When does the v-tec kick in on the '02 Si?

[snubnose]

Please forgive the ignorance of the question, but I'm reading about other cars with v-tec that have a point when it kicks in.

Does the '02 Si have a point at which it kicks in?

Thanks in advance for your help and knowledge.

[JSIR]

it seems to switch over around 4600 rpms on the dyno reading (which is more accurate than your tach reading), on the tach it seems to read around 4800-5000 due to the mechanical error in the tach system. Its a very smooth transition however, not that noticeable in stock form. It seems to be more noticeable with a few mods added. hth

[punkdork]

Dude.. read up. Its not VTEC anymore its I-VTEC. Its all varriable and what not.

[02SilverSiHB]

Originally posted by punkdork
Dude.. read up. Its not VTEC anymore its I-VTEC. Its all varriable and what not.
meaning it kicks in at various rpm levels correct? It doesn't have a set rpm where it will engage i-VTEC

[punkdork]

Originally posted by 02SilverSiHB

meaning it kicks in at various rpm levels correct? It doesn't have a set rpm where it will engage i-VTEC

Exactly.. a little while ago I posted a link to a page that explained it in way more detail than I could ever hope to do.

[02SilverSiHB]

Originally posted by punkdork


Exactly.. a little while ago I posted a link to a page that explained it in way more detail than I could ever hope to do.
yeah, I remember seeing that post. Very involved it was :D

[snubnose]

I remember trying to read that article, but it was too hard to understand. Can someone dumb this whole thing down for me.

What rpm does it kick in at 2nd gear?

What rpm in 3rd gear?

What rpm in 4th gear?

What rpm in 5th gear?

[SmoothOperator]

well let's see....

[chunky]

the cam lobe changeover point is fixed, it is NOT adaptive.

however, the timing profiles for the intake cam ARE. the timing varies according to RPM & engine load. I'm not sure of the exact mechanisim, but I'll be sure to inform you when I find out.

but as far as I know, the VTEC lobe is engaged @ 5000rpm. since the maximum rpm drop is 2000rpm on the 1-2 upshift, that ensures that the car will stay in VTEC during hard acceleration. But to be honest, it doesn't matter if it stays in vtec b/c of how smooth the powerband is.

[2k2civicSi]

yeah it has not set time it kicks when it feels like you need it

[chunky]

Originally posted by 2k2civicSi
yeah it has not set time it kicks when it feels like you need it

no, it kicks in at the same RPM everytime.

on the rsx, i know it's @ 5500rpm b/c you can hear it. on the si, it's much harder to feel & hear, but my dyno seems to indicate somewhere around 5000rpm.

[SiVTEC]

Honda doesnt really state a 'changover' in the Si or base RSX engine, but for the RSX Type-S "Above 5,800 rpm, the intake and exhaust valves are operated by high-lift, long-duration cam profiles, for maximum high rpm horsepower."

[civic hatch boi]

chunky... on the rsx. that's not the vtec that you hear.. that's the sound of the second cam opening... common mistake tho.

[chunky]

Originally posted by civic hatch boi
chunky... on the rsx. that's not the vtec that you hear.. that's the sound of the second cam opening... common mistake tho.

1) the "second cam opening" would usually mean that vtec has engaged.

2) I think you're referring to the dual plane intake manifold on the base RSX. keep in mind that the type-s doesn't have that.

3) I should have clarified and stated that I was talking about the rsx type-s having a vtec engagement of 5500rpm

[MagusDC5]

RSX Type S engagement is 5800rpm... you really cant tell tho audibly until 6k rpm. As for the Base and Si (A3) im assuming it would be 4800rpm.

[kylenls]

i am not trying to start a fight but i am wondering, why with intake and catback exhaust i vtec is so noticeable power and sound at around 5000 to 5200 rpms and everyone is saying that its different in every gear i dont hear or see that happening in the vidoes that i have downloaded everyone with those mods has the very distinctive vtec sound and pull apparently of old.

[BlasTech]

I think that the "i" part of i-vtec which advances the timing overlap possibly makes an aggressive jump at that point,

BUT

the ONLY time the lobes on the intake cam change over (vtec) is when you first get going above 2200rpm... basically turning off the super-efficient, low emissions mode and switching to a more-aggessive peppy mode.

