What is the difference with a HKS and a Tial BOV?

[driftdriven]

If I could please get technical reasons and not just sound preference. I wanted to know which lasts longer and causes less problems.

[Krugar]

Taken from BerkTechnology Post in another thread:

I think the Tial looks the best, but it is a spring type actuator. Under high boost these tend to leak and they do not react as quickly as diaphragm type blow off valves. The more boost you run with a spring type, the they have a greater tendancy to leak. To fix this you run a stiffer spring which makes it react even slower.

I suggest that you guys use a diaphragm type. With diaphragm type blow off valves, the more boost you run, the tighter the seal. Their reaction time is independent of the boost pressure.

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HKS SSQV is a Diaphragm type BOV. Tial you may have to adjust a spring for the valve to open/close on the HKS you do not.

At least this is what i've read so far about these things.

[driftdriven]

Okay that helps, thanks!

Any other things?

[denial]

From my experience a draw back of the diaphragm type BOVs is that they tend to fail over time--that is, the diaphragm eventually ripped after a period time (Greddy Type-S). I eventually gave up on the diaphragm type and switched to the piston type BOV.

I haven't had any personal experiences with HKS BOV's. Perhaps they are more durable.

[dad]

The HKS can be reconfigured to run in recirculation mode - this isn't necessary for the N54 - or VTA while the TIAL is strictly a vent to atmosphere (VTA) BOV. The design of the HKS is such that the boost pressure actually keeps it closed and it will open only under vacuum - closing of the throttle plate. In this way it is a bolt it up and forget about it BOV. It won't leak until boost is higher than 30 psi. The tial is generally recognized as one of THE best bovs on the market. It uses a spring that can be changed. IMO they look the best by far but the HKS is probably a better design for moderate boost applications. Finally the HKS is a sequential bov and will give the sound of a flutter under throttle closure after low boost. This should not be confused with compressor surge.

Both are excellent pieces. I'm going with the TIAl b/c that shit is just dead sexy. Here's a pic of it installed in a 335i. http://www.cp-e.com/2044.html

[driftdriven]

So is Tial the piston design?

[agent_grey]

I am an Instrument Eng. Tech. and Automation Eng. Tech.

first thing.... a valve is a valve(assuming they are both built with proper materials and design). after that its the actuator.

Spring actuated valves out last Diaphrams by a long shot. But diaphrams work better and faster. Piston actuated valves are a comprimise. I would say the best of both worlds. longevity and speed. They are also the only valve I have seen to continue to function after a failure.

After that it is totally application dependant. But in my experience and I do deal with valves for a living pistons will be safer. The only problem with a piston failure is you probabley won't know there is a failure unless you have a boost gauge and are paying attention.

Think of a piston actuator as being like a diaphram made out of solid steal. The only thing that can fail is the orings.

A boost gauge is a must to catch a failure. whether it be failure to presurise or failure to depresurise.

[driftdriven]

^^^THANK YOU!!!

This explains a lot. Now my next question is which is which with the Tial and HKS? Is Tial a piston and HKS a diaphram?

[dad]

^^^
yes, you got it.

[itsthechuck]

I had a Tial BOV on my built wrx a few years ago, it was definitely a quality piece, worked very well for me didn't seem to leak at all.

[scrapiron7]

I had an HKS SSQV on my previous RX7 for a few years. Pretty loud and noisy, but it did the job well and never failed or had any issues. HKS generally makes good products.