BCS powervalve quick video

[mrpbailey]

A quick vid of my new BCS exhaust, pretty obvious when valves open and silencer is by-passed.

Hopefully the link works.....
https://www.dropbox.com/s/grc1o6g98m3iu1t/BCS%20ex...

[JW027]

Very nice although the sound on go pros is abysmal at least you didn't get wind noise. I bet it sounds awesome on full chat.

As an owner/lover of the older style BCS exhaust what are the benefits of your version Mr P?

I love the fact mines loud all the time!

[stevegto3]

I can definately agree with that Jed - I nearly threw up when we were both lined up in that tunnel due to the sound ;-)

[andygtt]

Like the concept.... this is similar in concept as external waste gates, i.e. the exhaust goes unsilenced when you have boost (well on external waste gates it goes unsilenced on max boost only).

Ive run external waste gates for some years on my noble and they fail all track limits and I had to fit a silencer to them, worth remembering if your planning track work.

[V1DL3R]

I'm in the market for a new exhaust system. Hayward Scott or BCS? Is there much difference in price?

I was going to go loud but specify regular circular tail pipes and fit silencers for track days.

[mrpbailey]

JW027 said:

Very nice although the sound on go pros is abysmal at least you didn't get wind noise. I bet it sounds awesome on full chat.

As an owner/lover of the older style BCS exhaust what are the benefits of your version Mr P?

I love the fact mines loud all the time!

ld imagine if you have standard style BCS exhaust (non-valved) then your 'loud' is probably my quiet, as yours will be going through the silencer back box all the time. Unless the silencers are totally different. When mine comes on boost 2 valves open on a pipe which bypasses the silencer so is in effect a straight through system.

[mrpbailey]

andygtt said:

Like the concept.... this is similar in concept as external waste gates, i.e. the exhaust goes unsilenced when you have boost (well on external waste gates it goes unsilenced on max boost only).

Ive run external waste gates for some years on my noble and they fail all track limits and I had to fit a silencer to them, worth remembering if your planning track work.

The beauty of this system is that the bypass valves don't open til it's on boost, so static noise testing for track won't be an issue as with valves closed it's not overly loud. If I get flagged cos noise is too loud on a drive by I can simply disconnect the vacuum hose and run with bypass valves disabled.

[andygtt]

mrpbailey said:

andygtt said:

Like the concept.... this is similar in concept as external waste gates, i.e. the exhaust goes unsilenced when you have boost (well on external waste gates it goes unsilenced on max boost only).

Ive run external waste gates for some years on my noble and they fail all track limits and I had to fit a silencer to them, worth remembering if your planning track work.

The beauty of this system is that the bypass valves don't open til it's on boost, so static noise testing for track won't be an issue as with valves closed it's not overly loud. If I get flagged cos noise is too loud on a drive by I can simply disconnect the vacuum hose and run with bypass valves disabled.

Fantastic... I passed the static noise very easily, failed all the drive by's by some margin... to be fair mine bypasses not just the silencer but also the turbo so its a little loud lol

Unfortunately i can't just disconnect my waste gates, maybe I need one of these bypass valves to route my wastgates to the main system... would save me running the 4kgs extra silencer
now you have me thinking lol

[JW027]

mrpbailey said:

ld imagine if you have standard style BCS exhaust (non-valved) then your 'loud' is probably my quiet, as yours will be going through the silencer back box all the time. Unless the silencers are totally different. When mine comes on boost 2 valves open on a pipe which bypasses the silencer so is in effect a straight through system.

If that is the case yours must be incredibly loud on a straight through system on boost! I suspect many people would be deafened in a vicinity of 2 miles But all the science makes sense and I suspect you are correct but I don't know the exact spec of my system. All I know is it sets car alarms off when I start it & In town is perfectly acceptable but just loud enough to make car guys aware it's nicer than your average.

Can't wait to hear it soon

[StreetDragster]

Mine is the other power valve car, to me it's almost quieter than standard with the silencers are in the circuit, and is deep once the valves have opened but in the cabin it's not to loud.
Not sure about outside the car, I can't get a decent accurate sounding video according to my friends who have heard it in the flesh and then on film.

Matt

[Gadgeroonie]

you need to get a dyno run of it open and closed to see if the noise is worth it

[andygtt]

Gadgeroonie said:

you need to get a dyno run of it open and closed to see if the noise is worth it

Don't think there is a 'need' for a dyno run as I'm guessing the valves job is purely for musical pleasure rather than power?

[mrpbailey]

I wouldn't say it was loud when going through the silencers, haven't tested it yet but would guess around 95-98dB (comparing to other exhaust systems). Pretty quiet to me but then I am used to loud systems.
To me the car actually feels quicker/more responsive since having the exhaust fitted, and was already making 493bhp before the exhaust.
It's at Jetstream now for the next few weeks and they're gonna check everything is running ok while there.

[chuntington101]

andygtt said:

Fantastic... I passed the static noise very easily, failed all the drive by's by some margin... to be fair mine bypasses not just the silencer but also the turbo so its a little loud lol

Unfortunately i can't just disconnect my waste gates, maybe I need one of these bypass valves to route my wastgates to the main system... would save me running the 4kgs extra silencer
now you have me thinking lol

Andy, is there no way of 'spreading' the sound out more? Im thinking if you can get the sound traveling in all directions then it should be quieter should it not? How about fitting a flat plate say 4 inch from the exit of the exhaust? would that distribute the sound better?

I have seen racers that angle the exhaust to the floor to help spread out the sound.

[mrpbailey]

andygtt said:

Don't think there is a 'need' for a dyno run as I'm guessing the valves job is purely for musical pleasure rather than power?

Agreed. The valve only bypasses the silencer, still goes through the rest of the system inc. the cats. Only reason I can see there being a difference is the pipe diameter is 3" all the way through, where I think the previous was only 2.5"

[Blu3R]

mrpbailey said:

Only reason I can see there being a difference is the pipe diameter is 3" all the way through, where I think the previous was only 2.5"

Are the valve bodies themselves 3" diameter too?

[mrpbailey]

Blu3R said:

Are the valve bodies themselves 3" diameter too?

Yeah valves are 3" too if I understand what you're asking correctly

https://www.dropbox.com/s/fw7sgnza9c8ko40/DSC01565...

[Blu3R]

Are you certain it's a 3" system Paul? That Mikalor clamp doesn't look stretched and is designed for 68mm max as seen in your picture. It's also clamping two thicknesses of material so I'd say the system was probably 63mm or 2.5" throughout.

[mrpbailey]

Pretty sure it's 3" as I'm almost certain the valves are 76mm. Matt at Jetstream mentioned it being a 3" system too