The exhaust cam has only one set of lobes on the A3, and it never moves.

This was originally the concept behind vtec-e on the VX and HX civics.

[Ph0nK]

Originally posted by BlasTech
I think that the "i" part of i-vtec which advances the timing overlap possibly makes an aggressive jump at that point,

BUT

the ONLY time the lobes on the intake cam change over (vtec) is when you first get going above 2200rpm... basically turning off the super-efficient, low emissions mode and switching to a more-aggessive peppy mode.

The exhaust cam has only one set of lobes on the A3, and it never moves.

This was originally the concept behind vtec-e on the VX and HX civics.

So does that mean if I want to get the best gas mileage in day-to-day driving, I should stay below 2200 rpms in all gears?

[CIVICBOOST]

The K20A3 motor found in the Si and Base Rsx, only have Vtec engagement on the Intake cam like BlasTech stated, The Si under 2200rpm only runs on 12 valves and over 2200rpm switches to 16 valves. This info is provided by Hondata, and as to why there is the Vtec sound my "guess" would be the intake cam adjusting itself after sensing the load of the upper RPM range and advancing the timing/air/fuel to compinsate.

[DavidT]

I thought everyone knew this already. The actual VTEC change over is at 2200 RPMs (Going from 4 valves to 8 valves on the intake side). The "i" part of i-VTEC phases the cam timing throughout depending on load and speed, meanining it's varible all the time. VTC is most agressive at 5k plus, that's where you feel that little bump near 52-5500 RPMs depending on load. Hope everyone understands. Our VTEC is only used to turn on the other 4 intake valves for better breathing above 2200 RPMs.

[savesteve]

From what I read it's as follows:

Our Engine below 2200 RPM is effetely 12 valve. And above 2200 starts to use all 16.

This however is not our motor's Vtec point merely a fuel economy setting.

Depending on throttle position the Vtec will switch to the wilder cam profile between 4400-5400 RPM.

At WOT it engages at 4400 RPM, or if at any point between 4400-5400 RPM you go to WOT, but if your foot isn't to the floor it waits until 5400 RPM. Hence the I in our i-VTEC.

Again this is a fuel economy thing.

I forget where I read this info but the valve thing is on hondata site. The Vtec engagement was from a different site I don't remember

Enjoy.

Edit : heheh got the H of the end of the vtec's :)

[trk]

Originally posted by savesteve
From what I read it's as follows:

Our Engine below 2200 RPM is effetely 12 valve. And above 2200 starts to use all 16.

This however is not our motor's Vtech point merely a fuel economy setting.

Depending on throttle position the Vtech will switch to the wilder cam profile between 4400-5400 RPM.

At WOT it engages at 4400 RPM, or if at any point between 4400-5400 RPM you go to WOT, but if your foot isn't to the floor it waits until 5400 RPM. Hence the I in our i-VTECH.

Again this is a fuel economy thing.

I forget where I read this info but the valve thing is on hondata site. The Vtech engagement was from a different site I don't remember

Enjoy.

its vtec not Vtech.

[savesteve]

Originally posted by trk
its vtec not Vtech.

spellchecker in word ousting me again :)

[Tenacious G]

Originally posted by savesteve
Depending on throttle position the Vtec will switch to the wilder cam profile between 4400-5400 RPM.

At WOT it engages at 4400 RPM, or if at any point between 4400-5400 RPM you go to WOT, but if your foot isn't to the floor it waits until 5400 RPM. Hence the I in our i-VTEC.

and by VTEC you mean the VTC, right? traditionally, VTEC was used to describe the engine switching intake and/or exhaust cam lobes to longer lift/duration.

in this case, the "switch" you refer to from 4400-5400 would be the VTC advancing cam timing. there is no VTEC switch at that engine speed.

[HokieSi]

VTEC Enguages @ 2200 rpm, period.
-purpose of this is to get better fuel economy in stop and go traffic, because as you know you aren't getting very good fuel economy at a stop. This enables us to get better city gas mileage than most cars with smaller engines.

VTC Variable Timing Control - this is on the intake only and what it does is maximize power and effeciency based on throttle input and engine load (i.e. going up hill or carrying cargo).

http://www.hondata.com/techk20general.html

http://asia.vtec.net/article/ivtec/

I hate to say it but our i-vtec is an "economy" vtec while the k20a2, rsx type-s, engine is the real deal.

