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V-Tec Advantage - Or Not


BiKenG

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Again. no inside knowledge here, but I doubt that's the case. The noise isn't that pronounced and in any case, changing to chain doesn't mean they had to include V-tec.

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Optimizing engine breathing: how VTEC works

3_a1.gif

An elegant, simple mechanism

Switching between high and low valve lift using two cam profiles and two rocker arms per cylinder.

3_a2.jpg

The switch is made using hydraulic pressure to push/release the sliding pin, locking/unlocking the middle rocker arm and the other rocker arm.

At low engine speeds, the pin is retracted, disengaging the middle rocker arm. The valves are operated by the two outside, low-profile cams for a low valve lift.

At higher engine speeds, increased hydraulic pressure pushes the pin, engaging the middle rocker arm. The valves are operated by the middle, high profile cam for high valve lift.

VTEC: a deceptively simple mechanism that uses hydraulic pressure to switch

VTEC was around BEFORE increased emissions restriction .

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Well I guess that depends on your understanding of the concept "deceptively simple". I never liked the way the hydraulic pressure just smashes the locking pin against the rocker and hopes to locate into the hole as it moves past. A horrible idea that makes me think of terribly mashed up pins ends and rocker holes. But it doesn't appear to actually happen and it's all as reliable as anything Honda. Doesn't mean I have to like it though.

I wouldn't object to such complexity if there was any actual value to it, but that's my point really, there is no value. They just use it because they can and they thought it up a long time ago when it had more relevance, which it doesn't any more in today's age of electronic control. I don't lie awake at night worrying about it, but I do believe the VFR800 would be a better bike if they dropped V-tec.

If you want simple variable valve control, look at Suzuki's new GSXR1000 due for release soon. Instead of Ducati's hydraulic control, on the Suzuki the cam wheel uses a simple ball and ramp mechanism to move the relative position of the cam as the speed increases, which is essentially all you need. Soft timing at low rpm and moving SMOOTHLY to greater overlap with increasing engine speed. Doesn't even need any fancy electronic control as far as I can tell.

Now that's what I call "deceptively simple" :biggrin:

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Ken yr wrong. Rob got it right in post #6. Honda introduced the VTEC to enable the VFR to pass international emissions legislation. Simple as that. The Gen 5 would have failed and the costs to get it through would have been astronomical when they had VTEC sat on the shelf as a technology waiting to go.

Nope. I am 99% sure that is not correct. I may not actually have any inside information on this, but having worked for Honda I have a pretty good idea how they think and they do love to hang on to any special technology they have developed. As for needing it to pass emissions. Nah, I don't believe that. There's nothing wrong with the pre V-tec engine that requires this additional technology to comply and that couldn't be done with electronics. It is a very well designed engine after all. When introduced on the VFR, all the hype was about spread of power, no mention of emissions which I believe have nothing to do with it.

V-tec is a worthless technology. As I said, if it's so good, they'd use it on other bikes. They don't because it provides nothing that cannot be obtained by other better means. But Honda see it as their unique technology and don't want to be seen to give up on it.

As for the 6th Gen VFR, I am not knocking the bike, nor those that choose to buy and ride one. I'm not saying it's a bad choice. My complaint is levelled solely at Honda for forcing customers down this route, unnecessarily and just for their own reasons that have nothing to do with good bike design. This is not a rant, just an interesting technical discussion. I don't care whether Honda continue with V-Tec or not, even if I disagree with their choice. I'm not interested in any VFR as standard. I like my 1200 eVo4 conversion and my 800 will similarly fit my requirements. I don't need Honda to produce any new V4 just to suit me, that's not what I'm saying. In fact, I didn't even start this topic to argue against V-tec. All I actually wanted was some power comparison data for my own interest and I had no intention to ruffle anyone's feathers. My apologies if I have.

Let's agree to disagree then. :beer:

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If Ken will forgive a bit more friendly argument about the rationale for VTEC...

