turbo+TVIS

[45aken]

hello again,
just wondering what is the go when putting forced induction into the RWD 4age motor. i have heard that the inlet runners on the rwd manifold have to be welded up? something to do with the butterflys bending.

can anyone elaborate on this for me?
thanks

[slide86]

i would (and have) removed the TVIS plate completely when i did it. i have also heard that they can bend, and even worse. apparently they can come flying off and go into the engine! not good!

i would remove them. i dont think the difference would be really noticable, it would still feel like the engine is off boost and a bit laggy even with the TVIS fitted.

[-==L=a=N=c=E==-]

I removed t he tvis butterflies when i rebuilt my old 3sgte. The difference was next to nil. Some will argue it benefits from low dow torque, but i let the turbo do the talking when it comes on spool.

As slide86 has already mentioned, the tvis is just another thing to 'fail'. I too have heard of the plates coming loose and wrecking havoc to an engine. Especially at higher boost/airflow levels.

[Jt_70R]

T-VIS is actuated by vacuum pressure, wouldnt there need to be some form of conversion to the diaphragm?

Also, T-VIS was developed to provide the NA motor good torque down low while still giving good power at high RPMs, so by its very nature it probably isnt very well suited to forced induction application. You turbo boys dont need to worry about 'good' manifold design as the turbo simply jams the air in.

[JustCallMeOrlando]

My 1G had TVIS, and I see no reason to remove it. I personally wouldn't remove it. I've driven with my TVIS locked open, and locked closed, and there is a marked difference to lower end torque.

Just because there is a turbo there doesn't mean the basics don't apply. Low RPM, we're not going to have positive boost pressure so are going to need all the help we can get.

The 1GGTE uses a vacuum cannister with a one-way valve to get around the positive pressure problem. KirK actually rigged his up so the butterflies opened with positive pressure and he seems happy with the result. I personally will be retaining the factory style setup when I go aftermarket ECU.

[kingmick]

just becareful how much boost you use! the main diffrence beside bending or loosing a butterfly is that it creates more turbulence for air going into the chamber in 4ag or 1g. so you miss out on a few extra HP. but if the engine is for street use and reasonalbe power it wont really matter.
i would take them off, just for safety!

[JustCallMeOrlando]

I've not seen anything but speculation about anyone actually bending or breaking the butterflies by adding forced induction.

[kingmick]

ive have seen a 4ag with one that cam off in atmo form but its more a saftey point that is another moving part that can let go in the induction system. boost puts pressure on every thing and changing cames does it aswell! the resonance changes and i have a big horsepower {i mean really big} that keeps cracking the manifold hat because of resonance!
if it can crack a hat it will loosen butterflys if it has the chance.

[SilverGhost]

T-VIS is actuated by vacuum pressure, wouldnt there need to be some form of conversion to the diaphragm?

Also, T-VIS was developed to provide the NA motor good torque down low while still giving good power at high RPMs, so by its very nature it probably isnt very well suited to forced induction application. You turbo boys dont need to worry about 'good' manifold design as the turbo simply jams the air in.

T-VIS was not designed mainly around N/A applications. The only reason why T-VIS was put into the 1G, 3S and 4A motors is due to the port design. They wanted larger ports to more effectively feed the multi-valve design at higher RPM's effectively raising peak power.

What they realised was there wasnt enough airflow at low RPM's to atomise fuel correctly and provide ideal VE. Thats where T-VIS comes in, wether it be a turbo or N/A motor the butterflys stay shut up until around 4200 rpms becuse it has been found that with a smaller entry point into a motor the air is pulled into the motor at greater speed allowing for greater VE and fuel dispersal. Above 4200 rpm the engine is moving enough air that it can take advantage of the port/valve design and the butterfly opens.

I would debate that turbo motors need to worry about manifold design just as much, if not more than an equivalent N/A motor as they shift several times more air. The weaknesses in the flow setup of a manifold would be more pronounced under greater volumes.

[kingmick]

you mean like i said?

[stradlater]

I took mine off cos I didn't want the hinderance, seeing as they weren't hooked up properly anyway.

That said, they are designed to give the turbo motors more torque down low, so I wouldn't say they are just for N/A's.

[30psi 4agte]

get rid of it. On a turbo set up its a waste of time!!!


they only time i would keep if is my motor was stock.

[Jt_70R]

Wow, some people on here really like having the last word! I think you missed the word 'probably'. I also should have said 'you turbo boys dont need to worry -as much- about manifold design'. Sorry bout that.
I am well aware of manifold design with tuned lengths etc. being a final year mechanical engineering student, involved with out formula SAE team. I was just trying to say i think its more important to look at manifold design, ie. runner length, on a NA engine than a forced induction motor.

[45aken]

hahaha wollongong SAE team OWNS you guys every year!!!!!!!

how would i go about taking out the tvis? isn't it just the plate between the manifold and the head?

word..

[Ghetto-AW11]

you can remote the butterflies from the said plate, and either use metal epoxy or weld them up. The plate is a good spacer because if you completely remove it you have mounting issues and clearance issues.