Forge atmos dump valve for VAG 2.0T - Page 2

MarkB · 18-08-2006, 02:18 PM

The theory behind venting to atmos is that the air that would otherwise be recirc'd has been heated by the turbo so you want to dump it in favour of fresh air

RedRobin · 18-08-2006, 02:27 PM

[ QUOTE ]
If you want the noise and knowledge that you aren't loosing power or fecking with the system then get an CAI instead, as this amplifies the standard DV nicely.

[/ QUOTE ]

....My Carbonio CAI on Mk5 GTI doesn't make much extra noise at all (unfortunately) - Just more of a soft 'Phwack' on gear changes. The GTI's 2.0T FSI has a Diverter rather than Dump Valve. I've got a proper 200+ mile drive tomorrow so we'll see if I hear more turbo 'noise'.

The same Carbonio CAI fits Audi A3, VW Jetta and Passat 2.0 FSI engines.

My VW dealer fitted it for me so warranty should be preserved. I don't know enough to fiddle with my engine system.

danksy · 18-08-2006, 02:39 PM

You will lose power from using an atmospheric "dump" valve since the air that has been "dumped" has already been metered, hence the fueling will be wrong [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img]

A recirculation, or diverter valve is what is fitted OEM, however the original valves have had some quality issues in the past, which has made them slow to release.

Horse for courses really, had them both changed from OEM diverter valve to Forge Diverter Valve (re-circulating) on both TT's but for peace of minds sake since i got through 3 OEM Bosch DV's on my first TT [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img]

MarkB · 18-08-2006, 02:54 PM

[ QUOTE ]
You will lose power from using an atmospheric "dump" valve since the air that has been "dumped" has already been metered, hence the fueling will be wrong [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img]

A recirculation, or diverter valve is what is fitted OEM, however the original valves have had some quality issues in the past, which has made them slow to release.

Horse for courses really, had them both changed from OEM diverter valve to Forge Diverter Valve (re-circulating) on both TT's but for peace of minds sake since i got through 3 OEM Bosch DV's on my first TT [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img]

[/ QUOTE ]

Different type of valve completely to the one fitted on the 2.0T

RedRobin · 18-08-2006, 03:24 PM

These two illustrative pics may help to further explain the DV on the 2.0T FSI:

My apologies if everyone already knows this info or if I'm barking up the wrong tree.

danksy · 18-08-2006, 03:24 PM

Principle is still the same though for recirculating vs atmospheric [img]/ubbthreads/images/graemlins/169144-ok.gif[/img]

danksy · 18-08-2006, 03:29 PM

Where does the output from the OEM dv go? Back to the airbox?

RedRobin · 18-08-2006, 03:46 PM

[ QUOTE ]
Where does the output from the OEM dv go? Back to the airbox?

[/ QUOTE ]

....I've no idea! I just supply the artwork!

It's part of a 36-page pdf - I'll have a look but don't hold your breath. [img]/ubbthreads/images/graemlins/169144-ok.gif[/img]

danksy · 18-08-2006, 03:50 PM

[img]/ubbthreads/images/graemlins/lol.gif[/img] My reply popped up after you posted your diagram [img]/ubbthreads/images/graemlins/169144-ok.gif[/img]

The air inside the closed loop-recirculating DV has indeed been metered, and is let back into the throttle body once the DV closes.... Thus if this air is vented to atmosphere "dumped" the fuel/air mixture will be all wrong, and you will lose power [img]/ubbthreads/images/graemlins/169144-ok.gif[/img]

RedRobin · 18-08-2006, 04:53 PM

....So, if I understand it correctly, because the metered air is not 'dumped', we don't hear any 'whooshy' sounds.

What's the soft airy 'phwack' I'm hearing on gear changes since fitting my CAI?

Btw, here's another illustration if it helps anyone:

18-08-2006, 02:18 PM	#11 (permalink)
MarkB Citroen C1 GT Join Date: Jun 2005 Location: Farnham, Surrey Posts: 121	Re: Forge atmos dump valve for VAG 2.0T The theory behind venting to atmos is that the air that would otherwise be recirc'd has been heated by the turbo so you want to dump it in favour of fresh air __________________ Mark Audi S4 2.7T Quattro The only Twin Turbo in the village...

18-08-2006, 02:27 PM	#12 (permalink)
RedRobin (old) Fruit and (carbon) Fibre Join Date: Jul 2005 Location: BIALI Motorsport Posts: 22,627	Re: Forge atmos dump valve for VAG 2.0T [ QUOTE ] If you want the noise and knowledge that you aren't loosing power or fecking with the system then get an CAI instead, as this amplifies the standard DV nicely. [/ QUOTE ] ....My Carbonio CAI on Mk5 GTI doesn't make much extra noise at all (unfortunately) - Just more of a soft 'Phwack' on gear changes. The GTI's 2.0T FSI has a Diverter rather than Dump Valve. I've got a proper 200+ mile drive tomorrow so we'll see if I hear more turbo 'noise'. The same Carbonio CAI fits Audi A3, VW Jetta and Passat 2.0 FSI engines. My VW dealer fitted it for me so warranty should be preserved. I don't know enough to fiddle with my engine system. __________________ *PLEASE CHECK OUT MY MUSIC: HERE ON MYSPACE* Still grinning about my Throbbin' Red VeeDub Mk5 GTI DSG - Now Revo'd

