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The mkiv Supra Owners Club

BOVs


Fulcrum2000

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Hi All

 

Anyone know which BOV is best for getting that lovely staggered fif fif fif fif sound like Noble etc? I will need one for BPU and the last one I had released the gas in a one-er and after a while became terribly tiresome not to mention scaring the general public. Which Make and model do people prefer? I want some volume dont get me wrong just not like I'm part of the space program.

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I'm curious about this too. I understand the stu-tu-tu-tu is created by running no BOV, but at the moment we have a 'PHSSHHHH' one fitted (I know, my technical terms are on point).

 

I have heard that not running a BOV can be detrimental to the life of the turbos though due to compressor surge? Can anyone shed some light? And can it be done with a stock intake manifold? Our car is a bone stock TT6.

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A great philosopher once wrote;

 

There's a vast amount of rubbish talked about blow off valves. They were designed to stop customers complaining of "funny noises" on early turbo cars' date=' they do nothing to aid spool, can be unreliable, add weight and complexity, and are now used to do the exact opposite of their original purpose. That is they are now used to make silly noises, a mechanical means of shouting "I have a big one" from under the engine cover of the car. (IMHO). To say they stop shock loadings is also incorrect. If they aided spool and added turbo reliability every turbo charged 24 hour Le Mans prototype, and every F1 engine in the turbo era would have had one. The fact is, none did.... Maybe all the drivers were supremely endowed?[/b']

 

In the F1 era turbos often didn't last a single race, so if a simple BOV would help them live longer, what do you reckon they'd have fitted?

 

Le Mans is won or lost on reliability, to a large extent. Again, a simple BOV would be fitted if it gained reliability. Honestly, a lot of the stuff on the net is garbage on this subject.

 

If I/C's are splitting and pipes blowing off it's more down to unsuitable I/C's and piping systems being used than no blow off valves, per se. If you DO choose to believe they help spool then you would certainly need a recirculating BOV achieve any hope of this. A proper intercooler designed for the higher boost pressures will not split, nor will pipework joined by proper Adel Wiggins fittings blow off.

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Certainly try without one, what intake have you got, stock or aftermarket?

 

Mine has stock intake which conventional wisdom has told me is the best option power wise. I much prefer an induction but am going to try and get as far into the early 400s as I can power wise on stock turbs. I think the stock release is just too quiet but the single release just gets annoying and in traffic through town etc its just embarrassing. There is also a body of thought that BOVs do take pressure away from the turbs better and therefore extend the life of them which surely is no bad thing considering BOVs are pretty cheap. Besides which I love the staggered fi fi fi fi fi ala Noble etc and would love it on my Supe. I'm in no hurry as my underbody is booked in for October for a full restore and epoxy so no point shoving shiny bits on until all thats been done but I am just getting together my BPU shopping list ready for after that.

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A great philosopher once wrote;

 

All of that is good common sense, some F1 cars did actually have BOVs though, especially the monstrous early Renaults. Anyone remember them? But I digress. I think if it has a tiny amount of safety thats great but we are basically looking for a cool sound to come out mainly which - like the whole point of owning a Supe - makes us smile. If it was all about speed we'd be ripping our back seats and door panels etc out and goodness knows what. Sometimes its just about the little pleasures :)

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This is the kind of noise I am after, HKSS sound more screamy to me, its more of a flutter. Anyone ever achieved this or anything approaching it and if so with what equipment? The more I research BOVs the more I see they can be lived without until you mosey into high pressure APU country but they do no harm and potentially a little bit of good to turbo life so why not?

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You won't get that sound from the stock twins, only a external wastegate off of a single turbo will you get that.

 

I've recently bought a new HKS SSQV4 with purple fin and changed from my old ARC, much prefer the sound as is more high pitched and does have that flutter on lift off.

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You won't get that sound from the stock twins, only a external wastegate off of a single turbo will you get that.

 

I've recently bought a new HKS SSQV4 with purple fin and changed from my old ARC, much prefer the sound as is more high pitched and does have that flutter on lift off.

 

Any chance of a uick vid on youtubeee dooby doo Rob?

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you mean you want a wastegate chatter

 

 

listen from .32 seconds onwards

 

Wastegates don't chatter and wastegate chatter doesn't exist. The sound you can hear is air moving the 'wrong' way across the turbocharger's blades when you come off the throttle and instantly create vacuum in the intake system. Effectively it's the turbo's blades chopping through the air. Think about it and it makes a lot of sense :)

 

You won't get that sound from the stock twins, only a external wastegate off of a single turbo will you get that.

 

I've recently bought a new HKS SSQV4 with purple fin and changed from my old ARC, much prefer the sound as is more high pitched and does have that flutter on lift off.

 

The noise is directly related to the BOV. If you don't run one, then it'll be louder and sound more like a pigeon. If you have a BOV with a very loose spring it's unlikely to happen much at all. You can also buy adjustable BOVs, which allow you to customise the noise.

 

Google is your friend, loads of Supra BOV videos on there. Just search and decide which sound you want, also search "turbo flutter" whilst there.

 

Its technical name is compressor stall :)

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Wastegates don't chatter and wastegate chatter doesn't exist. The sound you can hear is air moving the 'wrong' way across the turbocharger's blades when you come off the throttle and instantly create vacuum in the intake system. Effectively it's the turbo's blades chopping through the air. Think about it and it makes a lot of sense :)

 

I stand corrected! Makes perfect sense now someone who knows has explained it :)

 

Although in my defence there's plenty of Youtube videos with the term on there and I thought that was a loosely used phrase for it. What is the correct term for "air moving across the wrong way of the turbo blades when coming off throttle", just so I don't make the same mistake again lol

 

Edit: seen the last part of your thread, got it!!

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I stand corrected! Makes perfect sense now someone who knows has explained it :)

 

Although in my defence there's plenty of Youtube videos with the term on there and I thought that was a loosely used phrase for it. What is the correct term for "air moving across the wrong way of the turbo blades when coming off throttle", just so I don't make the same mistake again lol

 

Edit: seen the last part of your thread, got it!!

 

:thumbs: no hassle. Youtube has a lot to answer for!

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