Right, I have had my Impreza 4 years now and it came with a VTA dump valve. When I first got it I loved the sound but I can't decide if I still want it on or not now

The aim of this thread is to provide me with info about what route is the most beneficial on a turboed engine. So should I stick with my VTA d/v, fit a recirc d/v or delete it all together?

I'm not after a flame war or arguments about whether one or the other is chavvy or not, just cold hard facts about which is best!

My engine is a standard turbo 2000 engine running an FMIC (purely for looks atm ) and cone air filter. I'm hoping to upgrade turbo, ecu and associated parts etc to gain cica 280hp early next year

 

It's not about which is chavvy or not - I believe the general consensus is that it's not good for the engine unless you've heavily modified it beyond standard.

As you haven't I'd get rid and get a recirc valve, or just re-fit your old one.
I know several members who experienced engine running problems (including idle problems, and hesitation under acceleration) with VTA valves, which disappeared as soon as they re-fitted the OEM recirc valve.

That to me says leave well alone! The Impreza sounds great as is in my honest opinion. Get a decent exhaust and you won't worry about a DV!

 

Another vote for the recirculating valve. My 05 Blob runs much better with the standard dumpvalve than the V.T.A which was fitted when I bought the car. Steve.

 

As said above the car is designed to run on a std recirc valve,as the excess air is vented back into the system,if you have had a dumpvalve on your car for 4 years and had no running issues at all,you've sort of answered the question.I presume your car has a td04 turbo on ,as your looking to upgrade your turbo in the near future,the fmic as you say is for looks isn't really benefitting such a small turbo apart from reducing your inlet temps. 280 bhp is achievable with a remap & a few supporting mods, and if you like the sound of the dv going off your mapper should be able to map it with the dv in place,which is a safer option as just bolting one on can make the car run a little rich,which can cause pops and bangs from the exhaust.

 

I agree, don't have a dump on your car, just not good.......

A recirc valve is all round the best option.

Simon

 

The pupose of the BOV as the name suggests is to allow boost pressure to release when the car has been running boost and suddenly the throttle is closed. The boost has to go somewhere hence the BOV. With no BOV the airflow will reverse as it seeks the route of least resistance and flow back through the intercooler to the turbo amd I guess beyond. Running with no BOV can signifigantly alter the noise heard through the induction
Vent to atmos or recirc? Advantages to both and in part it depends on what ECU you run. VTA is simple and easy to do when fitting an FMIC and generally is my preference but that view is generally for use on cars without MAF Sensors. Retaining the top mount and MAF sensor and I would tend to go recirc.

 

I'm running a standard recirc with my FMIC.

The noise of a VTA got on my **** after a while, then noise got on my **** when I blanked the DV off.

I think, though, that I may need to change to a different recirc, as my car doesn't appear to make the same boost pressure. Could be the warmer weather.

 

It should be easy to check if the DV is leaking. Just blank it off and then check boost level again. If you have a Forge for instance it is easy to overhaul.

 

I changed to a vta dump valve on my classic tmic, two weeks ago I took it off and put

re-circ on and it's been smoother and more responsive, it does affect it.

As it has been said dump valve on a FMIC, re-circ on a TMIC

 

Eight years on mine is still fine thanks... Forge VTA maximum spring stiffness running at 1.5 bar and 400+ bhp.

Runs lumpy, farts & burps, and then does an impression of "**** off a shovel", I luv it !

dunx

 

Forge VTA all the way on my V3 Sti with FMIC. Running 1.4 Bar on my VF35 setup approx 370+bhp no leaks or running issues.

In my opinion the Forge DVs are by far the best I have seen for function and reliability.

Cheers Iain

 

+1
I have Forge and i'm very impressed

 

Some interesting viewpoints there, cheers My car has no running issues whatsoever with the VTA d/v on, so I guess its down to whether I want the 'tish' noise or not

 

My car i think is runnin a little rich and after reading this I think its due to the dump valve. I dont have the standard one as it was like this when i bought the car. Is this a major problem? should i be in a mad rush to get a re-circ one fitted or not really worry as im plannin on mappin the car in 6 months anyway. Thanks guys

 

I have an HKS VTA fitted, but seems it must have been wound right up to max compression, as it only blows off when under heavy acceleration. Won't just go off if i rev it whilst stationary like my old Impreza.

Is this normal?

 

In my experience hard springs are usually the cause of more problems than solving problems.
As your car doesn't make boost from revving the engine without load on it do not expect the blow off valve to operate under the conditions you describe.