3s Q??

[SIDE_FX]

do 1st gen (st165) 3sgte's have tvis, if so is it better to disable it

[Adydas]

TVIS eh.. i belive you will find the answer is Yes.. to back my self up.

The 3SG was introduced in 1986. This engine series was initially available in a FWD, AWD, or mid-ship configuration. Transverse. The block is based on the S series engines- a lightweight steel block that was earlier used with SOHC heads. Again this is an evolutionary engine. The 16-valve design is very similar to the 4AG and 7MG, in fact valves, springs, lifters- are very close dimensionally. The head is of the G type, meaning it was designed as the performance model as compared to the F types that are designed for torque and low-end response. Our concern here is performance so we will discuss only the G models.

There are 4 distinct generations. The 1st generation, most common in the US, is TVIS inducted (dual-runners with large ports) available in NA or Turbo editions. The 2nd generation was also available in both NA and Turbo forms, but had a different intake system (and smaller ports). The old TVIS system was replaced with a new short/long ram induction system on the NA models. This was achieved using a plenum that redirected air thru a shorter or longer passage- depending on throttle position and vacuum. On the turbo models the manifold just went straight to the head. This resulted in a much better throttle response, and with the added compression gained both HP and torque. The 3rd generation revised the valve adjustment set-up. The shim adjustment originally on top of the lifter, was moved under the bucket- like the old 2TG/18RG set-up. This was to correct a problem with shims falling out at very high RPM’s (on modified engines specially with aftermarket sports cams). This was a modification introduced earlier for higher lift and longer duration cams by sport tuners.

[sergei]

if it is working leave it on, if it is bung fix it or chuck it away... unless engine is extensevly modiffied then chuk it away... most common problem - ripping/cracking of diaphramm (spelling) inside of accutator, so it will leak vacuum and not hold the butterflies closed.

[samlloyd]

when my mr2 goes past 5,000 rpm it goes into a noticable 'monotone'. is this tvis? (1992 3sge)

[sergei]

not quiet, its "variable intake length system" or whatever it is called

[Ae92typeX]

If its all working, I'd keep it imo.
lots written about it on various forums, but keeping it local:

viewtopic.php?t=30916&

Unless you have done some reasionable mods, or it is faulty, its not beneficial to remove. Lets think for a second- if it was best removed, would toyota have spent all the extra money putting it in?

[CozmoNz]

when my mr2 goes past 5,000 rpm it goes into a noticable 'monotone'. is this tvis? (1992 3sge)

This would be tvis, which then went onto acis (instead of 2 runners down to the head same length, one opens one shuts etc, they had 2 but different lengths, (one short, one long) which opened the short one at 5000rpm)

Then i think there was 3 way acis i remember someone telling me (3 individual runners, all different lengths) etc.

Its what they did before vvt i guess, some hondas use i think its acis? which is what makes the noticeable Boobaa.... also the reason why nzcelica had A HONDA CELICA X_X. bahahah

[Malcolm]

The 3SG was introduced in 1986. This engine series was initially available in a FWD, AWD, or mid-ship configuration. Transverse.

Well that's not true No mr2 had a gen 1 3sge or 3sgte....

he 2nd generation was also available in both NA and Turbo forms, but had a different intake system (and smaller ports). The old TVIS system was replaced ...... On the turbo models the manifold just went straight to the head.

False again. The 2nd generation 3sgte (found in MR2 turbos 1989-1993 and ST185 Celicas) had T-VIS, it wasn't until the 3rd generation that they removed it on the 3SGTE, at which point it became a basic single runner system.


Anyway, IMO don't take it out, it does it's job just fine. Sometimes people with modified engines decide to use a V-TEC controller (or similar) to change the switch over point as it's set up for the ideal change over for an unmodified engine, and there can be gains had by make the butterflies open at lower RPM on modified engines. Taking it out completely is an option for more extensively modified engines, although at that point it [i]may[/b] be worthwhile changing to a later model head to maintain good port velocity at low RPMs. I have taken the T-VIS out of my MR2 (being a light car I decided it would be fine without it). Spools like crap with the steel ct26, but I'm thinking about going gen 2 NA or gen 3 head at a later date anyway...

[Adydas]

well google turned up them answers.. just shows how Bs info in the net can be

[Malcolm]

it does indeed. Think I've read the site that stuff came from

[Soulhaven]

if it is working leave it on, if it is bung fix it or chuck it away... unless engine is extensevly modiffied then chuk it away... most common problem - ripping/cracking of diaphramm (spelling) inside of accutator, so it will leak vacuum and not hold the butterflies closed.

diaphragm... if you're curious... how dumb is language sometimes?? what's with that g? goes to show how close you were, tho...

[samlloyd]

when my mr2 goes past 5,000 rpm it goes into a noticable 'monotone'. is this tvis? (1992 3sge)

This would be tvis, which then went onto acis (instead of 2 runners down to the head same length, one opens one shuts etc, they had 2 but different lengths, (one short, one long) which opened the short one at 5000rpm)

Then i think there was 3 way acis i remember someone telling me (3 individual runners, all different lengths) etc.

Its what they did before vvt i guess, some hondas use i think its acis? which is what makes the noticeable Boobaa.... also the reason why nzcelica had A HONDA CELICA X_X. bahahah

not quiet, its "variable intake length system" or whatever it is called

I see that some honda people make a little VTEC led, and have heard on this forum people mentioning vvt lights. Can i do anything like that with whatever the hell my car has at 5k rpm +??

(general enquiery, please dont piss take)

[MrOizo]

you'ld need a normally closed relay so when the TVIS turns off the LED lights up. TVIS doesn't happen up top, its happening down bottom (ie, below 5krpm)

TVIS actually turns off and opens up the runners as the runners are normally open, vacuum holds them closed at lower rpm.

[samlloyd]

oh really, i see...

Has anyone ever done this?
Is it possible? Preferably without ripping up dashboard

Thanks

[Ae92typeX]

Different engine, same topic
explains how to basically do it, you'd just need to look at an ecu diagram for your engine:

viewtopic.php?t=33272&highlight=tvis+light