So, coming from the Honda car world, where VTEC started back in 1989 or so, there have been a few iterations of the system that I can recall.
The most similar to the VFR I would have to say, in terms of feedback into the chassis and jump in power, is probably the Integra Type-R's B18C5 engine. This engine was a very high performance engine. It was a 1.8L that was very EASILY tuned to 200 horsepower on a chassis dyno. This without changing anything dramatic like camshafts or anything. In stock trim, the VTEC 'kick' was very apparent in both tone and in power. But the funny thing about a VTEC B18C engine is that when tuned properly all that goes away. Ironically enough, the system in the B- engines was different than in the D- engines. The D- engines did the whole, open two valves in low and open four in high deal, but that system is significantly less dramatic than the B- engine one where the valves all open a little in low and then open a lot more in high.
I am very much of the mind that Honda designed the VTEC kick in the VFR to be overly apparent. It is bugging the crap out of me. The leap in power is simply ridiculous. Before buying the bike I heard the grips but I thought "ah these guys are just pussies...VTEC is COOL!" But the VTEC in the VFR, while fun and entertaining, is not confidence inspiring. Honda wants us to know VTEC works, so they made it obvious. But really, it should be a smoother transition in terms of power.
One of the biggest parts of tuning a VTEC engine is getting the timing and fuel right all across the rev range. And if power drops off on the low cam then leaps at VTEC crossover, you should lower the VTEC crossover point to make it all more linear.
The only issue with this I can see is, on my 07, I cruise at like 85 or so, and I am just right under the VTEC point as it is. Lowering the crossover would put my IN VTEC at cruise. Very bad for cruising. Just the same....it would be ideal for more spirited sessions.
Has anyone actually been able to finely tune this engine? I mean, tweaking the VTEC crossover? Does the PC even do this? How much better would the VFR be if we cracked the code?
You need to get a PCIII or PCV (I have a PCIII so I can only speak for that one) and download Cozy's MAP from these forums... you won't be disappointed.
I actually love the VTEC Transition. That sound... that little pull...
You need to get a PCIII or PCV (I have a PCIII so I can only speak for that one) and download Cozy's MAP from these forums... you won't be disappointed.
Even with all the tuning available with a Powercommander, the jump in power is still very noticeable, but thankfully there is no longer a kick or lurch. I don't believe the reason for the jump in powerr is retarding the ignition or anything done on purpose, but more the fact that two valves is really running out of puff by then. Hence one of the reasons they dropped VTEC engagement from 6800rpm down to 6400rpm with the 2006+ onwards model. I bet it didn't get rid of the jump completely though.
Just check out the results of my custom tune for an example - it's a big jump when VTEC kicks in (this is WOT of course).
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The only true solution is available from A&A Performance, and it blows. :laughing6-hehe:
I guess I could have worded it a tad better, but I didn't mean to imply the transition is gone. It is a hell of a lot more fun and tolerable now with my PCIII and MAP than it was at stock. I was in his shoes, hating the VTEC transition being a VTEC noob when I bought it. But now, it is simply a much better transition.
I'm not crazy about it, either. The VTEC transition is very apparent at WOT; however, it's hardly noticeable if I ease into the VTEC transition point (7k RPM on my bike.)
The way I look at it, if VTEC is so great, why isn't Honda using it on all their motorcycles? And why did they drop it when they redesigned the bike? As for why VTEC isn't noticeable on some Honda/Acura engines, I don't know. My guess is they spent far more time and R&D dollars on it than they spent on the VFR engine.
The idea of trying to get all 16 valves operational at all times isn't new. In the only instance I recall reading (where somebody was able to do it), the engine ran poorly. I don't recall ever reading whether or not the person was able to make the engine run properly by working out any fuel-related issues through a PC3. If he was able to, I'm sure we would all know about it.
On a final note, a couple years ago, somebody here posted a link to a European motorcycle forum where an Englishman did a write-up (complete with pictures) of how he swapped the VTEC engine in his 6th gen. VFR with a VFR engine (i.e. non-VTEC) from a 5th gen. ('98-'01) VFR. He succeeded admirably. As for why he did it, he said he wanted gear-driven cams.
My bike, bought used, supposedly HAS a PC in there, although I am not sure which one. I will look into getting another map on it and see whats up!
If you're truly adamant about ensuring the fueling is 100% optimal, you may want to have your injectors cleaned before doing any fine-tuning with a PC3.
The only issue with this I can see is, on my 07, I cruise at like 85 or so, and I am just right under the VTEC point as it is. Lowering the crossover would put my IN VTEC at cruise. Very bad for cruising. Just the same....it would be ideal for more spirited sessions.
Is your gearing stock? If I'm cruising at 85, the VTEC transition is 15mph away, up at 100, and getting there is not exactly instantaneous in 6th gear.
kaldek, on 04 June 2011 - 06:33 AM, said:
I don't believe the reason for the jump in powerr is retarding the ignition or anything done on purpose, but more the fact that two valves is really running out of puff by then.
