being a woman i havent a clue what they are all about and was wondering if someone could shed some light into their purpose and are they a good thing to have on a TT

 

thanks

Dont know about a TT but good with a cup of T!

I take it you mean 'Dump Valves'? :D

 

http://en.wikipedia.org/wiki/Dump_valve

Dont know about a TT but good with a cup of T!

 

 

And toast lol

:rofl: now that im an expert on

I take it you mean 'Dump Valves'? :D

 

http://en.wikipedia.org/wiki/Dump_valve

 

see told ya i didnt know anything about them :confused:

see told ya i didnt know anything about them :confused:

 

I anit that far behind you :)

It's a can of worms really, some people will say are pointless, and infact can be detrimental to the engine, some will say they benefit it, and some just like the sound they make! If ya like the noise then get em is what i say, personally i do, might get me some! :-)

on a turbo'd car the whole induction system is pressurised under boost. as soon as the throttle closes, theres a massive surge of pressure due the the tubos still spinning but, no where for the pressurised air to go, in extreme cases causing the turbo to stall. a dump valve or blow off valve vents this unwanted pressure to atmosphere, allowing the turbos to wind down safely. depending on the vac load pressure which in some valves is adjustable, you can controll the rate at which the intake system holds pressure to keep the turbos spinning between shifts. combine this with an electrical boost controller and you will have a fast responding setup :)

 

 

 

oh, and they sound good as well :D

on a turbo'd car the whole induction system is pressurised under boost. as soon as the throttle closes, theres a massive surge of pressure due the the tubos still spinning but, no where for the pressurised air to go, in extreme cases causing the turbo to stall. a dump valve or blow off valve vents this unwanted pressure to atmosphere, allowing the turbos to wind down safely. depending on the vac load pressure which in some valves is adjustable, you can controll the rate at which the intake system holds pressure to keep the turbos spinning between shifts. combine this with an electrical boost controller and you will have a fast responding setup :)

 

 

 

oh, and they sound good as well :D

 

Nice explanation, now get those stickers off your doors ;)

 

Allan

Nice explanation, now get those stickers off your doors ;)

 

Allan

 

Hahahahahaha :rofl:

on a turbo'd car the whole induction system is pressurised under boost. as soon as the throttle closes, theres a massive surge of pressure due the the tubos still spinning but, no where for the pressurised air to go, in extreme cases causing the turbo to stall. a dump valve or blow off valve vents this unwanted pressure to atmosphere, allowing the turbos to wind down safely. depending on the vac load pressure which in some valves is adjustable, you can controll the rate at which the intake system holds pressure to keep the turbos spinning between shifts. combine this with an electrical boost controller and you will have a fast responding setup :)

 

 

 

oh, and they sound good as well :D

 

As he said :D

 

But dont the recirculating ones do the same but without the sound :confused:

Well i have them fitted to mine, dosent make it go any quicker, but it sounds the nuts going through tunnels of west sussex, give it some full boost and then let them off. Sound is amplified greatly!!!!! plus traffic coppers on motorbikes, think they sound loud as hell, or so i was told by him..........

May I draw you attention the my Wikipedia link I posted at 13:32 today......... ;)

i did read your link all about them very imformative, my friend had them on her renault 5 and i liked the sound of them then, so i might get some just for the noise, im getting bored of driving along and shouting out TSHHHHHHHHHH :rofl:

being a woman i havent a clue what they are all about and was wondering if someone could shed some light into their purpose and are they a good thing to have on a TT

 

thanks

 

Their noise is subjective. Personally think they sound stupid, like the air brakes on a Scania truck. As to their purpose. They don't really have one other than make the noise like the airbrakes on a Scania truck. If yours is an auto, they won't work at all! A dump valve will only operate when the accelerator pedal is released when running positive boost pressure! This doesn't happen on an auto.

 

 

When using dump valves, the air is released into the atmosphere and this means that the space between the turbo compressor and the throttle bodies has to be regained and this causes a noticeable delay in boost pressure.

 

Also, the ECU is programmed to expect the unused air to be recirculated back into the intake and if it doesn't arrive, then there is a momentary 'rich' running and this can cause hesitation.

 

There is definately no performance gain from fitting dump valves. Infact the opposite.

 

They only really offer a viable alternative if you're running aftermarket engine management.

Very true words Si............ but i love 'em!!!!

 

Al.

I'd rather glue brussells sprouts to my vacuum lines! :rofl: ;)

entirely down to your own choice - the stock recirc valves will prevent the turbine stall you may get with a system that has neither atmospheric nor recirculating valves.

pointless on an automatic as you have to throttle off for them to dump whereas on a manual you have to throttle off to change up anyway (unless youre being chased by bogeymen!)

they will cause a slight drop in performance as your turbos have to build up again (unless youre mad enough to have anti-lag installed (you know who you are! ;) ))

some see them as bragging rights or the sign of a powerful car - some see them as boy-racery.

it's up to you - i have them on mine and enjoy them! :smw:

I'd rather glue brussells sprouts to my vacuum lines! :rofl: ;)

 

PMSL....... you are one in a million matey!! LOL!!!

 

Al.

im with si on this one

A quick question on setting up the spring activation on Dump valves. I have a set of Apexi dump valves. they have a nut and screw on the front, to alter the boost at which they dump the boost.

 

How do you set them up correctly? Is there a procedure?

 

Regards

 

Kev

to set the apexi's up, screw the grub screw in until it's sticking out aprox 4mm of the locking nut. give it a run and tighten if they let off with too lower boost or slacken until they let off at all.

to be honest, 4mm should be pretty spot on with the apexi's

So what would happen if you wound the grub screw in too far or not far enough?

Their noise is subjective. Personally think they sound stupid, like the air brakes on a Scania truck. As to their purpose. They don't really have one other than make the noise like the airbrakes on a Scania truck. If yours is an auto, they won't work at all! A dump valve will only operate when the accelerator pedal is released when running positive boost pressure! This doesn't happen on an auto.

 

 

When using dump valves, the air is released into the atmosphere and this means that the space between the turbo compressor and the throttle bodies has to be regained and this causes a noticeable delay in boost pressure.

 

Also, the ECU is programmed to expect the unused air to be recirculated back into the intake and if it doesn't arrive, then there is a momentary 'rich' running and this can cause hesitation.

 

There is definately no performance gain from fitting dump valves. Infact the opposite.

 

They only really offer a viable alternative if you're running aftermarket engine management.

 

 

Hi Si,

 

Mine is an auto, but i get the sound sometimes, can you explain why they only do it occasionally ?

 

Cheerz

 

Chris

So what would happen if you wound the grub screw in too far or not far enough?

 

if you wound it in too far, then they valve wont let off, causing the turbos to stall. not good!.

 

if its not wound in enough, the valve would leak and result in poor boost.