Vtec Engagement!

[pgclee]

Wats the Different between a Low Rev Vtec's Kicks in and a High Rev Vtec Kicks in??

Low means 4500RPM kicks in...
High means 7400RPM kicks in...

any answer?

gimi some knowledge people...
wanna hear what people will say...hmm...cause i have no idea...hehe..hmm...hehe...

[bizee_1]

umm hmm.....about 2900rpm ?!? :P
what exactly do you mean ? using standard cams, ecu, engine etc ?

since we're on topic...is it possible to change the engagement point ? (using stock ecu, no vtec controller) ie: header, full exhaust, gear ratio's, bad sensors etc....



gimi some knowledge people...
Johnny 5 need INPUT ! (Short Circuit)

[2ds]

the current vtec cross over point as set by honda is optimal you will lose power if you change it even a little bit.

-2ds

[bizee_1]

what is the current optimal cross over point for stock B16A ? (5500rpm??) and what is considered "even a little bit" ?

as my xover point is approx. 4700-5200rpm. have done i/h/e.

[[[d a n n y]]]

mines not 5.5 spot on it's abit over 5.7 or 5.6 dunno mayb i am mis reading it

[Kit]

the exact vtec engagement point can vary slightly.
it relies on factors such as throttle position, oil pressure, engine temperature, engine load etc etc.

but under WOT, it should be in the 5600-5800rpm range

[2ds]

what is the current optimal cross over point for stock B16A ? (5500rpm??) and what is considered "even a little bit" ?

as my xover point is approx. 4700-5200rpm. have done i/h/e.

that's definatly enough to lose power. don't even think about changing the x-over without dynoing the car on both the low and high cams and comparing the dyno sheets

-2ds

[Civic Type R]

mine is at 5650rpm. - stock B16A.

[bizee_1]

Hmmm....i understand what you guys are saying.
[/b]http://www.ozhonda.com/forums/album_pic.php?pic_id=553
If you look at these dyno runs.
Look at, around the 120kph[blue] & 140kph[red]. (or is it 105 & 110) You will notice that VTEC engages earlier.
The only changes i had done in between before & after were, cat back to full exhaust, and a change of plugs.
My mechanic told me the change of plugs i got done elsewhere, were the wrong ones. And he changed them again.

But still, VTEC engages at the same place WOT.

[pgclee]

nobody seems to answer me question..

not using standard cams and not standard ECU

[Kit]

pgclee, i'm not quite sure what ur original question meant

[geo41e]

it hink he's talkin bout his power bands..??
low vtec kick in ? where u hear that from ?
theres only one kick..and thats when vtec hits full stop

however the NSX is different..got like..3 owerbands,,and 3 diff engine note
love that sound!

[Setanta]

/me thinks pclee is on the crack - I have no idea what the Q is either.

BTW - adjusting the VTEC engagement is bad. I don't care what a dyno shows - I've seen the boys at Croydon make a dyno show a stocl old-school VW show 100kw @RW.

It is a bad thing to do - end of story.

[Weq]

There are 4 engagement points. i think this is what pcglee is getting up.

VTEC engages while revving up, and also while revving down.
High engement means from redline -> 0rpm,. when should the cam kick in, and when it should dis-engage.

[Civic Type R]

I think he means at what RPM does the high cam lobe actuator pin engage... ?

[ECU-MAN]

VTEC on the B16A2 cuts in at 5500rpm, when its not in VTEC the ecu reads the low speed fuel and timming maps in the rom, when VTEC is engaged then the ecu reads the high speed fuel and ignition maps. changing the vtec point with aftermarket equipment will not change the fuel maps so its a big waist of time. vtec point can be changed on a factory ecu by editing the ROM data.
4 things determin VTEC engagement
- engine temperature
- engine load
- vehicle speed
- throttle position

[Civic Type R]

mine definately kicks in at about 5650 dude.

[pgclee]

what i mean is that..

why after market cams has a higher RPM of engagement on Vtec....
but the standard ones are only at around 5800rpm....and i know lots of people set it at 4500rpm...or 5000rpm...why is that?...does it do alot of goods??

by the way..mine kicks in at 7400rpm...but why?....

is the question clear enough...

and by the way setanta...very funny...
and by the way...i'm talking bout Vtec...not VW....look clearly before answering...

if me question still isn't clear enough...then thats alrite...
and yes...is got something to do with the power band as well...

but why higher and why lower??..hmmm....still confusing me...

[wynode]

by the way..mine kicks in at 7400rpm...but why?....


