Vento blow off valve?

daylers

Hello, just wondering does anybody know if it's possible to for a blow off valve to a 1.9tdi vw vento?

I presumed it would be possible but have been told that it's not possible to fit a blow off valve on the standerd setup on the car and just want anoter opinion

Renegade Mechanic

They're set up differently. There's no "back pressure" as such on a diesel intake, because there's no throttle that snaps shut when you release the accelerator.

In order for a dump valve to be fitted to a diesel, the valve needs an accompanying system to operate it when the accelerator is released, to make the sound, as the pressure build-up isn't there.

Unfortunately, this actually hinders performance a bit as the turbocharged intake has lost important pressure (as theres no "over" pressure) and must spool up again after you've changed gear.

It you don't mind losing a little pole, they're perfectly doable, if more complex and expensive than ordinary petrol valves.

Done Deal, Ads and EBay regularly have diesel kits for sale.

CiniO

I thought every turbo charged combustion engine is equipped with blow off valve these days anyway.

rex-x

CiniO wrote: »

I thought every turbo charged combustion engine is equipped with blow off valve there days anyway.

Just no....

Desolation Of Smug

You wanna booo? Here's what you do...

burke027

Why oh why would you even want to do this to a tdi car is beyond me

jimgoose

Is it "Booo" or "Phsss" you're after? If the former, what you want is a straight-pipe kit and possibly a wastegate. If the latter, this is indeed the blowoff-valve (a.k.a. dumpvalve) sound and diesels do not use or need blowoffs because they have no throttle plate per sé. So for adequate "Phsss" you'll have to use one of the many fine electronic simulators available here and there, including eBay.

Special Circumstances

Chooooooooooo be honest I can't see the attraction either.

jimgoose

Renegade Mechanic wrote: »

They're set up differently. There's no "back pressure" as such on a diesel intake, because there's no throttle that snaps shut when you release the accelerator.

In order for a dump valve to be fitted to a diesel, the valve needs an accompanying system to operate it when the accelerator is released, to make the sound, as the pressure build-up isn't there.

Unfortunately, this actually hinders performance a bit as the turbocharged intake has lost important pressure (as theres no "over" pressure) and must spool up again after you've changed gear.

It you don't mind losing a little pole, they're perfectly doable, if more complex and expensive than ordinary petrol valves.

Done Deal, Ads and EBay regularly have diesel kits for sale.

'Lectric wan bah, all the Jacinta panty-wetting with no drop-off in actual boost:

Renegade Mechanic

Ah here

Renegade Mechanic

Although do you know what, if they could get it to properly emulate the psssssSSSSSSS TSCH TSCH TSCH TSCH that you'll get from wastgate chatter, I'd actually be half tempted to stick that on a six cylinder diesel

jimgoose

Renegade Mechanic wrote: »

Although do you know what, if they could get it to properly emulate the psssssSSSSSSS TSCH TSCH TSCH TSCH that you'll get from wastgate chatter, I'd actually be half tempted to stick that on a six cylinder diesel

Rally-style antilag would be even more fun.

Renegade Mechanic

jimgoose wrote: »

Rally-style antilag would be even more fun.

Easy enough to sort!

rex-x

burke027 wrote: »

Why oh why would you even want to do this to a tdi car is beyond me

To be fair if you are into heavy tuning they are required as if you are running 30+ psi on a nice high flowing vnt turbo and you lift off the throttle you end up with the air stalling the compressor as it has nowhere to go but I am guessing the OP's tdi is not heavily tuned.....

jimgoose

rex-x wrote: »

To be fair if you are into heavy tuning they are required as if you are running 30+ psi on a nice high flowing vnt turbo and you lift off the throttle you end up with the air stalling the compressor as it has nowhere to go but I am guessing the OP's tdi is not heavily tuned.....

I'd say a wastegate is what you want on a turbodiesel in that case, no?

kona

Just buy a real car

rex-x

jimgoose wrote: »

I'd say a wastegate is what you want on a turbodiesel in that case, no?

