Apexi VAFC for our beloved Honda...

[minivan]

Guys/sifus,

The car i bought comes with a VAFC. Never really bothered to play around with it, just leave it be. But now, i wanna start toying with it. What interests me is the VTEC engagement point function. Currently Lo to Hi is 5500rpm and Hi to Lo is 5000rpm. Was thinking of testing it at 5200 and 4800 respectively. But suddenly chicken.... heheh...

before i do it, was wondering....

Will i need to adjust the fuel curve if i change the VTEC engagement point??
Will doing so (changing VTEC engagement point) effect any other settings??

coz i was just thinking to myself, if VTEC engages and fuel is insufficient, is'nt that like... not good.. :p

Thanks guys

Cheers... :D

 

[carnage]

interesting topic... any komen sifus? read thru'
foreign tech webs; highly debatable dis is... 2 many
parameters affecting engagement pts... if i not mistaken,
fuel/air feed these stuff can adjust, but ignition mapping?
i know dats y spoon kontroler doesnt give same effect as
the normal engagement pts... correct me if i wrong

www.hondata.com/featuresvtec.html

 

[zero4]

dont u need ITC to control adjust ignition timing using apexi products? i mean if you use VAFC lah

 

[Riezal-R]

Yes you need to adjust fuelling if you are adjusting VTEC engagement point. It is quite important.

But there is one thing you should know. Changing VTEC engagement point will not help much, if your cam settings are stock. That is, if your cam powerband is set to kick-in at 5800rpm and you set the VTEC to engage at 5000rpm, it might not result in any power increase. Although the VTEC is already engaged, still the cams have not reached its max powerband, due to the timing of the cams. But if you are changing VTEC engagement points by 100-200rpm, then I don't think this will be a problem.

In theory, sometimes low cams can perform better than hi cams at lower RPM. For instance, if you engage Hi cam at 3000rpm, the car might no pick-up speed as fast as the low cam does at 3000rpm. The low cams are somewhat 'lighter'. But then some people say "how often do you drop to 3000rpm when you whack the car?". So it depends how you want it set up. Some cars engage VTEC all the time, it never closes. As long as you don't go lower than 4000rpm, you'll be fine :)

 

[carnage]

dont u need ITC to control adjust ignition timing using apexi products? i mean if you use VAFC lah

i think that gives us newbies some better lead already...
thanks

 

[Riezal-R]

dont u need ITC to control adjust ignition timing using apexi products? i mean if you use VAFC lah

Before engine management systems like e-Manage, Haltech, etc were widely used.. the best combination was chipped ECU + AFC + ITC. ECU to give the base setup, AFC to fine tune fuelling and air correction, while the ITC controls ignition timing. The result was a nicely purpose tuned engine, the 'traditional' way :)

Now people prefer to use management systems, because they have all the functions in one unit. You just need to find a good tuner.

 

[carnage]

But there is one thing you should know. Changing VTEC engagement point will not help much, if your cam settings are stock. That is, if your cam powerband is set to kick-in at 5800rpm and you set the VTEC to engage at 5000rpm, it might not result in any power increase. Although the VTEC is already engaged, still the cams have not reached its max powerband, due to the timing of the cams. But if you are changing VTEC engagement points by 100-200rpm, then I don't think this will be a problem.

bro riezal, does vafc/vafcII allows 4 these cam powerband
resettings? or is this where aftermkt cams comes in handy?
thanks

 

[zero4]

Yes you need to adjust fuelling if you are adjusting VTEC engagement point. It is quite important.

But there is one thing you should know. Changing VTEC engagement point will not help much, if your cam settings are stock. That is, if your cam powerband is set to kick-in at 5800rpm and you set the VTEC to engage at 5000rpm, it might not result in any power increase. Although the VTEC is already engaged, still the cams have not reached its max powerband, due to the timing of the cams. But if you are changing VTEC engagement points by 100-200rpm, then I don't think this will be a problem.