Tell us what mods etc are done to the car and we'll tell you WHY.

[SIKCVC]

HOLY CRAP! 7400 :P are you sure your not talking about the red line on the dash :P You still havnt told us anything about your car. At all.

The 4500 Vtec enguagment point has been answered. It doesnt work!
Think of it this way, if you've got a opening into a stadium, and your letting 10 people in at once through the entrance, and they go through fine and all 10 fit fine, now you open up the gate bigger and let through 10 people at a time, you arn't letting more people through, theres still only 10 people going through the gate. Thats whats happening when you lower the VTEC enguagment point, your opening the valve wider and longer, but the same amount of fuel is going through. So the power should platou.

In answer to why they do it! They're uneducated idiots who were coned into buying the unit, that or they have mods that can cope with a change of VTEC cross over.

I hope that answered one of your questions.

The VW thing is to prove a point... Dynos mean Shit! they give you an IDEA of what you've got, dont take it as gosple.

If your VTEC is kicking in at 7400 and your engine is stock, theres a problem. coz that would mean you've got what, 600-800RPM in VTEC.

Also What engine you have would be great information :D

[LatinoHatchCrap]

PGCLEE: you're making absolutly no sense.
The reason why aftermarket cams "may" have higher VTEC engagement points is because the cam profile is not the same as the stock cams. This means that the aftermarket cams will benefit from adjusting and tuning to find the most appropiate point at which to switch.
Also most aftermarket cams will have the ability to rev higher than stock cams thus VTEC must be set higher in order to take advantage of the added RPM.
But even on my B18C stock cams my secondaries (VTEC) open up at 5300 which was "at the time" the best point at which James decided to set it at. On the stock ECU VTEC engagement is at 5800.
In summary your question should read: When is it necessary to switch VTEC engagement?
Sorry if some of this doesnt make sense its late and I h\just came from watching a 3 hour movie :P

[wynode]

But even on my B18C stock cams my secondaries (VTEC) open up at 5300 ....

Thats a bit confusing........usually when people say 'secondaries' they reffer to the secondary intake runners and NOT the VTEC cam lobes/actuator.
Also, from what I have heard, Hondata can't activate the secondary intake runners(?)

[bizee_1]

what i mean is that..why after market cams has a higher RPM of engagement on Vtec....but the standard ones are only at around 5800rpm....and i know lots of people set it at 4500rpm...or 5000rpm...why is that?...does it do alot of goods??
no it doesn't do it a lot of good. Except sound comes in earlier. that great sound of the 2nd cam phase.


BTW - adjusting the VTEC engagement is bad. I don't care what a dyno shows - I've seen the boys at Croydon make a dyno show a stocl old-school VW show 100kw @RW.
It is a bad thing to do - end of story.

The VW thing is to prove a point... Dynos mean Shit! they give you an IDEA of what you've got, dont take it as gosple.

vtec point can be changed on a factory ecu by editing the ROM data.
i don't take it as gospel. 100kW or 10kW. i didn't post my dyno graph as to show that i produced so many kW. It was to show that VTEC engagement points have changed, of which seems to be from changing my exhaust system.
i haven't adjusted the VTEC engagement point or had the ECU ROM edited since having the conversion done either.
As far as dyno goes....if CRD or anyone can manipulate the curve/peak of the dyno graph, it doesn't matter, as now VTEC engages around 4.8k - 5.2k rpm WOT. dyno graph or not, it used to be 5.5k-6k rpm WOT with old exhaust system, & now is lower.
Am running rich atm. would that have anything to do with it ?

[mugsee]

Some people lower the vtec point to smooth out vtec engagement. Someone was explaining to me that on a dyno graph, after vtec kicks in, the power dips down for a little bit and then starts to climb up again straight after. The lowering of the vtec point is to smooth out this dip and make your powerband more linear.

Why not just get vtec killer cams? ;) at least you won't be worrying about when vtec kicks in.

[Setanta]

lol pclee - you still make no sense. My post was about the supposed "reliability" of dyno tuners and the fact that many operators make mods to your car and then dyno it to "prove" that the money that you just spent is worthwhile (BTW - In no way am I making this comment about Croydon, it's just I saw them do it for fun). How about YOU read before you post in future.

bizee: running rich means your car is not running optimally - VTEC cars do tend to run rich while they are on WOT to protect the motor from detonation - in your case the early activation may be affecting the AF ratio (this last is just a very uneducated guess).

