Re: Vtec ?

I have a 92 Integra with a b16. I been thinking. When I hit 5k rpm in the teg I can totally feel the vtec kick in. The engine gets louder and you can feel the car pull harder. Why can't this be felt with the k24? Is it just cuz the E is huge or is the engine just set up differently?
L.

I can definitely feel the Jeckyl and Hyde treatment when the vtec kicks in on the K24. I was thinking though, on my friend's Auto E for some reason the transition doesn't seem nearly as dramatic.

 

Re: Vtec ?

There have been advancements in the technology, The Computer, Specifically. That makes the power come on more smoothly. It also Broadens the power band, making the engine seem smother. the valve timing starts to change at a lower rpm, adding torque sooner. That yields less of a surge than the old K-24.

 

Re: Vtec ?

There have been advancements in the technology, The Computer, Specifically. That makes the power come on more smoothly. It also Broadens the power band, making the engine seem smother. the valve timing starts to change at a lower rpm, adding torque sooner. That yields less of a surge than the old K-24.

I actually think more of this engine management tuning is done for the Auto tranny models since they don't specifically do well under high RPM's and generally require a more torquey powerband. I'm willing to bet there are seperate valvetrain controll modules for both the Auto tranny and the manual tranny.

This would explain why every honda with vtec I've driven that had an auto tranny seemed more sedate as far as engine note goes.

 

Re: Vtec ?

I don't know the engine names but the 2.4L vtec the element has is totally different than the type that has a mild and agressive cam lobe function.

The element has 2 intake valves and a cam set-up with 2 lobes per cylinder. One intake valve is operated by the normal cam lobe, and the other at rpms below 1800-2000 is operated off a cam with a tiny amount of lift, which increases velocity to the regular valve and swirl off of the low lift valve. At 1800-2000 the low lift valve joins the other valve on the same rather mild cam profile and we don't notice any transition.

Really a totally different concept than the "traditional" vtec.

 

Re: Vtec ?

I don't know the engine names but the 2.4L vtec the element has is totally different than the type that has a mild and agressive cam lobe function.

The element has 2 intake valves and a cam set-up with 2 lobes per cylinder. One intake valve is operated by the normal cam lobe, and the other at rpms below 1800-2000 is operated off a cam with a tiny amount of lift, which increases velocity to the regular valve and swirl off of the low lift valve. At 1800-2000 the low lift valve joins the other valve on the same rather mild cam profile and we don't notice any transition.

Really a totally different concept than the "traditional" vtec.

Is that the "i" in i-VTEC?

 

Re: Vtec ?

Is that the "i" in i-VTEC?

I think the "i" is related to the variable cam advance/retard feature, not sure though.

 

Re: Vtec ?

the "i" in "i-VTEC" stands for VTC = Variable Timing Control...

the other engine is the k20, and elements have a k24 engine...

 

Re: Vtec ?

I think the "i" is related to the variable cam advance/retard feature, not sure though.

The "I" refers to intelligant v-tec......

http://www.canadiandriver.com/articles/jk/at_011205.htm

 

Re: Vtec ?

the "i" in "i-VTEC" stands for VTC = Variable Timing Control...

the other engine is the k20, and elements have a k24 engine...

you're correct however vtec itself stands for Variable Valve Timing and Lift Electronic Control

The i stands for "intelligent" because Honda added something called a variable valve opening overlap mechanism to the VTEC system which allows continuously variable valve opening overlap between the intake and exhaust valves during engine operation.

This is the VTC which is located on the intake cam

 

Re: Vtec ?

I just found this yestersay and I think it is the best explaination on the different types of VTEC available.

http://www.theksource.com/news/04/k-series-vtec-breakdown/

Hope it helps.

 

Re: Vtec ?

I'm a bit confused by that article. It says there are two variations of i-VTEC: the "real" i-VTEC K20A2 (RSX Type-S) and the "i-VTEC-E" K20A3 (Civic Si). Since according to the author the Element uses the K24A4/K24A3 (or is the -A3 in the Accord?), does that make it yet another i-VTEC variation? This is his explanation of the Element's valvetrain:

K24a4/k24a3- the Honda Element and Accord ... does not use the conventional [variable valve timing and lift electronic control] mechanism from the earlier B series motors but does have [variable timing control]. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lob[e]. This motor has no Vtec mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening.

This sounds more like the description of the not-exactly-i-VTEC K20A3, and the author later says "This system is used in engines powering the ... Element." So the K24A3/4 apparently uses the same, or similar, i-VTEC system as the K20A3, despite the "two systems" wording.

 

Re: Vtec ?

the "i" in "i-VTEC" stands for VTC = Variable Timing Control...

the other engine is the k20, and elements have a k24 engine...

Which word starts with the i?

 

Re: Vtec ?

Which word starts with the i?

I gues the "intelligent" part doesn't apply to me since I didn't finish the thread before adding my smart__s remark

 

Can anyone really feel the VTEC kick in? If you can at what rpm's does it happen? I don't ever rev it above 5,000 so I don't think I feel anything.

