Hi Guys

I posted a thread a short while ago regarding the probable failure of the dv on my Octy.

I took the car to BigBoysToys in Thurrock, who fitted a replacement (whilst installing Koni FSD's and H&R's). There was a 2cm rip in the diaphragm. Local Skoda dealer wouldn't fit another because they were unable to detect a loss of boost or any error codes. Skoda-uk were also indifferent to the evidence saying that reimbursement wasn't possible as (a) the dealer hadn't identified and rectified the problem AND - more importantly, ( nobody, apart from myself, had reported a problem with this part, so a recall is No Go area.

PLEASE - Is there anyone out there willing to increase the level of complaints to Skoda-uk to more than one? This way there may be a slight chance of us getting the message over to Skoda (VAG) that we won't be fobbed-off, and even better that we demand a better dv unit than the rubbish (compared to Forge FMDVFsiTA etc) they think is adequate for the standard car - i.e VAG TFsi's.

Cheers

Guys424

Guy you are onto a loser for a start mate and I think you know why yours failed. The OEM DV unit is generally ok with normal boost pressures.

These are less than £25 to buy and until an aftermarket option (launched next week by Forge I believe) is available then I'm afraid it's the perils of the changes you've made to your car. There is an option available in the US already but in general even our US friends are waiting for Forge.

Also you mention the Forge Diverter Valve, it's an entirely differnet component mate. Simply a noise maker.

Is a diverter valve the same thing as a dump valve, if not, what's the difference?

Dump goes to atmostphere, diverter does back into the inlet.

The TFSi uses an electronic Diverter. It does not have a 'Dump Valve' as we know it (Like the 1.8t etc).

There is a part manufactured by Forge which they call a Blow off Valve. It's simply a spacer that fits between the turbo and the above shown Diverter to allow waste boost pressure to atmosphere and create the noise.

it's the perils of the changes you've made to your car. There is an option available in the US already but in general even our US friends are waiting for Forge.

I take it you mean by this a remapped/modified car. Does the revision C stand up to the extra boost pressure of a remapped car or will people who have remapped cars need one of the forge diverter valves pictured above to solve problems of the diaphram ripping?

Anticipating the next question, here is a pictorial of the N249 Diverter Valve showing it's location and method of operation.

Boost Pressure Overrun

If the throttle valve closes when the engine is in overrun, back pressure develops in the turbo housing. Back pressure reduces the speed of the turbine, which reduces boost pressure and increases turbo lag when the engine accelerates again.

At other engine speeds, the tumble flaps are open to eliminate flow resistance and reduction in engine performance. To avoid this, the Turbocharger Recirculating Valve N249 is opened by an electrical actuator. This allows the compressed air to flow back to the intake side of the circuit through the turbine. This maintains turbine speed.

The Turbocharger Recirculating Valve N249 closes when the throttle valve opens again and boost pressure is immediately available.

I take it you mean by this a remapped/modified car. Does the revision C stand up to the extra boost pressure of a remapped car or will people who have remapped cars need one of the forge diverter valves pictured above to solve problems of the diaphram ripping?

The revision C was developed by VAG to fix the problem of stock cars ripping valves. The Forge diverter wasn't developed with the problem of the splitting DV in mind simply to provide owners with a whooosh noise on lift off. Forge are currently working on a solution to fix the problem of ripping DV's.

I would think most Octavia will have the revision C unless it was a really early one.

This is one solution but not one I would advise -

The Performance Driver :: . :: ATP Diverter Valve Block Off for 2.0L FSI Turbo Golf/Jetta/GTI Audi A3

I can't find the link to the other at the moment.

Thanks Stu

Should have believed you the first time i.e. regarding Forge dv. So may others have tried to convince me that it's a direct replacement. Money now not wasted. Shall wait for independent/OEM upgrade. You also confirmed that I already had revision C. So expect it to fail again.

Would be grateful of any posts, as and when, an improved version arrives. Cheers.

Guy

PS Thought that there was evidence of 'stock' vRS (GTi Mk V) dv failures?

Thought that there was evidence of 'stock' vRS (GTi Mk V) dv failures?

There may well be but I think the C revision should have cleared most of that up. As with anything there may be a small number of faulty items produced - who knows.

Most of the info originates from the US where they've had the TFSi for a while and are quite well into tuning the engine now.

If you have VAG-COM then it may well be worth logging the boost pressure with the new valve in place as a bench mark and then if you notice a drop in performance or at regular intervals check the pressure again.

Many of our US counterparts have installed boost guages for real time monitoring.

Speaking of boost gauges, where would a suitable location be in the cabin to mount a VDO 52 mm gauge? I used to have one in my 1.8T Mk4 GTI.

How long after a remap can I expect my dirverter valve to last and how will I know when it has failed?

How long after a remap can I expect my dirverter valve to last and how will I know when it has failed?

Can't really say to be honest. It might not even happen, its also depends on your remap. The more boost, the more likely it will happen.

You will know when you lose power at the top end and you may hear a hissing noise at top end. If you have an induction kit it will amplifly the noise.

If it does go and you don't notice, you no worse off!

Development is on going and looking good.....more news soon.

Excellent news!

I was 100% sure my DV had a rip in it again (after having it replaced when it was at forge). But when the new one was put on it was intact! bizzare. Must be the weak spring then?

A little taster. This is a mechanical valve that will be electronically actuated.

-

Can't come soon enough!