vtec

[slugmike]

at what rpm does the vtec "kick in" on our pilots?

I've heard 4500rpm...?

I know there's not a huge surge in power at the changeover point like with DOHC vtec engines, but the tone does seem to change around 4500.

[xGS]

Originally posted by slugmike
at what rpm does the vtec "kick in" on our pilots?

I've heard 4500rpm...?

I know there's not a huge surge in power at the changeover point like with DOHC vtec engines, but the tone does seem to change around 4500.

Quoting from hondanews.com:

VTEC Valvetrain

Honda's innovative Variable Valve Timing and Lift Electronic Control (VTEC) technology helps to maximize performance across the engine's full operating range. The VTEC system has two distinct modes to optimize both volumetric efficiency (breathing) and combustion of the fuel-air mixture. Less air is needed in the lower portion of the engine's operating range so rocker arms are programmed to follow cam lobes with a lower lift profile and reduced duration (shorter time open with less valve lift). The two low-speed intake cam lobes for each cylinder are purposely different to provide asymmetric air/fuel mixture flow into the cylinder. This yields a swirl effect that improves combustion efficiency for better performance, fuel efficiency and reduced exhaust emissions.

At 4300 rpm, a control module directs the VTEC system to switch intake valve operation to the high-speed mode. An electric spool valve opens to route pressurized oil to small pistons within the intake-valve rocker arms. These pistons then slide to lock the three rocker arms together. As a result, both intake valves follow a central high-lift, longer-duration cam lobe. The switching process takes just 0.1 second and is undetectable by the driver. The extra lift and longer duration provide the added air and fuel the engine needs to produce high peak horsepower and a broader torque band.

[mgorbsk]

Originally posted by slugmike
at what rpm does the vtec "kick in" on our pilots?

I've heard 4500rpm...?

I know there's not a huge surge in power at the changeover point like with DOHC vtec engines, but the tone does seem to change around 4500.

I've never heard it in either the Pilot, or the Accord. I've also never felt it in the Pilot and don't know if I've ever taken it to 4300rpm. I can tell you I've definitely seen higher rpm in the Accord EXV6 Coupe and definitely feel when it kicks in. It's pretty fun to drive it.

[2muchfun]

My civic has a cold air intake kit, so the only thing I notice is the change in the sound when it kicks in. I dont think I feel it at all... but then maybe if it wasnt there I would feel the difference

[jcantanixon]

Originally posted by 2muchfun
My civic has a cold air intake kit, so the only thing I notice is the change in the sound when it kicks in. I dont think I feel it at all... but then maybe if it wasnt there I would feel the difference

The VTEC systems in SOHC engines are setup mainly for fuel economy, so you don't get that semi-dramatic power shift that you do in the DOHC engines.

[slugmike]

Originally posted by xGS


Quoting from hondanews.com:

VTEC Valvetrain

At 4300 rpm, a control module directs the VTEC system to switch intake valve operation to the high-speed mode. An electric spool valve opens to route pressurized oil to small pistons within the intake-valve rocker arms. These pistons then slide to lock the three rocker arms together. As a result, both intake valves follow a central high-lift, longer-duration cam lobe. The switching process takes just 0.1 second and is undetectable by the driver. The extra lift and longer duration provide the added air and fuel the engine needs to produce high peak horsepower and a broader torque band.

Great info, thanks!!

[ecsw]

4300rpm? I remember my TSX was at around 5400rpm. Guess it's different between V6 and i4 and DOHC and SOHC then.

[rocky]

Definitely hear that change in the engine note around 4500. Hell I do it coming out of toll booths for fun every so often.

I love this engine

[2muchfun]

Originally posted by jcantanixon


The VTEC systems in SOHC engines are setup mainly for fuel economy, so you don't get that semi-dramatic power shift that you do in the DOHC engines.

Thanks for the info.

Now I have to go out and stomp on the Pilot to see what happens

[brianmsmith]

Yet another reason to fit the K&N filter - the sweet sound at higher revs.

[slugmike]

is there a noticeable change in the sound with just a drop-in k&n filter?

[humanoid]

Originally posted by slugmike
is there a noticeable change in the sound with just a drop-in k&n filter?

No... unless you open up the airbox.

[ctobio]

I love performance as much as the next guy, but who cares what the sound of the intake is?

Does it work? Does it work well? Can it be made better (without serious detriment to other systems)? That's my criteria for how I feel about a modification.

How it sounds frankly ranks pretty low in my opinion. Unless its a stereo.

That said, A K & N filter will not likely change much of the intake tone. It never has in any of the other cars I've had.

I tend to lean nowadays away from K & N filters. I don't think they provide much benefit, and maintained improperly they will do more harm than good. In normal daily driving, a paper filter will do just fine so long as its changed with reasonable frequency. I rarely follow the manufacturer's guidelines on this. I usually change more frequently, based on a visual inspection.

[brianmsmith]

Originally posted by humanoid


No... unless you open up the airbox.

Well, actually I beg to differ. I can hear a distinctly deeper/raucous note above 3000 rpm after the K&N had been in for ~5000 miles. This may be coincidence, it could be the engine becoming fully run in (15,000 miles). However, the K&N master distributer here told me from the outset that the engine WOULD sound different after a few thousand miles of K&N use. I won't go into efficiency again, that was dealt with exhaustively a month or so ago. Just suffice to say the K&N filter does what I want of it - lets the engine breath better - and filters enough for me. The changed sound is a little bonus; I don't like noise but I do appreciate sound, especially a fine engine on song.

[jay]

I appreciate a fine song without any engine noise.