Permanently Open Exhaust Valve Exige 350 Sport

[Belgarion]

Hi All

I have an Exige 350 Sport and I want to permanently open the exhaust valve. I've read a number of topics on the subject of opening the exhaust valve either by pressing the switch on the steering column or by disconnecting and plugging the hose that leads to the exhaust.  When I purchased the car it was already fitted with the Alias 23 induction system so the plumbing is not as standard. Whoever installed it has taken the red hose directly from the supercharger down to the exhaust. I believe this is correct for a V6, but for a 350 sport my understanding is that the solenoid that opens the valves in the air intake and exhaust should still be utilised otherwise an error light can be thrown up on the dash. Whether correct or not I'm not seeing an error light.

In its current configuration I don't seem to be able to open and close the valve manually. At Idle, if I press the button on the steering column a message on the dash says exhaust valve open but I cant hear a difference . I've also tried to kink the red hose from the supercharger to exhaust and again cannot hear any change. Touring mode and sport mode sound the same but in race mode I do notice the exhaust sound is louder but also the tick over seems to rise ever so slightly.

Was a bit surprised to find that kinking the hose to the exhaust made no difference.

Was hoping someone could advise since following the usual steps on previous topics does not appear to work.

Thanks

Simon

 

[Paul_D]

Kinking the hose if the valve was already closed wouldn’t give a change, as you’d be ‘trapping’ the vacuum. 
 

The OEM solenoid not only removes the vacuum, but vents the valve diaphragm to atmosphere. 
 

Can you see vacuum solenoid in the engine bay, and if any pipes are connected to it? 
 

At a guess it sounds like you need to put the main vacuum tube back to the solenoid inlet, and connect the red exhaust tube back to the other other solenoid connection. 

[Belgarion]

Hi Paul

Thanks for replying.

I will try to take a picture of the solenoid tomorrow and post. But from what I can see it appears to have 2 black pipes entering it both of which have been blocked with screws. I think you are correct with regard to reconnecting the solenoid, the Alias 23 instructions do state that the connections for the 350 sport should be different to the earlier V6, mine seems to be as per the V6.

Think I would need a longer tube to reach from the supercharger to the solenoid, I should be able to use the current tube that goes from the SC to the exhaust to take into the solenoid for the output side.

Thanks 

 

[Paul_D]

Yeah, it may be that whoever did the install cut and threw away some of the hose. 
 

Generic vacuum tubing is available from a lot of places quite cheap, so you could always just get some and redo it all with new tubing the correct length. 

[Belgarion]

Hi Paul

Here are some pictures showing the solenoid and blanked pipes together with the red pipe from SC to EX.

From you earlier response am I right in thinking that in the current configuration the SC creates a vacuum that causes the EX valve to close but if I go through the solenoid it will vent to air when switched to valve open?

I'd prefer that option if that is the case but I assume also that cutting the red pipe and blocking it would leave the valve always open, prefer not to do that if switchable is possible.

Thanks for your help.

 

[Kristof Thys]

That's not the solenoid that is operating the exhaust valve.  It's the solenoid that operates the flap in the OEM airbox for low and high rpm air intake trajectory.  That one is correctly "decommissioned".  The exhaust valve solenoid sits further down, just above the chassis rail, left rear towards the bottom of the car.  That red hose will connect to it.

Most likely that solenoid is seized closed, so valve on exhaust sprung open, pretty common due to water ingress.

If that is the case, just replace.

 

FYI - if you want to have full control (permanent open/closed) with an aftermarket switch, just run a switched 12v+ line to that solenoid.

 

[Belgarion]

Hi Kristof

Right ok, thanks for clarifying, just as well you pointed that out.

Do you know what the switch on the steering column is controlling then in order to open and close the valve. I'm assuming its the solenoid you mention?

Thanks

 

[Kristof Thys]

The switch on the dash controls the exhaust flap solenoid, but it is probably stuck closed hence the exhaust flap remains open.

