Reply With QuoteI'm currently running the standard DV on Phase 3. Plan to upgrade it but not in a hurry as it's not causing any issues. I don't think they are as bad as some have made out to be previously.Originally Posted by PoloGIT
Volkswagen Fan
There's a shiny new 008 in the shed...just taking my time putting it on. Think I read a comment from Gavin in these pages suggesting he'd changed his opinion on the original (presumably meaning they weren't as bad as first thought), hence I've been lazy.
Volkswagen Enthusiast
I'm currently running the standard DV on Phase 3. Plan to upgrade it but not in a hurry as it's not causing any issues. I don't think they are as bad as some have made out to be previously.
2006 GTI Polo - Big Turbo Build - Louis19's Build Thread
Volkswagenist
Nup there isn't anything wrong with them. Do you think porsche would have stuck these things on 911's if they were as utterly crap as people say. They might have longevity problems but just replace one when its shredded. They hardly cost anything. They actually have two big advantages over aftermarket piston style DV's too.
One is that they react far quicker. My Turbosmart piston style plumback on the supplied spring was causing compressor surge. You could hear the ch ch ch ch when you got off the throttle. That sound isn't a DV venting sound, its the compressor wheel of your turbo jerking because pressure waves are smashing into it that could have been avoided if the DV had opened quicker. Went to the next softer spring and it was better but still doing it a bit so back to stock and problem solved. Through all this there was not one iota of difference to boost curve or peak between the DV's.
Also the stock DV will unseat and float beyond about 10in/Hg. Piston style springing won't allow that till much later. If you've ever wondered why the stock DV is so much smoother to drive off boost in traffic, its because its giving a portion of your inlet air the ability to short circuit/bypass the turbo and head straight around to the engine where it probably arrives cooler and freer of restriction and is less susceptable to unintentional boosting from accidental throttle twitches. A piston style DV will for the most part force all your inlt air through the turbo all the time. So the stock DV can flow in this opposite direction too which is better for fuel economy Watch how quickly your car will go into closed loop and the fuel consumption will fall into the 5's when you are below about 12-15in/hg with a stock DV. Piston style DV's have a very hard time 'floating' at mild vaccum pressures because they still 'leak down' around the sides of the bores with sustained vacuum (eg mine has a seating seal but not a bore ring seal) The piston cannot stay up when you suck on the vac tube like a diaphramtaic DV will.
Having said all that though and going back to the original issue this guy had, a leaking DV could cause the boost fluctuations. A piston style DV's base seal/seat could be turd or a stock DV's diaphram could be leaking. Or an over reactive N249 could be pulling it open at strange times. My N249 was doing that - you could hear/see the DV release at bizarre times so I deleted it. There's a good youtube video of a guy with a mk4 golf who rigged a LED up to the N249 and you should see how often it was acting on the DV.
Last edited by sambb; 13-09-2015 at 10:57 PM.
Volkswagen Fan
I don't have a tune but an aftermarket dv. And the only time I can feel surge is first thing in the morning when I'm taking off a little hard.
Volkswagen Fan
sammbb, a question about DVs. The Forge, Turbosmart, etc are all piston style, the APR is a diaphragm. I've forgotten but what is the original, is that diaphragm as well? It's been a long time since I changed mine, I've forgotten a lot about the negatives of the piston type until I read your reply
Dub Crazy
VWwA Super Moderator
Std is diaphragm too.sammbb, a question about DVs. The Forge, Turbosmart, etc are all piston style, the APR is a diaphragm. I've forgotten but what is the original, is that diaphragm as well? It's been a long time since I changed mine, I've forgotten a lot about the negatives of the piston type until I read your reply
Volkswagenist
Don't get me wrong, piston types arent bad, not at all. They have the more bullet proof design of the two when it comes to lasting under more severe conditions. They still need to be maintained though to prevent piston stiction in the bore and to keep the base seal clean. Some designs just rely on perfect machined mating surfaces to seal ie no o-ring on the piston base so it wouldn't take much crud to give you a drama. The stock diaphram one will do everything the piston design does (and more - see the vacuum stuff above) andmore or less maintenance free, right up until the point that the diaphram tears. I haven't compared APR ones to stock diaphram ones - I actually was going to get one 'till I saw the price.
Volkswagen Enthusiast
I ran an APR one for 7 years without issue - can't fault that!
Cheap, Fast, Reliable. Choose two.
Volkswagen Fan
thanks for the reply
I've had my APR R1 DV coming up to 7 years like Stuwey ... problem free so far
Ultimate Dubber
I'm not sure what different versions Porsche use, but I'm talking only about the N75 controlled diaphragm diverter on the 1.8T. I have the electronic controlled diverter on my 2.0T S3, which is totally different and has a piston revision to the original diaphragm which had some minor issues. The main issue with the stock diverter was how it wore over time with the higher boost pressure (double and tripple stock boost).
I never had issues with my stock diverter, I upgraded early on. If someone has boost issues, it is definitely something to try, even borrowing one for a spin around the block to see if it makes a difference. I had no issues with the Forge 007, but still upgraded to the 008 which I preferred, I cant comment on the different types, brands and styles. I bypassed all the VAC and N249 system as well, seemed to work best with CC, but never did back to back testing, just how it felt at the time.
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