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EricF

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  • 4 weeks later...
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  • 10 months later...

So how does one choose what size BOV to get? I'm looking at a Turbosmart recirculating BOV and they come in 32mm and 38mm outlet sizes? What size outlet do you get?

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Needs to be big enough to flow enough air to keep the compressor to the right of the surge line when the throttle is closed suddenly. If in doubt and you're not up on your fluid dynamics, go with the bigger one. :rolleyes::lol:

But basically, figure out what your compressor wheel speed is when WOT, worst case. Then figure out where that wheel speed meets the surge line, then you know how much flow at a given pressure drop the thing has to be able to do, assuming you know what else the air is flowing through to get there (before or after IC, how many bends, what ID tubing, etc..) If you know the valve diameter and Cv, you can do some ballpark estimates on whether or not it'll flow enough.

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So how does one choose what size BOV to get? I'm looking at a Turbosmart recirculating BOV and they come in 32mm and 38mm outlet sizes? What size outlet do you get?

On a small turbo like a TD04-18T, it doesn't really matter. However, 38mm seems to be the most common size.

That said, I use an eBay GReddy ripoff on my car. 38mm as well.

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Well I got the spring assortment for my Forge CBV so will see if I can dial in the CBV a lil better. Thanks for the feedback on choosing a BOV.

On a small turbo like a TD04-18T, it doesn't really matter. However, 38mm seems to be the most common size.

That said, I use an eBay GReddy ripoff on my car. 38mm as well.

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  • 1 month later...

Sorry if I'm mistaken here, but in my 87 745T, (and my saab 9K aero), the cbv offers bypassed air back into the intake tract, right before the TB. Isn't that to reduce spool time in situations where its opened quickly? (like between shifts)? Whereas a BOV just dumps that air back to atmosphere?

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Sorry if I'm mistaken here, but in my 87 745T, (and my saab 9K aero), the cbv offers bypassed air back into the intake tract, right before the TB. Isn't that to reduce spool time in situations where its opened quickly? (like between shifts)? Whereas a BOV just dumps that air back to atmosphere?

I'm no expert but it should recirculate air from between the turbo and TB to between the MAF and turbo, in other words since the MAF has accounted for the air already this keeps its calculations correct and therefore prevents improper AFR's. If you dump the air via BOV that has been measured already the MAF has no way to recognize this, but if the car had a MAP sensor instead a BOV causes no problems since the sensor will register the drop in pressure. As for spool I don't believe its really effected, but it may make a small difference. If i'm completely wrong someone please correct me.

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  • 8 months later...
  • 3 months later...

My Turbo XS RFL BOV is sucking air in at the horn. I took it apart and it just has a piston in a cylinder and no sealing rings or seals of any kind..How can this manufacturer think this thing wont leak. My 850R is running really rich and I'm getting P0101 MAF code. I think the MAF is bad because when I cleaned it the car leaned out alot..Should I just thow away this RFL? What is a good replacement BOV that does not leak and will fit into my intercooler hose?

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I'm running a turbosmart bov, dual port, but have it set to full atmospheric. The car runs very lean on initial startup, pretty much off the afr gauge. When the car wanna up, it returns to normal. At idle, the piston remains somewhat open. On throttle it's sucked closed. Is this normal?

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  • 3 weeks later...

There is a video on youtube of my stock 2.5T and how LOUD the BOV sound is on an AUTOMATIC CAR. The video sound doesnt do a lot of justice, I mean it is loud, it echos off of houses and yes it is stock turbo and "blow off" from volvo, there are only a few little tricks I did that make it sound VERY loud! It cost about 15 bucks, and effects the engine only by letting it run cooler! link is below - - if anyone wants to say BOV cant be heard on an auto or is a waste of time, you can come meet me I will give you a ride!

http://www.youtube.com/watch?v=GCK6LailB9U&list=UUh61bpdjY7aq_JPMN1PbRpg&index=1&feature=plcp

http://www.youtube.com/watch?v=GCK6LailB9U&list=UUh61bpdjY7aq_JPMN1PbRpg&index=1&feature=plcp

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  • 1 month later...

Greddy clone, recirculated (not venting to atmosphere), on an automatic...

...it's loud.

Ive had many BOV's on auto cars, from greddy, turbo smart, SSQV, Ebay knock off's, RFL....and others. The loudest one yet has been my GReddy Type S. Its been modified numerous times, with different springs and shorter/longer adjustment bolts. The only issues ive had over the years is sometimes at a red light/stopping the rpms drop a bit, and loud backfires. The SSQV takes the cake on reliability thou. never once did I have a drop in RPM's or leaking/vacume issues

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