HAPPY

excuse me if i am dumb but:
will an aftermarket dump valve increase the performance of my my99 uk car?i allready have a pipercross induction kit.
if it will improve anything,what will it be and how will it do it please?

i can't part with money without understanding why!

MatthewR

Happy,

An aftermarket dump valve will not increase horsepower. However, you might notice an improvement in throttle response following a gear change, and it will likely assist in protecting the turbo from backspin. Essentially all a dump valve does is open a valve to dump (hence the name) excess pressure back into the air intake of the turbo. You can get aftermarket externally venting dump valves (though these can cause problems with rich mixtures). Best to vent to the air inlet system as with the standard dump valve.

You have a MY99... I believe these have a larger dump valve than earlier (pre-97) model, so you wouldn't notice as much of an improvement (if any) over standard as the owner of a pre-97 car would.

They do look nice though...


Matthew

[This message has been edited by MatthewR (edited 26-02-2000).]

FrankM

Have fitted a recirculating one from PE on MY99(on their web-site it's the right one)The PE valve works again a spring the original against a diaphragm. What I could say is that there is definitley a better/smoother throttle response and a little bit more "whoooosh" if you lift the accelarator.

steve McCulloch

So a seqential HKS blow off valve is a no-no on a slightly modded sti 5 then.

Only wanted it because I liked the sound it made

MorayMackenzie

Steve,

FYI, I had an HKS SSeqBOV on my last car. As standard, it makes a very high pitched whistle noise. Women liked it but men thought it sounded camp! You can get a different vane for it which stops the whistle, blokes prefer the new sound, women complain they liked it better before!

I suspect you won't get running problems with one of these on your car as the Possum Link doesn't use the MAF sensor IIRC. I have heard that the HKS SSBOV isn't the strongest valve out there, and that they can fail spectacularly.

ROBERT BARNES

ive got a blitz piston vent to atmosphere DV on my MY97and no problems with running slightly better response and a great noise if your into that sort of thing.

JOHN BRODERICK

piston valves dumping to atmosphere may confuse the ecu, as the air meter reads alot of air coming in. and then you dump and more air rushes in.the ecu then decides the richen the mixture and walla your running rich ,pincking .so when you fit a dump valve make sure they set you up properly. I know the wossh sounds great but a fully plumbed dump valve would be the way to go.

john

MorayMackenzie

With an external venting BOV, the ecu measures the air coming into the system, and expects a recirculating BOV to keep it in the system. If you vent to atmosphere, the ecu still thinks the air is present in the system and maps fuelling accordingly, hence the mixture goes rich.

I suspect that Possum Link users won't have a problem using an externally venting BOV as (IIRC) the Possum ignores the MAF sensor.

HAPPY

my standard valve now vents to air because of the induction kit,how can i re-plumb it to be recirculating?
yes i love the sound but would like to see if it will run any differently if recirculating.

MorayMackenzie

Happy,

What 'induction kit' and dump-valve are you running on what car?

Moray

HAPPY

moray,
pipercross induction kit(big cone thing)
standard valve,
uk my99 car

pete