[Jobe10]

So I have fitted a Remus race for more sound. All very nice, but it's a lot louders than I expected.
This could be a problem at the race track.
Hence my question: Does tracking the car with valves closed do any harm? A friend of mine said this is bad for the car because the exhaust gasses can not be released soon enough and there is not enough free flow.

Anyone with actual knowledge on this?

[Needsdecaf]

Eh, I doubt it. Plenty of people run some ridiculous setups at tracks around the world that have sound limits, and have no issues.

[TopJimmy]

Originally Posted by Jobe10

So I have fitted a Remus race for more sound. All very nice, but it's a lot louders than I expected.
This could be a problem at the race track.
Hence my question: Does tracking the car with valves closed do any harm? A friend of mine said this is bad for the car because the exhaust gasses can not be released soon enough and there is not enough free flow.

Anyone with actual knowledge on this?

You’re not 1K HP, so you’ll be fine.

[FriedPiston]

Unless you have an aftermarket valve controller, you’ll need to run the car in Efficient mode on the G8x platform. This means the engine won’t be at full power, along with decreased throttle sensitivity.

I got flagged twice at Laguna Seca (92db sound limit), so my only choice was to run in Efficient mode with a full titanium exhaust and stock downpipes. At WOT on a long stretch, the car can still build enough exhaust pressure to partially open the valves against its intended setting — the real concern should be more with the valve assembly breaking over time…

[Jobe10]

Originally Posted by FriedPiston

Unless you have an aftermarket valve controller, you’ll need to run the car in Efficient mode on the G8x platform. This means the engine won’t be at full power, along with decreased throttle sensitivity.

I got flagged twice at Laguna Seca (92db sound limit), so my only choice was to run in Efficient mode with a full titanium exhaust and stock downpipes. At WOT on a long stretch, the car can still build enough exhaust pressure to partially open the valves against its intended setting — the real concern should be more with the valve assembly breaking over time…

You can put everything in sport plus and push the exhaust button so the valves stay closed. It works.

[FriedPiston]

Originally Posted by Jobe10

You can put everything in sport plus and push the exhaust button so the valves stay closed. It works.

Noted. I’ll have to play around with my M1/M2 settings

…but on that note, having the engine in Sport+ would further increase exhaust pressure, thereby also opening the exhaust valves against its intended position.

Here’s a quick video of the valves opening in Efficient Mode (Sao Paulo Yellow):

[Info@mad-us.com]

Shouldn't be an issue with running them closed but, if you have non oem valves/motors it could shorten their lifespan from the heat. You can also lose a few hp depending on the design and diameter of piping used for the diverter pipes.

[mike@x-ph.com]

Im not aware of any issues caused by the valves being closed.

[MagicF8x]

Personal experience while dyno testing, it won’t hurt the car but there will be a difference in power

[mike@x-ph.com]

Originally Posted by MagicF8x

Personal experience while dyno testing, it won’t hurt the car but there will be a difference in power

What was the power difference in your experience?

[MagicF8x]

Originally Posted by mike@x-ph.com

What was the power difference in your experience?

On 3 pulls I’ve seen a decrease in 15-17 hp less

[Hit_Apex]

Just a thought - the AWRON valve controller has a safety feature that overrides user settings and the panic button feature to ensure valves are open above a certain RPM. There must be some risk under load, perhaps related to backpressure.

[Jobe10]

Originally Posted by Hit_Apex

Just a thought - the AWRON valve controller has a safety feature that overrides user settings and the panic button feature to ensure valves are open above a certain RPM. There must be some risk under load, perhaps related to backpressure.

Wouldn’t the stock valves also have that feature where they open up at a certain load? I sure hope so than 🥲

[tom @ eas]

Originally Posted by Hit_Apex

Just a thought - the AWRON valve controller has a safety feature that overrides user settings and the panic button feature to ensure valves are open above a certain RPM. There must be some risk under load, perhaps related to backpressure.

and heat.

[Info@mad-us.com]

Originally Posted by Jobe10

Wouldn’t the stock valves also have that feature where they open up at a certain load? I sure hope so than 🥲

I know there is a egt threshold for burbles not so sure about the valves.

[alyabiev]

Originally Posted by Jobe10

Wouldn’t the stock valves also have that feature where they open up at a certain load? I sure hope so than 🥲

OEM exhaust flap control is using current gear and RPM to lookup set accelerator pedal position threshold after which the exhaust flaps are opened.

There are different exhaust backpressure models (offsets) to account for open or closed flaps gas flow to be used for boost control logic.

[Reprosal]

Originally Posted by alyabiev

OEM exhaust flap control is using current gear and RPM to lookup set accelerator pedal position threshold after which the exhaust flaps are opened.

There are different exhaust backpressure models (offsets) to account for open or closed flaps gas flow to be used for boost control logic.

So there is bad things that could happen having them permanently open too? Am I understanding that right?

[mike@x-ph.com]

Originally Posted by Reprosal

So there is bad things that could happen having them permanently open too? Am I understanding that right?

No issues have ever been reported with either case. You are fine to do what you wish, its only affecting the sound

[alyabiev]

Originally Posted by Reprosal

So there is bad things that could happen having them permanently open too? Am I understanding that right?

No, no harm at all.

However, If you leave the exhuast flap actuator disconnected DME will trigger “flap open” state regardless of the actual flap position. This case may throw boost control calibration a tiny bit off if you have an aftermarket exhaust flap controller and keep the flap closed “manually”.

[Jon H]

There was a post I saw with on FB or the forums where a guy with a MK5 Supra had one of his valves get stuck in the closed position at a track day. Melted his bumper in that area. Something to keep in mind.

[Info@mad-us.com]

Originally Posted by Jon H

There was a post I saw with on FB or the forums where a guy with a MK5 Supra had one of his valves get stuck in the closed position at a track day. Melted his bumper in that area. Something to keep in mind.

Most likely his muffler was not sticking out of the bumper enough. Track days create some serious heat. I've seen license plate frames melting to exhaust fires.

[Jon H]

Originally Posted by Info@mad-us.com

Most likely his muffler was not sticking out of the bumper enough. Track days create some serious heat. I've seen license plate frames melting to exhaust fires.

Factory valve failed so I'm assuming OEM exhaust in the OEM location.

I didn't notice in the picture that he had an aftermarket diffuser that may have been redirecting some of that extra heat upwards.