Hi all,

Well I had my dump valve fitted today and I have to say it is amazing. All I have been hearing is negative comments regarding the dump valve and I just dont understand why...

Since having this fitted I have noticed massive improvements in both performance and turbo spool up time. Its just amazing. I was expecting a loss in performance but when fitted it feels like a whole new car. Also, another advantage is the noise! I have been going around town dumping everywhere, and the attention you get is out of this world!

Anyone who is thinking about getting one of these....Trust me you wont regret it.

I have been going around town dumping everywhere, and the attention you get is out of this world!

O

M

G

I'm off to buy a new car.

Trust me you wont regret it.

A matter of opinion I'm sure.

£300 to make your car go "psssh"

I'd rather have 312mm brakes and a whiteline RARB for that.

£300 to make your car go "psssh"

I'd rather have 312mm brakes and a whiteline RARB for that.

I actually got it for £130 from a friend, and did you not read - Like I said there is clearly improvements in performance....I bet my turbo will last longer than yours now....

I actually got it for £130 from a friend, and did you not read - Like I said there is clearly improvements in performance....I bet my turbo will last longer than yours now....

Performance? No...

It will just dump the boost produced and you will lose the woosh. Sorry.

Performance? No...

It will just dump the boost produced and you will lose the woosh. Sorry.

And how do you know? You got one fitted???

Stop jumping on the briskoda band wagon and get your own opinion...

And how do you know? You got one fitted???

Stop jumping on the briskoda band wagon and get your own opinion...

I just happen to know how they work!

Sorry for following the concensus on a car mod from a car forum

If a dump valve has improved performance on a car with a variable vain turbo, then something is seriously wrong, as it would suggest you are getting overboost without the dump valve. It is possible that the turbo vanes have stuck, due to EGR soot and PCV gases gumming up the works.

Still, if it works and your happy then that's fine.

If a dump valve has improved performance on a car with a variable vain turbo, then something is seriously wrong, as it would suggest you are getting overboost without the dump valve. It is possible that the turbo vanes have stuck, due to EGR soot and PCV gases gumming up the works.

Still, if it works and your happy then that's fine.

I dont know enough to know how they work. But I have noticed a massive improvement.

Thanks for having a different view and not just jumping on the briskoda band wagon.

It's not a bandwagon. Turbodiesels do not require dump valves they need to keep the back pressure high to allow for the correct regulation of the fuel (in diesels the turbo tend to be connected to the fuel supply so that the correct fuel in injected in relation to the boost being generated, hence why remapped diesels tend to be far too smoky due to overfuelling).

To compensate for this turbos on diesel cars tend to use variable vanes (working on the principle of centrifugal force) so that at low rpm the turbo can spin up quicker and when it gets fast enough the vanes extend to their full reach.

All a diesel dump valve does is isolate a small section of the air pressure then when you change gear it releases it into the atmosphere.

Well I will always try to give a technical response, and try very hard to respect everyones opinion, it is after all your car. I agree a dump valve sounds cool.

The variable vain turbo (VNT) has vanes that can alter their pitch, rather like aircraft propellers. They reduce turbo lag, and also prevent over boost. If the vanes get gummed up and stick, you end up with a static angle on the vanes, performance goes out the window, you get horrid turbo lag, and in severe cases over boost that will blow hoses off, or cause the car to go into limp mode to protect the engine and turbo.

I would expect a dump valve to do nothing in a standard un-mapped car, unless it is designed to dump before normal peak boost levels are reached. If that was the case, power would be lost rather than gained.

General note to everyone on the Forum. This has always been a very friendly place to visit and give technical advice, and have some banter. Please, lets not allow the Forum to turn into a flame war site, as that tends to cause people to get really miffed and leave. Best regards to everyone.

It's not a bandwagon. Turbodiesels do not require dump valves they need to keep the back pressure high to allow for the correct regulation of the fuel (in diesels the turbo tend to be connected to the fuel supply so that the correct fuel in injected in relation to the boost being generated, hence why remapped diesels tend to be far too smoky due to overfuelling).