True statement. You can see this issue easily if you've ever goosed it when the engine was warm but not up to VTEC temp yet. Once you get used to having juice at 7,000 rpm, to not feel it there is really disheartening.
The only issue with this I can see is, on my 07, I cruise at like 85 or so, and I am just right under the VTEC point as it is. Lowering the crossover would put my IN VTEC at cruise. Very bad for cruising. Just the same....it would be ideal for more spirited sessions.
Is your gearing stock? If I'm cruising at 85, the VTEC transition is 15mph away, up at 100, and getting there is not exactly instantaneous in 6th gear.
Ok, so maybe I cruise a bit faster than that :pinocchio:
The only issue with this I can see is, on my 07, I cruise at like 85 or so, and I am just right under the VTEC point as it is. Lowering the crossover would put my IN VTEC at cruise. Very bad for cruising. Just the same....it would be ideal for more spirited sessions.
Is your gearing stock? If I'm cruising at 85, the VTEC transition is 15mph away, up at 100, and getting there is not exactly instantaneous in 6th gear.
Ok, so maybe I cruise a bit faster than that :pinocchio:
Understood, and I sympathize completely. :biggrin:
The VTEC transition is said to be smoothed by making sure the intake throttle bodies are sync'd for flow. That, and making sure all filters are in good condition, and the injectors are acting right, should probably be done first before playing with a Power Commander.
The reason some car VTEC's aren't too noticeable is that Honda have some that really aren't very performance oriented, but with more of an economy goal to the camshafts. Going from a weak camshaft to a slightly less weak cam is nothing like doubling the operating valve count like what happens on an RC46 800 VTEC.
A PowerCommander will allow you to tune the fueling. I have always wondered why there is no option for adjusting timing as well. Adjusting timing could really fine-tune that, plus, if you used a higher octane gas, you could advance it at WOT and high RPM's and see a few more ponies as well.
The reason some car VTEC's aren't too noticeable is that Honda have some that really aren't very performance oriented, but with more of an economy goal to the camshafts. Going from a weak camshaft to a slightly less weak cam is nothing like doubling the operating valve count like what happens on an RC46 800 VTEC.
Yep. The other thing I was thinking is that a change in timing (or especially number of valves) is going to be a lot bigger "kick" relatively speaking, on a bike with a lb/HP ratio of 5 or 6 as opposed to on on a car with a ratio of more like 14 or 15...
As the valves tighten the smoother it gets, 87,000 mile no valve check . As a recall in the first few thousand miles sometime it hit hard enough in the low gears to hurt your hands.
One of My friends had his vtechs adjusted and he swears the hit was much more noticable afterwards.
As the valves tighten the smoother it gets, 87,000 mile no valve check . As a recall in the first few thousand miles sometime it hit hard enough in the low gears to hurt your hands.
One of My friends had his vtechs adjusted and he swears the hit was much more noticable afterwards.
You certainly can't be accused of being a poser. An '06 VFR with 87,000 miles???
As the valves tighten the smoother it gets, 87,000 mile no valve check . As a recall in the first few thousand miles sometime it hit hard enough in the low gears to hurt your hands.
One of My friends had his vtechs adjusted and he swears the hit was much more noticable afterwards.
You certainly can't be accused of being a poser. An '06 VFR with 87,000 miles???
If I hadnt been laid off twice in the last 2 years, it would be over 100,000
The economy systems in the cars is actually more like the vfr...where the valves open in different counts in low and high. The high performance systems actuate all 16 valves in low and high with different cam profiles.
The point to finer adjustment isn't get more power during the transition, but to tune more power at the peak of the low range.
So I am clear, the ignition is computer controlled but it isn't tunable with a PC.
DOES EVERY SINGLE AUTO MANUFACTURER OFFER A FORM OF VARIABLE VALVE, LIFT, AND OR TIMING? Every honda sent to the us has some form of vtec or I-vtec. Hell the new Dodge Hemi crap has variable valve timing.
Most vtec systems on honda cars are for economy. The B-16, B-18, B-24, K 20, s2000 actually switch cam lobes. This is the real VTEC performanece. Ours came from the first REV system, 1983, japan only.
Our system is from the rev, and it is more like a 94-02 accord vtec. It ran 3 valves and then open to 4, the transition is hardly noticeable. The newer systems rely more on the timing aspect. Which can change duration and lift.
As far as the bike, The best thing I have found, and I do it everytime I start the bike is CYCLE THE KEY TWICE. I have put 62k miles on mine and the vtec transition is like butter now. It only makes a little sound and starts to really pull. It's a non issue.
DOES EVERY SINGLE AUTO MANUFACTURER OFFER A FORM OF VARIABLE VALVE, LIFT, AND OR TIMING? Every honda sent to the us has some form of vtec or I-vtec. Hell the new Dodge Hemi crap has variable valve timing.
Most vtec systems on honda cars are for economy. The B-16, B-18, B-24, K 20, s2000 actually switch cam lobes. This is the real VTEC performanece. Ours came from the first REV system, 1983, japan only.
