Testing dump valve off car? Correct procedure?

[jimBNR32]

Got round to returning the car to a recirc setup and while the bumper was off thought I'd pressure test the dump valves.

Just wanted to confirm I'm testing them correctly, basically hooked up the same pressure source to the top take offs and the main pipe itself. I assume like how it operates as stock?
It was leaking slightly at the valve (I think the extra spring tension not quite holding it shut). Decided to clean as best as I could and removed them from the pipe, reinstalled. Now it's leaking from the gaskets as well, :-/.

I'm assuming dump valves should not be leaking at any point if equal pressure is applied to the top and main pipe?

I've reinstalled as I've no choice if I want to use the car, and I can't notice any ill effects, but any leak is a bad leak, wish I hadn't bothered testing em.

Where can I get these 2 dump valve gaskets?
Anyone confirm I was doing the test correctly?


Cheers
Jim

[Skym]

Those BOV gaskets have a ridge near the middle and once the ridge is crushed, gasket has to be replaced (use once only).

Also stock BOV's leak. They are a push type BOV, so boost pressure can force them open (overboost protection). You can block the little hole next to main valve on bottom of BOV's, but BOV's won't open at lower boost levels and when back off throttle, while offboost and get back onto throttle engine hesitates then accelerates. With a good BOV (Synapse BOV) engine doesn't hesitate when offboost, car just accelerates (similar to NA engine).

This is the stock BOV mod, but makes it adjustable -

http://www.thedodgegarage.com/turbo_bov_mod.html

Watch this (testing stock Mitsubishi BOV and Skylines have a Mitsubishi BOV) -

http://www.youtube.com/watch?v=5ZjxL-Or0Eg

[jimBNR32]

Cheers for reply.
I didnt notice a small hole on the underside of the valve :-/.

I thought oem valves were great? I've read of big hp cars running them and can hold any amount of boost due to design? Ie more boost the tighter the seal gets.
It's the reason I wanted to use them on top of being able to recirc them.

I'm having no luck finding the gaskets.

That second link doesn't exactly look like a DiY home tester, lol.
I don't need a test like that to see it's leaking.

[Skym]

Cheers for reply.

You're welcome.

I didnt notice a small hole on the underside of the valve :-/.

Small hole should be there on alot of BOV's (boost feed on Synapse BOV). From what I understand, the small hole is there to help stock BOV quick release.

I thought oem valves were great?

OEM BOV's leak, but don't seem to leak with stock BOV mod (doesn't leak on dyno graph boost plot) and some go to the extreme of crushing the top of BOV to add more preload to spring. Factory designed engine to last (I think was past the 100,000km?, 3year? warrenty period), so have many safety features to prevent engine failure.

I've read of big hp cars running them and can hold any amount of boost due to design? Ie more boost the tighter the seal gets.

They are a push type BOV, so boost pressure can be too much for spring, valve opens (stock BOV mod helps to stop them leaking). Some smash the top of BOV to make the spring shorter (similar to adjusting nut on top of push type aftermarket BOV).

It's the reason I wanted to use them on top of being able to recirc them.

Synapse GTR BOV kit -

http://synapseengineering.pinnaclecart.com/index.php?p=product&id=624

It uses O rings on flange, so no gaskets necessary. Also can recirculate air and can be a push or pull type BOV, can rebuild them.

I'm having no luck finding the gaskets.

Gasket = Nissan Dealership. Parts department can look it up with Fast software (what Nissan use to find part numbers). I think there's a Fast part number thread on here somewhere which might have the part number.

That second link doesn't exactly look like a DiY home tester, lol.

Looks like he's using hub dyno computer, software (can monitor boost pressure).