 

Yep, kicks in like a MF at 6000 rpm....................on my S2000 :lol::lol:

 

I don't necessarily feel the iVTEC kick in as a sudden sort of thing, but I can definately tell that I'm driving a Honda, since the real power comes by running the living daylights out of the motor. As I merge onto the freeway, my acceleration in 3rd (MT) noticably increases as I wind up the gear more and more...

 

No you won’t feel anything. Keep in mind the iVTEC that is in the E's is more for fuel/emissions efficiency and not power.

John

 

I believe the VTEC threshold in the E's K24 is around 3500 RPM. It's a pretty subtle transition, but above that point the engine is much more willing to rev up.

Early VTEC's like the B20 had very obvious transitions, which is what the ryce racers are referring to when they talk about the 'VTEC kicking in'. Ten years ago I was driving a CRX with an early 2.0 Prelude engine swap, and the VTEC transition on that motor was almost like shifting down a gear: push-you-back-in-the-seat kind of stuff.

 

Honda has done the proper engineering so the "kicking in" of the V-TEC is seemless. The fact that the engine just keeps building up revs and still produces torque and power at the same time is proof. Frankly, the engines would not last long if it just "kicked in" on demand. The same holds true to under-engineered turbocharged and supercharged engines. Kicking in for a racer that only has to hold together for a 1/4 mile or at most, a 500 mile race is a fine thing. I doubt I would be interested in owning any car that couldn't go a couple of hundred thousand miles without major work.

Just my 2.5 cents.

 

VTEC----VTEC----VTEC!

VTECH=Cordless phone maker

Honda has done the proper engineering so the "kicking in" of the V-TECH is seemless. The fact that the engine just keeps building up revs and still produces torque and power at the same time is proof. Frankly, the engines would not last long if it just "kicked in" on demand. The same holds true to under-engineered turbocharged and supercharged engines. Kicking in for a racer that only has to hold together for a 1/4 mile or at most, a 500 mile race is a fine thing. I doubt I would be interested in owning any car that couldn't go a couple of hundred thousand miles without major work.

Just my 2.5 cents.

 

it may be just in my mind, but i feel it kicking in around 4100 rpm. a noticable surge in acceleration above that.

 

VTEC----VTEC----VTEC!

VTECH=Cordless phone maker

Just fixed it!

Frank

 

The vtec our Elements have kicks in at 2200 rpm, if you can call it kicking in.

From

http://www.theksource.com/news/04/k-...tec-breakdown/

"...This motor does not use the conventional VTEC mechanism from the earlier B series motors but does have VTC. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lobe. This motor has no Vtec mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening.
Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?

VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs."

 

Link does not work

The vtec our Elements have kicks in at 2200 rpm, if you can call it kicking in.

From

http://www.theksource.com/news/04/k-...tec-breakdown/

"...This motor does not use the conventional VTEC mechanism from the earlier B series motors but does have VTC. Instead it only has 2 cam lobes on the intake side and 1 on the exhaust lobe. This motor has no Vtec mechanism on the exhaust cam and runs on 12 valves before 2200rpm with the other 4 slightly opening.
Note: in a VTEC-E engine, there are no high-RPM performance cam profiles; this engine is supposed to be tuned for fuel economy, right?

VTC - Variable Timing Control. This is a mechanism attached to the end of the intake camshaft only which acts as a continuously variable cam gear - it automatically adjusts the overlap between the intake and exhaust cams, effectively allowing the engine to have the most ideal amount of valve overlap in all RPM ranges. VTC is active at all RPMs."

 

Link does not work

Try this, though everything needed was in my post.

http://www.theksource.com/news/04/k-series-vtec-breakdown/

 

Early VTEC's like the B20 had very obvious transitions, which is what the ryce racers are referring to when they talk about the 'VTEC kicking in'.

The B20 is a non Vtec motor, similar to the old B18A and B.

Honda has done the proper engineering so the "kicking in" of the V-TEC is seemless. The fact that the engine just keeps building up revs and still produces torque and power at the same time is proof.

The newer K series motors make more low end torque than the old B series engines. They also have smarter ECU's as well as VTC to control the transition, which is why the crossover isn't as noticeable as the B series.

Frankly, the engines would not last long if it just "kicked in" on demand. The same holds true to under-engineered turbocharged and supercharged engines. Kicking in for a racer that only has to hold together for a 1/4 mile or at most, a 500 mile race is a fine thing. I doubt I would be interested in owning any car that couldn't go a couple of hundred thousand miles without major work.

The old B16a/b and B18C/1/5/6 had a noticeable crossover, that, when modded, became somewhat violent compared to today's Kseries motors. There are a ton of post 200k engines on the road today. Honda reliability was really proven through the B series era.
They'll last as long as they're cared for with proper maintenance, just like any other Honda motor.