[savesteve]

Originally posted by HokieSi
VTEC Enguages @ 2200 rpm, period.
-purpose of this is to get better fuel economy in stop and go traffic, because as you know you aren't getting very good fuel economy at a stop. This enables us to get better city gas mileage than most cars with smaller engines.

VTC Variable Timing Control - this is on the intake only and what it does is maximize power and effeciency based on throttle input and engine load (i.e. going up hill or carrying cargo).

http://www.hondata.com/techk20general.html

http://asia.vtec.net/article/ivtec/

I hate to say it but our i-vtec is an "economy" vtec while the k20a2, rsx type-s, engine is the real deal.

yeah what he said :)

[sniperSI]

We do not have a real vtec,

Our intake lobe is smaller below 2200 rpms for emissions so we get the ULEV mark or whatever because a fuel engine is most inefficent at idle, the 4 valves being closed allow some exhuast gas to reciruclate back into the cylinders to lower emissons, not stop and go traffic, who in the world can drive below 2200 rpms.

Once out of 2200 rpms we have a 1 type of intake 1 type of exhuast, where REAL vtecs have 2 lobes on each, and a change over point in the upper RPM Range, we have no change over point unless you call the switch over from fuel efficent lobe to normal lobe at 2200 rpms a change over.

We only truely have a VTC for performance, that tweaks the overlap +/- 50 degrees depending on engine load, there is no change over point like there would be in a type R or type S, because we do not have a real vtec system, we have 4 valve operation and a small lobe for emissions then the vtec intake lobe swtichs to the large lobe @ 2200 rpms along with the 4 more valves to enhance performance, come on guys we've been over this 10 millon times. Vtec is supposed to help performance, by allowing more air into the engine to burn more fuel, and allow the engine to breath easier while under heavy load, or light load depending on its needs. we do not have anything like that, we just have cam overlap.

But on the bright side, i-vtec now is to civic as vtec was 10 years ago.

[nyxie]

i feel a kick at 5k so i'm gonna say vteck hits at 5k.

[CIVICBOOST]

Originally posted by nyxie
i feel a kick at 5k so i'm gonna say vteck hits at 5k.

I think you should scroll up and do some reading:D

[kylenls]

no i agree i do feel an extra kick around 5200 rpms i know that this is probably not the ivtec kicking in but maybe at its most wide open position.

[CIVICBOOST]

the "i-VTEC" is always kicked in so you dont have to wait for it. The intake cam constantly readjusts itself to provide you with optimal power for whichever throttle position your driving in. The kick in the upper RPM is just the intake cam advancing which makes the car suck more air/fuel and the ignition timing is also advancing to compensate for the added fuel and when all of these things advance it makes the engine louder. I think I've said all I'm going to on this topic, if you people want to pretend that your car has "real" top end VTEC then go ahead but dont take our word for it call Honda.:rolleyes:

[nyxie]

uhhhh, yeah. you're such a dork.

[CIVICBOOST]

dont hate

[kylenls]

i dont think anyone here is claiming to have the real vtec just fishing for answers on why and how it works you dont have to be a dick. i stated that what they are feeling is the intake valve at its most wide open position and ivetec doesnt kick in until 2200 rpms as stated ealier on other posts, so its not always on.

[CIVICBOOST]

If you read up to my post before last you will see that I'm talking about the intake cam adjusting itself constantly thats "VTC" which is also the "i" in i-VTEC, actual VTEC on the intake cam is at 2200rpm in which the motor switches from 12 valves to 16 valves so you might as well say its always on. The VTC is always on, from idle to WOT. I dont mean to be a dick I've never had to be towards anyone on this site and I apologize but when people are so naive and oblivious of the truth it makes me ask myself, why did they ask?

[HokieSi]

This has been talked about before and I believe the kick at 5k or so is just a weird stock intake resonance thing.

[BlasTech]

Of course, if you go test drive an RSX-S or an S2K, you'll realize what the real vtec "kick" feels like, and probably not want to talk about it anymore.

[S800Racer]

Originally posted by sniperSI
We do not have a real vtec,


I do.:D And after I get Hondata it will kick in at 5200 and scream to 8600rpm:cool: