V-Tec Advantage - Or Not

[dgordon]

Switch, I am aware of the thread I posted to. :-) Just seemed some commentary contrary to VTEC. I love all the VFR's. ALL of them. Had to state it. Love the cam gears but also love the VTEC too. Imho, no bad generation of VFR. If I had my choice, I would have kept with the cam gears, but bikes are already SO expensive. The fact the VTEC's run on regular is a bonus, and run well they do. :-)

Cheers

Dave.

[Duc2V4]

I had a little giggle the other day when I saw this Cadillac's license plate frame...Do you think he owns a 5 Gen too?!

[MaxSwell]

Or is laughing at all VTECs. LOL @ your VTEC!

[Switchblade]

Switch, I am aware of the thread I posted to. :-) Just seemed some commentary contrary to VTEC. I love all the VFR's. ALL of them. Had to state it. Love the cam gears but also love the VTEC too. Imho, no bad generation of VFR. If I had my choice, I would have kept with the cam gears, but bikes are already SO expensive. The fact the VTEC's run on regular is a bonus, and run well they do. :-)

Cheers

Dave.

Me too and I dont post topic's that attempt to cause grief to anyone generation of VFR's.

[Kingmdm]

That Dino chart with the VFR1200 overlayed is revealing. The 1200 has some power. Seems like the modern VFR should have 1000cc so HP can be 150+/-. Honda could do that today.....and without VTEC.

Dyno. Hate predictive text!!

[MaxSwell]

A lot of "frequent posters" here complain about the power. I suspect that the "silent majority" of VFR owners are fine with ~100 hp. I know that I'll never need more power. I'm already a danger to myself. But I'm old.

How many average VFR riders exploit even 80% of the capability of these fine machines? That is The question. Would Honda sell enough 150 hp VFRs. I know I'd not trust myself with a liter bike. A wrong twitch could be my last twitch.

YMMV

[Kingmdm]

I know. Honda's philosophy has always been about balance unlike Kawasaki for instance which has always been about motor.

[Duc2V4]

Or is laughing at all VTECs. LOL @ your VTEC!

Well considering I was in my car, I'd have to say ALL VTECs!

[Ultimatevfr]

A lot of "frequent posters" here complain about the power. I suspect that the "silent majority" of VFR owners are fine with ~100 hp. I know that I'll never need more power. I'm already a danger to myself. But I'm old.

How many average VFR riders exploit even 80% of the capability of these fine machines? That is The question. Would Honda sell enough 150 hp VFRs. I know I'd not trust myself with a liter bike. A wrong twitch could be my last twitch.

YMMV [/fon

Lol, probably more truth in that then most of us would care to admitt to. I feel like I have the best of both worlds, my ZX9R fills in the gaps very nicely(162hp / 382 pds) even for a 15 yo bike! But I love my Honda. :)

[CornerCarver]

A lot of "frequent posters" here complain about the power. I suspect that the "silent majority" of VFR owners are fine with ~100 hp. I know that I'll never need more power. I'm already a danger to myself. But I'm old.

How many average VFR riders exploit even 80% of the capability of these fine machines? That is The question. Would Honda sell enough 150 hp VFRs. I know I'd not trust myself with a liter bike. A wrong twitch could be my last twitch.

YMMV

Honestly the only time I need more power is when two up and passing or moving away from a situation caused by an inattentive driver.

Now I want more power when hooning around lofting a wheel and trying to slide the rear on corner exits without the aid of a wet damp paint stripe on the road.

The throttle by wire characteristics of such an animal would allow 2-4 preprogrammed settings for 'taming" the beast depending on factors.

[twitte]

I would be curious to see what the actual cost of the 6th gen engine is next to the 5th gen engine. From an engineering standpoint, I love the gear driven cams. Remember when Aprilia offered this as a very expensive upgrade for the RSV4 so they could run in Biaggi's WSBK? For me the VTEC offered a ton of complexity for no benefit.

