TVIS

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Terry

TVIS

Post by Terry »

Can anyone sum up for me the pro's and con's of gutting the T-VIS plate?

I understand its there to help the engine produce more torque @ lower RPM, but what real benefit would you get from gutting it??

Thanx



P.S. Like the improvements to the site, excellent. :wink:
raptor95GTS
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Re: TVIS

Post by raptor95GTS »

Terry wrote:Can anyone sum up for me the pro's and con's of gutting the T-VIS plate?

I understand its there to help the engine produce more torque @ lower RPM, but what real benefit would you get from gutting it??

Thanx



P.S. Like the improvements to the site, excellent. :wink:


I think its the other way round, more power at higher rpms but you loose the torque low down in the rev range. No doubt the experts will correct and rightly so :lol:
Terry

Re: TVIS

Post by Terry »

From what I understand its the restriction of the TVIS @ lower RPM that creates a higher velocity of air in the intake manifold which enables the engine to produce more torque lower down.

(Please feel free to correct me if im completely wrong here)

Is it just the fact that the TVIS even when fully open will still create a restriction in the intake at high RPM?


Basically what im trying to get at is, is it worth me gutting the TVIS if im only running a small turbo (TD05SH-16G @ 1.2bar max).

:?: :?: :?: :?: :?: :?: :?:
Brian_S

Re: TVIS

Post by Brian_S »

You can disable the TVIS, which forces it open permanently. This is the best way to achieve what you want. You can try it, and if you don't like it you can always go back. There are several articles on the net about doing it.

The way to properly remove it means getting hold of a machined plate that you stick in place of the TVIS system, or you have to weld up the holes that the butterfly spindles used to occupy, etc.

Do a google for "TVIS disable" or similar and you should get a bunch of results. Everyone reports different things about driving with the TVIS opened. Most do report a smoother power delivery though.
^Trickster^
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Re: TVIS

Post by ^Trickster^ »

You only really need to gut the TVIS after 300hp when it starts becoming a restriction.

Graeme
Brian_S

Re: TVIS

Post by Brian_S »

It makes the engine characteristics different though. Driving with it fully open, compared to it being normally closed and only open at higher engine revs makes a difference on even a standard engine. It's not about removing it just because it's a restriction to flow at higher power levels.
Terry

Re: TVIS

Post by Terry »

Unfortunately my engine is in bits still so im unable to play around with the setup.

I've had the car about 8 months now but only driven it for about 5hrs (coasting it back from up north to down south with a leaky turbo and a blown head gasket).

The engine is far from standard and my major restriction to power is guna be the turbo. But the TD05 does give very little lag.

Im using HKS 272 cams both intake and exhaust with shimless buckets which isnt guna help low down torque too much, and is why im not so sure it would be such a good idea to gut the TVIS.

But to help things along I've got lightened resized Eagle conrods, JE pistons, lightened and balanced crank, fidanza ally flywheel and a lightweight Spec Stage3 FDisk clutch.

Obviously if the car was running I could chuck it on the rollers, run it as should be and then run it with the TVIS wide open to compare the results.
(Has anyone done this by the way?)

I've got no problems machining a plate to replace the TVIS and match it to the head and manifold, but I dont want to have very limited grunt at the bottom end and on the other hand I dont want a sudden burst of power at around 5k that may upset the back wheels.

:?
Brian_S

Re: TVIS

Post by Brian_S »

Power delivery is smooth without the TVIS operating, it is better when it's got rid of.

The best way forward is to tig weld, or aluminum putty the holes left by the spindle when you remove it. Then knife edge the back of the TVIS plate. There's no point reinventing the wheel just to get rid of the middle section, when the runners on the intake will give you the same thing! This will blend the ports together a bit better.

Head work will compliment this on the earlier revision head. You should make the side walls a much more gradual change than they are to begin with. You should be able to see good flow from it.

A friend is currently rebuilding with a TD06 and this is what we have done to his. He has not gone too far on the head as he will also not want an engine that feels gutless lower down.

If your still rebuilding in the new year, I can probably let you know how his build went as it should be finished by late jan / early feb.

Should be able to get a few photos for you too.
Terry

Re: TVIS

Post by Terry »

Yeah let me know how you get on, im aiming to get my engine built back up for around late Feb. Im not looking to go for all out power, im more interested in a responsive hard revving power plant. :wink:
Stef Derner
Posts: 486
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Location: Notts. UK

Re: TVIS

Post by Stef Derner »

Here's a little info on T-VIS. It's a Celica info site but hey, it's the same for us. Personally, unless I was going for a big turbo and loadsa mods, i'd keep it, unless you want to keep the revs up there where the power is. The T-VIS giving low down torque and helping the launch is mostly what makes the rev 1 and 2 NAs half a second quicker to 60 than the rev 3 on cars.

http://www.toyotacelicaonline.com/celica1/TVIS.htm
AM TUNING
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Re: TVIS

Post by AM TUNING »

ive just got my engine running after a top end rebuild , ive removed the tvis plate and knife eged the plate and had a very mild port job done and i have to say the engine feels the same , torque is still there ,


i would say do it ,

andi
Terry

Re: TVIS

Post by Terry »

Im goin for a high rev limit around 8k, this will depend on a number of things, mainly the turbo running out of puff.

Andi, are you running a standard turbo with standard boost?

Anyone used the boost control of a Hydra Nemesis 2?

Would it be worth keeping my AVC-R?
AM TUNING
Posts: 601
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Re: TVIS

Post by AM TUNING »

my spec is turbo tech hybrid , st205 charge cooler , water injection, downpipe,mongoose system, unichip,rev 3 inlet cam,1.4 mm head trd gasget,hild ported head and tvis plate,

at the mo im only running 10 psi the engine has only been running 24 hours, so im still being cairfull,

i feels a little flat on boost but it hasnt been mapped synce the turbo,cooler,and water injection were fitted,

i will be running about 18psi when it finnaly mapped and hoping for 300 or oblove at flywheel

i have no idea what hydra boost control is like ,
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