Stock Blow Off Valve...good ?

[EdmundVR4]

Is the stock blow off valve any good ? Do you think it leaks at stock or raised boost levels ? Is it worth replacing ? If I do replace it what gains in performance might I see or feel ?
Lots of questions, I would really appreciate your comments & opinions.
I have free flow exhaust from the turbo back, fuel pressure regulator, 255lph fuel pump, fuel controller, electronic boost controller. Currently I get up to 18 psi which drops fairly quickly to between 10 - 13 psi at redline, depending on which gear I'm in.
I'm wondering if my blow off valve is leaking....maybe I can hold boost higher & longer with an aftermarket blowoff valve.
What you think guys ?
Ed

[pjjohnson]

I was running similar boost to you with the standard valve, and had it changed on the advice of an 'expert'.

I couldn't feel any performance increase, and the boost pressure still dropped off at high revs. The only noticable difference was the noise, and a hole in my wallet. The new valve did eventually start to leak causing problems at idle, so had to buy another. Now got the HKS one - no performance increase, boost still drops off, sounds OK.

[zedy1]

my opnion is if u replace the internal bov with an external one you will loose a bit of power, have u changed your internals eg pistons to run your car on 18 psi

[EdmundVR4]

Thanks for the input guys. I think I will continue using the stock bov.
Zedy, all internals are stock. I only hit 18 psi for maybe a second and then it starts to drop off. Thats why I installed the rising rate fuel presuure regulator & the 255 lph fuel pump, so that I ensure there is enough fuel. The car feels much stronger now, just wish I could keep a higher boost level to redline. My tuner thinks I need bigger turbo's.
Ed

[Nick Mann]

I knew a guy who did some serious modding on a twin turbo GTO INSERT INTO post VALUES (was measured as 515 bhp at the wheels!) and he said what many people on here have also said - "the turbos are tiny, and increasing the size of them is a good and easy way of increasing power". I may see if I can contact him, to find out where, who and how much it was.

[zedy1]

i took a qoute and i think the price qouted was 1100 quid foe the 2 put not too sure