What happens at 5500~rpm on the 2.0 Mazda 3?

[spotch]

Since I've owned my Mazda 3i sport 2.0 (5speed) I've noticed that at around 5500rpm (indicated) the engine starts pulling noticeably harder and the engine tone changes slightly. It reminds me of the sound/feel of a second set of intake runners opening up, but I'm not certain (I thought that occured at a lower rpm). Anyone have any insight on this?

It seems like whatever is happening here is happening a few hundred rpm too late... like if there is a little boost in power there I'm wondering if it was moved back a few hundred rpm that it would make the overall power band a little more linear and gain a couple tq/hp from 5000-5500~ rpm.

 

[Turbospeed2010]

You are likely experiencing a change in the valve timing. All of the 3's have variable valve timing (VVT). I'm not certain the rpm in which the timing changes but it would make sense that with a 6500rpm redline on the 2.0 the VVT would be around 5000.

 

[spotch]

Could be... I always experienced valve timing changes as being a LOT smoother/less noticeable. I've never heard the induction noise actually go up just from a timing change (unless it's timing AND lift at once, like in an older vtec honda, but this is even louder than the vtec crossover in stock old b16 Si... although not as loud as one of those once you add a filter).

Anyway, you could be right. I'd just be really surprised if it's not something on the intake manifold opening up.

 

[wingzero_]

Could be... I always experienced valve timing changes as being a LOT smoother/less noticeable. I've never heard the induction noise actually go up just from a timing change (unless it's timing AND lift at once, like in an older vtec honda, but this is even louder than the vtec crossover in stock old b16 Si... although not as loud as one of those once you add a filter).

Anyway, you could be right. I'd just be really surprised if it's not something on the intake manifold opening up.

On the 2.5 you get the VVT sound effects at 4250rpm. Since I put the Simota on the sounds is very noticable.

At 29 seconds you can hear it in 4th. Well you can hear it in the other gears as well but I didn't really hang on to it.
http://www.youtube.com/watch?v=9zmqHcTBrKE

I was only using about 50% throttle, its louder when you come on to it.

 

[Circle9]

Vtec!! I kid, I kid

 

[krimsonviper]

You are likely experiencing a change in the valve timing. All of the 3's 2006+ have variable valve timing (VVT). I'm not certain the rpm in which the timing changes but it would make sense that with a 6500rpm redline on the 2.0 the VVT would be around 5000.

Fixed.

 

[Leathersoup]

Vtec!! I kid, I kid

haha I was waiting for someone to say, "Vtec just kicked in yo."