18-08-2006, 02:39 PM	#13 (permalink)
danksy Porsche GT3 Join Date: Sep 2001 Location: near the thames Posts: 10,596	Re: Forge atmos dump valve for VAG 2.0T You will lose power from using an atmospheric "dump" valve since the air that has been "dumped" has already been metered, hence the fueling will be wrong [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img] A recirculation, or diverter valve is what is fitted OEM, however the original valves have had some quality issues in the past, which has made them slow to release. Horse for courses really, had them both changed from OEM diverter valve to Forge Diverter Valve (re-circulating) on both TT's but for peace of minds sake since i got through 3 OEM Bosch DV's on my first TT [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img] __________________ For Fun - White and Black Honda CB 600 FA Hornet -HRC carbon tank protector, Ermax nose screen Honda Fireblade (tweaked) -

18-08-2006, 02:54 PM	#14 (permalink)
MarkB Citroen C1 GT Join Date: Jun 2005 Location: Farnham, Surrey Posts: 121	Re: Forge atmos dump valve for VAG 2.0T [ QUOTE ] You will lose power from using an atmospheric "dump" valve since the air that has been "dumped" has already been metered, hence the fueling will be wrong [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img] A recirculation, or diverter valve is what is fitted OEM, however the original valves have had some quality issues in the past, which has made them slow to release. Horse for courses really, had them both changed from OEM diverter valve to Forge Diverter Valve (re-circulating) on both TT's but for peace of minds sake since i got through 3 OEM Bosch DV's on my first TT [img]/ubbthreads/images/graemlins/smashfreakB.gif[/img] [/ QUOTE ] Different type of valve completely to the one fitted on the 2.0T __________________ Mark Audi S4 2.7T Quattro The only Twin Turbo in the village...

18-08-2006, 03:24 PM	#16 (permalink)
danksy Porsche GT3 Join Date: Sep 2001 Location: near the thames Posts: 10,596	Re: Forge atmos dump valve for VAG 2.0T Principle is still the same though for recirculating vs atmospheric [img]/ubbthreads/images/graemlins/169144-ok.gif[/img] __________________ For Fun - White and Black Honda CB 600 FA Hornet -HRC carbon tank protector, Ermax nose screen Honda Fireblade (tweaked) -

18-08-2006, 03:29 PM	#17 (permalink)
danksy Porsche GT3 Join Date: Sep 2001 Location: near the thames Posts: 10,596	Re: Forge atmos dump valve for VAG 2.0T Where does the output from the OEM dv go? Back to the airbox? __________________ For Fun - White and Black Honda CB 600 FA Hornet -HRC carbon tank protector, Ermax nose screen Honda Fireblade (tweaked) -

18-08-2006, 03:46 PM	#18 (permalink)
RedRobin (old) Fruit and (carbon) Fibre Join Date: Jul 2005 Location: BIALI Motorsport Posts: 22,627	Re: Forge atmos dump valve for VAG 2.0T [ QUOTE ] Where does the output from the OEM dv go? Back to the airbox? [/ QUOTE ] ....I've no idea! I just supply the artwork! It's part of a 36-page pdf - I'll have a look but don't hold your breath. [img]/ubbthreads/images/graemlins/169144-ok.gif[/img] __________________ *PLEASE CHECK OUT MY MUSIC: HERE ON MYSPACE* Still grinning about my Throbbin' Red VeeDub Mk5 GTI DSG - Now Revo'd

18-08-2006, 03:50 PM	#19 (permalink)
danksy Porsche GT3 Join Date: Sep 2001 Location: near the thames Posts: 10,596	Re: Forge atmos dump valve for VAG 2.0T [img]/ubbthreads/images/graemlins/lol.gif[/img] My reply popped up after you posted your diagram [img]/ubbthreads/images/graemlins/169144-ok.gif[/img] The air inside the closed loop-recirculating DV has indeed been metered, and is let back into the throttle body once the DV closes.... Thus if this air is vented to atmosphere "dumped" the fuel/air mixture will be all wrong, and you will lose power [img]/ubbthreads/images/graemlins/169144-ok.gif[/img] __________________ For Fun - White and Black Honda CB 600 FA Hornet -HRC carbon tank protector, Ermax nose screen Honda Fireblade (tweaked) -

18-08-2006, 04:53 PM	#20 (permalink)
RedRobin (old) Fruit and (carbon) Fibre Join Date: Jul 2005 Location: BIALI Motorsport Posts: 22,627	Re: Forge atmos dump valve for VAG 2.0T ....So, if I understand it correctly, because the metered air is not 'dumped', we don't hear any 'whooshy' sounds. What's the soft airy 'phwack' I'm hearing on gear changes since fitting my CAI? Btw, here's another illustration if it helps anyone: __________________ *PLEASE CHECK OUT MY MUSIC: HERE ON MYSPACE* Still grinning about my Throbbin' Red VeeDub Mk5 GTI DSG - Now Revo'd

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