Diverter Valve.

[mjmallia]

I think K03s eat DVs quicker than K04s due to the heat down there.

Totally agree

[JoshB]

So if my diverter valve is knackered then I shouldn’t be hitting boost right?
Just done some logs tonight using the “Calculated Boost” on the CarScanner app and it hits 22psi then tails off to 20ish psi.
I just don’t know how accurate the “Calculated Boost” is…

Thing is it’s peachy and responsive up to about 3k rpm, then just goes flat.

[MattC]

So if my diverter valve is knackered then I shouldn’t be hitting boost right?
Just done some logs tonight using the “Calculated Boost” on the CarScanner app and it hits 22psi then tails off to 20ish psi.
I just don’t know how accurate the “Calculated Boost” is…

Thing is it’s peachy and responsive up to about 3k rpm, then just goes flat.

The car will still boost just not as strong. I had a leaking DV for 3 years before I checked my boost values lol...
My car hit peak boost of 7psi stock with a leaking DV. Assuming your car is stock and you haven't subtracted ambient pressure you're hitting 8psi. I think stock should be hitting about 11psi.

[G-olf]

Recently checked my DV  and although I don't know how old it is, it is a revision G and looks in good condition.
If yours was split or there was a leak, would it hold that much boost? Wondering if it could be a fuel or timing problem?

[ald1717]

k03 stop pulling hard after 5k  anyway,  start building boost at 1700rpm when the dv closes, but you wont feel it until just after 2000rpm peak torque is around 3000rpm and will really drop off at 5000rpm,

[mjmallia]

A split DV will also make a blow off noise with a standard airbox, and not feels punchy. ..........a great reason to fit a boost gauge, to keep an eye on things.

[imprezzaworks]

Looking to fit mine this afternoon just waiting for the ramp to be free in work.

[imprezzaworks]

Fitted. Just took it up the road with a smile on my face. It's back to how it was when I bought it, quick.

The old one looks OK. Part number 06F 145 710 C

Looks to maybe be an aftermarket one?

[pudding]

I've only seen A, D and G revisions personally.

If you google 06F 145 710 C, it does come up with 'RIDEX' and 'BORSEHUNG' type brands, so maybe a cheap copy. 

It's good when cheap parts restore the power 

[imprezzaworks]

Did see a thread with a chap who had one on his ed30. Then swapped it to the G and was like it feels like it has 80bhp more ha ha.

But yeah very happy :)

[ROH ECHT]

I giggle at VW revisions of their DVs. They keep circling back around to slight "improvements" on past designs of both the Diaphragm and Piston types. They seem unable to "PICK" one.

I.e. the diaphragm designs of Rev.-G and those it supersedes.
And then Revision 'C' and 'J' are very similar piston-design diverter valves;