what is TVIS

[Al]

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

Look at your dyno plot it should spike like mine.

If they werent operating it would be as slow as the ke70.

[l1ttle_d3vil]

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

this should tell you what you want. http://www.hachilife.com/garage/?manual=em_45

thanks for the info crankn, I will look in to that!! everyone has told me tvis makes no difference so Ive never bothered wiring mine up...maybe i should

[Caveman]

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

this should tell you what you want. http://www.hachilife.com/garage/?manual=em_45

thanks for the info crankn, I will look in to that!! everyone has told me tvis makes no difference so Ive never bothered wiring mine up...maybe i should

That is a good test but it will not tell wheather the butterflies are sezied open/closed. This has happened to someone on here before.

[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?

Look at your dyno plot it should spike like mine.

If they werent operating it would be as slow as the ke70.

Ahh, there is a big jump at 90k, which thanks to Fivebob's little page tells me is 4450rpm...also a corresponding drop in a/f to a shade over 11:1 (yes the thing was running uber lean). Sounds about right time for TVIS to open yeah?

[Al]

Yep.

Can you get an rpm switch for the linkplus? To smooth the curve out you just lower the point of TVIS opening, would be somewhere around 3500-3800rpm or so. I find the higher boost level I run... that dip then spike is even more noticeable to the ass dyno. Because the ct20b spools so damn fast but the TVIS butterflies are closed and it cant do anything with it, they open, you lose velocity then WHAM, you are in the back of your seat

[Dell'Orto]

Yeah, the LinkPlus does have outputs for things like that....could be worth looking into.

[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...

[Dragger_Dan]

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...

Weight isn't a huge issue, the whole TVIS setup weighs perhaps 2kg at the most.

[CozmoNz]

if you have a poddie in your car, you can easily notice when tvis *changes* over.

acis is the same (noise anyway).

boobaa styles .

[Drifter4ag]

basically guys if it aint plugged in then the butterflys are open.

[l1ttle_d3vil]

basically guys if it aint plugged in then the butterflys are open.

how do you close the butterflies then? if I just wire it up then turn the ignition on will the butterflies automatically close since theres power, or will i need to take my manifold off and close them myself?
just wanting to make sure as I wired it up tonight but it doesn't seem to have made a huge difference to how it runs but they may still be open.

[Dragger_Dan]

What I would suggest is to take it out for a drive... if you are free revving it with no load on it isn't that distinctive.

Find a nice long straight piece of road, put it in second or third and put your foot into it. You should be able to notice a distinct chance in induction noise a bit before the 4500 mark, and it should be really roaring by about 4700 at the latest. If you start off slow and use second or third you will get a nice slow increase in RPM which will make the TVIS come across really distinctive.