Guys - If you are running BOVs, would you be able to please post a pic of your set-up? This is my next installation, as I would like to reduce the compressor surge at 1bar.

Thanks!

Yasin

 

I second the motion!
I'm finishing up a conversion to 993TT brakes all around and my next step is to throw away the factory 930 CBV setup and fit a large recirculating BOV.

 

I'm using the one from EVO motorsports. It's billet and actually called Baileys.

 

Any pics you can share Sameer?

 

here you go..

 

If we change to those Blitz or HKS BOV, will they make those hissing, whoosh shounds?

 

I like the "PFFFSSSSHHHH" sound.

 

Me Too!!

 

You can not vent outside the intake track. It will cause the fuel plate to stall for a moment thus causing a lean spot in the range. This will cause damage down the road.

 

Stephen,
So there is no way of that "woooosh" sound?

 

FWIW we've found our Stock Toyota BOV to be better than any on the market. Go here for a good write up: http://www.jekylhyderacing.com/bov.htm

The By-Pass-Mode alone is worth it. It'll improve your low end power and throttle response when off boost. It allows air to go around the turbo when under vacuum. Don't forget the engine has to work to pull air over the impeller when not at boost. That robs power.

Go here for a good photo of the unit on the MR2: http://mr2.noegruts.com/engine/engine.htm

And here is a basic operating description from the Toyota Mechanics Manual (what we refer to as the Big Green Book- BGB)

 

So, has anyone adapted this to their 930? What have been the results?

 

Very interesting Senna21. I would assume that drawing the air on vacuum spins the turbo at some speed, with the toyota bypass would the turbo be spinning much slower and what effect if any does this have on spool up? Would it be insignificant? What is the vacuum source for the two lines and in which line does the VTV go?

Stephen, Kevin....thoughts?

 

I dont think these BOV make that much of a difference in perfrmance other than they are just much more durable compared to the stock plastic ones.

 

The driving force of the turbo will always be the exhaust turbine. The engine would have to be making massive amounts of vacuum to be increasing turbine speed on the intake side over the exhaust. If that were the case then the turbo would be scavenging exhust from the exhaust manifold and cylinders on the exhaust side. I suppose that could be occuring but, I've never heard of it. I've never run my car without the stock BOV so I don't have any personal experience with spool difference. But, it shoud be a bit faster. As I've said the turbo's RPM is always gong to be driven by the exhaust. So, as we haven't changed that it will spool as normal. But your car will be able to make more power under vacuum which means that HP before boost will be improved and there by reducing the "lag". It'll pull more air in at non boost RPM, there-by increasing the volume (to the exhaust turbine) at those RPMs, which will result in more exhaust gasses at those RPM. That extra exhaust gas will result in a faster spool time and along with the extra HP before boost will make the transition from vacuum to boost less abrupt. As the intake charge moves from vacuum to boost the valve closes. You can see the vacuum line runs to the intake. You can see the set up on the photo ( http://mr2.noegruts.com/engine/engine.htm ). If you like I can annotate it for you showing the BOV and lines more clearly.

Also, and I’m not sure on this, we have the BOV routing air directly around the Turbo before the intercooler. The intercooler is another place where air has to be dragged through under vacuum. It may be better to mount the valve after the intercooler as well allowing the most direct path to the intake.

Thoughts?