No a vnt turboed car doesn't have or need a waste gate as the boost is regulated by the vane position. A waste gate is for exhaust gasses, a blow off valve is for intake boost pressure. Two different systems with different functions

jimgoose

rex-x wrote: »

No a vnt turboed car doesn't have or need a waste gate as the boost is regulated by the vane position. A waste gate is for exhaust gasses, a blow off valve is for intake boost pressure. Two different systems with different functions

I'd say two different and separate ways of accomplishing the same thing. And I take the view that if a turbodiesel is overboosting at the intake side the turbo is too big, and/or not controlled properly. We had this with the Daihatsu parts-bin turbochargers on the turbo bikes of the mid-'80s.

rex-x

jimgoose wrote: »

I'd say two different and separate ways of accomplishing the same thing. And I take the view that if a turbodiesel is overboosting at the intake side the turbo is too big, and/or not controlled properly. We had this with the Daihatsu parts-bin turbochargers on the turbo bikes of the mid-'80s.

Its two different was of accomplising two different things it has nothing to do with over boost, it just means that there is not enough of an exit for the air when you lift off, like on a petrol with the throttle plate, hence the need for the blow off valve

jimgoose

rex-x wrote: »

Its two different was of accomplising two different things it has nothing to do with over boost, it just means that there is not enough of an exit for the air when you lift off, like on a petrol with the throttle plate, hence the need for the blow off valve

There is no throttle plate, so you can release the overpressure at the other end. Unless the sodding turbo is too big!

rex-x

jimgoose wrote: »

There is no throttle plate, so you can release the overpressure at the other end. Unless the sodding turbo is too big!

The other end is the compressor wheel, that causes compressor stall which will kill your turbo in short time, hence the need for the blow off valve

jimgoose

rex-x wrote: »

The other end is the compressor wheel, that causes compressor stall which will kill your turbo in short time, hence the need for the blow off valve

By the other end, I mean the exhaust. And the turbo is still too big!

rex-x

jimgoose wrote: »

By the other end, I mean the exhaust. And the turbo is still too big!

How do you get air trapped in the intake into the exhaust? The only way is via the engine but if the engine can't take it all as in a lift off then it goes back through the turbo...... You can't magic it to the exhaust

Renegade Mechanic

Hang on now, bit a confusion I think, we're on about diesels, in which case a blow off valve isn't necessary as such. Anyhow :

A blow off valve (dump valve) regulates the sudden surge of pressure that is generated when a throttle is closed but the turbo is still at full pelt.

A waste gate regulates the exhaust pressure driving the turbo itself, as the overall system pressure increases exponentially as the revs increase. More air/fuel > More bang/exhaust > More turbine drive > More air > More fuel allowed > Much more exhaust to drive the turbo.

That cycle very quickly spirals out of control unless the exhaust pressure is regulated.

TLDR;
Blow off valve = Intake pressure regulation
Wastegate = Exhaust pressure regulation

jimgoose

rex-x wrote: »

How do you get air trapped in the intake into the exhaust? The only way is via the engine but if the engine can't take it all as in a lift off then it goes back through the turbo...... You can't magic it to the exhaust

The turbo is too big and/or not controlled properly. It's a diesel Volkswagen, not an RS2000 Cosworth!

rex-x

jimgoose wrote: »

The turbo is too big and/or not controlled properly. It's a diesel Volkswagen, not an RS2000 Cosworth!

This is what happens when you tune a diesel, nothing to do with control or oversizing just simple flow dynamics

jimgoose

rex-x wrote: »

This is what happens when you tune a diesel, nothing to do with control or oversizing just simple flow dynamics

From the file marked "Tits on a bull"!

rex-x

jimgoose wrote: »

From the file marked "Tits on a bull"!

How many cosworths do you know running vnt turbos making 250 HP at 40psi, a cosworth could do that on about 6 psi

jimgoose

rex-x wrote: »

How many cosworths do you know running vnt turbos making 250 HP at 40psi, a cosworth could do that on about 6 psi

Hell yeah! A 3l Essex could do it on a Roots blower!

CiniO

rex-x wrote: »

Just no....

So how is excess pressure in a charger released if you don't need it (release accelerator)?

Hachiko

burke027 wrote: »

Why oh why would you even want to do this to a tdi car is beyond me

A secret tool to blind everyone on the road within 2km with black soot.

keithclancy

jimgoose wrote: »

'Lectric wan bah, all the Jacinta panty-wetting with no drop-off in actual boost:

Facepalm

daylers

wanna make her boo just for the fun of it...tiz just an old vento after all:P

Desolation Of Smug

daylers wrote: »

wanna make her boo just for the fun of it...tiz just an old vento after all:P

Straight through exhaust - whip out the cat and bosh on a backbox..Boolicious..:D

Tea 1000

Why do you want to make your car sound like a pidgeon? No fun in that. Sounds daft. Just put a speaker in and have random animal noises when you beep the horn, that'll do the job for less money and is much more fun!