To compensate for this turbos on diesel cars tend to use variable vanes (working on the principle of centrifugal force) so that at low rpm the turbo can spin up quicker and when it gets fast enough the vanes extend to their full reach.

All a diesel dump valve does is isolate a small section of the air pressure then when you change gear it releases it into the atmosphere.

Actually it dumps when you let off the throttle...Its just a coincidence that it dumps when you change gear because you are releasing the throttle....

So your opinion cannot be trusted as you do not even know the basics of a dump valve.

This thread makes me chortle

Diseasal's do not require, or see any benefit in a "dump valve", because they need the extra back pressure, whereas a petrol turbo needs to vent.

This thread makes me chortle

Diseasal's do not require, or see any benefit in a "dump valve", because they need the extra back pressure, whereas a petrol turbo needs to vent.

Save your breath - he isnt listening and is just baiting people.

This thread makes me chortle

Diseasal's do not require, or see any benefit in a "dump valve", because they need the extra back pressure, whereas a petrol turbo needs to vent.

Learn how to spell..

see?

actual 150mph(nearly 160mph indicated) in a fabia is impressive and pretty dangerous, what pther mods do you have?

Learn how to spell..

he was making a joke

Save your breath - he isnt listening and is just baiting people.

Aye lol

Learn how to spell..

Every English word in my post is correctly spelt, "diseasal" is made-up word, so I can spell it how I like

DONT FEED THE TROLLS

I actually got it for £130 from a friend, and did you not read - Like I said there is clearly improvements in performance....I bet my turbo will last longer than yours now....

Bottom line, if your happy with it, great! If it feels better, great! However although I hate to burst your bubble it's just not possible for it to improve you performance and/or make your turbo last longer. Get a dyno printout or check your boost curve, you may have a shock

Do you know how it works?

You could start with anyone of these...

http://briskoda.net/fabia/dump-valve/22559/

http://briskoda.net/fabia/dump-valve/13106/

http://briskoda.net/fabia/dump-valve/46931/

http://briskoda.net/fabia/dump-valve/52006/

http://briskoda.net/fabia/dump-valve/53022/

http://briskoda.net/fabia-i/forge-diesel-dump-valve/138518/forums/fabia/pos...lve-vrs/53968/

http://briskoda.net/fabia/forge-diesel-dump-valve/138518/forums/fabia/dum...y-probs/62672/

http://briskoda.net/fabia/vrs-dump-valve/73498/

http://briskoda.net/fabia/forge-diesel-dump-valve/138518/forums/fabia/fab...p-value/79675/

http://briskoda.net/fabia/dump-valve/81239/

http://briskoda.net/fabia-i/forge-diesel-dump-valve/138518/forums/fabia/dum...bia-vrs/99163/

http://briskoda.net/fabia/dump-valve/104861/

I would also like to draw your attention to the horse's mouth

http://briskoda.net/fabia-i/forge-dump-valve/110672/2/#post1310836

If your too lazy to go through those, I have summarised in an earlier post which I will quote here;

If you search on dump valves you will find a plethora of information and opinions.

However I recently wrote a post over on the Fiat Forum (Punto section) in reply to a post about fitting one to JTD. Here is the jist of it (Please appreciate I wrote this for the Punto forum although the same will apply to the VRS as it is also fitted with VNT);

"In your petrol engine your turbo is spinning at say 100k revs.... suddenly your throttle closes, and turbo is still spinning due to inertia... consequently the air has nowhere to go because the thottle plate is shut... so the dump valve opens and allows this air to escape to the atmosphere(or back into the air box if a recirc is fitted)... this has the benfit of allowing the turbo to keep spinning in a partial vacuum for a longer period of time, and therefore takes less time to get back up to speed after you reapply the throttle..

