Damocell

iTrader: (1)

Sorry for the long post!!!!

I know this has been debated hundreds of times but I felt I had to post my experience of VTA and OE dump valves.

I bought my UK 99 turbo in February of this year and immediately fitted a Bailey VTA dump valve for no other reason than the noise it makes. Everything was good I loved the noise and the pops and bangs however on the motorway the valve was open quite alot of the time when on part throttle, never really thought anything of it.

In the mean time I read lots of posts from people discussing the merits of VTA dump valve, otherwise known as "chav valves". Personally I don't believe this and don't consider myself to be a chav.

Recently I bought an STI 8 intercooler and OE dump valve, because of this I tried to look into the benefits of VTA dump valves. I found this and read with interest Andy.F's comments about half way down the page...

https://www.scoobynet.com/drivetrain...highlight=jolt

especially about MAF revertions and over fuelling, as my car was quite jerky coming off boost and for teh aforementioned comment about driving on the motorway.

So last weekwnd I fitted my STI 8 intercooler with a VTA dump valve, the MAF revertions felt like thay had got worse to the point of really shaking the car when coming off boost, possibly due to the lower back pressure within the intercooler. So today I fitted the STI 8 OE dump valve....

What a difference. the car is so much smoother, doesn't jerk and actually feels like it has less lag. I couldn't believe the difference its literally like night and day, the car is so much more of a joy to drive, no longer is the car "snappy" when shutting the throttle at full boost. Maybe its a placebo effect after reading all the threads slagging off VTA dump valve, but I'm sure under boost the engine sounds smoother????

I'm all for the sound of a VTA dump valve but would not use one in future.

I'm sorry for the long post but just wanted to share my findings with everyone.

Does anyone else have any thoughts???? (Flame suit on)

Damo

drb5

iTrader: (4)

Take the flame suit off Damo, you've done exactly what every scoob owner with a VTA should do! They just can't seem to grasp that it's a bad thing.

Damocell

iTrader: (1)

Don't get me wrong, I actually like the sound, but I prefer driving the car!!

I found I was having to think about coming of the throttle slowly when changing gear (not too much of a problem beacuse I double de-clutch) because of the jerkyness.

Now I don't have to worry about it, plus when going from full throttle to the brakes the car is MUCH more settled. Always a bonus when entering a corner quickly

Damo

drb5

iTrader: (4)

banny sti

iTrader: (68)

Damo i found exactly the samething on my sti 3, going from a baileys to the standard plastic dv.

banny

funkyspider

My SSQV is comming off as soon as I get chance

Dspeed

I suffered really bad turbo stall on gear changes in my my00 so changed to a vta. And it improved straightline acc. But made cornering more challenging. Think I will change back and give mine another go. Maybe my standard unit was on the way out? How much are they new? And what aftermarket recircs are there?

EddScott

Did exactly the same a week ago.

https://www.scoobynet.com/scoobynet-...ifference.html

Its not just you mate. The difference is so pronounced its untrue.

I've also come to the conclusion that if your changing the turbo, especially on a UK car, your more likely to have transmission issues IF you have a VTA - for all the reasons stated above.

Hol

iTrader: (1)

I actually went from a Forge RC to a standard RC on my newage as it handles the front mount better. Same issue with 'slugged' boost.

Dspeed

Done mine 2day, jurry still out. Can you buy an uprated recirc?

The Rig

iTrader: (13)

well,im going to tempt fate now and say mine is no different with/without the VTA, i prefer the VTA, i dont like sleepers,if a car can go it should sound so, hence why i have mine !

SoNiCa

Good post! I have the same problem now. It happens at low rpms and jerk the car. I have a STI8 Intercooler and TurboXS RFL bov. I tried to fit the oem dump valve but i couldnt success on that because of the AVO inlet turbo hose restrictions.

I actually have done a lot of things to overcome compressor surge problem. In the end, today I fitted an HKS EVC5 if this is an solenoid issue. No matter! Lastly, I have fitted HKS Racing Blow off valve which helps a bit but didnt clear all the surge. It is still surging at fifth gear.

BTW, a manual boost controller works. I think manual boost controllers bleeds some amount of air when turbo starts to spool up.

I'll try to fit the oem dump valve anyway.

Dspeed

No standard recirc is coming off. Its better to drive with regards to part throtle but on a run up through the gears its boost, change gear, stall, wait SMACK boost, Change gear. Not very smooth at all. And gives a massive kick to the drive train. I may buy a different valve tho, Looking for an upratted recirc but no one can tell me of one yet. (MY00 UK Classic)

funkyspider

Forge, and there was one for sale here

https://www.scoobynet.com/private-sa...-clearout.html

Keep scrolling, its hidden at the bottom.