what is TVIS

[auch]

hey guyz what is TVIS and what does it actually do? it seems people take them off...

[Jebus]

Its a series of electric superchargers in your inlet manifold, thats why 4AGE's are so fast.

A quick search may help.

[auch]

so technically a 4agze are twin charged, electrically and mechanically...

so why dont old single throttle 4age adapt this system into their intake system?

what exactly are these TVIS located? if they were to be faulty, would it fully restrict the intake path?

[Caveman]

http://forums.toyspeed.org.nz/viewtopic.php?t=30916&

4AGZE dont have tvis.

[Alex B]

He was joking, do a search.

[Jebus]

No im sorry dude, im taking the piss cos you didnt search

Anyways theres a plate between the motor and the inlet manifold, which has 4 butterflys on it, below 4350rpm they are closed so the motor only has half the intake port size (to give it better low down torque) then above that rmp they open giving you full power.

This lets them get good drivability and low down torque with relatively big ports

[RedMist]

Bugger Jebus, that could have gone so so far!

[Jebus]

Reckon I could get away with it and make some $$$ on trade me

[Malcolm]

http://forums.toyspeed.org.nz/viewtopic.php?t=30916&

4AGZE dont have tvis.

ah I was looking for that thread, why hasn't it been FAQ'ed?

[Dell'Orto]

Good point, have done so.

[l1ttle_d3vil]

just had a brief read over that thread...is it possible thats partly whats wrong with my engine? I don't have the tvis wired up, but still have the butterflies bolted in.

its still not running consistently, after I replaced the temperature sensor on the back its running ALOT better and much quicker but not all the time. other times its either really crap right through the range or its not until it gets to 4500rpm that it takes off.

any thoughts please? im pretty pi$$ed off as after I replaced the temp. sensor it seemed to fix it and run consistently, but not any more...

[crnkin]

just had a brief read over that thread...is it possible thats partly whats wrong with my engine? I don't have the tvis wired up, but still have the butterflies bolted in.

its still not running consistently, after I replaced the temperature sensor on the back its running ALOT better and much quicker but not all the time. other times its either really crap right through the range or its not until it gets to 4500rpm that it takes off.

any thoughts please? im pretty pi$$ed off as after I replaced the temp. sensor it seemed to fix it and run consistently, but not any more...

hmmm

if you have no tvis wired up but the butterlys are still in the spacer plate, theres a good reason why your car isnt revving out, its a/f ratio is super super low, and i presume also that its flapping around causing inconsistancies, as 4500 is where tvis really shines, and other times they will be closed, having no top end power.

Maybe you need to look at wiring it up or taking the butterflys out

[auch]

a sweet... so the TVIS pretty much works the same as giving variable intake volume same aim as the v-tecs. plenty of low end torque and lots of support during the top end.

so do you guys think this wasnt developed any further?

[auch]

hey thanks for the link, it was a good read. i might missed reading it but i'll ask anyway... how are TVIS activated? thru crank or cam sensor? is it a flap valve similar to a throttle butterfly or a fan like blade that produces head positive pressure as it is pneumatically coupled?

by the way, what does TVIS stand for?

[crnkin]

i forget the actual thing of what it stands for but i always thought it was toyotas variable length induction system. Its controlled by air pressure sorta like a turbo wastegate.

The ECU triggers a vacuum solenoid that opnes them at the set RPM.

um its a butterfly, pivots in the middle... annnnnnnnnnnd its nothing like vtec, but same aim- yes, that of low end torque high end power and minimum trade off between around town and boosting it. They probly didnt develop it much cos of the vvti system thats successful on blacktops

[ee904age]

Toyota Variable Induction System.

They are butterlies, just like in a throttle body. The ECU triggers a vacuum solenoid that opnes them at the set RPM.

[auch]

ok so its vacuum operated thru opening of a negative pressure via electric solenoid...

wow thats pretty good how toyota innovation came up with this method but why do you guys think all manufacturers nowadays have taken the route of variable cam timing instead? i mean aside from the secondary/TVIS butterfly valves creating flow restriction and the fact that the mechanism is alot heavier which promotes more weight and bulkier intake system...

good stuff guys keep it coming

[Alex B]

Because its just that, more variable especially with VVT-i

[Dell'Orto]

Interesting, I wonder if my TVIS is actually wired up...does anyone have a link to a page on how to test it?

[RedMist]

Actually manufacturers are using variable length intake systems. Mitsu, BMW just to name a couple. Just nothing as basic as TVIS. The Variable intake timing or lift doesnt negate the need for a variable length intake system.

F1 cars still run Variable length runners.