[mr crex]

vtec change over point varies from model to model as stated before ...

the 1st Gen b16a (EF8/9) kicks in at around 5200rpm
the 2nd Gen b16a2 kicks in around the 5500rpm
and so on ...

as for 7400rpm kick in ... theres gotta be something wrong with your ecu or engine to be doing that man ... if your vtec is kicking in at that point your redline must be around the 10-11k rpm mark to bother getting any power out of vtec ... and judging from your low knowledge on the subject I doubt you have a car capable of such efforts.

7400rpm sounds more like your redline
:roll:

[Setanta]

EF9 is at 5400 using the stock ECU - this I know for fact (/me points to sig and avatar as proof). I don't know where the 5200 figure comes from.

[SIKCVC]

mines been around the 5800 mark latly although it was 5500 a few days ago... Strange. I think it was 5500 again tonight, maybe its the pod instead of panel filter. stupid pods are too noisy!!!

[Setanta]

yep - dunno if it'd make a difference or not to VTEC - but did you reset the ECU (pull the hazard fuse/battery terminals for 10 minutes)?

[SIKCVC]

huh? reset the ECU for a filter change over? pull the fuse for 10 mins? I just take out the ECU back up and replace it strait away, that clears all the codes for me. well it has done when my knock sensor wasn't wired up properly :P

[Setanta]

I do it for 10 to be on the safeside so that nothing is left residual. Old '80 comp mentality I guess :)

I found that the ECU needed a reset when I was testing pod vs cai vs panel. No idea why.

[pgclee]

nobody answer me also ler...
always saying the same thing...
why higher not lower...why lower and not higher...
gimi some detail please..

[SIKCVC]

its been answered about 5 times dude... read all the posts.

I even explained it in lamens turms for you :shock:

Not that i really understand what your asking clearly, but if your asking why you WOULD make it kick in later, because if your using more agressive Cams it might not be optimum to open them up at low RPM... with stock cams, theres not much point kicking them in higher.

If your asking why not to kick them in LOWER< well i along with about 8 other people have explained why... Opening up the VTEC cam is pointless unless you let in more fuel, and adjusting the VTEC point without adjusting the fuel map will result in JACK SH|T. Some people have altered theres but they have also altered the fuel map, they've done this by tuning the engine to its optimum, but usually honda engines are tuned fairly spot on for a STOCK engine.

Please if you still havn't had your question answered... consult an translator. No offence intended but we have answered your question... several times. SO you must be confusing what you mean to ask.

[Nuttz]

ok let me have a go to make it simple..

think about itr this way. your motor has 2 cams,

-cam 1 is the low rev cam which gives u peak power at around 2000-5000 rpm. which is good for low speed driving
-cam 2 high rev cam which gives u peak power at around 5000-7000 rpm. which is good for high speed racing. :D

each cam has its own peak.
to choose a vtec crossover point, you have to find the point inbetween the 2 because if u rev too high with cam 1 u would be losing power, and if you dont rev enough for cam2 it would be running worse that cam1.


I have heard of some people changing vtec point lower so when they change gear they can stay in vtec when the revs drop

hope that helps.
.

[pgclee]

ohh...hahaha...i'm abit lagging...

[mr crex]

EF9 is at 5400 using the stock ECU - this I know for fact (/me points to sig and avatar as proof). I don't know where the 5200 figure comes from.

damn man ... mine is kicking in at 5000-5200rpm and my ecu is standard :?

[Setanta]

That's weird mate. :? I have to admit though, I do hate having to hit 8100 to keep the engine on VTEC just above the 5400 on gearchange if I'm really in a hurry ;)

[pgclee]

and now the weird part comes....
tell me how the Dyno Graph should be?..
after 7400rpm, will it haf a sharp boom? or.....??

[Nuttz]

a good tune should have no sharp jump in power. if it does it should be as less as possible.

basically when the power of cam1 is dropping off and if u have set vtec too high u will get crossover to cam2 in the middle of its power peak and get a sharp jump.

setting vtec at 7400 u will get a jump for sure :) and have power for 1 second then u'd have to change gear becasue u would be at redline by then.

[SIKCVC]

Yeah sharp jumps on the standard ECU's suck... too much wheel spin in the wet... so i heard :?

