The 4AGE 16V TVIS System...

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jondee86
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The 4AGE 16V TVIS System...

Postby jondee86 » Sat Jul 05, 2014 4:46 am

As everyone knows, TVIS stands for Toyota Variable Induction System.
These are the initials badged on top of the inlet manifold on every AE86
GTS sold around the world. Variations of the TVIS system were also used on
other Toyota engines built around the same time as the 16V 4AGE.

The TVIS system consists of a aluminum plate, matched to the 8-runner
intake manifold, and containing a set of four butterflys. The TVIS plate is
sandwiched between the intake manifold and the head. The butterflys are
arranged so that when the TVIS is activated, one intake runner for each
cylinder is blocked off. The TVIS plate looks like this...

Image

You can see the butterflys in the 2nd, 3rd, 6th and 7th openings. In the
center is a vacuum servo and linkage to rotate the butterfly spindle. Below
is a vacuum reservoir and a 12V vacuum switching valve (VSV) controlled
by the ECU. Under 4200 +/- rpm manifold vacuum is applied to the servo
and the butterflys are closed . Above 4200rpm the ECU activates the VSV
and vacuum is removed from the servo, allowing the butterflys to open.

The purpose of the TVIS system is increase the velocity of the air being
drawn into the cylinders by forcing all the air to flow thru one runner. This
improves fuel vaporisation and introduces turbulance in the cylinder for
better combustion and enhanced low rpm torque. Once the engine rpm is
high enough, the second butterfly opens and the engine benefits from the
increased flow for high rpm power.

The TVIS 4AGE engine is often referred to as a "bigport". In fact, many
people believe that the intake ports are actually too large for decent low
rpm operation. Therefore, keeping the TVIS system on stock or near stock
engines is a good idea. The later model "smallport" 4AGE reduced the
intake port size for improved intake air velocity, and has satisfactory low
rpm performance without the need for a TVIS system.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

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oldeskewltoy
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Re: The 4AGE 16V TVIS System...

Postby oldeskewltoy » Mon Jul 07, 2014 12:04 pm

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

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saiGone
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Re: The 4AGE 16V TVIS System...

Postby saiGone » Tue Jul 08, 2014 12:48 pm

Club 4ag needs a like button
Club 4AG member since 05 (Formally SaigonsSon)

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InfernoAE86
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Re: The 4AGE 16V TVIS System...

Postby InfernoAE86 » Fri Jul 11, 2014 12:46 pm

Great. I just realized I'm missing the VSV and reservoir. :(

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oldeskewltoy
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Re: The 4AGE 16V TVIS System...

Postby oldeskewltoy » Mon Jul 14, 2014 9:34 am

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

Enjoy Life... its the only one you get!

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TIVRUSKI
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Re: The 4AGE 16V TVIS System...

Postby TIVRUSKI » Fri Jul 18, 2014 5:00 am

@ jondee, is that a TVIS out of a setup without the EGR system?

The AE86's:
Image

The AE82's (I think), should still be the same vacuum setup:
Image
If you have the time, please vet the info on my AE86 smallport swap checklist :ugeek:

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jondee86
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Re: The 4AGE 16V TVIS System...

Postby jondee86 » Fri Jul 18, 2014 3:47 pm

TIVRUSKI wrote:@ jondee, is that a TVIS out of a setup without the EGR system?

Yes. Engines without EGR take vacuum directly from a tapping
in the TVIS plate itself. You can see it here with the gasket removed...

Image

This is a FWD 4AGE setup (big pic) with EGR delete markup...
http://img.photobucket.com/albums/v101/dorihachigo/egr_layout.jpg

The actual TVIS plate and actuator are the same, but there is
some connection to the EGR system, and the vacuum source does
not come directly from the TVIS plate.

Cheers... jondee86
The reasonable man adapts himself to the world; the unreasonable one
persists in trying to adapt the world to himself. Therefore, all progress
depends on the unreasonable man.

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