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Discussion Starter #1
Hey guys, I haven't studied all the details on the mechanical differences on the 1zz VVTI and the 2zz VVTLI but I know there's a somewhat significant difference. I was able to search and find that the 2zz changes cams at 6000rpms but I wasn't able to find out when the 1zz changes over. Can anybody answer this for me? Maybe there is a margin of error where it doesn't always engage at the same time? If so roughly when? It's hard for me to tell exactly when but my guess would be 5000-5500 from how it sounds. I'll study up on it later but I'm just looking for a quick answer here. Thanks guys!
 

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Discussion Starter #3
Ok, that's good to know... except it does variate timing though right? Like I said, I will have to read into it further but does this mean it only changes timing (IE what cam gears would do) at higher RPM's or does it have a 2nd cam lobe? The engine sounds much more agressive up top but maybe that's just the cam timing. Maybe I just answered my own question? All I know is it seems to pull a lot harder at 5k+.
Thanks for the input :)
 

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Zettai Unmei Mokushiroku
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The valve timing occurs at every RPM on both the 1ZZ and 2ZZ. The ECU determines whether you're driving normally or hard, and then adjusts the timing (via infintely variable cam gear) to either gas saving or power. Only the GT-S has the second cam lobes, and they aren't variable. Lift kicks in at 6000 on some 2000 GT-Ss and 6200 on the rest, and lasts until the rev limiter at 8400 (7800 on '02s). Lift allows more air to enter the engine, leading to more power and the ability to have the limiter at 8400 without losing power from revving too high (the 1ZZ would be straining at 8000 if it could sustain revving that high without blowing).
 

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Originally posted by Blue Bomber
The 1ZZ only has one cam profile, unlike the 2ZZ which has two, so there is no changeover on the 1ZZ.
if its also dohc, I thought they worked independantly.
 

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Zettai Unmei Mokushiroku
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Originally posted by NoRulzAt140 Mph
if its also dohc, I thought they worked independantly.
They do, but on a 2ZZ, there are actually two sets of cam lobe profiles on each camshaft: a smaller one for under 6K, and a larger one for over 6k.

EDIT: Here's a pic of the 2ZZ's cams:

 

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well maybe he meant when it changes from the low cam to the high cam??
 
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