s2konroids

Okay, i have a VAFC2 I'm happy with it, I know its not the best but it hasnt learned over settings in WOT after 2 revisits (months after, which i was concerned about).

What are people running AFR wise in the last 500-600rpm?

I run 12.78 AFR, namely because i think its 'safer' thus richier as i have lack of ignition timing adjustment (but didnt notice knock/retarding) but alse pistons speeds at this rpm range.

I did notice it hits fuel cut alot quicker! no doubt honda did this delibretly.

I was going to push it to 13.2 AFR at the last 500-600 rpm's but i think it could be a bad idea.

FYI the car runs around 13.2AFR throughout rev range in WOT, i have heard figures of 13.5AFR but my mate swares by 13.2 for a bit of safety.

camuman

go to a dyno. u wont know what AFR makes the most power until you can quantify yuor changes. i made the most power at 12.3:1 header collector reading. if your quoting tail pipe readings and have been to a dyno then u would know what is best for your car.

13.2 is prolly a tail pipe sniffer reading. which is more like 12.7ish at header collector, which makes more sense.

s2konroids

I've gone to a dyno mate thats how i tuned it (wideband 02 etc, and yes a tailpipe sniffer) I'm saying i didnt push it as i believed it was maybe bad idea pushing more than 12.7?

camuman

i didnt explain myself well.

since you were on a dyno using a tailpipe sniffer then you saw a few things.

u can only remove fuel with a vafc not add. ecu freaks out if you add. BUT,

since you were running 12.7 at tailpipe that means your more like 12.3ish at header collector, which is more accurate to read from. SO,

try 13.0 at tailpipe and see if you gain power, then try 13.3 at tailpipe and see if you gain power. if you dont, go back to 12.7 at tailpipe, as there is no reason to run leaner if your not benefiting from it.

side note, your buddy swearing at 13.2 as ideal, is a tailpipe reference point, which is more like 12.7ish at header collector, which is more what i beleive is closer to NA ideal.

my opinion is 12.3ish NA ideal, 11.7ish FI ideal. just what my car likes.

its funny, but until you see the WHP correlation to AF, u dont realize that richer ussually is better

wadzii

mine made the most power at around 13.3 afr.

remember that removing fuel the the vafc adds timing, adding fuel takes timing away.

s2konroids

My mate has tuned looking at the logs around 120 cars now all different ones but only 1 s2000, it was a westfield kitcar with an F20c drop-in - i helped with that it was an emerald standalone ECU but far more advanced than a vafc2 (timing etc).

I tuned my car myself but he said to me, I'd leave it at 12.7AFR.

I've just spoken to him about an hour ago he said leave it at 12.7 AFR i could well bump it up but best to leave it (just towards the eng of the rev range) reasons were (as i thought plus a few others)...

*Piston speeds are at their fastest
*heat
*Unknown exactly how ignition timing would react (vafc2)
*My car has over 100k on it
*It might hit fuel even quicker - i noticed it quicker for sure ~12.7
*Sometime its not worth pushing to the extreme boundaries for the sake of 1BHP
*More fuel is safer he started going on about atomising and stuff .

He said if it was his car he'd leave it as its already been bumped up to the lower end of the power making scale (12.7 to 13.2), he'd rather it be more reliable and would not like me to blow it up

So i think I'm going to leave it.

Thanks for the chat though

s2konroids

Thanks i was aware of this, hence it can be undesirable.

I only removed fuel at one point by about 2% (rest was leaned out) i had a spike which was lowered to 13.5 which is still safe for a very short period of time it was lower down IIRC around 5-5.5k rpm.

Gernby

The AP1 runs super rich incomparison to the AP2. I've datalogged totally stock AP2's that run AFR's in the mid 13's.

When I had my '02 with a VAFC-like piggy back, I tuned it to about 13.7 across the whole rev range, as read by my LM-1 with the sensor in my test pipe. I never had any trouble with it, and traded it with 75K miles. My '08 is now also tuned to somewhere between 13 and 14, depending on which sensor data I use (AF or AF Corr).

Here is the before / after on my '02

s57_s2k

how do you know you are not getting knock retard ??????

s2konroids

Because i used detcans and knock sensor, also you can tell to a certain extent on a dyno.