2AZ vvt-i question

by **Jackass-Jeff** » Sat Jul 12, 2003 11:03 am

For 2AZ owners...

Do you notice that your VVT-i will kick in if you're already moving and then step on it hard but it doesn't kick in if you're flooring it from a dead stop... or is it just me and Richard?

I think the VVT-i is set in the ECU to be used while passing vehicles on highways so there is some "safety" that prevents the use from full launch situations... unless the VVT-i kicked in seemlessly w/o and power jump whatsoever... =\

Anyone have the answers? =\

Website · by **DavPak** » Sat Jul 12, 2003 11:29 am

i'm not totally sure, but i think the vvt-i (on all toyota engines), doesn't kick in until ~4,000 rpms. if that's the case, you wouldn't notice it on launch.

by **AzN_DrAgoN48** » Sat Jul 12, 2003 11:56 am

what is vvti exactly?

by **Jackass-Jeff** » Sat Jul 12, 2003 12:01 pm

i dont mean on the direct launch... usually if i'm doing normal driving and want to pass someone, i step on it... when it hits about 4000, i feel the jolt.

from a dead stop, there is no jolt when I hit 4000 =(

VVT-i = Variable Valve Timing with Intelligence. The easiest way to explain it would be to compare it to Honda's VTEC. At higher RPMs, the intake valves open slightly bigger and longer so you can get more air and fuel in. This allows high end power. In the old days... before my time, you had to buy cam shafts that were tuned for low end, mid range, or high end power; you couldn't have it all. Now, you can have a good low end, a decent mid range and a good high end by using various systems of "VVT-i". Nissan has CVTC, BMW has VANOS, Honda has VTEC and i-VTEC, Mazda has VVT, Mitsubishi has MIVEC, Subaru has AVCS, and Toyota has the original VVT, the currently most used VVT-i and the best one... only in the Calica GTS right now... I think... the VVTL-i.

They all pretty much do the same thing... some are more advanced than others.

by **Anthony** » Sat Jul 12, 2003 12:25 pm

AzN_DrAgoN48 wrote:what is vvti exactly?

Variable Valve Timing. See link below:

How Camshafts Work - Variable Valve Timing

Anthony
2002 SLE V6[/url]

by **NASTY** » Sat Jul 12, 2003 1:22 pm

From Toyota's site:
"Variable Valve Timing with intelligence (VVT-i)
This system selects the ideal intake and exhaust valve overlap under all engine operating conditions. VVT-i virtually eliminates the traditional compromises between low-end torque and high-rpm horsepower. It also helps enhance fuel economy and reduces emissions so effectively that it eliminates the need for the exhaust gas recirculation (EGR) emissions device."

xravexboix, im sure vvt-i is always active, isnt it true you wont feel the 'boost' unless you have vvtl-i(read def'n above)?
(oh, and youre sure youre not just feelin a downshift right?)

by **impactX** » Sat Jul 12, 2003 1:43 pm

It's an on/off switch compared to Porsche's Variocam

by **indiglosolara** » Sat Jul 12, 2003 4:34 pm

Hey Jeff to answer your question, i talked to someone at the toyota dealer. they told me that the reason why you only feel it while driving under normal conditions is that the ECU will auto kick it. if you floor it from a complete stop it will not kick in cuz the ECU knows that you have your throttle fully opened. and when your moving at a slow pace the throttle is only have or not even half open. that is where the VVTI kicks in and pushes the throttle more open to give you that kick.

i dunno thats what the guy told me...

Later

Kenny

by **Jackass-Jeff** » Sun Jul 13, 2003 1:00 am

NASTY wrote:From Toyota's site:
"Variable Valve Timing with intelligence (VVT-i)
This system selects the ideal intake and exhaust valve overlap under all engine operating conditions. VVT-i virtually eliminates the traditional compromises between low-end torque and high-rpm horsepower. It also helps enhance fuel economy and reduces emissions so effectively that it eliminates the need for the exhaust gas recirculation (EGR) emissions device."

xravexboix, im sure vvt-i is always active, isnt it true you wont feel the 'boost' unless you have vvtl-i(read def'n above)?
(oh, and youre sure youre not just feelin a downshift right?)

lol no I know what a downshift feels like... there is this dip near my house (corner of New and Garvey, for locals...) on the side of 7-11. If you drive it, you know you have to go really slow, then you can step on it. When going on it, I know I'm in first gear because I just let the car roll over it. Then when I step on it... my engine pauses and then I feel a huge pull.

Ahh Kenny, so my theory was right... must... adjust... ecu... haha somehow =x

by **Jackass-Jeff** » Wed Jul 30, 2003 1:05 pm

Ahh! Question finally answered.

VVT-i is continuous... BUT the "kick" is felt because the sets of cams are most efficient at 2 rpm levels: 2500 and 5000.

It's so true!! No wonder I accelerate so fast then I keep it at 2300-2500 =x (compared to other cars that are probably going to that range too)

by **Eddiman** » Wed Jul 30, 2003 7:50 pm

is the vvti similar to hondas vtec? or is it completely different?

by **onefiend** » Wed Jul 30, 2003 9:16 pm

Eddiman wrote:is the vvti similar to hondas vtec? or is it completely different?

Its similar. VTEC is alot like the Celica GTS' VVTL-i.

by **Jackass-Jeff** » Wed Jul 30, 2003 9:29 pm

Nope. COmpletely different systems.

VTEC only opens up the ports during high rpms (5000? depends on car)

VVT-i is continuous and works throughout all rpms and adjusts a little or a lot depending on rpm and throttle position.

VTEC is "on/off" while VVT-i is a little, medium, a lot... but sensitive... so it's sort of like comparing analog (vvt-i) to digital (vtec). But VTEC does have "lift" already... VVTL-i has lift. i-VTEC has 2 "VTEC ZONES" so you will feel the "VTEC" power jump 2 times, but it still not continuous like vvt-i. VVT-i is the most advanced/complex/expensive system to make until BMW put out Double VANOS on their 3 series... (it also does exhaust ports... VTEC and VVT-i, from my knowledge, is only on the intake)

by **SKYravefever** » Wed Jul 30, 2003 10:56 pm

xravexboix wrote:... until BMW put out Double VANOS on their 3 series...

M3!

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