We have two alternative theories in play here:

#1) VTEC was introduced as a performance enhancement

#2) VTEC was introduced as a flawed(?) response to stricter regulation

Now I don't have any real evidence and I've read hardly any industry press over the past twenty years, so I am a poor historian. Still, I can't quite bite on theory #1. To my mind, the decisive evidence against theory #1 is the almost total lack of actual performance improvement. Other than some small gains at the very top of the HP curve, the VTEC mill fails to improve upon the 5th Gen and, worse, it pays for this lack of improvement with an unsettling notch in the middle of the power curve and troublesome valve maintenance.

I'm prepared to lay any of the usual corporate sins at Honda's feet: misreading the market, being short-sighted, etc. But I can't bring myself to believe they don't understand motorcycles or aren't competent engineers. They saw then the same power curve comparisons we see now.

I have seen the marketing blurbs Switchblade posted. I see the way that bolsters theory #1. In my mind, I file that under "the marketing department being the marketing department". They will always put the best possible spin on a development regardless of whether or not that spin reflects the actual history of that development.

I guess if I really wanted to move this beyond coffee house speculation, I would have to research whether or not any significant new regulations were actually introduced around 2002. It could have been later than that, as Honda would need to anticipate the full life of the 6h Gen.

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If Ken will forgive a bit more friendly argument about the rationale for VTEC...

We have two alternative theories in play here:

#1) VTEC was introduced as a performance enhancement

#2) VTEC was introduced as a flawed(?) response to stricter regulation

Now I don't have any real evidence and I've read hardly any industry press over the past twenty years, so I am a poor historian. Still, I can't quite bite on theory #1. To my mind, the decisive evidence against theory #1 is the almost total lack of actual performance improvement. Other than some small gains at the very top of the HP curve, the VTEC mill fails to improve upon the 5th Gen and, worse, it pays for this lack of improvement with an unsettling notch in the middle of the power curve and troublesome valve maintenance.

I'm prepared to lay any of the usual corporate sins at Honda's feet: misreading the market, being short-sighted, etc. But I can't bring myself to believe they don't understand motorcycles or aren't competent engineers. They saw then the same power curve comparisons we see now.

I have seen the marketing blurbs Switchblade posted. I see the way that bolsters theory #1. In my mind, I file that under "the marketing department being the marketing department". They will always put the best possible spin on a development regardless of whether or not that spin reflects the actual history of that development.

I guess if I really wanted to move this beyond coffee house speculation, I would have to research whether or not any significant new regulations were actually introduced around 2002. It could have been later than that, as Honda would need to anticipate the full life of the 6h Gen.

I never quote anything from "Honda" .

Just to be clear .

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I never quote anything from "Honda" .

Just to be clear .

Fair enough. I saw this:

"The purpose of the VTEC system on the Interceptor, of course, is a broadening of the power curve. Operation on two valves per cylinder at lower rpm levels increases power and torque, while operation on four valves per cylinder at higher rpm levels increases horsepower and torque. Most engines must be tuned to compromise power at one (or both) extremes of the rpm range. With VTEC, the Interceptor does not have to accept this compromise. "

...in quotation marks earlier in the thread and assumed it was some bit of marketing-ese from Honda (maybe a second-hand quotation passed along via industry journalists) back when the VTEC VFR was being rolled out.

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I never quote anything from "Honda" .

Just to be clear .

Fair enough. I saw this:

"The purpose of the VTEC system on the Interceptor, of course, is a broadening of the power curve. Operation on two valves per cylinder at lower rpm levels increases power and torque, while operation on four valves per cylinder at higher rpm levels increases horsepower and torque. Most engines must be tuned to compromise power at one (or both) extremes of the rpm range. With VTEC, the Interceptor does not have to accept this compromise. "

...in quotation marks earlier in the thread and assumed it was some bit of marketing-ese from Honda (maybe a second-hand quotation passed along via industry journalists) back when the VTEC VFR was being rolled out.

No it was in a magazine.

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My friend Makota San was a previous Chief Engineer Honda R&D who
invented Honda's VTEC... he calls VTEC "his baby" and recalls his boss
being super skeptical of the idea working at all...

