gives no info on this at all and im just curious as to what these % numbers mean

 

Percentage more or less than what is actual at that point.

 

you have to elaberate on what exactly your trying to figure out, i have a vafc II and I dont know what your talking about, im assuming your speaking of the air correction. if thats the case send me a list of your settings and i can help you out.

 

its a vafc1. if you go to monitor, its the"cor" top right side. it gives a percent value when monitoring it.

if my car is just sitting at idle, it will be at -15%. as soon as i start to drive it will drop with increased throttle and rpm but never goes above -7% on the low cam. as soon as the cam switches over to the vtec lobe, instantly the % jumps up to about +10% and stays there till about 6k rpm when under wot. after 6k it will start dropping back down towards 0% and reaches 0% by mid-high 7k's. at 8k-8.3k it reads about -1% or -2%. again this is at wot.

do i want to tune it so that it stays around 0% on the high cam throughout the rev band?

sorry if this is a little confusing. im trying my best to explain

 

anyone?

 

How does the car run so far?
Is your ECU chipped?

 

Those are percentages of MAP voltage being added or subtracted.

If the adjustment maps for HI/LO cam and Lvt/Hvt are all at 0 correction, then it's the ECU is using the fuel and ignition maps as is.

 

ok, i am running a jhp.com ffs1 program ecu if that matters at all.

so there is no ideal % where it should be running for the low and high cam? i guess it will just come back to the "get to a dyno with wideband" correct?

 

first off if you have a chip its already remapping your emissions system, and im not very familar with your vafc, have you adjusted your controller or are those the factory default settings? if their default its your chip, if their yours change them. Ive found throug the SOHC'S and DOHC'S, 5G is a good V-tec point and have it drop out at 45G or 48G. at about 48G start adding fuel and air corr till 68G or 7G and slowly cut the fuel and air corr. hondas run pretty rich, so adding a little fuel to make up for the earlier v-tec point and trimming it out evenly works good for a seat of your pants settiing. hope i helped you some what but obviously the new controlers are a lot different.

 

actually, ive found that anything over 4600 for my vtec x over causes a dip in the power.(stock internal b18c1).

the ecu has a 5500 vtec x-over and i have it set at 4500 with the vafc. so you think i need to add fuel from 4500 -5500? i actually leaned out the mid and upper rpms a bit and it seems to run smoother in the mid range. and not much different on the high end,

 

Theoretically you would need to add fuel, but the remapped ECU might have enough fuel regardless. You won't know until you measure first.

In such the case where you lower the VTEC cross point, you would use the VTEC unmount parameter and adjust the LO->HI to adjust that rpm range b/w the Vti and Vto.

 

ok, i got it.

now, is it safe to baseline tune(conservative) with just an a/f guage? or should i try to hold off tuning completely till i can get on a wideband?

 

Wideband. A narrow-band won't show you the whole picture.

 

B16lsvtec w/ chipped P28, X over point is @ 4800 rpm.
Corr = -6% idle. As throttle goes up, Corr goes from -6% all the way to -3% even -2% and when vtec hits Corr goes to +6%.
That's the best setting I came up tuning with narrowband a/f ratio and a lot of test runs.

 

sorry for interrupting this conversation. I'm also running VAFC 1 on my B16A1 engie. Using chipped P30 JDM ECU.
I'm still not sure on settings my Vtec Unmatched correction, which now i set it to Hi - 50% and Lo - 50%.
Vtec engage at Hi-5800rpm and Lo-5400rpm.
And i set my Narrow Throttle and Wide Throttle with same fuel enrichments. Should i sets both of it with the same amonts? or else?
Thanks.

 

from what ive learned, the +/- % means nothing unless you are on a wideband. every engine and ecu program are different. so the numbers that work for one case may be terrible for another.

im not messing with it anymore till i get on a dyno with wideband tuning.