Pug 306 1.9 tdi dump vavles??

2donskoy2

Wrench Pro
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58
From
lincolnshire
Car
ford festa mk5 1.7
i have just bought my pug and i am looking for a dump valve kit for it, its a phase 1 306 1.9 xltd, could any1 suggest any for this, possibly any sites??
 

turbonutter69

TC ModFather
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642
From
Alone in the dark.
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Insignia SRI.
Don't listen to Hdi. He's gettin on abit. ;)
Have a look on ebay for a dump valve I'msure they'll be some on there. Other than that find a diesel tuning specialist and they should be able to supply you with one.
 

HDi fun

TC ModFather
Points
637
From
Buckinghamshire UK
Car
Passat 2.0 TDi
By doing what? They might make a noise but it's fake and pointless. There's no benefit fitting a dump valve to an engine without a throttle.
 

HDi fun

TC ModFather
Points
637
From
Buckinghamshire UK
Car
Passat 2.0 TDi
It relieves pressure when the throttle is closed during a gearchange.

But a diesel engine does not have a throttle so there is no pressure to relieve. There's no throttle housing, no butterfly to shut off the airflow.
 

HDi fun

TC ModFather
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637
From
Buckinghamshire UK
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Passat 2.0 TDi
It still goes straight in to the engine as there's no throttle to restrict the airflow. But there's very little boost as the fuelling has been cut completely (trailing pedal) or back to idle level if the clutch is down. You can't get boost without fuel as there's no mass of hot exhaust gas under pressure to drive the turbo. Effectively the turbocharger just freewheels.

A dump valve is fitted to petrol turbo cars so that the slug of compressed air that's built up doesn't slam into the closed throttle butterfly(s) and bounce back causing sudden slowing of the turbocharger.

With a diesel turbo engine it just goes into the cylinders as normal and comes out as normal. But without any (or very little) fuel being injected so the same volume of gas comes out, just that it's been compressed and then uncompressed again in the cylinders.

There's nothing to bypass as such.

There is still a wastegate but this is under ECU control to vent excess exhaust gas round the turbo. They just give a fluttering effect to the turbo hiss you hear when accelerating. It's especially noticeable between 2000 and 3000rpm where there's more potential boost available than the engine can actually utilise.
 
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turbonutter69

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From
Alone in the dark.
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Insignia SRI.
oritre thanks people didnt mean to start an argument im stikll going to go ahead with it though thanks any way(y)
Don't worry mate have a look round the forum and you'll soon see me an HDi are always at it. We good friends really but we do like a Good debate.
Go for it buddy I would do the same.
 

HDi fun

TC ModFather
Points
637
From
Buckinghamshire UK
Car
Passat 2.0 TDi
Don't worry about that. As TN says we get on very well.

The only thing you'll gain with a dump valve on your XUDT engine is some strange noises.

It certainly won't help the performance.

If you want to do something serious then start looking into altering the wastegate actuator.

There's one around somewhere which went to over 130bhp with some changes to fuel boost compensation.
 

jarrus

Pro Tuner
Points
317
From
West Midlands, UK
Car
Suzuki Swift Sport
You're right in saying that diesels don't have throttles how ever you still need a device to get rid of the pressure when you're off the 'gas' because you don't need that amount of air when you're shoving less diesel in the cylinders.
The XUDT comes with a recirculating valve on it which does the same job (almost) so why would Peugeot fit it if it didn't need it?
 

davalav

Moderator
Points
387
From
Essex, England
Car
Mini Cooper S R56
I heard you actually loose small amounts of power from fitting a dump valve, to a diesel as the boost from the re circulating gas is expelled meaning you loose boost. Correct me if I am wrong. I can't remember where I heard it but I do like the noise though....
 
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davalav

Moderator
Points
387
From
Essex, England
Car
Mini Cooper S R56
Sorry for the mumbo jumbo... I replied on my phone. If I can find the article, then I'll post it. Where the DV has to be located means it expells the gas from the inlet, meaning you loose boost, it's almost like a boost leak... I wish I could explain things better, and actually remember what I am trying to say! Was that a reply to me, TN?
 

pgarner

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From
Lockerbie, SW Scotland
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Octy smoke machine
yeah it was in reply to you. a proper dump valve, ie on a petrol, is actuated when the throttle body closes this causes an area of higher pressure between the turbo and butterfly on the throttle body causing the spring to lift and the gas to go out.

from what ive seen of diesel ones they are actuated by a switch rather than pressure to allow the air out. as most diesels dont have a conventional throttle body then this air would still be going into the engine but as you should be off throttle at the time then no diesel should be getting injected so no lose in power.
 
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