Disabling The Tvsv Or Is It Tvis? Or Are They 2 Different Things? St18

[sweatyfox]

I just fitted a boost gauge to my 1991 GT4 (running super chip with race spec steel head gasket) and these are the boos figures im getting:

1st Gear 7.5psi

2nd Gear 9.5psi

3rd Gear+ 14.5psi

I have read there is some valve jobby (TVSV / TVIS) that limits the boost in the first 2 gears on the ST185, so if your going to up the boost then the first thing that needs junking is this restriction.

Is there an easy way this can be disabled without pulling loads of things apart? I read somewhere you can earth out a wire, or blocking a certain pipe.

Can anyone help me out here, pics would be appreciated.

Thanks

[Bibbs]

Cut and block the pipe from the actuator to the plenum.

There are two hoses from the actuator .. cut the NON turbo one. Block both ends.

[sweatyfox]

Cut and block the pipe from the actuator to the plenum.

There are two hoses from the actuator .. cut the NON turbo one. Block both ends.

Has anyone got a pic of the pipe in question? Im quite a newbie when it comes to all this stuff & I just want to make sure I dont block the wrong one!

Thanks

[Bibbs]

it's obvious .. not the one about a foot long from the turbo, the one about 6" long and goes from the Actuator to the Plenum ..

[sweatyfox]

it's obvious .. not the one about a foot long from the turbo, the one about 6" long and goes from the Actuator to the Plenum ..

Cheers, I'll get bodging later tonight

[Bibbs]

BTW - it'll put you in constant "low" boost, you need need a g-valve or electronic controller to up this "low" boost setting.

[GT4 BOOSTER]

I hope he reads that before hacking the pipework :!Removed!:

[Bibbs]

I hope he reads that before hacking the pipework :!Removed!:

Fingers crossed hey

[sweatyfox]

I hope he reads that before hacking the pipework :!Removed!:

Fingers crossed hey

Ok, im confused now

I thought by blocking this pipe it prevented bleeding off the excess air in 1st & 2nd and gave you the full boost?

Will the superchip not override the low boost setting?

[Bibbs]

Basically that tube allows the stock ECU to add 4 psi .. which it doesn't add when running in 1st/2nd.

You disable the ECU's control (by cutting it) and then add in a boost controller to get the desired boost all the time.

[sweatyfox]

Basically that tube allows the stock ECU to add 4 psi .. which it doesn't add when running in 1st/2nd.

You disable the ECU's control (by cutting it) and then add in a boost controller to get the desired boost all the time.

I read this snippet from the www.gtfours.co.uk website under the 'how to' section:

"Cut and ground the TVSV wire.

I'm not a fan of snipping wires, seems quite agricultural to me...this will however keep the VSV open and allow the higher boost pressure in all gears."

So if I can keep the TVSV permanently open that will allow max boost in all gears? Are there any other ways I can achieve this?

Does anyone know what wire needs to be cut & earthed?

Or is this not advisable?

Cheers

[GT4 BOOSTER]

goto www.st205.net and buy a k1ano valve for #26 quid , add a boost gauge and you can up the boost till you kill the engine if you like.

[daktari]

Basically that tube allows the stock ECU to add 4 psi .. which it doesn't add when running in 1st/2nd.

You disable the ECU's control (by cutting it) and then add in a boost controller to get the desired boost all the time.

I read this snippet from the www.gtfours.co.uk website under the 'how to' section:

"Cut and ground the TVSV wire.

I'm not a fan of snipping wires, seems quite agricultural to me...this will however keep the VSV open and allow the higher boost pressure in all gears."

So if I can keep the TVSV permanently open that will allow max boost in all gears? Are there any other ways I can achieve this?

Does anyone know what wire needs to be cut & earthed?

Or is this not advisable?

Cheers

It`s probably better - and it`s the way i did it - to cut and block the TVSV vacuum tube and add a boost controller & gauge. Cutting the wires will fool the ECU into thinking that the valve is closed (or is it open??? ) and enable higher boost, but if you want to put it back to normal at any time, Soldering wires in and trying insulate them properly to make it look neat in an enclosed space will be much more difficult than replacing a piece of vacuum hose. Just my opinion for what its worth.

I`ll try and dig out a photo of what neeeds to be cut. Watch this space.

[daktari]

[sweatyfox]

So basically its pointless getting a GT4 chipped unless you disable the TVSV and fit a bleed valve, cos all you wiill gain otherwise is just more boost in 3rd, 4th and 5th.

Is there much point in getting a GT4 chipped at all? May as well just disable the TVSV and fit a bleed valve.

[Sketchy]

So basically its pointless getting a GT4 chipped unless you disable the TVSV and fit a bleed valve, cos all you wiill gain otherwise is just more boost in 3rd, 4th and 5th.

Is there much point in getting a GT4 chipped at all? May as well just disable the TVSV and fit a bleed valve.

Indeed, In my humble personal opinion if you gonna got to the expense of paying out for a superchip or unichip you might as well save up a few hundred quid more and do it properly with a replacement ecu like the link unit or apexi power fc and get it properly mapped. :D