On a diesel engine it isn't required because there is no throttle body, so the air doesn't get trapped like it does on a petrol engine.... in fact the excess air actually reduces the emmissions output from the engine and also has a mild intercooling effect on the combustion chambers

You can get electronically actuated valves for the JTD but TBH the only thing you will get out of it is a Noise and it might actually adversly effect the performance. A DV cannot increase performance. There is nothing for it to do other than go PSCHTTTTTTTT and unless it's perfectly actuated and it gets it spot on it will loose you boost pressure.

The boost pressure is generally highest on a diesel when the accelerator is on the floor and the engine is as max power, just before a gear change. If a dump valve is set to relieve the pressure just below max boost, it will sound similar to that on a petrol engine, but it will be dumping air while the engine is on power, not when the accelerator has just been released. All it can do is make the turbo less efficient. The wastegate tries to control the boost pressure and that will just increase the exhaust back pressure if the pressure is being dumped by a dump valve.

Now also figure in the fact the fact the JTD turbo is a VNT (GT1749V I belive if it's the 85bhp version) and this works works by adjusting the gas throat section at the inlet of the turbine wheel in order to optimize turbine power with the required flow velocity. At low engine speed and small gas flow, the turbocharger reduces the throat section, increasing turbine power and boost pressure. At full engine speed and high gas flow, the VNT increases the throat section, avoiding turbocharger overspeed and maintaining the booster pressure required by the engine. How do you think sticking a remote control hole (Which is what the valve is really) in the system will effect this? It will defeat the object totally and all it will do is work against it.

I would really like to see a dyno run of a standard car and the one fitted with a DV back to back. I think the run with the valve would show early boost loss and spikes where the VNT is struggling to compensate. The only way it could be perceived to increase performance is if you mapped around it which is pointless because you might as well have just mapped a standard engine

It's an expensive toy and about as useful as a catflap in a submarine"

There may be someone with a deeper knowledge than me who will pick a few holes in my understanding of VNT's but I am not that far off the mark.

If you really want that noise there is also One of these Evil pieces of equipment

But then you end up with a car that goes like this

It's down to you what you do, it's your car and if we all followed the marker then we are all doomed so just you make sure you are happy

I appreciate I have just thrown the troll a bone but I was at a loose end anyway. If it carries on we always have the Troll Spray [TM]

Edited 22 February, 200917 yr by DGW
Some links repaired.

Bottom line, if your happy with it, great! If it feels better, great! However although I hate to burst your bubble it's just not possible for it to improve you performance and/or make your turbo last longer. Get a dyno printout or check your boost curve, you may have a shock

Do you know how it works?

You could start with anyone of these...

http://briskoda.net/forums/fabia/dump-valve/22559/

http://briskoda.net/forums/fabia/dump-valve/13106/

http://briskoda.net/forums/fabia/dump-valve/46931/

http://briskoda.net/forums/fabia/dump-valve/52006/

http://briskoda.net/forums/fabia/dump-valve/53022/

http://briskoda.net/forums/fabia/pos...lve-vrs/53968/

http://briskoda.net/forums/fabia/dum...y-probs/62672/

http://briskoda.net/forums/fabia/vrs-dump-valve/73498/

http://briskoda.net/forums/fabia/fab...p-value/79675/

http://briskoda.net/forums/fabia/dump-valve/81239/

http://briskoda.net/forums/fabia/dum...bia-vrs/99163/

http://briskoda.net/forums/fabia/dump-valve/104861/

I would also like to draw your attention to the horse's mouth

http://briskoda.net/fabia-i/forge-dump-valve/110672/2/#post1310836

If your too lazy to go through those, I have summarised in an earlier post which I will quote here;

I appreciate I have just thrown the troll a bone but I was at a loose end anyway. If it carries on we always have the Troll Spray [TM]

Umm, hate to say this mate but only 1 of your links works.

Even if the links don't work it goes to show how many threads there have been backing up what moggy said

Just remove the 'forums/' part of the link - it is due to the redoing of the links

I have managed to repair a fair few of the links.