In theory, sometimes low cams can perform better than hi cams at lower RPM. For instance, if you engage Hi cam at 3000rpm, the car might no pick-up speed as fast as the low cam does at 3000rpm. The low cams are somewhat 'lighter'. But then some people say "how often do you drop to 3000rpm when you whack the car?". So it depends how you want it set up. Some cars engage VTEC all the time, it never closes. As long as you don't go lower than 4000rpm, you'll be fine :)

reizal is right, use my case as reference, i'm using stock type R cams, powerband is suppose to be 5800rpm, but my spoon ecu is so smart (because it is design for spoon cams), vtec kicks in at 5000rpm. What happen then? u will hear vtec kicks in, and then? you feel nothing until it reaches 5800 when the cams start to work

so there u go, set ur vtec point wisely if you got a management, make sure ur vtec engaging point suit the cam that you have

 

[zero4]

i think that gives us newbies some better lead already...
thanks

no probz, we are all learning

 

[Riezal-R]

You need an adjustable cam pulley to advance/retard the cam timing.

 

[minivan]

wah... ok... thankfully was'nt 'gatal' enough to toy around with it and follow the logic i thought about... :D

are there products out there that when you adjust 1 parameter, other parameters follow suit to change to accomodate the parameter that you changed?? would'nt that be cool... for example, you change VTEC engagement point, and the fuel curve automatically adjusts itself to accomodate the change you made. An "i-VAFC".. :D

so you can toy around all day finding the perfect engagement point on your own...

 

[zero4]

and plz, for those who are looking for cam pulleys, dont get the local produced ones, they costs around 300-400, add a bit more to get better quality ones, WITH PROPER MARKING, LOL, seriously

 

[Riezal-R]

i'm using stock type R cams, powerband is suppose to be 5800rpm, but my spoon ecu is so smart (because it is design for spoon cams), vtec kicks in at 5000rpm. What happen then? u will hear vtec kicks in, and then? you feel nothing until it reaches 5800 when the cams start to work

Perfect example here. I bought a VAFC, and dragged my car every night (behind the TTDI skool zero4, LOL) testing different engagement points and fuel settings. Overall, the result was that you hear the nice VTEC sound kick-in at 5200rpm, but the power only comes at 6000rpm. No point adjusting, especially for Type-R engines due to the cam setting.

In the end I sold the VAFC. Not because it wasn't good, but because it wasn't what I needed at the time. The VAFC is a good unit, no doubt.

 

[minivan]

and plz, for those who are looking for cam pulleys, dont get the local produced ones, they costs around 300-400, add a bit more to get better quality ones, WITH PROPER MARKING, LOL, seriously

what about ones that make own holes so they become adjustable?? :p

 

[Riezal-R]

They will most likely break after heavy use. That will then damage other engine hardware. And all that just to save a few hundred :)

 

[916EK]

so does that means that a vafc is useless without setting the iginition timing?

no point adjusting the vtec to open at 5K + adding sufficient fuel at 5K above?

 

[carnage]

what about ones that make own holes so they become adjustable?? :p

aiyooo ini macam pun ada ka?
sounds like cari penyakit only? i say we trust the japs on
these? THANKS 4 THE TIPS, VTEC LORDS

 

[zero4]

so does that means that a vafc is useless without setting the iginition timing?

no point adjusting the vtec to open at 5K + adding sufficient fuel at 5K above?

in a way yes, unless you push ur cam, always tune ur engine refering to your camsloh

 

[carnage]

so does that means that a vafc is useless without setting the iginition timing?

no point adjusting the vtec to open at 5K + adding sufficient fuel at 5K above?

yes sireee it says here:

www.hondata.com/featuresvtec.html

i've tried a vtec with spoon ones, engages at 3500
tadak rasa lar!

 

[zero4]

They will most likely break after heavy use. That will then damage other engine hardware. And all that just to save a few hundred :)

riezal is right, minivan you shud see the screws they used for local produced cam pulleys, u will be surprised how fragile the screws they produced looks, and they ARE that fragile


that's why u hear ppl say, mine damn tuning lari, LOL