BOV Removal

[Nic]

Anyone running a Rev3 Turbo without a BOV? Any pics or advice how best to block it off?

[simpson_eh]

just put it to recirc you dont really want to block it off or you will get backpressure on the turbo

[Magic Beans]

You can get a block off plate here - http://www.racerxfabrication.com/misc.html

[glen n]

I've heard conflicting stories about running no bov at all. Does it do your turbo harm?

[Nic]

I know race engineers who never run BOV's on their cars, who say they're only fitted to road cars for noise suppression of the turbo. I know the other side of the augment that says it'll harm the turbo. I've run turbo cars with and without them and never noticed a difference either way.

I currently have a recirculated HKS SSQV fitted and was thinking of removing it and blanking it off. I'd be interested in people's experiences/opinions of the MR2 (mine's a Rev3 Turbo) with or without a BOV.

[Magic Beans]

On a standard turbo I'd have some concerns, just in case the ceramic fins let go due to back pressure and end up in the engine

I run a no BOV type set-up on mine, with the VTV on the stock recirc valve switched the other way around so it doesn't open.

[gnzyza]

my opinion not professional is unless your turbo is 100% healthy wouldn't do it, lifting off under high boost then flooring it would seem unhealthy.

compressor surge/stall whatever they call it can't be good on a turbo with say some play init, seems it'll just accelerate wear. Saying that Turbo do put up with a hell of alot.

keen to hear other people thoughts.

[mrturbotom]

I've known similar cars one with and the other without. Ones without normally do suffer turbo failure.
Plus you get lag between changes without a bov

[jimGTS]

Plus you get lag between changes without a bov

disagree


keeping some pressure in the pipes by not having a bov increases spool up between shifts. fast shifts anyway.

i alternated between bov and no bov on my old car, that had a large apexi turbo, significant difference between fast shifts by having no bov.

dont forgot spool up builds pressure in the IC system, when you vent to atmos, you expel all that IC pressure, by running no bov, you keep some (not all) of that pressure in the pipes for longer, and in turn you can be back to full boost quicker.

i would be wary doing it with a ceramic turbo, but many are running without on the US forums these days (on ceramics) after people finally came round to the notion that bov's do nothing but make a sound.


the subject will divide opinions, lol

[jimGTS]

I run a no BOV type set-up on mine, with the VTV on the stock recirc valve switched the other way around so it doesn't open.

the vtv isnt a one way valve, so id imagine it will still partially open

[bobhatton]

From the ones that should know, Garrett.

What are the components of a turbocharger?

The layout of the turbocharger in a given application is critical to a properly performing system. Intake and exhaust plumbing is often driven primarily by packaging constraints. We will explore exhaust manifolds in more detail in subsequent tutorials; however, it is important to understand the need for a compressor bypass valve (commonly referred to as a Blow-Off valve) on the intake tract and a Wastegates for the exhaust flow.

The Blow-Off valve (BOV) is a pressure relief device on the intake tract to prevent the turbo’s compressor from going into surge. The BOV should be installed between the compressor discharge and the throttle body, preferably downstream of the charge air cooler (if equipped). When the throttle is closed rapidly, the airflow is quickly reduced, causing flow instability and pressure fluctuations. These rapidly cycling pressure fluctuations are the audible evidence of surge. Surge can eventually lead to thrust bearing failure due to the high loads associated with it.

Blow-Off valves use a combination of manifold pressure signal and spring force to detect when the throttle is closed. When the throttle is closed rapidly, the BOV vents boost in the intake tract to atmosphere to relieve the pressure; helping to eliminate the phenomenon of surge.

[jimGTS]

From the ones that should know, Garrett.

who also as it happens, are in business with bov traders, so will of course say all of this.

[Ryan S]

Plus you get lag between changes without a bov

keeping some pressure in the pipes by not having a bov increases spool up between shifts. fast shifts anyway.

this is exactly as i understand it as well, letting out all of the pressure is a bad thing, you need to retain some of it you can get BOV that can release only some pressure, this is meant to be the optimum way to run a BOV, releasing all the pressure means you have to build that pressure up again, resulting in.....lag

[mrfil13]

There were some very long threads on the US forum about this with some pressure drop graphs of with and without. The benefit was only really noticeable when shift quickly but if you are able to do so and need to then the time it takes to get the pressure back was noticeably shorter without the BOV from the graphs.

[adaz]

You may find this discussion interesting! Have a look what karl on there says (page 10+).

http://www.mr2.com/forums/turbo-engine- ... ov-10.html

[Ethan21]

You may find this discussion interesting! Have a look what karl on there says (page 10+).

http://www.mr2.com/forums/turbo-engine- ... ov-10.html

This argument sounds much more interesting

this conversation reminds me of the guys who try to convince people not to use Intercoolers because the heat is actually good for your engine.

actually, the honda F1 turbo engines did have intercooler bypass valves whose function was to maintain higher intake temperatures. but like i said, that's a whole different situation