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is blow off vale useful or just making noise?

PostPosted: Mon Feb 15, 2010 11:44 pm
by subarugt
Does the BOV helps with the performance or it just makes noise?

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 7:43 am
by Hotwire
A vent to atmosphere BOV does nothing for performance, just 100% wank factor :roll:

Do a search as there has been plenty of discussion on this...

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 7:44 am
by swingn
Yes it helps performance by holding boost pressure & expelling gases more efficiently.

In some cars (Polo GTI for example) the standard BOV's tend to leak boost pressure which makes the car feel like it's running out of puff... When my mate wacked on my old HKS SSQV, it did make a difference into how the car pulled in the higher revs... Albeit, it wasn't a significant change, but there was a change non the less.

That being said, if you read around the forum, the standard unit used on the Gen 4's appears to be pretty good... Personally, I can't see how a plastic BOV can perform the same as good quality after market unit which is metal etc.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 7:47 am
by Hotwire
Matty - I think you need to clarify that is only at higher than stock boost pressures. The stock unit will perform just fine for many hundreds of thousands of kms for stock boost pressures. If you run 20psi, then yeah, you'd be wanting an aftermarket unit possibly, but just the BOV alone does NOTHING for the performance of an otherwise stock car.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 7:53 am
by swingn
Hotwire wrote:Matty - I think you need to clarify that is only at higher than stock boost pressures. The stock unit will perform just fine for many hundreds of thousands of kms for stock boost pressures. If you run 20psi, then yeah, you'd be wanting an aftermarket unit possibly, but just the BOV alone does NOTHING for the performance of an otherwise stock car.


Can't speak for the Lib, as I said, I feel that a good after market unit in the way to go.

BUT, in some cars, like the Polo GTI I used as an example, the standard BOV was leaking boost pressure... & that was a completely stock car... No tune or anything.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 7:58 am
by subarugt
i see thanks for the info. I am new to car mods. So I am just asking questions here and there trying to find out what's the best way to mod the my10 GT without costing too much. I personally don't a fan of noisy cars. well used to love it when I was young but I am getting old so i would prefer a car that goes and accelerates fast silently than a car that makes so much noise but slow.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 8:13 am
by Hotwire
Best bang for buck has always been a tune on the Liberty GT's, I dont see that would have changed for the MY10. If you want more performance without additional noise, find a good tuner and go that route.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 8:44 am
by tangcla
I go between love and hate with the BOV sound. I like it at the moment, as for the past few months. I'll probably hate it soon and will have a GFB Stealth FX for sale :P

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 9:53 am
by GTSPECB STI
swingn wrote:That being said, if you read around the forum, the standard unit used on the Gen 4's appears to be pretty good... Personally, I can't see how a plastic BOV can perform the same as good quality after market unit which is metal etc.


Subaru use plastic instead of metal on all sorts of parts under the bonnet..go have a look some time. Aftermarket BOV is an absolute waste of coin unless you have already modded engine, exhaust, and turbo and are producing huge amounts of HP and higher than stock boost.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:07 am
by teK--
I've always loved the turbo flutter sound (running no bov at all or an undersized bov) even if it is very bad on the turbine blades ;)

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:15 am
by Arith
Ok, so it's agreed. Aftermarket BOV is one of the essentials for a moderate to heavily modded Liberty running higher than stock boost. With stock or near stock, stick with the factory unit. :P

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:16 am
by subarugt
Hotwire wrote:Best bang for buck has always been a tune on the Liberty GT's, I dont see that would have changed for the MY10. If you want more performance without additional noise, find a good tuner and go that route.


I was told by MRT that the my10 gt is already well tuned by factory. So it won't get much performance out of it if just tune it without changing after market parts? honestly I don't want to spend more than $5k turning this car. 5k is maybe the max amount of money I am willing to spend modding it. So I am going to do alot research and compare prices before doing anything I think. these forums and you guys really helps alot by providing useful infos.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:25 am
by GTSPECB STI
A subaru factory tune will be rich and all over the place...more like factory detune, its not just about getting more killawasps. Turboback exhaust and tune will run you $2500-3000. You would also be wise to look at the suspension set up for some modding unless you like to roll outback style. Get yourself some nice linear lowering springs and a good wheel alignment and allow for $700. Also get yourself an aftermarket panel filter $100. All up well under $5K and your car will be nicely improved.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:47 am
by subarugt
To me I'd like handling and safety more than just performance. I tried some cars with very bad tunes they are very powerful but even a novice like myself can tell those cars are very dangerous to drive. That's what I am really worry.

Re: is blow off vale useful or just making noise?

PostPosted: Tue Feb 16, 2010 10:48 am
by Arith
andygt wrote:I was told by MRT that the my10 gt is already well tuned by factory.

MRT has a different approach to tuning. Well, that and a lot of lying and scare tactics. I know you've used MRT in the past, but no one here buys into MRT propaganda. :P