vRS Dump valve

[nickl0]

Hi all, just wondering if any of you can give me some advice. I bought a Forge dump valve recently and have fitted it, but ever since I'm regretting what I've done tbh. I like the whoosh sound, so *please* don't start any 'what a waste of money' comments

Firstly, I had issues with the springs included not being strong enough, but a friend sorted that for me while I was away on holiday last week.

The second problem is that my MPG is reading much lower than usual - normally I get an average of about 43mpg, and that's usually with the car being driven pretty hard, but now I can only achieve about 38mpg when just tickling the throttle on the motorway. Could this just be because I had to tap into the grey/blue wire from pin 69 on the ECU, and it's just reading falsely on the computer? There doesn't seem to be any boost leaks - there's no oily deposits around any of the boost pipe conections.

Lastly, I don't know if it's me, but the performance seems to have dropped, although this could just be psychological as I'm not happy with the DV at the moment!

TIA for any comments on the above, I've already ordered a standard boost pipe to put the car back to stock, but if I can get this working properly it'll save me having a £300 paperweight...

Cheers,

Nick

[fletch555]

Do a brim to brim check and see if the economy is effected.

[Welshy]

A dump valve on a TDi lol.
Firstly clearly even on a petrol unless your on a race track its totally pointless - as far as I know only the Bugatti EB110 has it.
Remember these makers spend billions on R&D and if a dump valve added any real benefit do you not think that the best engineers in the world would demand that they are used on all engines?

Secondly a TDi is totally different to a petrol you are not chasing the red line your probably never breaching 3,000rpm as you use the torque to accelerate. Hence blowing off the pressure it has built up is a total waste of time & will cost you in performance.

I know I always post similar statements but its so true "if you want a fast car buy a fast car in the first place as its so much cheaper in the long run think reliability, resaleability insurance and component lifespan."

The whole thing about the Fabia vRS is that its a Q car (its not fast its nippy) however Cahving it up like this totally spoils it.

When looking longer term say 20-25 years what do people pay top £ for? Totally bog std prestine models which have been really looked after their whole lives. Putting on go faster nonsence to the majority of the population will indicate that this car will have been driven much harder than is the norm and will put off a lot of people (even if it has not been driven hard).

[farky77]

Originally Posted by Welshy

A dump valve on a TDi lol.
Firstly clearly even on a petrol unless your on a race track its totally pointless - as far as I know only the Bugatti EB110 has it.
Remember these makers spend billions on R&D and if a dump valve added any real benefit do you not think that the best engineers in the world would demand that they are used on all engines?

Secondly a TDi is totally different to a petrol you are not chasing the red line your probably never breaching 3,000rpm as you use the torque to accelerate. Hence blowing off the pressure it has built up is a total waste of time & will cost you in performance.

I know I always post similar statements but its so true "if you want a fast car buy a fast car in the first place as its so much cheaper in the long run think reliability, resaleability insurance and component lifespan."

The whole thing about the Fabia vRS is that its a Q car (its not fast its nippy) however Cahving it up like this totally spoils it.

When looking longer term say 20-25 years what do people pay top £ for? Totally bog std prestine models which have been really looked after their whole lives. Putting on go faster nonsence to the majority of the population will indicate that this car will have been driven much harder than is the norm and will put off a lot of people (even if it has not been driven hard).

He clearly states in his post that he likes the 'Whoosh' sound, hence buying it for that reason, not for any performance gains

[jmd]

A dump valve on a diesel shouldn't affect the performance.

A diesel doesn't have a throttle so what you are doing is using the break vacuum via an electronic switch every time you press the clutch.

There are benefits on certain petrol turbos but the ONLY thing it does on a diesel is make noise.

[nickl0]

Originally Posted by farky77

He clearly states in his post that he likes the 'Whoosh' sound, hence buying it for that reason, not for any performance gains

Thankyou Farky, I'm grateful for you *actually* reading my questions. Comments like the the previous 'essay' to your post are not what I want... I've read enough of that on Briskoda recently, hence my wishes to not have lectures on why I've fitted a DV

Anyone else have something constructive to add? Does tapping into pin 69 on the ECU affect the dash display re:MPG?

This thing's gonna be binned by the weekend otherwise as I'm now in posession of the standard boost pipe, even though, ultimately, I'd like to keep it.

Cheers,

Nick

[Snoopie]

Originally Posted by Welshy

A dump valve on a TDi lol.
Firstly clearly even on a petrol unless your on a race track its totally pointless - as far as I know only the Bugatti EB110 has it.
Remember these makers spend billions on R&D and if a dump valve added any real benefit do you not think that the best engineers in the world would demand that they are used on all engines?

Secondly a TDi is totally different to a petrol you are not chasing the red line your probably never breaching 3,000rpm as you use the torque to accelerate. Hence blowing off the pressure it has built up is a total waste of time & will cost you in performance.

I know I always post similar statements but its so true "if you want a fast car buy a fast car in the first place as its so much cheaper in the long run think reliability, resaleability insurance and component lifespan."

The whole thing about the Fabia vRS is that its a Q car (its not fast its nippy) however Cahving it up like this totally spoils it.

