Tuesday, January 26, 2010 - 11:59 am, by: Austen Menze(Mercyfulfate)
Yep finally installed the Turbosmart blanking plate and plug this morning as I suspected my BOV was leaking.
The power increase is definately noticeable pulling hard all the way to redline, where as before you could feel the torque drop off slightly after about 12psi. With the EBC turned off it was fine though.
The spring in the stock BOV seemed to be a lot softer than the spring in my GFB and it must have been opening slightly under higher boost pressure.
Tuesday, January 26, 2010 - 12:17 pm, by: Daniel Clarke(Dieseltrain)
It has nothing to do with the spring pressure . The stock BOV actually has 2 diaphrams it uses boost as well as the spring . SO once boost is created that boost also comes from a line from the manifold tot he BOV to help " push " the bov closed as well .
Thats how BOV's work
Good to hear you noticed an increase , but i would like to see it backed up on a dyno , before + after would be neat
I am toying with just blocking my stock one altogether and see if it makes a difference .
Tuesday, January 26, 2010 - 12:38 pm, by: Austen Menze(Mercyfulfate)
Ahh, yeah I've never been to a dyno before but will be soon when the T13 harness rocks up for my EMU
Your explanation on how BOV work has me curious now.. I might rip the stock one open and have a look inside. Maybe there's a cracked diaphragm or something?
The GFB was installed on my car when I bought it on the intake pipe in between the throttle body and intercooler. Later on I'd have it plumbed back to just behind the air filter so I can still get that PTSSHH but be legal about it
Tuesday, January 26, 2010 - 10:02 pm, by: Boris Siljanoski(Z2tt)
From what I've seen, all stock 1jz recirculation valves leak, and have been told by a few tuners that that's how they are like from factory, whether it was intentional or design fault I don't know.
Tuesday, January 26, 2010 - 11:04 pm, by: Austen Menze(Mercyfulfate)
I couldn't get my BOV open as the edges around the cover are crimped over all the way around and I don't really want to start hacking it up with the Dremel yet...
It would be interesting if people have had similar experiences.
I figured it may be Toyota's typical over engineering to go hand in hand with boost cut, because on 11-12psi EBC off it worked fine pulling hard to redline.
Wednesday, January 27, 2010 - 08:01 am, by: Blake Gloyn(Blakenz)
i had heard that the factory ones can leak at higher boost pressures, causing a loss in power, so i modified a spare one so it could not open, and did a before and after dyno. Sadly, there was no gain (19psi boost).
Wednesday, January 27, 2010 - 06:39 pm, by: Ryan McDonough(Ryan)
Have run may car with both the stock bov and a hks one, at 15psi, there was no difference in power at all. The stock one works great, fits as it should and gives me no police problems. Its a winner for me.
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Oh dear .