Our system is from the rev, and it is more like a 94-02 accord vtec. It ran 3 valves and then open to 4, the transition is hardly noticeable. The newer systems rely more on the timing aspect. Which can change duration and lift.
As far as the bike, The best thing I have found, and I do it everytime I start the bike is CYCLE THE KEY TWICE. I have put 62k miles on mine and the vtec transition is like butter now. It only makes a little sound and starts to really pull. It's a non issue.
My bike, bought used, supposedly HAS a PC in there, although I am not sure which one. I will look into getting another map on it and see whats up!
If you're truly adamant about ensuring the fueling is 100% optimal, you may want to have your injectors cleaned before doing any fine-tuning with a PC3.
Thinking of this, you are completely right. However, my bike only has 4600 miles on it...I feel pretty comfortable tuning as is.
I have a PCIII, and just installed the software on my computer. Now to find out what map is on there, and what map I might change to!
So I am clear, the ignition is computer controlled but it isn't tunable with a PC.
This is correct.
Well, technically you could control ignition timing with the old PCII's, (they worked by altering the signals going INTO the computer and then the computer would adjust) but I don't know of anyone who has done this.
PCIII and PCV work by adding or subtracting fuel from the stock map. They plug in just upstream of the fuel injectors.
I just gought a Gen 6 last night. It has a PC III in there from the prior owner.
I was surprised that WOT performance doesn't seem vastly improved over my carbureted Gen 3 with K&N and 2Bros pipe. Sure, the VTEC engagement is like the turbo in my Volvo R wagon kicking in, but overall the digits fly by at about the same rate.
I guess that I need to investigate the PC software and map choice. Any suggestions in that regard?
I just bought a Gen 6 last night. It has a PC III in there from the prior owner.
I was surprised that WOT performance doesn't seem vastly improved over my carbureted Gen 3 with K&N and 2Bros pipe. Sure, the VTEC engagement is like the turbo in my Volvo R wagon kicking in, but overall the digits fly by at about the same rate.
I guess that I need to investigate the PC software and map choice. Any suggestions in that regard?
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I just gought a Gen 6 last night. It has a PC III in there from the prior owner.
I was surprised that WOT performance doesn't seem vastly improved over my carbureted Gen 3 with K&N and 2Bros pipe. Sure, the VTEC engagement is like the turbo in my Volvo R wagon kicking in, but overall the digits fly by at about the same rate.
I guess that I need to investigate the PC software and map choice. Any suggestions in that regard?
First it is important to know that the VFR VTEC is not the same as the automotive VTEC from Honda. It is simply a transition point from 2 valves to 4 valves of operation. This was done for emissions purposes. Not performance. The engine gets louder but if you look at dyno curves of the 6th Gen you will not see a spike in the power curve after VTEC has engaged.
Changing your fuel maps will help smooth the VTEC transition so it doesn't kick as you described it but short of taking the VFR to a shop and having them dyno tune it you are not going to get much of a performance increase. And even then the best results I have read about on the board was a peak of 111 hp. Not much more than the usual 100-105 hp you see stock (as bikes vary).
If you want a real boost in performance then you are talking the Torocharger at a price tag of around $5K just for the kit. The VFR was not designed as a super sport but as a sport bike with touring capabilities. A 600 cc sport bike can out accelerate the VFR in a straight line once it hits its power band with riders being equal. The trade off for comfort comes in weight. Since the VFR is plenty fast for me and I don't care to race I am quite content with what I have. I even sold my R6 after having both bikes side by side for a couple of years because the VFR was just a better fit.
If you are looking for sheer acceleration factor you may want to consider another bike. But if you like to bend it in the twisties and being able to do so all day long then the VFR is an excellent choice. :fing02:
I have always thought that my gen 3 VFR with Hyperpro/Racetech suspension was the best of all worlds for me. I'm much more Sport Touring than SuperSport/Race Replica.
I did assume that a VTEC V4 would be higher performance than non-VTEC. I didn't realize it was just for emissions and marketing.
I do believe that handling and smoothness are more important than raw acceleration. Anyone can whack open the throttle. It takes skill to stay on it in the twisties, and my VFR always rewarded in that regard.
Well said vanion2...... exactly the way I feel. I actually love the kick of my 08. I don't care to go to the track or race through the twisties at crazy speeds.... I got it for light touring with a little grin factor thrown in!
I do this every time to and my VTEC transition has been super smooth without an added power commander ( I do have the 330 ohm resistors in though that act as O2 sensors). Turn the key, let everything cycle (but do not hit the starter button). Turn it off. Turn the key again then hit the starter button while the fuel pump is still whining (or whenever really). Easy fix (for my bike at least). No hesitation anywhere. I can cruise at 4k, 5k, 6k, 10K etc all day without any hick ups.
Give it a try.
I have a pcIII on my 06' and the transition was smoothed out when I had the dyno tune done. This was of, after I installed the two-bro's and the k&n filter. If you want my map, I can send it to you. just PM me if you want it.
End of thread · 29 posts recoveredWayback Machine snapshot 11 Jun 2011