I kid that VTEC means... Vacillating Torque Engine Compartment... seriously it worked on heavy cars
but it's proved to be too radical on a lighter bike... radical for Honda is that 50% love it but 50% hate it...




2013MakotoSanMrRC45_zps119ae64b.jpg


Makota San also worked on the NR500 oval piston racer and he plans to
visit the Busy Little Shop some day because I have 2 cylinder blocks
off the NR500 that I packed out of Japan in 1981...
gallery_3131_5511_17541.jpg

Makota San down on cannery row...
gallery_3131_5511_48694.jpg

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Often is the case that design engineers get a bee in their bonnet about some engineering concept that they see as "their baby" whether it is a good idea or not.

Having owned 4th gen 5th gen, 2x 6th gens, and now an 8th gen, in my opinion both the 6th and 8th gen bikes would be better bikes and more popular without the unnecessary complication of vtec

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Honda tried to spin it otherwise, but by introducing the Vtec on the 6th gen VFR, the 2002 VFR already meet the tighter emission standards coming in 2006.

To the OP I don't see the point of this conversation unless your just asking about the 8th gen VFR. The Pro/Con of Vtec has been beaten to death here for the last 14 years so unless your just Trolling I don't see the point??? :unsure:

Spend a few weeks reading the dozens of threads on the subject from 2002 on and come back when your done. :491:

BR

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It's the downward spike at 6500 that ruined the VFR. Honda.....end the V-Tec. It may work in Civics but it singlehandedly killed the legendary VFR. That's why I ride an RC36.

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If it were in fact for emissions, wouldn't more bikes have/need it? The Civic and Integra fans went crazy for the V-tec...........It seems like Honda wanted another feather in their cap........

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Spend a few weeks reading the dozens of threads on the subject from 2002 on and come back when your done. :491:

BR

If I read this post correctly, content in generations was just purged to no more than 600 days.

http://www.vfrdiscussion.com/forum/index.php/topic/82906-i-did-a-bunch-of-server-maintenance-this-morning/

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If the 6th gen bike was built with all the same modifications ( styling, suspension, exhaust, engine upgrades, ect.) but instead of VTEC still had the gear driven cams would it be a better bike? In my book, yes. No 6000 rpm dip, a flatter curve and easier to service and more reliable valve train I believe would have made the 6th gen a true upgrade from the 5th. The gear driven cams were Honda's response to major cam wear issues. They sought to restore public confidence with a high end solution that made their V4 rise to the echelons of motorbike engineering. I have a 6th gen and am fine with it's performance but for me keeping the gear driven cams would have been a win win.

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To the OP I don't see the point of this conversation unless your just asking about the 8th gen VFR. The Pro/Con of Vtec has been beaten to death here for the last 14 years so unless your just Trolling I don't see the point??? :unsure:

Spend a few weeks reading the dozens of threads on the subject from 2002 on and come back when your done. :491:

There's always one isn't there. Sigh. Why do you feel the need to be so disrespectful of others.

I've already been quite clear about the reasons behind my original request for data (to which Dutchy kindly responded with the information I sought). I see no reason to have to repeat them for your benefit.

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Honda tried to spin it otherwise, but by introducing the Vtec on the 6th gen VFR, the 2002 VFR already meet the tighter emission standards coming in 2006.

To the OP I don't see the point of this conversation unless your just asking about the 8th gen VFR. The Pro/Con of Vtec has been beaten to death here for the last 14 years so unless your just Trolling I don't see the point??? :unsure:

Spend a few weeks reading the dozens of threads on the subject from 2002 on and come back when your done. :491:

BR

I agree and why post a topic like this, for what purpose Ken? Are you trying to persuade yourself into purchasing a 6th. I don't get it.

It's like the big let down when the 7th gen was released. You know I don't like the bike BUT I respect the members that purchased the 7th gen.

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I already explained why I asked the question and already thanked Dutchy for his information which is all I wanted. Try reading instead of trying to start an argument.

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I already explained why I asked the question and already thanked Dutchy for his information which is all I wanted. Try reading instead of trying to start an argument.

Take your own advise !

If you just want Dutchy advise just email him and spare us the rest of the BS.

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