I've never driven a VTEC-equipped Honda.
There's obviously a lot to be said for some of their engines as swap donors, and I've got this underpowered MGB GT...
But I loathe the idea of an engine that hits some RPM (or other threshold) and suddenly changes power and/or character... Sounds like as much fun as turbo lag or carbs that open the secondaries in the last few percent of pedal travel. No me gusta.
Terrible movie representations aside, what is the VTEC driving experience actually like?
On every Honda I have driven you can feel the VTEC but its not like you just gained 20 hp. Its more of a noise thing. Same with a '00 Celica GT-S.
In all honesty, you should not feel the change over on a well tuned car. My S2000 has the VTEC changeover lowered via Hondata Flashpro and if you drive it you would not be able to tell where it changes over.
What he said. If the VTEC switchover is set correctly then you don't feel a change at all, the engine just keeps pulling hard all the way up the rev range. You might hear the change though, if you have more open intake and exhaust. I don't feel the change in either my NSX or K24A2 powered Civic.
The VTEC switchover on the K24 is a great aural experience, the intake honk is really a great noise..the feel is less like a laggy turbo coming into boost and more like just an engine that's happier at higher revs and builds more power as it winds up.
Yep, it's not like opening secondaries or sudden turbo boost. The pull just gets more fierce as the revs climb. I bought a '96 Integra GS-R brand new, and back in those days the 8k redline was crazy (still is today, I guess). Honestly, I felt the engine to be a bit lifeless below 5k rpm, but the build up was progressive and not sudden. It was glorious at high rpm.
It's about the same as switching your A/C off during a hard pull. You can feel it some, but it's doubtful anyone else will.
Stock switchover on the S2000 is sort of abrupt, intentionally. Not anything crazy, but if you are near peak traction (in an autox slalom for example), it can cause some issues. Once the crossover is tuned right its just a slight change in the slope of the power graph. Very smooth.
Very subtle. In my unmodded/stock tuned RSX, it just kept on delivering torque at a rev range where you expected it to stop. And the sound was like it was saying, "Holy crap! I can finally breathe!"
Highly recommended. They're fun.
For a silly thread jack, this is a dyno plot of a 6th gen Honda VFR 800 Interceptor, where that VTEC system is a transition from two-valve to four-valve operation. The plot is actually a before & after from an aftermarket cat-back exhaust but it should give you an idea of what this feels like;
It's a bad dead spot followed by a really hard pull at anything over half throttle. Depending on the riding conditions at the time it might be kind of fun, like turbo lag, or it might be kind of awful and try to upset the handling like turbo lag.
In reply to pres589 (djronnebaum) :
It looks like the switch point should be about 500rpm earlier.
In that VFR dyno if you just pull the transition down about 1k rpm then it will be a nice smooth curve and transition between the two cam profiles.
In reply to Pete. (l33t FS) :
Honda played with the switch point over the years. I think in the early days of that engine it was 6400. Then they moved it to 7000. Then I think they moved it again on the 8th gen VFR800 to some other position, possibly 7200.
The real answer, I think, is to get a 5th gen which doesn't have VTEC at all.
Completely without evidence, I always assumed they set the switchover with two thoughts in mind:
1) Feel a difference - VTEC! (tho some reports here suggest it's not really like that)
2) Accommodate production variances. You'd hate for the switchover to cause a drop in power in some cars.
My 98 Prelude was not subtle at all. As I recall it happened around 5500 RPM and it felt and sounded strong. In 1st and 2nd redline came on quickly and rev limiter after that. It was not like my 03 WRX as the turbo spooled up.
The Ridgeline kicks in around 4500 rpm. Yes, you can feel and hear it. It is not significant but it is noticeable. Like the world's smallest turbocharger giving you a couple of pounds of boost.
The sound increases and the torque curve doesn't fall off.
Depends a whole lot on which VTEC motor. B16? K20Z? H22? Oh yeah. Single jingle VTEC? K20A? Not so much. Even the same motor can sometimes feel different in different cars. I had a Celica GTS and an Elise, both with the 2ZZ. The Elise hit cam audibly and in the seat of your pants, the Celica, much less so. Could have been a worn cam though. IME, the lower displacement/revvy motors don't have like a torque "hit" that upsets the chassis. It just gets more urgent. I also owned a VTEC VFR, and that was annoying. The 2 valve/4 valve switch was something only in the bikes though, and not shared with the cars. It's more noticeable in a moto, because any kind of power herky jerky can either make the bike want to stand up or flop, or upset corner drive leaned over.
Really? 4 hours in, a dozen and a half posts, with no VTACK KICKED IN YO memes?
Duke said:Really? 4 hours in, a dozen and a half posts, with no VTACK KICKED IN YO memes?
This is serious thread. (you know the meme, probably)
I have never driven a stock tuned performance VTEC engine, but on the generic K20/24s and D16s you mostly just notice the intake sound get deeper/more forceful. In the V6s I never noticed anything significant.
In the Insight it is very noticeable, but in the Insight's case it shuts off all of the cylinders, running them on "blank" lobes, so there is no engine braking. That is the generator's job.
In reply to Duke :
Well fine, now I need to post the licence plate on the NSX
In reply to Fatallightning:
Totally, there are actually 3 kinds of VTEC. The single cams and economy stuff is usually not that much difference in the cam lobe change. The DOHC VTEC stuff has the much bigger lobe changes for performance. The K stuff also can adjust the cam gear timing, so some of those are only cam timing changes (K20A in EP3 Civics, K24 in the Accord/CRV/ETC), and the performance versions of the K have both the cam timing change and the cam lobe changes (like the Civic Si and TSX, RSX-S)
In reply to Sonic :
The generic K engines have VTEC, too.
There are two acronyms here, VTEC (different cam lobes, lost motion assemblies on followers) and VTC (variable camshaft timing). Combining them is what Honda calls iVTEC. (afaik you will only find VTC on engines with timing chains. No variable cam timing for the J engines)
Now, the generic K engines' VTEC is different in that there is no high RPM lobe. What they have (going off of memory, here, it has been a few months) is each intake valve has its own lobe, one of which is smaller than the other, to promote intake airflow motion to create combustion chamber motion that they figured was important. When VTEC engages, it locks the two rockers together, so both valves operate from the high lift lobe.
Hert from Hoonigans talks about how as a dumb teenager, he had an Accord with an automatic and a non-VTEC F22 as a first car. He put a loud exhaust on it and VTEC decals and when racing friends, he would drive at 80% throttle until like 4000rpm, and then go all the way to the floor to simulate VTEC crossover.
Tuned correctly feels like a stage 1+/Stage2 cam without sacrificing drivability and low-end.
Tuned poorly it can feel like going from 70% throttle to 100% throttle at a specific rpm.
The 99-00 Civic S with the B16 I had the pleasure to drive quite a bit in the 2000's definitely perked right up when it hit VTeK YO! Super fun car, the drivetrain was OEM and young, sounded fabulous and loved to spin. Fast is was not- but the great gearbox, snappy turn in, fairly neutral handling, decent brakes, and relatively low mass made for a great secondary road car. 100 hp per liter NA is still uncommon- It is worth experiencing IMHO.
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