[CandyRedRC46]

I think nearly everyone missed the point on this thread. The VFR800 VTEC does not implement the traditional Honda performance VTEC, it actually implements a form of VTEC-E. Where the E stands for economy.

This is totally different than your typical Integra GSR or Civic SI VTEC system where you have a 3 lobe per cylinder (DOHC) or 5 lobe per cylinder (SOHC) camshaft that has a separate high and low lobe to combine the power characteristics of a race cam with the idle quality/clean emissions/low end torque and drivability of a small economy camshaft.

In VTEC-E, the primary benefit is to introduce a swirl in the combustion chamber that allows for a fast burn or otherwise know as "Lean Burn" combustion event. This is done for fuel economy purposes as lean burn heads can safely run up to about 20:1 air to fuel ratios while under light load and low RPMs. This is why the VFR VTEC has implemented an open loop fuel injection system that will go into closed loop mode under light steady throttle and low rpms. This is also why everyone complains of a surging effect at light steady throttle on the VFR VTEC. What you are feeling when your VFR VTEC is surging, is your bike running in closed loop lean burn, referring to the signal from the o2 sensors and the ecu leaning the air fuel ratio to the absolute limit (well over 15:1 air:fuel).

This is why when people disable their o2 sensors and add a power commander on a VFR VTEC, the added smoothness and low end torque is usually accompanied by a loss in MPGs (depending on habits and riding style).

It is my feeling, based on my research on various variations of variable valve implementations, that Honda made the VFR800 "VTEC" primarily do to it lowering emissions, lowering sound output and raising MPGs, but the marketing team decided that they could spin this in another direction to aid in sales. I feel like the marketing team decided to cash in on the VTEC name and ride the coat tails of the Integra gsr/Type R/NSX/Type S/ etc and label the VFR800 as VTEC and not VTEC-E, even though it is clearly an implementation of economy VTEC.

Here is a quick description found on google of what VTEC-E really is:

"VTEC E was a special form of VTEC used in the VX, and HX civics from the early 90s to the early 2000s. Most VTEC systems engage a pin at higher RPMs that lock in a new set of lifters that follow a more aggressive cam lobe; the result is better efficiency at higher RPMs.

VTEC E works on a different principle, instead of engaging a more aggressive set of cams at a 5000+ RPM, the system engages around 3000 RPM, and instead of engaging different lifters, it engages the rest of its valve train. Did you miss that? I'll explain a little more in depth.

Before VTEC only 12 valves out of 16 work. 4 intake, and 8 exhaust valves (as you can see in the video). Why do this? One can argue that Honda has some slick engineers but I know that Toyota found something out in the early 80s by total mistake that likely lead to Honda improving on the method. By speeding up the intake charge at lower RPMs you get a different flow into the head, this is commonly referred to as a "swirl effect." Toyota, as the story goes, found this out by accident when experimenting with different intake methods. The system they designed in response, know as Throttle Varied Intake System or T-VIS, blocked off 4 of the 8 intake ports into the head of the 4AGE below 4200 RPM. the effect was similar to the VTEC E system in the civic HX and sped up the intake charge causing a "swirl effect" although it was not as effective as VTEC E.

The result of TVIS was improved mixture of the fuel which lead to more low end torque, and once the engine got up to speed the TVIS system would open up to allow all 8 ports to feed the head.
Improved mixture of fuel not only means in increase in torque, it also means that it is more stable when being combusted, which means that there is less of a chance of predetonation and damage to the engine.
VTEC E accomplishes the same thing, however its directly IN the head and causes a more dramatic increase response and torque. On top of that it has a set of fuel maps that take advantage of the heads ability to mix the fuel and can lean out as far as 25:1 AFR. On a warm sunny day with an unmodified engine a driver can get as high as 51 mpg going 65 on the highway.The engine can accomplish higher AFRs by use of a wideband O2 sensor, another interesting facet of the HX.

