Exhaust bypass valves

[andygtt]

I've always planned to have some kind of bypass valves so that I can effectively switch to loud mode at will.

My package is a twin scroll single turbo on a v6 with dual external wastegates, I have a separate silencer that I can remove for the wastegates and they run a separate exhaust system currently.

I've started looking at the exhaust bypass valves, and they run off a Y peice, that is blocked off in 'quiet' mode, all the companies claim a power gain but that's when it's open, how does it effect the efficiency of the exhaust system when runs hut as I will do on all track days?
To me it looks like its going to create loads of turbulence which is something I don't want, but then the wastegates work off a similar Y so am I being worried over nothing?

I have wondered, is there a way to manually open my wastegates on idle? I'd need to pressurise it a style spring is 0.6bar?
If this is possible I might do this and have a bypass valve on that so I can bypass the wastegate silencer rather than just removing the silencer which is what I do now lol.

Of cause I could just implement the anti lag in my motec, but that's pretty aggressive on everything lol

Edited to add a couple of pics

Edited by andygtt on Friday 23 August 19:30

[andyiley]

Just one comment, I gather you are planning to run it in "loud mode" at track days.

Have you had it noise tested in this state, as track days are very hot on too much noise & will pull you off the track if you are tripping the drive-by noise meters.

They also test the cars before they go on track.

You could say you will do the test in "quiet mode" but then that is not fair an everyone else who will be tarred by the same brush if local residents complain!

[stevieturbo]

You can buy cutouts that are electrically operated, so you can open them whenever you want.
QTP I think are the main brand.

Really dont see the point of them though in most cases, makes a lot of cars sound like they have a broken exhaust

[CrutyRammers]

andyiley said:

Just one comment, I gather you are planning to run it in "loud mode" at track days.

I read it as he's going to run with the valve shut on track days, i.e. quiet mode.

[Lawbags]

I'd guess you'd need the car mapped/tuned with it in both modes too and have it switchable on a AVCR or similar

[andyiley]

CrutyRammers said:

andyiley said:

Just one comment, I gather you are planning to run it in "loud mode" at track days.

I read it as he's going to run with the valve shut on track days, i.e. quiet mode.

OK. I see what you mean re-reading it. I took it to mean that as the OP was talking about an increase in power with it open, that this was in "loud mode", and this was how he intends to run it on track.

[andygtt]

andyiley said:

CrutyRammers said:

andyiley said:

Just one comment, I gather you are planning to run it in "loud mode" at track days.

I read it as he's going to run with the valve shut on track days, i.e. quiet mode.

OK. I see what you mean re-reading it. I took it to mean that as the OP was talking about an increase in power with it open, that this was in "loud mode", and this was how he intends to run it on track.

correct, in 'loud mode' with unsilenced wastegates I fail the drive by's on track (pass the static easily)... I had a silencer made for the wastegates specifically so I am not too noisy for track days as it doesnt matter (and usually not used) on the road... worth mentioning they are very good at identifying and kicking off cars that pass static tests but fail drive by's.

[andygtt]

Lawbags said:

I'd guess you'd need the car mapped/tuned with it in both modes too and have it switchable on a AVCR or similar

not really as the existing exhaust is very efficient and not at all restrictive as its a turbo the back pressure isn't required so its only job is to get rid of gasses (unlike an NA exhaust)... I would be amazed if the engine saw any difference at all between the bypass being open or shut so I wont need separate maps etc.