When looking longer term say 20-25 years what do people pay top £ for? Totally bog std prestine models which have been really looked after their whole lives. Putting on go faster nonsence to the majority of the population will indicate that this car will have been driven much harder than is the norm and will put off a lot of people (even if it has not been driven hard).

Constructive.

[ForgeMotorsportUK]

I hope that you can sort out your problem , as states above the dump valve will nor effect your performace ,as long as its fitted correctly......, give us a call we will help with the information ....if we cant fix your problem and your not 100% happy just it send it back and we will refund all your money ...... its no good having a parts that your not happy with...

[nickl0]

Originally Posted by ForgeMotorsportUK

I hope that you can sort out your problem , as states above the dump valve will nor effect your performace ,as long as its fitted correctly......, give us a call we will help with the information ....if we cant fix your problem and your not 100% happy just it send it back and we will refund all your money ...... its no good having a parts that your not happy with...

Thankyou I'm going to play around with it tomorrow and see what I can do... My friend spoke to your (and I must add he said VERY helpful) staff last week and established all is installed correctly, so I'm gonna give it one last whirl. Thankyou for the offer of the refund, I'll be in touch if necessary

[SteVRs]

Originally Posted by Welshy

Secondly a TDi is totally different to a petrol you are not chasing the red line your probably never breaching 3,000rpm as you use the torque to accelerate.

You still changing at 3k for max speed Welshy

Seriously, go do some timed runs.

[Lummox]

Originally Posted by Welshy

Firstly clearly even on a petrol unless your on a race track its totally pointless - as far as I know only the Bugatti EB110 has it.

Want to clarify that? A standard petrol VAG turbo car has one,

[Spudgun]

didnt the ford cosworths sierra escort have a recirculating valve as standard as well

[jmd]

Almost every turbo petrol engine has a recirc.

[Deano]

i had one on my FR 150 leon and didnt like it tbh i thought it seemed to cause the turbo to stall between gears as it had lost all pressure, it was noticeable when you wanted to fully use the cars power.

it didnt make a difference to my MPG that i noticed i retained around the 45 mark.

i took it off when the car was remapped

[53FabiaVRS]

My old Focus RS had a recirc valve on it. It was a bosch plastic cheap thing. I changed it to a GGR atmospheric one and it helped prevent turbo stall. I also quite like the whoosh sound when you change gear and have considered fiting one to my VRS. But its the price that puts me off!!
By fitting an atmospheric valve will not cause any loss in power. The only way that could happen is if you have an air leak somewhere? If you are using jubilee clips, check all the pipes connect properly and they all are secure. Also check the jubilee clips themselves are working properly. Sometimes they can be overtightened and this damages the thread, preventing them from tightening correctly. Be sure to buy the thickest and strongest jubilee clips. The ones that came with my atmospheric valve were quite thin clips, so I went out and bought some heavy duty ones to be sure!
Also check the connection to the ecu. Make sure the connection is tight with the scotch lock.
The actual drop in performance could be psychological as you are unhappy with the way car is performing at the moment.
I would just double check the above or if you are still unsure. Depends on how close you live to Forge? I would pop in and let them take a look for you.
Either way, dont be put off by it or by peoples comments. Im sure it will be fixed soon!

[martyrobertsdj]

I'd suspect that all petrol turbo cars have a dump valve. The reason theye are there is to prevent the turbo "stalling" when the throttle is closed during gearchanges, etc.

The turbine blades are still spinning and creating boost, the throttle closes, pressure builds up between turbo and throttle body, this stalls the turbine......you then open th throttle again and the turbine blades have to get going again........cue massive lag!! The dump valve allows the turbine blades to keep spinning as the throttle is closed and therefore they don't have to speed up so much again, reducing lag and.......saving from destruction of the turbo into the bargain.

I don't know about the "suck through" cars though, as the throttle is before the turbo rather than after it............maybe Forge can answer that for me? I'm curious now!

[nickl0]

Well, spent this morning removing the dump valve and replacing the standard rohr pipe and the car now seems to run much better - back to it's old self.

On the downside, the MPG is still reading way low and the only thing I can assume is that the scotchlock connector that was clipped in to the grey/blue wire from the ECU has damaged the cable - this cable reads the throttle position so the electrical gubbins knew when to activate the dump valve. I suppose if it's damaged, the computer is getting false readings and thinks I've got my foot down harder than I actually have, still I hope that's what it is. If the weather gets better this arvo I'll break the cable and resolder it properly and go from there... If that then fixes it then, hey I may well even try re-fitting the DV and having a further play around. If it doesn't then I'm gonna have to send my car to the main stealers for them to see why the MPG is reading way low... Bloody cars!

[SteVRs]

One for the techies - what's the difference between a wastegate and a dump valve? Surely the wastegate relieves boost pressure and so does the dump valve?

[53FabiaVRS]

Basically, a dump valve is designed to dump excess boost pressure to prevent turbo stall.
A wastegate is designed to control the boost pressure from the turbo.

[TommyC]

More to the point, a dump valve will be in the inlet/compressor side of the turbo and a waste gate will be on the exhaust/turbine side of it.

A waste gate "wastes" the exhast gasses past the turbine preventing them driving it (and ultimately the compressor).

A dump valve "dumps" excess boost whilst the throttle closed, preventing it building up and choking/stalling the compressor.

Hope this clarifys things