Single or double piston Dump Valve ?

[chrjen]

Can anyone please explain to me, what will happen if I use a single piston Dump on my T5R ?

I got a nice one from my friend, but I am unsure whether it will work.

[cameron]

Single piston DV's have a tendancy to jam open, and will cause a big problem.

Go Twin Piston everytime if you really want one :)

Something like a Bailey DV26

[chrjen]

what exactly is BIG PROBLEM ?

[cameron]

It would kill the Turbo due to not being able to dump the pressure.

It could bend the fans or the rod and you'd need a new turbo.

[irf]

It would kill the Turbo due to not being able to dump the pressure.

It could bend the fans or the rod and you'd need a new turbo.



http://www.epicallyfunnypictures.com/FunnyPictures/ORLY/O_RLY.jpg

[gareth]

I think it has more to do with single piston ones opening with idle vacuum and dumping metered air, thus confusing the air flow meter and affecting how the car idles - i.e. like a Belle minimix -and for a 5cyl that's not good.!!.
As for not dumping excess pressure and damaging the turbo.... no chance. Less than two bar pressure in there.
I ran a Forge blank plate and no dv on my first 855 T5 for about two months and it sounded wicked and no damage either and no real visible sign of compressor stall either.
Sounds like this too. Although this was not my car the "chirping" was almost identical:
http://www.youtube.com/watch?v=EnjUgYVwHSc&feature=related

[cameron]

Only stating what ive been told by another VPC member.

Wrong or right i still wouldnt use a single piston DV.


http://www.epicallyfunnypictures.com/FunnyPictures/ORLY/O_RLY.jpg

[shaun850]

The car will not idle with a single piston DV.

Car's that run mass air flow sensors have to have a twin piston

shaun

[gareth]

i still wouldnt use a single piston DV
I'll definitely second that.
They do sound cool with none though I bet someone will say that is more likely to f up the turbo.

[t5 pete]

I ran a Forge blank plate and no dv on my first 855 T5 for about two months and it sounded wicked and no damage either and no real visible sign of compressor stall either.
Sounds like this too. Although this was not my car the "chirping" was almost identical:
http://www.youtube.com/watch?v=EnjUgYVwHSc&feature=related

By not having a recirc or dv i would have though you would be causing the back pressure to stall the compressor and getting turbo chatter through the air filter i personally wouldnt use a set up like this but every one to there own.

[gareth]

Hi Pete, I do agree that this is not something that should be used as a permanent set up.
However I never really noticed any significant stall in terms of reduced performance but as I said I only ran the setup 'cos i knew the turbo was coming out anyway.It was already passing oil and smoking on idle. Aside from the already known wear there was no visible signs of damage on removal however the new one went in with a DV26 installed too.
My point really was your turbo will not self destruct or anything nearly as catastrophic by using no dv or a single piston one.

[chrjen]

If I leave the original recirc. valve on WITHOUT blanking it off as eg. Forge and others do in their kits, and then use this single piston DV - then there shouldn't be any idle problems or...?

This would just dump air two places instead of one - would it work ?

[gareth]

I'd say there are three real options for you: 1. Leave as standard, 2. Blank standard and fit something like a DV26, 3. Fit a "high performance recirculating i.e non atmospheric, dump valve like this; http://www.forgemotorsport.com/content.asp?inc=product&cat=0006&product=FMDV006

[T5arrrgghh]

what about option 4 reverse ic piping and an hks ssqv? hmmmm i think that is the way i will go. i have mental turbo chatter, sounds awesome but needs sorted i guess.