Is200 Techincal Question

[Porkins]

On the way back from collecting my IS200, I chose to partake in the 'Wacky Races' event from the Severn Bridge toll plaza.

I noticed that when the revs hit just below 4500rpm, theres a kick of power. What exactly is that?

[Fidgits]

the engine has VVTi - variable Valve timing...

the engine has two camshafts, and basically the 4,500 line is when the cams switch from economical to performance...

or in other words, the IS200's power band is 4,500-6,250 rpm...

and...

if you shift well on the 6,250, you'll find you stay in that power band all the way through the gears... ;)

[Noel]

Toyota's magical VVti :D

[BernardTamHK]

hahhaa. ..... kick of power ..... never heard of it in the IS200 .... must be a factory defect ... u should probably bring it back to check it out ....

[RX-Men-8]

the engine has VVTi - variable Valve timing...

the engine has two camshafts, and basically the 4,500 line is when the cams switch from economical to performance...

or in other words, the IS200's power band is 4,500-6,250 rpm...

and...

if you shift well on the 6,250, you'll find you stay in that power band all the way through the gears... ;)

Colinbarber may come along soon to add to that... It's a common misunderstanding that VVTi makes this "kick" like in early versions of Honda's VTEC (which switches to a different cam lobe) but it is not. VVTi is continuously variable so you wouldn't notice it continuously adjusting.

The "Kick" in power comes from the induction tract shortening (ACIS valve - Acoustic Control Induction System - , which opens and shortens the air intake path), and ignition timing advancing. A long induction path is beneficial for low end torque, and a short path for better breathing at high revs ;)

Cheers,

RX-Men-8

[ColinBarber]

the engine has VVTi - variable Valve timing...

the engine has two camshafts, and basically the 4,500 line is when the cams switch from economical to performance...

or in other words, the IS200's power band is 4,500-6,250 rpm...

and...

if you shift well on the 6,250, you'll find you stay in that power band all the way through the gears... ;)

Colinbarber may come along soon to add to that... It's a common misunderstanding that VVTi makes this "kick" like in early versions of Honda's VTEC (which switches to a different cam lobe) but it is not. VVTi is continuously variable so you wouldn't notice it continuously adjusting.

The "Kick" in power comes from the induction tract shortening (ACIS valve - Acoustic Control Induction System - , which opens and shortens the air intake path), and ignition timing advancing. A long induction path is beneficial for low end torque, and a short path for better breathing at high revs ;)

Cheers,

RX-Men-8

Not much more for me to add :)

Only VVTL-i has dual cam lobes like Honda's V-TEC however that technology hasn't been used on a Lexus, as far as I know it's only been on the Celica 190 in the UK.