TVIS... to pull or not to pull

TVIS

  • Remove

    Votes: 1 100.0%
  • Keep on

    Votes: 0 0.0%

  • Total voters
    1

omgitsroy326

New member
Should I remove it ?

I'm gettin my head redone by ths one shop... What exactly do i need to take off... is it just the butterfly part?? anyone got pictures???

BraveUlysses had said that it's beend dyno proven to inscrease low end torque
 

CMS-GT4

Active member
If your power goal is only 350 or so, I would keep it. It has been proven to be of benifit if you control it. There is a thread on this around here somewhere.
 
Removing the TVIS unit would cost you torque down low

Controlling the opening point (if I remember right its at 3800 vs
the 4200 rpm stock opening point) actually improves on the stock setup

You would want to gut the unit (or buy a Manj phenolic spacer at $225)
so you keep the stock TB (and TB stay) geometry

Unless you are making a pile of power (and then you would probably
get an aftermarket intake manifold anyways) I would keep the unit. My 2 cents
 

C-dubb

New member
omgitsroy326":2pynroys said:
i wanna go to whatever stock internals can take me w/ a new metal head gasket... what would that be around?

with that said i would keep the tvis and controll it. i'm not sure what kind of power you can make on stock internals with reliability in mind...? I would think they could hold a good 17psi...i have heard of some MR2 owners running 20psi on stock internals.
 

muneo

New member
I remember seeing a good article on this using the 4age? motor. I forgot the exact motor but another toyota motor was dynoed with and without the TVIS system. the results showed that ona stock motor, the system is quite helpful. Anyone remember the site or link to this?
 

saved_1992

New member
just remove the butterflys, if you are going to be running higher than stock boost there will put more strain on the butterfly screws. plus if the butterflys come off say hello to alot of internal noise and possible damage to valves,cyld. walls and pistons.
 

___Scott___

Active member
Actually you don't notice any strange noises, just an immediate loss of power. The cylinders survive quite well, but the head and pistons get thoroughly trashed. Valves and seats require a re-grind at a minimum.

I say keep the butterfly plates, but center-punch the screws on the end that comes through the shaft so that the end of the screw is flared slightly and can't back out.
 

ruffneck

New member
say keep the butterfly plates, but center-punch the screws on the end that comes through the shaft so that the end of the screw is flared slightly and can't back out
On the ones that I have seen, this is already done from factory? I am going with a gutted plate on my new engine, if you drive it with the vac line pulled so the tvis is always open you will find a little loss, but not a huge deal....and in my experience I don't get much out of my 3sgte/ct27 below 3100 rpm. It's recommended to open it at 36/3700 rpm, so big deal, lose 500 rpm.. I say gut the tvis and KeepItSimple/Safe.
 

gearhead313

New member
start hogging that b*tch out...




porting2.jpg
 

935motorsports

New member
It depends on how much you drive your car.

I used to drive my ST185 quite a bit, stop and go stop and go. I always thought my car was fairly zippy, coming from ST165 land.

However, when I changed my clutch I noticed that the TVIS was actually not hooked up!

After I hooked it up and going for the same drives day to day, it was 10x better! I had insta torque for the low end and loved every minute of it.

So from a daily driver aspect, keep it. However, after you up the boost, get exhaust, etc. you will find that it does not open early enough anymore. An rpm controller would be nice, but otherwise just leave it disabled.
 
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