stRodda

iTrader: (1)

i know stock, the tl-s' run high 11:1's, which is pretty rich. i even emailed unichip, and they said they lean out to 12.9:1 to low 13's.

i was looking into a vafc2 but ive read about instances where gains werent made and sometimes loses actually came up. not sure if there is any truth to this, but i heard a mention of the ecu's being able to adjust themselves. meaning, if we make changes using the vafc on the dyno, it might show immediate gains... but after driving the ecu will notice the leaned out fuel map and add fuel accordingly. basically voiding the vafc tune.

fact or fiction?

SatinSilverTypS

iTrader: (1)

given the way the VAFC interfaces to the ECU i would highly doubt that it's possible for the ECU to override it (although someone here may prove me wrong).

there aren't much gains to be had from the VAFC if your N/A with no mods (your mods aren't listed, so i'm assuming no mods). VTEC is preset at the best possible point from the factory. i know other people have tried moving it around with little or no luck. if you go forced induction then you may want to get one to help smooth out your a/f curve and tweak the most gains you can out of your setup.

the unfortunate truth is that there are no worthwhile computer mods for an n/a tl, or even if you have i/h/e i still have a feeling it wouldn't be worth using a VAFC.

SSTS

MrAlex

i heard that 12-13 is the best ..

stRodda

iTrader: (1)

right now i have an intake and tanabe catback. im getting headers, but i was just wondering about what i heard.

even if gains are huge, im also looking to get better mileage. but again, that is if what i heard is incorrect.

SatinSilverTypS

iTrader: (1)

well if i recall, the supercharged guys only were able to tweak another 10 or 15hp using a VAFC, and that's really only to smooth out their a/f curves for what the included comptech module can't do.

i would highly doubt you'll see more than 5hp if you're normally aspirated with only i/h/e. not worth the price and the time you have to spend tuning it properly imo.

not to say you shouldn't do it if you have your heart set on it, just don't be disappointed if you don't get anything out of it.

to answer your question, i would imagine that your gas mileage will go down since presumably you would tune the car to run richer (more power) and vtec to come in lower. both are destroyers of gas mileage.

SSTS

stRodda

iTrader: (1)

well unless the j32 is different, lean makes power. but thanks. guess i wont worry about it now. just gotta deal with the fact that v6's get shitty mileage.

Costco

a little confused. wouldn't lean make our cars have better gas mileage? and since our cars run rich isnt that why we don't get the best fuel economy?

snowman81

Yeah, lean makes power and it would probably give better gas mileage but the difference would be minimal IMO. I've looked into the VAFC II and decided against it because of the cost compared to the gain. It's just not worth it to me unless you go forced induction. Pure Adrenaline has a VAFC and has messed with the tuning. I think I remember him saying that he adjusted the VTEC engagement point and lost power. Overall, I think he said it really isn't worth it but don't quote me.

SatinSilverTypS

iTrader: (1)

yeah you're right. i think i had "rich" on the brain for some reason. maybe i should go buy a lotto ticket....

regarding VTEC, one thing you can do to determine the best place for it is the following: dyno the engine with it off the whole time. re-dyno with it on the whole time. put the two curves over eachother and see where they cross (and yes, they will cross since you lose power with VTEC on all the time at low RPMs). you'll probably see that where they cross is exactly where the stock engagement point is. we proved this on a taurus SHO which has a dual stage intake that gives more power at high RPMs when the second stage opens (via 6 extra vacuum operated butterfly valves). alot of us thought that if we opened the second stage early we could get a few extra ponies. we were wrong. we used the little trick i mentioned above to dis-prove our theory.

the factory tuning is real good on the TL. the only thing that would push it out of bounds is forced induction really. as was mentioned earlier.

SSTS