TVIS turbo operation

[Andy from the block]

Im trying to setup TVIS for my 4agze turbo and by looking at
http://www.celicatech.com/forums/printthread.php?t=412
I was thinking since the TVIS butterflys shut when there is vacuum
to the actuator, could I simply plumb a hose from the actuator to
the intake manifold?
Since I run a turbo would this go something like this?
no boost = vacuum = butterflys shut = better low end torque
boost = no vacuum = butterflys open = better top end power
Could this be an alternative to the rpm switch?
Cheers.

[4age_rage]

Personally I'd just get rid of the TVIS

[crnkin]

Personally I'd just get rid of the TVIS

idiot

[deaf_rattle]

Personally I'd just get rid of the TVIS

wow, you really answered the question well there.

[Crampy]

I'm leaving it standard to start with, so the computer is still going to open the butterflies. I was thinking about doing what you're talking about, but I think it is better to leave the butterflies closed for a bit longer than that. As soon as you stab the throttle, the manifold vacuum will drop to zero and the butterflies will open, but you're turbo still wouldn't have spooled up. I might go to a RPM switch later on once I've got the car going again and play around with the switching point, to see what it does to down low torque and turbo spool up time.

You might be better off setting it up with a RPM switch as opposed to a vacuum switch. I think people set it to switch lower than the factory 4,500rpm though.

My thoughts anyway.

Personally I would keep the TVIS

[Si]

would you not benifit more by removing the resriction on the intake that TVIS is?

im no 4age expert, but there is a hell of alot of restriction there.

[Crampy]

I've seen guys that run their turbo big port 4AGE's without TVIS and then put it back on and say they'll never go back. Apparently it helps to spool the turbo up much quicker.

If you're going for mega horsepower, don't use the intake manifold, go for a custom one which is designed better for forced induction.

[matt dunn]

If i was doing it, I would have it boost switched, but at about 4 psi or so,
depending on the actual boost level that you are going to run,

Because even at 7000 rpm, if you on light throttle, the butterflies closed may still help torque and fuel efficency,

but you will still really need them to help response off boost and down low in the rpm.

Matt

[atmosports]

From my experience with TVIS type setups it's generally best to find a decent tuner & have a play on the dyno. Some engines like them open then closed, some you run them open, then close & then open again etc. There can be some reasonable gains there if you have them working properly, probably not as noticeable on turbo but definately with N/A applications if you are sticking with the factory manifold for some reason. We played with this sort of setup back in the old 2L touring cars days a lot & it made a difference on the 3sge & made a hell of a lot of difference on the Telstar V6's, though we run either Motec or Autronic Ecu's & switched using vacuum,tps,rpm or a combination of those.

[ATAl]

This thread reminded me that the tvis on my car was disconnected, so I've just hooked it up just as you are suggesting and the only difference is that the idle is better and possibly it drives a little more smoothly, on boost there is no difference.

So at least it can't hurt.

[matt dunn]

This thread reminded me that the tvis on my car was disconnected, so I've just hooked it up just as you are suggesting

If you run it straight off manifold vacuum, it will be a waste of time as when you need them closed most is at Full throttle, off boost at low to medium revs,
and straight off manifold vacuum they will be open not closed.

Matt

[Andy from the block]

Thanks for the technical feedback guys.
Yeah that 4psi setting sounds like a good idea Matt and getting a dyno
tuned setup is a good way to go to atmosports. However Im not too fused at the moment in getting the exact tuning of the TVIS right at this point. In response to people who think I should take out the TVIS becuase it causes a restriction, I already have the TVIS plate installed and my car has plenty of power up top and Im not in search for more at this point. What I would like, is to setup the butterflys to work since they are currently open at all times. In the meantime while getting a rpm switch or boost switch or getting my link to control the TVIS I was just wondering if I could try and plumb the TVIS actuator to a vaccuum line from the intake manifold (ie: my first post). I want to try this and was wondering if this would possibly damage the TVIS actuator or have any weird effects when I hit 19psi? as I take it the TVIS actuator was designed to see vacuum only?

[Andy from the block]

This thread reminded me that the tvis on my car was disconnected, so I've just hooked it up just as you are suggesting and the only difference is that the idle is better and possibly it drives a little more smoothly, on boost there is no difference.
So at least it can't hurt.

Thats what I was expecting cool so I can go and try it ,at least it will help with my idle, right now its a pain with my heavy duty clutch so I need all the torque I can get.

[~SlideWays~]

FYI / for interest sake re: tvis and boost.

I've had this tested on Speedtech's dyno and it shows a big difference between having tvis open all the time or having it set to open at a certain rev point. I previously had the car running with a std gze ecu BB t28 with no TVIS and it was GUTTLESS off boost and slow to spool. With the TVIS and a LINK tuned its a huge difference, granted the timing etc is changed but off boost it has much more torque and a definite reduction in spool up.

Andre did 2 back to back runs and the best point (for my car) was to have it closed until 4700rpm then open, pretty much the same as a standard bluetop IIRC. It is such a smooth power delivery that I could barely feel the transition. So much so that it didn't even have a big kick like you would normally have with most turbo's.

[Crampy]

If your worried about the boost hurting the TVIS, just put in a one way check valve. I'm doing that.

They only work on vacuum, so with the check valve, it doesn't see any boost at all.