i recently found a decent site for aftermarket performance parts and they are selling a "surge tank" for a 3S-GTE with no "TVIS" of my first question is what the heck is TVIS and second what is a surge tank the description isnt really that great as far as what it actually is because it has a picture of what appears to be an intake head so would it be an aftermarket header??

http://www.more-japan.com/product.php?prod...at=0&page=1

surge tank = intake manifold
$3.400 for an intake manifold?! ill pass.

tvis = butterfly valves inside every other runner in the stock 3sgte manifold, used to increase air speed velocity at low rpms to promote higher torque.
at higher rpms they hinder air flow so it is common practice to remove them.

JUN surge tank (a.k.a. intake manifold) is designed for MR2.
It won't clear the firewall on 5th gen.
Not sure about 6th gen.

Not too sure about your explanation of TVIS.

The thing with the butterfly valves within the manifold I thought was ACIS.

TVIS was GT4 boost related. Something to do with upping the boost in first/second gear IIRC. You can deactivate this so you have the same boost pressure in each gear.

>
What you are referring is TVSV, not TVIS.
TVIS = Toyota Variable Induction System
TVSV = Turbo Vacuum Switching Valve
Might wanna read this:
http://www.gtfours.co.uk/what/tvis/tvis.htm

My bad, you are right.

I read about it a while ago, knew it was T something.

What's ACIS then? I could have sworn that's something to do with butterflys in the inlet manifold?

ACIS = Acoustic Control Induction System
ACIS varies the length of the intake manifold while TVIS varies the cross sectional area of the intake manifold.
Both system have the same purpose: to improve driveability over the range of engine RPM.