Vtech Lag - Tell me about it..

Hi All,

I'm thinking about pulling the trigger on the 02+ VFR800. I've heard mixed things about the VTech.. I don't like the sound of an abrupt lag coming on in the middle of the power band. Could you explain what this feels like, and your thougths on it? Is it super annoying? Is it abrupt? What are your thoughts.

 

Also, any years to stay away from in the '02+ years? Also, is there any true remedy for this? Power Commander?

 

The feel depends on the gear I'm in and how much throttle I'm putting into it. Sometimes I don't feel it and sometimes it's pretty noticeable. I would compare it to an automatic transmission downshifting when you hit the gas. There is a slight lag (as when a transmission is downshifting) and then it really picks up speed. It seems mostly noticeable in third gear and lots of throttle. Sometimes I don't feel a lag at all just a sudden pick up in power. It's definitely something to be mindfull of in a turn as it tends to upset the bike a bit. As for years to avoid - if you get an 02 thru 05 just make sure the wiring recall has been done or get it done soon after buying it. It's free. *You can give the dealership a call with the vin number to verify.*Also, check side stand bolts. They tend to come loose, just needs threadlock.

 

At WOT it can be abrupt, if you pass the vtec RPM easy you'll barely notice it if at all. This is my 2nd sesason with my '02 and I've come to enjoy it. I've had it kick in on corners and it wasn't a huge deal. You know it's there, you get used to it.

As far as rideability it's a non issue IMO.

 

most people who complain about the vtech .... do not even own a 6th gen

 

what is the nonsense about Vtec lag? i havent the faintest clue what you're talking about

 

....Lag?? not on my VFR ! When the VTEC comes in around 6700ish, she just pulls harder. Certainly no lag. You get used to it and in my opinion learn to love it. It's definitely something you want to be aware of, it's a characteristic of the machine and again, in my opinion, a good one.

 

Oh yeah, I especially love the change in tone.

 

In my opinion the VTEC is annoying but manageable. The best way to describe the transition is that it is almost like hitting the powerband on a two stroke dirt bike. At first it was kinda cool, almost like having a turbo on a motorcycle, but the novelty quickly wore off and I soon wished it wasn't there. The VFR is a great bike and I don't think having the VTEC should be a deal breaker but I do feel extra maintanance costs with the VTEC are simply not justified especially with very marginal benefit the VTEC brings.


Rollin

 

I've got an '06, which is when they changed to a lower RPM for the VTec. The only time I find it annoying is trying to keep it right at 100. It's 95 or 110. No 100. Not that I condone going that fast or anything, just sayin'.... But at first, yes, it was a unique sound, but as the engine gets broke in more & more, it becomes less noticeable, except for the sound.

 

Recently I tried this trick on my 07 and it seems to do wonders... (note that I have a stock "power commander", etc)

When I first turn the key, I let the computer setup until the pump stops and the FI light goes out. Then, make sure the bike is in neutral and... turn the key back off

Then, while holding the starter switch, turn the key back ON and the bike starts up. This seems to reset the Honda fuel computer ("power commander") and it behaves much better thru all RPMs up and down. The flat spot from 5-6k rpms no longer bugs me...

seriously...try it!

 

I wouldn't say the bike has lag at any point in the bike. Its the way honda has the cams ground and the fuel mix running in stock form. IMO they did a massive flat spot to meet the 08 CARB standards and later they found that they could move the RPM down to the 6400 point to make it a smoother. Almost all motorcycles are now designed with California standards generally they don't want to go through the problem of doing a 49 state legal bike.

My bet is that a set of custom performance cams would do this bike wonders. Right now if I can get my paws on a second engine I can start setting up a jig and get some bench flow numbers going to see if the cylinder head will support more lift. Second find out if there is clearance for the piston for a longer duration cam with a slightly higher lift profile.(I have a wife now so I highly doubt that is going to happen.) And this is where the beauty of having a chain drive system because often you can slot the bolts its easy to phase shift advance or retard and there is nothing the engine ECU can do about it. Though the lobe grind from the manual repair books is bigger than the previous gen 5's the fact that below the 6 grand range we are only running on two valves where they were running on 4. The difference in cam is less than .004ths of an inch. If you get out manny you will see the gen 5 had a 49 state version and the cam difference is .036 between 49 state and the California version which is a big jump.

Sorry if I did a bit of a thread jack.

 

i have a rwb 07. i dont notice the vtec kick in feel as much as the sound. also i agree on the throttle thing, easy on throttle easy on vtec, hard on throttle vtec kicks hard.

 

There is no V-Tec lag, like there can be with say a turbo. What there is, is a distinct change in engine character when you hit the V-Tec spot (engagement point changed thru model years). But it is entirely predictable and you will know when it is happening. What the sensation is like, is like on many bikes when you hit a certain RPM there is a real kick in power. It is like that but much more of a dramatic kick than any other bike I have ridden. It is like, and I don't actually have hard figures, just making up the numbers to give you an idea. If the average bike has a 20% increase in power in 1,000 RPM when they hit their "sweet spot" on the tach, with the V-Tec it is more like a 40% kick in power in like 500 RPM change. When it kicks in, it is almost like you downshifted, you know that sudden surge you feel? like that

 

A (dyno) picture is worth a thousand words!

Take a look at the dyno curves in the chart linked below:
http://www.motorcycle.com/gallery/gallery.php?g2_view=largephotos.Largephotos&g2_itemId=142876
The notch in the torque and horsepower curves can be felt at least some of the time, but is not always very noticeable. I have done NO real research, but my guess is there is a brief drop in manifold vacuum when the second intake valves open. Honda has tried very hard to tune it out, but the physics are fighting against them. I liken the feel of the sixth gen engine to an open class dirt bike - it pulls O.K. down low, but much stronger when it hits the tuned area of the pipe. I think Honda made a decent compromise to make the bike California legal on noise and emissions, I imagine the entire dyno run to pass the regs is done in the two valve region. Overall I am happy with the bike, I can still get my giggles on the far side of 6400 rpm, and the engine is MUCH easier to hear up there. YMMV.
-VFRGeek

 

Mine's a 2004. No lag, when I hit the 6700 line I can feel a surge and the exhaust note deepens; no control problems, just that extra power coming on.

 

Why not just keep your RPMs above 6700 whenever you ride? Pussies.

What's next - you gonna worry about your gas mileage when you're in the Vtec?


:wink:

 

That's hilarious. :high5:

 

maybe you have a loose chain... too much