steppyg

I have a very nice 04 wrx, done 36k, my lad is nattering me to fit a bov to make it sound "cool". I know what they do and why, but do they improve performance, and more importantly, can they do any harm?? Hope you guys out there can advise....Thanks

Splitpin

They don't improve performance. They either make no appreciable difference or make performance worse, and under certain combinations of circumstances, can cause harm.

Your car already has a dumpvalve, one that is matched to the characteristics of the engine and performs optimally alongside the other components in it. There's plenty more written on this subject so search is your friend.

powerwrx

iTrader: (11)

be prepared for the onslaught....

most on here are against them and say you should stick with the standard one...but if you do want one then stay clear of the cheap ones ie, ebay jobbies and bailey...they can cause issues such as flat spots, irratic idle, poor fuel consumption etc.. but having said that there are a few that run dump valves without any issues.

as for performance, there is none what so ever as far as im aware just by fitting one, wether they are a benefit when running high bhp and boost i dont know..

i have a 'forge' one forsale if you do decide to buy one
https://www.scoobynet.com/private-sa...forge-vta.html

360ste

iTrader: (1)

You already have a dump valve fitted it is to the right of the pipe from the intercooler to the throttle housing. The reason you don't hear it is because it is a recirculating item, this keeps the Mass Airflow meter happy. If you want the noise and decide to fit a vent to atmosphere unit the MAF sensor see greater airflow due to some of the air it has accounted for being vented to atmosphere. This will result in a slight increase in fuel usage. You may have other running issues which have been covered on here previously. If you want to keep your kid happy you could get a dual port, this means that on normal driving it works as a recirculating unit, keeps MAF happy, but when pushed hard it VTA's so you could use it such that when you and your kid are out you can let it VTA but on normal days have a nice economical(ish) car.
Good points in the previous posts.
Hope this helps Steve

steppyg

Thanks fellas I think that is knowledge spoken from experience! Thanks alot for your replies. Its that old saying "if it aint bust dont try n mend it" Cheers.

steppyg

Again Thanks for your quick and very concise replies, there are a lot of helpful folk out there in Scoobyland! Steve.

steppyg

by the way, POWERWRX, you dont really like pickled onion sarnies do you??

powerwrx

iTrader: (11)

2 slices of bread with a pickled onion in the middle... mine and Eddie Hitlers favourite

steppyg

wierd ????