ExOwner

odd that some people seem to think that vtec magically kicks in or otherwise. it doesn't.

vtec is a system, not a state. there are 2 profiles on the tl: low rpm profile and high rpm profile. at a certain rpm it switches from one profile to another.

let's say you set it up to always operate at the high rpm profile. you'd loose torque at low rpm which would make your car more slow.

vtec makes your car perform well at all rpm levels. it's always there, always working, always "turned on."

considering vtec to be "off" at low rpm is ridiculous. that's like saying your transmission is off unless it's in 5th gear. it's like saying your headlights are off unles syou have selected high beams.

the high rpm profile is no better or worse than the low rpm profile. you should be happy vtec does not "kick in" at low rpm vecause if it did your car would run rough and be slower.

if you want a way to verbalize what happens when vtec switches to high rpm profile at 5000 rpm or whenever it does, the correct way is to word this something like "my exhaust started wailing when my vtec switched to high profile."

ExOwner

Here's a link that helps explain:
http://www.howstuffworks.com/question229.htm

ABDomega

shut up

IXLR8TL3.2

HAHA, good for a laugh in the early afternoon

blingbling_girl

Wow.......can we all say.."know it all"?

I agree with ABDomega.....

Eternal TL2k3

nothing wrong with him giving correct information... thanks bud... greatly appreciated

SwampGas

The default state of VTEC is low RPM...so when someone describes it as "kicking on", they're referring to the change to high RPM. As in, "kicking on high RPM mode".

Not to mention you can definitely feel the car "kick into something" because it suddenly takes off.

car_lost

thanks for the info ex... i always thought it only kicked in at higher rpms. now i know its always on but u only feel it more at higher rpms.

doopstr

So I realized that when I got my ticket doing 85 that my VTEC was kicked in while in 3rd gear
or
So I realized that when I got my ticket doing 85 that my VTEC was in high profile while in 3rd gear.

Sounds to "Harvard" for me.

samkws

hahaahha

Mr Hyde

Yup there is a high cam profile and a low cam profile. The new 2.0 liter 4's have i-vtec which is continuosly variable for max gains across the rev band where as ours are still much more aggressive up high.

I agree with everyone else. Its much much easier to just say "then Vtec kicked..." than it is to say "then the Vtec switched from the low RPM cam lobe to the high RPM cam lobe...." but that does easily allow people who dont know about the system to get confused.

Also the VTEC system is different between cars as well. Some Civics like the Hx for example have their systems geared for max MPG. Accords, Civics, are geared for both acceleration and MPG and have less noticeable switch over points. while the GSR, S2000's, NSX''s are very aggresivley geared for acceleration, and have very noticeable switch over points which almost feels like a little extra boost kicking in.

baggsTLS

I always say, "Dang, when 3rd gear kicked in."






who cares what you say? we all know what we're referring to.

mp3coupe

"vtec makes your car perform well at all rpm levels. it's always there, always working, always "turned on."

This is not true. Depending on the yr and model... VTEC "Variable Valve Timing and Lift Electronic Control" is controlled by the ecu/pcm. When the car hits its 'RPM" say 5K. The VTEC Solenoid kicks on! When this happens it allows oil pressure to flow through the passage…. it moves a pin on the rocker arm locking the adjacent one making it as one allowing the valves to open further by riding on another cam lobe. When the car is below say 5k RPM there is no oil pressure flowing through the passage therefore the valves aren’t opening up all the way..

Therefore VTEC does kick on and off. As for always working….well I’ve replaced about 20 or so VTEC solenoids. so it doesnt always work


"considering vtec to be "off" at low rpm is ridiculous."
now is it? what about the valves that arent opening?
Im sure you say that your alarm clock went off this morning... well if it beeped or played music didnt it turn on?

devnull_RENAMED

Hey Sally Sensitive,

Are we actually getting politically correct on VTEC now??? Are people getting offended by the improper use of the term. For the love of God.

-Dang

samkws

those GS-R, S2000 have a stronger feel of kicking in coz of they have twin cam...

that's the effect of switching camshafts so u feel like VTEC kicking in

ChucksCL-S

I don't think there is anything wrong with us saying 'I hit VTEC and.." soforth. It's one of the coolest things about our cars.

tuRb0mikEy

Wow Exowner thanks for that great explanantion that made you seem so knowledgeable to all of the dumba ss newba here. Not even the normal newbs, but to the D U M B A S S newbs

fla-tls

Are you saying that when the engine is below the +/- 5,000 RPM mark there is only one intake valve opening?

Essentially an 18 valve engine - instead of 24?

ChucksCL-S

Fla-tls No, both intake valves open at all times. In the VTEC mode the valves follow the cam lobes that open them for a longer period of time and also more deeply to use the faster flowing air rushing in at high RPM's. At the low RPM's you don't want that- the valves are following the standard cam lobes which aids with good low end torque and MPG. In VTEC we're saying "give me the air and fuel and RPM's because my right foot is looking for horsepower!". The exhaust valves only follow one set of lobes.

y2ks2k

God, I knew this back in 91

jimcol711

we all know the ricers love to go vtec-ing!!!

fla-tls

Thanks for the response.

FYI - y2ks2k, there actually is a VTEC variant that closes off one intake valve at low engine speed. It's VTEC-E, which was used on the Civic HX (the first one to have a CVT tranny). It was designed solely for fuel efficiency.

Raheel