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wher can i put the dump valve on my 2.0 HDI
Please dont do it! you will ruin the sound and looks of the car. i hear gayboys in their corsa's with dump valves and all i think is what a massive cock that person is! makes me want to show them up in my stock foci. :lol:

do what i do (well not the rolling part) but rather mod your car so it looks and sounds normal but when you need the power ;) you have it. :thumb:
 

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Why you do not need a blow off valve (BOV)

Hi,
To be fair it is probably worth explaining why you do not need, or will get any advantage out of, a blow off valve on a diesel.

A turbocharged petrol engine will suffer from "lag" because the turbocharger takes a certain amount of time to heat up and "spool up" to its final steady state. This is felt as a delay or lag from when the driver puts his/her foot down to the eventual steady state power. To reduce this (and it is reduce - it can never be gone completely ) manufacturers use a throttle by pass system or Blow Off Valve. As far as I know this is universally used now & I think Porsche were the first.
A petrol engine has a throttle valve (connected to the pedal) which controls the amount of air entering the engine. When the throttle is closed (ie your foot is off the pedal) there is very little air flow through the engine and this will slow the turbocharger significantly. When the throttle is opened the turbocharger is going quite slowly and will take a while to accellerate to speed and boost. This is felt by the driver as lag. If the throttle is bypassed by a blow off valve this will allow the turbocharger to continue to spin and recirculate air and maintain a higher speed. In this situation, when the throttle is opened the turbocharger is spinning faster and will accellerate to speed in less time hence reducing the lag.

BUT
On a diesel engine (like the 406 HDI mentioned above and all others) there is no throttle valve. There is no restriction to air going through the engine. The speed and power of the engine is controlled by the amount of fuel injected into the cylinder.
So, when the "throttle" (and it is not really a throttle so I will call it a "pedal") so when the pedal is lifted, the turbocharger will still spin quite fast because there is no restriction - there is no throttle plate to stop the air flow. When the pedal is pressed again the turbocharger is already spinning at quite a speed and will accellerate to final steady state quite quickly.

There will be NO ADVANTAGE to fit a BOV to a diesel as there is NO throttle plate to bypass.

Regards,
FarmPug
 
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