[pgclee]

usually you guys will know that Vtec kicks in....exhaust changes sound..

but for me case...it changes sound at 5000rpm, and it changes again at 7400...damn weird...don't know why...

hopefully my car doesn't cut off at 8500rpm....and hopefully it can rev till 10krpm....then i won't have such short time to enjoy my Vtec...hahaha

[Kit]

usually you guys will know that Vtec kicks in....exhaust changes sound..

but for me case...it changes sound at 5000rpm, and it changes again at 7400...damn weird...don't know why...

hopefully my car doesn't cut off at 8500rpm....and hopefully it can rev till 10krpm....then i won't have such short time to enjoy my Vtec...hahaha

pglee,

exhaust changing sound is not a good indication of vtec crossover as it could have actually changed well before that point. The best method is to wire an LED to the VTEC solenoid and that way it will light up the moment vtec has crossed over. there are many articles on the net for doing this.

about it changing sound at 7400rpm I know what you are talking about, but that is not vtec changing over. I have found with the b16a (with exhaust and intake) that very high up in the RPM close to redline the engines induction noise does actually change slightly, it becomes more raspy and rough, but that definately isn't vtec cutting over again.

Chris

[pgclee]

me engine change sound ler...

[[twins]vtec]

But even on my B18C stock cams my secondaries (VTEC) open up at 5300 which was "at the time" the best point at which James decided to set it at. On the stock ECU VTEC engagement is at 5800.

hey dude remember me with the white DC2 VTi-R
just a note
the B18C not R
actualli engages VTEC at 4400rpm stock
and then at 5800 the IAB/butterflies opens- dual intake runner activates and the short intake comes into play
:)

[pgclee]

how come soo many Vtec point now??..which one is real??????

don't make me blur leh

[SPEEDCORE]

I think I'm about to scream!!!

How about you go to a dyno and find out what is the optimal Vtec engagement point for YOUR ENGINE, with YOUR MODS! If that is what you are after.

Jeebers people..... the OEM tachos are sometimes out big time too, so don't be too dependant/reliant on them.

[pgclee]

thank you for clearing that...

is just too many figures tat i don't know which is a Vtec point...
actually, the dyno doesn't show a significant increase of power when me-vtec kicks in...so i just wonder whats wrong thats all...

haha...giving soo much headache to you all...i feel bad...haha..

[SPEEDCORE]

I'm no expert man but if there is no BIG kick in power at the Vtec engagment point than to me it does not necessarly mean that it is not tuned badly, given the mods I think you are running.

The way I see it it has been tuned well and in such a way that the crossover is not very noticable.

I still believe that the B16 is the vtec engine with the most noticable switch over to highcam...... probably due to extreame lack of power and torque in lowcam.

B18.. less noticable even less in K20s.......

Anyone else think the same?

[H22ACIVIC]

I don't know man the h22 gives a pretty significant kick when vtec kicks in.

[SIKCVC]

only felt b16 and h22 but yes. I belive.

[SP0017]

pgclee,

some people believe that a linear power curve is much better, especially for track work.

When your vtec comes in, it does not necessarily mean that you will feel a surge as you do when boost kicks in for a turbo car.

When your vtec should kick in depends on your mods also. Furthermore, if your are using toda c, I think your low end might feel sluggish. That's nothing to do with your tuning but thats the characteristics of the cams, its meant for high end.

Don't think there is one set point that all vtec engines should use. Stock vtec engagement point is the best for STOCK cars. Once you have mods, it really depends on your setup.

[pgclee]

Kool....

this is clear enough for me now..

thank you guyz...

[LatinoHatchCrap]

But even on my B18C stock cams my secondaries (VTEC) open up at 5300 ....
Also, from what I have heard, Hondata can't activate the secondary intake runners(?)
The secondary runners are built into the stock GSR manifold. They are vacuum operated. The ECU has no clue whether the secondaries are there or not. The one caveat is that the stock program dumps in a bunch of fuel at the RPM when the secondaries are supposed to open. Hondata or a VAFC properly tuned should be able to fix any flatspots.

[wynode]

Then why was I told from a H22 owner (H22A also has secondaries) who has Hondata that Hondata fails to activate the secondary intake runners?

[BlitZ]

dont think there is much tuning that can be had from a honda that has limited mods such as IHE..... Sure u can get a few odd kw here and there, but no means is an ecu worth its money until to start tuning beyond IHE.

Some people claim that they can tune an almost stock b series to get massive power gains.. This cannot be done unless your willing to sacrifice honda's progressive linear power to a perky one...

Oh and another thing i realise....... By getting an exhuast and maybe (doubt it) air filter you are able to feel the vtec alot better.. Not sure if it because the change over point is crazy [booooooobbaaaaaaaaaa] loud, but the high exhuast flow would work much better with the more agressive cam profile when on vtec lobes.

