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General => The garage => Topic started by: adamthornton on 07 April 2004, 11:39

Title: Mk 4 Turbo Dump Valve
Post by: adamthornton on 07 April 2004, 11:39

Ive seen more and more 1.8T engines with dump valves fitted but when i enquired with a couple of suppliers, was told that it was not possible to fit due to it screwing up the ecu and engine management.

Does anyone know if this is true or wether the unit can be fitted successfully?

Adam.

Title: Re:Mk 4 Turbo Dump Valve
Post by: topher on 07 April 2004, 13:37

Have a read of this thread

http://www.golfgtiforum.co.uk/index.php?board=9;action=display;threadid=7530 (http://www.golfgtiforum.co.uk/index.php?board=9;action=display;threadid=7530)

Quite often people refer to diverter valves as dump valves, hope the link helps.

Chris

Title: Re:Mk 4 Turbo Dump Valve
Post by: mk1 on 07 April 2004, 19:36

Here is my take on it.
When you close the throttle the pressure in the inlet pipework from the turbo (compressor) to the throttle plate is dead ended. This can damage the turbo but it causes the compressor to slow down or stall and will take time to come back up to speed. This causes a lot of lag during gear changes.
A diverter valve recirculates the boost back into the inlet to the turbo and a dump valve vents to atmosphere, pssss. This takes the load off the compressor and allows it to maintain a higher RPM so taking less time to spool back up to speed.
The problem with some dump valves that vent to atmosphere is the type of fuel system. If you have a system that has a air flow meter before the turbo, the dump valve vents to atmosphere "metered air" and causes the engine to run rich as the ecu is injecting in the amount of fuel for the air that has passed the meter not what has gone into the engine. If you have a map sensor, this measures the inlet manifold pressure so it is not bothered by a atmosphere dump valves as he has not "seen" the air yet
Hope this makes some sense, (been a long day ::))
Steve.

Title: Re:Mk 4 Turbo Dump Valve
Post by: adamthornton on 08 April 2004, 10:27

brilliant all makes sense now. i have seen a couple of vids on http://www.veedub.web.com/ under the misc section they have a beetle that has oviously been tuned massively but also had the valve fitted and sounds brilliant. i think my v6 is gonna go and ill be back to the gti !!