BOV or no BOV?

[BlitzBoy]

Here we are BMW F1 turbo engine, not a BOV insight.
So sorry I dont buy the performance claim of BOVs, I can see why recirc valves would be used on small shaft tiny turbos in terms of noise surpression and maybe the relabilty of protecting the small shaft of a small turbo.

But a BOV giving a performance gain I disagree. Otherwise you would have seen them on the F1 cars and the group B rally turbo cars

[Kenji]

Wow... you really have a grudge against BOV\'s

[PGiljevic]

Ask you lecturer why most turbo rally cars dont run a BOV then?

Like most lecturers they don\'t know sh7t from clay! cause they have never done anything real in their life :eek Most academics are the same!

I had one Thermodynamics lecturer tell me in the early 90\'s that no cars can exceed 100% volumetric efficiency! I told him rotary engines can and have done easily from NSU to Mercedes tests, he did not believe me so I brought in the tests to show him! he changed his mind quick!

If the "lecturer" who has an "opinion" about BOV\'s got off his ass like I do for example and invested say $50,000 in instruments and his time to measure a real car (like I do) he would see that a BOV is pointless and is actually a negative step in regards to pressure and turbine speed on gear changes! ...... but this is why he is in a class room and not making fast turbo cars! :Talking1 rather he is doign this to students :Talking1

:Giggle BOV\'s are rubbish :spank

[RXSpeedy]

I wont be running a bov either :Nono! lol.

[the real podge]

No BOV on mine, apexi rx6 turbo, greddy gt spec front mount, apexi wastegate, stock injectors, sounds amazing:burnout

[B.Martin]

So, i\'ve read the ultimate thread spanning over 6 years! I\'m trying to digest the information, but understandably my small mind is finding a bit of a task. Basically BOV\'s are pointless except for the sound they make? They are more or less for people in their subaru\'s to try and look good? Or are there some uses for them in road use? It seems that when talking about BOV\'s in this thread everyone is talking track use, how does this relate on the roads? As i\'m sure i speak for a few people on this forum and its safe to say my FC TII will spend more time on the road than on the track.

Ben

[jackaleks]

been running my stock FD twins without a BOV for a bit now. i\'ve yet to see a compressor wheel come flailing through my bonnet in a firey mess :Hammer

seems to pick up a little bit quicker after a gear change, this is probably all in my head though!

[ChrisDubbya]

I don\'t have any real expertise on this but from reading it all I don\'t think referencing rally cars/F1 cars is really relevant the tolerances in their engines and turbo is far tighter than a production car and are likely to be rebuilt on a very regular basis.

Mazda and every production car manufacturer on the planet as far as I am aware have always but recirc/bov valves on turbo charged vehicles - this is an extra part that costs money to fit and offers no improvement in emissions or economy - why would they do this if it\'s unnecessary?  

No doubt they do the math 1 in x chance turbo will go pop, warranty fix costs for the cars that do VS cost of adding BOV

Might be a different story for aftermarket where production \'may\' be better

Just my 2 pence worth

Chris

[Vell]

No doubt they do the math 1 in x chance turbo will go pop, warranty fix costs for the cars that do VS cost of adding BOV

That\'s how companies are making money :King

[Lil-Steve]

Another point to add to this, 80\'s F1, Rally and high budget race cars in those situations aren\'t looking to make a turbo last at least 60,000 miles and if they we\'re they\'d be loosing performance and potential reliablity anyway.
 
It might be advantageous performance wise and in 90% of race applications be completely unnecessary but road cars are there to be used as a relaible mode of transport on the road. And as Chris says if a car comapny can save itself £30 a car and turn that into pure profit, you know they\'ll go for it...

[m1tch]

With the F1 car example I doubt the engine or ancillaries need to last very long lol I think with smaller shaft turbos it would make sense, on larger shaft turbos it isn\'t as much of an issue.

[BlitzBoy]

Mazda and every production car manufacturer on the planet as far as I am aware have always but recirc/bov valves on turbo charged vehicles - this is an extra part that costs money to fit and offers no improvement in emissions or economy - why would they do this if it\'s unnecessary?  

The reason why the FDs run recirc valves is noise reduction effort by Mazda

[B.Martin]

So do I purchase one for my TII or do I not? I\'m a total n00b I\'m afraid

[m1tch]

When my BOV goes off the fueling can\'t keep up meaning it suddenly goes rich...causing some nice backfires and flames

Mazda has fitted a BOV as OEM, I have kept it as Mazda designed it and have a BOV fitted.

[BlitzBoy]

D

Mazda has fitted a BOV as OEM, I have kept it as Mazda designed it and have a BOV fitted.

Its not a BOV its a Recirc valve as stock