Just my 2 cents of BS

[type one]

i once thought it odd after i started using spoon ecu that vtec suddenyl disappeared... but in fact as sp0017 said this is just because power curve is more linear... which in fact is much better... stock vtec kicks... hehehe... modded vtec screams!!!!

[sze5]

Does anyone drives an auto VTEC car?
How can you tell when the VTEC kicks in?

Scenario: if i am driving at 100km/h, full throttle the gas and i'll feel a kick, but not sure if the vehicle is dropping a gear or vtec kicking in.

[ECU-MAN]

when an auto changes gear at High speed the revs will drop, its noticeable. when vtec kicks in the engine will sound a little throatier all of the sudden, vtec change point in 4 gear is noticable eg 1000 rpmvrvrvrvrvrvvrvr5500rpmVRVRVRVRVRVRVredline.

sometimes on autos you can notice when the torque converter locks in , revs slightly drop, engine note changes. makes poeple think they got a 5 speed auto :)

[Toby]

I don't know man the h22 gives a pretty significant kick when vtec kicks in.

I would agree totally, my mate owns a "92 jap spec Prelude and yeah you really do feel it :D

[JaCe]

I know this might be in the wrong thread (or answered already?) but is there much difference between i-Vtec and Vtec in terms of engagement? On my Civic 06, it feels as if there's a sudden surge/kick at around 2000-3000rpm?

[AsH_]

stock about 5,800rpm

[JaCe]

So high?... is there a reason why the car feels a bit lax from standstill; but once moving a little bit the acceleration is considerably better?

[Benson]

stock about 5,800rpm

your spot on.. vtec engage at 5800 rpm....

the vtec crossover is activated by the ECU... there is no bs abt vtec kicking in early unless u have a vtec controller.... no mods can change the vtec crossover...

hope that helps

[industrie]

Wats the Different between a Low Rev Vtec's Kicks in and a High Rev Vtec Kicks in??

Low means 4500RPM kicks in...
High means 7400RPM kicks in...

any answer?

gimi some knowledge people...
wanna hear what people will say...hmm...cause i have no idea...hehe..hmm...hehe...

never heard of the term...theres only 1 vtec...thats when vtec is engaged

[JaCe]

your spot on.. vtec engage at 5800 rpm....

the vtec crossover is activated by the ECU... there is no bs abt vtec kicking in early unless u have a vtec controller.... no mods can change the vtec crossover...

hope that helps

Oh I thought he was answering my Q about i-VTEC.

[aaronng]

Oh I thought he was answering my Q about i-VTEC.
is your 06 Civic the 1.8L or 2.0L?

i-VTEC has cam phasing in addition to cam profile change. But VTEC can also be used to close 1 intake valve or just to boost mid range torque.

[JaCe]

1.8L i-VTEC.

[aaronng]

1.8L i-VTEC.
The 1.8L i-VTEC is special. It can activate the 2nd cam at any RPM by using hydraulic actuators. It depends on the engine load. At low engine load, you have your long duration intake cam that works with electronic throttle to do a full throttle, long duration intake stroke. When the intake stroke is complete, and the compression stroke is beginning, the intake valve is still open so that there is less resistance to the initial compression.

At high loads, you have the regular intake cam that is like in normal cars.

So technically, you have no VTEC point RPM! It can be at any RPM depending on the load on the engine.

You do have dual length intake manifold, which is using long runners from idle up to 5200RPM where it switches to the short runners at 5200RPM.

Watch this video. It's great info on your engine. Wish my engine had all those technologies such as the molybdenum coating.
http://world.honda.com/HDTV/news/2005-4050705a/

[type one]

how old is this freakin thread??

by the way does it sound stupid that vtec engages at 5,800 in EVERY b series engine with vtec??

old skool vtec as opposed ott his new i-ctec (WOOO) does still rely to an extent on load...it doesn't just automatically switch itself on at 5,800rpm...

[j3z3z]

if i hardly touch the acelerator i can rev past 5800 and vtec dont engage. my motor is stock and vtec engages normaly at 5200-5300. and not only that if i gun it out of a corner i can be doing 4300 and due to the load vtec will engage.

[tanalasta]

is your 06 Civic the 1.8L or 2.0L?

i-VTEC has cam phasing in addition to cam profile change. But VTEC can also be used to close 1 intake valve or just to boost mid range torque.

Is there anything special about the 2.0L in the sport?

[aaronng]

Nope, 2.0L is just a normal i-VTEC K20A. VTEC is only on the intake cam.