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Location:
Denmark
Registered:
July 2003
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TVIS
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Sat, 20 September 2003 18:09
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Hey again
Should I disconnect the TVIS option?
Jacob
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Location:
Epping, Sydney
Registered:
April 2003
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Re: TVIS
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Sun, 21 September 2003 01:42
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nah it rocks! It does make a difference, sorry to say this, but just search around here... there have been some rather lengthy discussions on the topic around.. hahah But basically the conclusions were it does help!
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Location:
Brisbane
Registered:
February 2003
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Re: TVIS
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Sun, 21 September 2003 03:10
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On a mostly stock engine it does help increase low RPM torque by increasing the air flow speed into the combustion chamber. On a high power engine it could become a restriction. If, for example you had stroked the engine to 2.2L or similar, then you'd probably ditch the TVIS as the stroker crank would make up the lost torque.
If you do decide to ditch it, then I'd do it properly and take off the intake manifold and the TVIS plate (sits between the intake manifold and the head) and actually take out the butterflys. That way you are truly removing the restriction, rather than just disconnecting it.
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Location:
South Australia
Registered:
July 2002
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Re: TVIS
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Sun, 21 September 2003 07:43
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I think someone really needs to write something permanent up on this. It seems to crop up quite often!
It makes me wonder how much bad press the T-VIS got though, alot of people are under the impression that Toyota (Yamaha designed tho) put it on there to make the engine perform *worse* (which is obviously bs)
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Location:
South Australia
Registered:
July 2002
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Re: TVIS
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Sun, 21 September 2003 07:48
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Oh - and one other thing...it's mainly on there due to bad (or should I say innefficient) port design, and you'd have to increase the stroke by *alot* (not just out to 2.2 litres) in order to gain a real benefit from taking off T-VIS...you would probably find it's not physically possible to stroke out the engine far enough to gain benefit from no T-VIS.
Once again, it really comes down to the design of the head and manifolds (port size, valve lift and duraction, intake manifold length etc)...and this has been covered before.
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Location:
Perth
Registered:
June 2002
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Re: TVIS
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Sun, 21 September 2003 08:38
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| FWDboy wrote on Sun, 21 September 2003 15:48 |
Oh - and one other thing...it's mainly on there due to bad (or should I say innefficient) port design
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I dont agree..... 3S-GTE heads flow extreamly well from the factory. 3S-GTE heads do not have innefficient port design
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Location:
Melbourne
Registered:
July 2002
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Re: TVIS
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Sun, 21 September 2003 08:43
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Leave TVIS on for near stock (ie not HEAVILY modified) engines. Check bill sherwoods page. Heaps of info there  http://www.billzilla.org/4agstock.htm
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Location:
South Australia
Registered:
July 2002
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Re: TVIS
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Sun, 21 September 2003 15:01
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Flow isn't the issue, it's streetable engine torque curve and streetable emissions that I'm assuming we are talking about. Of course, turbo and NA have different needs, so I guess in that regard the 3S-GTE/4A-GZE 'flows' quite well ... as opposed to the 4A-GE and 3S-GE.
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Location:
Denmark
Registered:
July 2003
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Re: TVIS
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Sun, 21 September 2003 20:28
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Thanks for all the answers
Jacob
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