To use TVIS or not to use TVIS.

use it.

 

depends on ALOT of variables but...........
short answer if your going for a drag style dyno killer then delete it
if you wanna do knanas, or just daily use where the car will be at low revs then use it.
Look at it like this. up til 4000rpm TVIS is closed after that its open.
decide wich side of that rpm point you want usable power and you have your answer

 

TVIS info and I quote :-

Toyota Variable Induction System, or T-VIS, is a variable intake system designed by Toyota to improve the low-end performance of multi-valve engines.

T-VIS is intended to improve the low-end torque of high-performance, four-stroke internal combustion engines - by changing the geometry of the intake manifold according to the engine rotation speed. The system uses two separate intake runners per cylinder, one being equipped with a butterfly valve that can either open or close the runner. All valves are attached to a common shaft which is rotated by a vacuum actuator outside the manifold. T-VIS does not actually keep one of the intake valves from opening or seal off the port for one valve.

The engine control unit (ECU) allows vacuum into the actuator by powering a solenoid valve when the engine rotation speed is low. At higher engine speeds (e.g. 4,200 rpm), vacuum is cut off and a spring inside the actuator causes the butterfly valve to fully open.

The idea behind the system is that in the lower engine speed band, the speed of the intake air will be increased because the intake runner cross section per cylinder is smaller. However, when engine speed increases, the second runner is opened, decreasing airflow speed, but increasing the airflow volume, better matching the engine's airflow needs at higher revolutions.

With modified engines it may be desirable to have the T-VIS open earlier than stock, because modifications that improve an engine's power output may do so by increasing airflow per engine revolution, resulting in a high airflow at a lower rpm.

In addition to providing more air at higher engine speeds, the system also creates a swirl in the combustion chamber at lower rpms. The swirl makes for more efficient combustion, and is due to the asymmetric nature of the airflow with one intake runner closed.



****** This is also very interesting, the dude that posted it should have used an easier reading font, if reading it starts to give you the shits then just copy and paste it into a RTF document and change the type of font........... http://websworld.org/marcel/tech/tvis/tvis.html

 

Just for everyone's information, my ST185 3sgte engine gained 18kws by the removal of the TVIS throttleblades. Shaft still insitu. So if you remove it complete, blades and shaft, you should expect 20kws of gain.

 

Don't want to be rude, but your 3s-gte is missing quite some kws itself so maybe your T-vis system was faulty anyways?? Again, not to be rude but being rational

 

I'm very aware that my engine has a mysterious hidden power issue, its just i was able to acknowledge that before the TVIS blades were removed, the engine only made 93kws, now 111kws etc.

 

[FONT=&quot]Engine compression values are as follows >
Cylinder 1: 195psi
Cylinder 2: 195psi
Cylinder 3: 190psi
Cylinder 4: 190psi[/FONT]


This equates to a brand new engine in my opinion. Overall, the engine made only 111kws to date. Boost wise, the dyno operator said it was pushing 10psi, but i dont know.

I cant see any boost leaks, so im pretty much stumped at the end. I just dont know where the other 30 odd kilowatts is. Whats boost cut, is it 8,10,12 or 14psi with this version 3sgte. Its a 1991 model st185. Top mount air to air, ct26. The car has a 2.5 inch mandrel bent exhuast, so at the end, i have lost up to 40 extra kilowatts.

 

Did you change your fuel pump to an ST185 one?

 

Its the standard 1.3 starlet fuel pump.


Its so far done the job. As per pic, afr's were low 11's on full load and i believe 10psi.


All possibilities and opinions welcome.

 

When I swapped my old 3SGE to the BEAMS, I had to swap the fuel pump too, the engine worked jerky with the original pump. The difference in your case is much bigger, so I would be very surprised if the fuel pump from an 1.3 engine could feed a 2.0 turbo. The injectors are at least double capacity, as I imagine.

 

he has a point, perhaps the motor is limiting its output to keep the afr at 10-11 because of less fuel supply

 

When using my old 3s-ge fuelpump my car drove shit untill I put in the 3s-gte fuelpump, so that might cost you some hp's. Worth a try?