Keeping exhaust valves shut

[elugelab]

Thinking of doing a track day in my new F-Type R. Bedford is the closest track, but of course noise limits mean I’d be laughed out of town if the exhaust valves were open….

I know there’s the button of course but I understand that above 4K revs the flaps open anyway, even if the active exhaust is off. Tell me if I’m wrong of course. So, wondering if there is any way to avoid this happening whilst on track, pulling a fuse, disconnecting vac lines etc?

And of course any thoughts on whether this is a bad idea much appreciated too.

 

[Anonymous]

You have to short a wire to ground to force the valves to close all the time, I don't know but if you driving at at full thottle the back pressure might get a bit higher than normal, will affect performance I would expect?

 

[gasgas]

how do you know it is over the allowed dbs?

 

[scharlton]

Hi elugelab,

I also have an R and in dynamic mode so valves open and at 3,500 rpm it measures 99Db. This has been measured several times at Castle Combe.

Not sure what the limit is a Bedford but would have thought you'd have been OK.

Let us know when you're going, I'm in Hertfordshire so not that far and have wondered about Bedford track.

 

[elugelab]

Thanks all. I must admit I’m guessing somewhat that it would smash the drive-by at Bedford, having been there a few times and seen others being black flagged. Not scientific but my car does feel a lot louder than those I’ve seen flagged there on the drive-by.

I might stick an line switch in as per suggestion above (under the boot floor) just to have the option if it did become an issue on the day. Would help with the early morning cold starts too…

Scharlton, would be happy for the company, will let you know when I’m thinking. I’m just outside of Harpenden in Herts so perhaps not far away from you.

 

[Tjp]

Thanks all. I must admit I’m guessing somewhat that it would smash the drive-by at Bedford, having been there a few times and seen others being black flagged. Not scientific but my car does feel a lot louder than those I’ve seen flagged there on the drive-by.

I might stick a line switch in as per suggestion above (under the boot floor) just to have the option if it did become an issue on the day. Would help with the early morning cold starts too…

Scharlton, would be happy for the company, will let you know when I’m thinking. I’m just outside of Harpenden in Herts so perhaps not far away from you.

 

[Sandytim]

In my 2014 R you can be in dynamic and revert to having the exhaust valves closed by simply pressing the exhaust valve button.
It’s stays in all the active dynamic settings but is virtually silent.
I use it when ever my wife’s in the passenger seat !

 

[Timbo]

In my 2014 R you can be in dynamic and revert to having the exhaust valves closed by simply pressing the exhaust valve button.
It’s stays in all the active dynamic settings but is virtually silent.
I use it when ever my wife’s in the passenger seat !

Still only up to 4k though as the valves will still open above that so not much fun on a track day, especially bedford
as that has a very low db reading, 90 i think!!

 

[scharlton]

Thanks all. I must admit I’m guessing somewhat that it would smash the drive-by at Bedford, having been there a few times and seen others being black flagged. Not scientific but my car does feel a lot louder than those I’ve seen flagged there on the drive-by.

I might stick an line switch in as per suggestion above (under the boot floor) just to have the option if it did become an issue on the day. Would help with the early morning cold starts too…

Scharlton, would be happy for the company, will let you know when I’m thinking. I’m just outside of Harpenden in Herts so perhaps not far away from you.

Hi elugelab,
Very close, I am in Welwyn Garden City.
Bedford shows Static 101 dB(A), Drive-by 87.5 dB(A) so could be an issue, most other tracks are 105 and 92
Also, I am very cautious about general track days and how many people are on track at the same time. I do castle Combe with the JEC as numbers are limited to 12 cars on track at a time. Apparenlty GoldTrack also limit numbers but open to recommendations from other people.

 

[elugelab]

Busyness is generally why I prefer Bedford. It isn’t the most engaging track in the UK but the GT circuit is massive so you get a lot of space generally. I did one in my Megane RS250 at the start of August at Bedford and it felt very well run without too many people on track. It helps that there are some very big braking zones which means you do need to take breaks to keep the car cool. The braking into turn one is easily 100 down to 25 and off the end of the back straight, could be upwards of 135 down to 40 if you are in a quick car.