Toyota VVTi Setups

[The Real Roadrunner]

i would hope that an engine of this calibre is atleast semi sequential, otherwise it wouldn't ber the most economical thing around.

meh, ill find out later and let you know either way.

cheers

[takai]

the question is - why 3 oddly arranged lobes are required to accurately position the cam with respect to a TDC trigger. as opposed to say 3 evenly spaced lobes, or even just one single lobe. why three (when theres already a cam sync on the front of the camshaft) and why oddly spaced?

After hashing it out with the other 3 engies here at work the only thing we can think of is that they wanted to trigger something at 135deg. Maybe a sensor reading, or to check something else, who knows, but its probably the only reason i can think of for a 5-3 setup.

[JustCallMeOrlando]

i would hope that an engine of this calibre is atleast semi sequential, otherwise it wouldn't ber the most economical thing around.

Wouldn't semi-sequential be paired as per the wasted spark anyway though? Who has a wiring diagram?

[oldcorollas]

oh.. i do.. i'll check tonight (others do too and will probably check sooner and not forget )

[wilbo666]

After hashing it out with the other 3 engies here at work the only thing we can think of is that they wanted to trigger something at 135deg. Maybe a sensor reading, or to check something else, who knows, but its probably the only reason i can think of for a 5-3 setup.

Maybe to check for the max 45deg advance / retard?

Cheers
Wilbo

[ed]

now theres thinking

liet me dig up my old vvti tech doc

[ed]

now mos - how certain are we that its a true 135deg angle on those lobes?

my measurement of the vvti throw is around 52deg at crankshaft (26 at cam) and the toyota tech docs suggest its 60deg crank throw

[TheToyman75]

This may help sort out some of the 1UZ VVTi related discussion !

http://www.toymods.net/~rod/Technica...comparison.pdf

Enjoy.

[gianttomato]

[Mos]

Hmm there's a strange thing right under Rod...'s post.

Ed - Do you really need to ask?

After hashing it out with the other 3 engies here at work the only thing we can think of is that they wanted to trigger something at 135deg. Maybe a sensor reading, or to check something else, who knows, but its probably the only reason i can think of for a 5-3 setup.

With this type of layout you know exactly where you are without having to look at any other sensor. You get two 270/135 degree gaps and one 180/90 gap so you know exactly where you are on the camshaft. If one of your 270 gaps drops to 240 degrees, you know the cam has moved by 30 degrees - you don't have to wait 690 degrees to know that something has moved by 30.
With evenly spaced lobes you still get the faster response, but you don't know where you are on the camshaft - whether that last bit is important I don't know.

The concept of wanting to trigger something at 135 degrees is flawed - the ECU knows exactly where the engine is based on the 36-2 sensor.

Mos.

[ed]

Ed - Do you really need to ask?

no not really but the idea of the sensor co-inciding with the limit of the vvti range of motion did make some sense

[ed]

ah fuck you all...

[The Real Roadrunner]

Good decision, well not the best but certainly the easiest.


When will it be running?

[ed]

when we overcome this little hurdle (x2 now - fuckers!)

[Sciflyer]

"1st gen" VVTi was hydraulic eg oil pressure controlled, whereas the latest engines are electric phase controlled yes?