Once you get up to 3000 rpm the intake air is getting too resistant to allow proper fuel and air intake through one valve, there is also so much load and fuel being used that the risk of detonation is too great. so the VTEC system kicks in (yo) and engages the other 4 valves in the head and it drops into a stoich mixture of fuel.

The stock cam journals on the D16Y5 motors (the HX) is similar to the Y8's. However the Y8 reigns superior in performance, some old D15 blocks from the VX used a two stage VTEC system that engaged an even hotter cam at a very high RPM. The system was complicated and very fun to explore.

The question is, is it an eco car? or a hot rod waiting to happen (here me out on this)? and the answer is both. The HX truly is a car that depends on driver input. running in power above 3000 rpm is going to suck your gas away, but you'll have much more pulling power in 5th gear than an LX civic. driving as the ECU asks (via the shift light) will gain you some serious change in your pocket. The HX is designed to be a highway machine, in top gear it is able to overtake traffic starting from a matched velocity rather quickly and without down shifting, in no small part due to the cams being more aggressive.

To add to that, the Y5 head has roller rockers to free up the drive train. and with that, anyone who knows about tuning these little engines knows where im going with this.

To sign off on this, in no way shape or form am I talking about race performance. The HX will get whipped by almost any other civic besides an LX. It just happens to have some oomph on the highway, some good starting power, and hilariously good mileage while doing it."

To further elaborate on the differences of the fifth gen vs the sixth gen VFR800:

It makes total sense on why even though the Honda marketing team touted an increase in performance (a blatant lie) with the VTEC (actually VTEC-E) valvetrain, it actually reduced performance (running extremely lean AFR mixtures will improve economy, but reduce power). This also makes complete sense as to why the VFR VTEC responds so well to fuel enrichment and ignition timing advance, while in 8 valve mode, as the swirl being created in the combustion chamber greatly improves combustion stabilization and allows for the ignition timing to be advanced much further with out detonation occurring, than the fifth gen engines could ever dream of.

It is really funny that the sixth gen VFR800 VTEC, is actually the perfect platform for "Hyper Miling" or as it is often referred to as "Eco Modding", but no one seams to have connected the dots yet.

One could, in theory, run a catless header (air fuel ratios well over 15:1 will destroy a catalytic converter), a complex tuning system, pick the fuel and ignition cells that correspond with light throttle/steady state highway cruising (say 2-3% throttle and 4000-5000 RPMs) and lean just those 6 cells out to and AFR of around 20:1 and advance the ignition timing, then get an obscene amount of MPG. (Eco Modders are getting well over 60 MPG out of the 1992-1995 Civic VX with the lean burn d15z1 engine and tall gearing, out of a car that is much larger and heavier than a motorcycle, with twice the engine displacement and no where near the aerodynamics)

[CandyRedRC46]

This is a good read for anyone wanting to learn about eco modding. It is a mind blowing read, as all the principles that you have learned for making maximum power (cold air, 13:1 AFR, conservative timing high compression etc), get blown out the water when you are talking about maximum efficiency. For maximum efficiency, you are talking about 21:1 AFR, a ridiculous amount of ignition advance (super lean air fuel ratios take much longer to burn, so they need to be lit much earlier), low compression ratio and extremely high intake temps (to vaporize the fuel for easier combustion).

http://www.d-series.org/forums/forced-induction/117099-i-did-some-fe-testing-64-8mpg.html

[Dustin]

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.

This is a very interesting point and we're actually seeing this same thing happening in response to the new Euro 4 regulations. Quite a lot of time, money and energy is being put into engineering bikes to meet the stricter noise and emissions regulations. I remember reading an article about the extensive engine noise dampening required for the new Ducati Panigale. The engine itself was far too loud, much less the exhaust.

As you said, Euro 3 regulations came into effect in 2006 and came with tighter emissions and noise requirements. The 6th gen is whisper quiet in operation compared to the 5th. I'm sure it's also cleaner burning.