[Mk2] [Turbo] Correct way to disable TVSV??

[se4njb7]

What is the correct way to disable the tvsv on a Rev 3 turbo and run high boost? Disconnecting electronically or blocking off the hoses?

[JAAASH]

Either way is perfectly acceptable

[Ryan S]

As above but having done it both ways i will never attempt blocking off the hoses again, total pain in the ar$e, just unplug the connector it's far easier

[killerferret666]

What's the benefit in doing this when running higher boost?

[2mad]

What's the benefit in doing this when running higher boost?

You need to disable/bypass stock boost control to run electronic/manual boost control .

[se4njb7]

Just I've unplugged mine electrically but been told to plug it in and and block the hoses so the ecu can still do its thing but never got told a reason as to do it that way.

[C35Rob]

I've blocked the hoses.. was told to do it this way by a specialist.

I can see the logic behind it.. leaving sensors/solenoids etc the ECU is expecting to see unplugged isn't the best way around things IMO, but whatever works for you....

[2mad]

I've blocked the hoses.. was told to do it this way by a specialist.

Capped mine off too .. on two cars .. no problems

[raptor95GTS]

pulled the electrical connection. Easier and quicker but works just as well as blocking the pipes correctly.

[Ryan S]

What's the benefit in doing this when running higher boost?

You can't use a boost controller if you don't, You will get full boost in 1st and 2nd gear though, With it still connected the boost is limited in 1st and 2nd gear, My understanding of this was to make the car feel more refined but I can't confirm that

[Marf]

Refinement? Nah, more like moron mitigation technology on a car where traction control was an option. Might have also had something to do with knobbling the car a bit so it wasn't as fast as a Supra out of the blocks.

Just unplug the unit. I did that before plumbing in my Blitz boost controller.

[Ryan S]

Just to add to my post the ECU will no longer control the boost based on temperature, So you will get full boost even if the car is cold with it disabled. Obviously try to stay off boost until the temp is up.

[Marf]

And disabling TVSV prevents limiting of the boost if the ECU thinks the engine bay is too hot, something easily achievable on the stock IC on a vaguely warm day.

[Al-sw20]

Boost was never 'limited' in first and second gear. Total myth.

The cars never had enough load to get the 11.8psi of max boost pressure in 1st.

Both my MR2 turbos, bought stock, both ran 11+psi in 2nd and beyond.

[Ryan S]

Interesting, how come a car with a boost controller will happily run well above 11psi in 1st gear then?

[jon]

Boost was never 'limited' in first and second gear. Total myth.

Not true for a Rev 3, the ECU has different boost curves for 1st, 2nd and 3rd+ gears. I know this from reverse engineering the ECU software.

[Marf]

Boost was never 'limited' in first and second gear. Total myth.

Not true for a Rev 3, the ECU has different boost curves for 1st, 2nd and 3rd+ gears. I know this from reverse engineering the ECU software.

Indeed, and the not enough load thing is bunk, I could hit 18psi in 1st gear no problem.

It's called having proper tyres fitted

[mr2magic]

What the T-VSV does:

TVSV
(Turbocharger Vacuum Switching Valve) is a "factory-installed boost controller". It is simply a solenoid-operated valve that, when energized (open) allows air to escape from the actuator, lowering the pressure in the actuator, and allowing the wastegate to modulate closed. This vented air actually flows back into the intake airstream between the airflow meter and the turbo intake so it does not distort the ECU's air/fuel ratio calculations.

The T/VSV is a normally closed-energized open valve. The ECU will energize (open) it whenever you boost IF 1) engine coolant temps are up to normal , and 2) ambient (intake) air temps are above ~ 32 deg F. (There may be some variation with that number). If the T/VSV is open (high boost mode) and the ECU gets a signal from the knock sensor, it will de-energize (close) the T/VSV. Likewise, if there is an over boost signal from the boost pressure sensor, it will de-energize the T/VSV as part of the "fuel-cut" sequence.

NOTE: Unless you have an aftermarket boost controller, disabling the T/VSV will lock you into low-boost mode!! It WILL NOT increase boost.

The normal range of max boost ranges from 7.1 to 11.8 psi, according to the Factory Repair Manual. Low boost problems are almost always a result of some problem in the boost control system and rarely with the turbo itself..

[raptor95GTS]

mr2magic - the rev3+ VSV is a PMW device and not a simple on/off

[mr2magic]

indeed it does. The reason for it's existence and the ways to disable it remain the same though