Alternatively, the red hose is connected directly on the exhaust flap, bypassing said solenoid (and it's not the one in the pics) and vacuum is applied immediately on startup.  In that case the flap immediately closes.  Kinking the line won't make a difference as the vacuum remains trapped.  Easy to test: just unplug the red line from the supercharger vacuum nipple and see if exhaust note changes.  It might be that your exhaust is always closing the flap and you're in "quiet" mode all the time 🙂

 

Reason for running a separate switch could be if you want the exhaust flap to be open or closed throughout the rev range.  The OEM switch doesn't allow for the flap to remain closed over 4500 rpm.  On the older style exhausts (pre 380), this is doable as the "quiet" trajectory on the muffler uses only slighter diameter piping compared to the "loud" trajectory.  This is not the case on 380 mufflers and onwards.

I have a custom muffler with in both cases 70mm piping, so I switch the exhaust to fully quiet if I want to.

Edited September 24, 2022 by Kristof Thys

[Belgarion]

Brilliant

Thanks for the explanation, think my brain is starting to get it.

I'll your suggestion of unplugging the red pipe to see if the exhaust note changes. I saw some comments in other topics where people had used and aquarium air valve to switch to on and off which I'm assuming works if the the pipe is directly connected to the exhaust flap.

I'll have a play.

thanks

 

[Paul_D]

@Belgarion

I did a write up to help explain the set-up to people a while back. May help you visualise what's going on:

 

[Belgarion]

Hi Paul

Ok thanks, I'll have a read through

 

 

[DH2]

2 hours ago, Kristof Thys said:

That's not the solenoid that is operating the exhaust valve.  It's the solenoid that operates the flap in the OEM airbox for low and high rpm air intake trajectory.  That one is correctly "decommissioned".  The exhaust valve solenoid sits further down, just above the chassis rail, left rear towards the bottom of the car.  That red hose will connect to it.

This is incorrect.  The Sport 350 only had a single solenoid, the airbox flap was unused, so the solenoid on the airbox was used to operate the exhaust valve - the solenoid affixed to the subframe on the Exige S, was deleted on the Sport 350.

As I have seen on most A23 intake installs, the exhaust valve will never operate correctly, because the vacuum accumulator that is part of the airbox, is deleted.  With the exhaust valve connected directly to supercharger, the valve will open and close of it's own accord, as vacuum comes and goes with the throttle.

To the OP, if you wish for your exhaust valve to operate as originally intended, plus with use of the button on the side of the column, you will need to reinstate the solenoid, and include a one-way valve and vacuum accumulator in the circuit.  This will ensure that the valve can remain closed, when there is no vacuum present at the engine - and get rid of the annoying valve opening and closing whenever you accelerate gently / change gear / etc.

Dave

[Kristof Thys]

59 minutes ago, DH2 said:

This is incorrect.  The Sport 350 only had a single solenoid, the airbox flap was unused, so the solenoid on the airbox was used to operate the exhaust valve - the solenoid affixed to the subframe on the Exige S, was deleted on the Sport 350.

Never knew this.  Many thanks for the info Dave!  Never too old to learn.  Cool!

Edited September 24, 2022 by Kristof Thys

[Belgarion]

Hi DH2

Getting complicated now for my poor old brain but thank you for your explanation

But does this still mean that if I decided I just wanted the valve open I could remove the vacuum by disconnecting the pipe. After your explanation, and looking at Dave's diagram, I was actually looking to disconnect the red pipe on the SC and bung it for now, and then put another short length of pipe onto the SC and bung that as well.

Perhaps at a later date install an aquarium valve so I have some means to open and close.?

 

  

 

Edited September 24, 2022 by Belgarion

[Belgarion]

Sorry I meant Paul's pictures not Dave lol

[Belgarion]

Thanks to all of you who helped with this topic.

I experimented a bit and unplugged the red pipe from the SC and did notice a change in exhaust volume. I also noticed that the tick over changed when I blocked the hose nipple from the SC, it behaved a little like it does when I switch race mode but not as pronounced.

I then installed a short length of pipe onto the SC without the engine running and blocked it with a screw, did the same with the end of the pipe that previously went into the SC.

Took it for a drive and certainly noticed it was louder at lower revs but its not massively loud.

At some point in the future may look at the layout DH2 suggested, but that will take a bit of investigating in terms of the vacuume accumulator needed and the one way valve.

Appreciate all the help

 

 

[Richlud99]

On 24/09/2022 at 13:19, DH2 said:

This is incorrect.  The Sport 350 only had a single solenoid, the airbox flap was unused, so the solenoid on the airbox was used to operate the exhaust valve - the solenoid affixed to the subframe on the Exige S, was deleted on the Sport 350.

As I have seen on most A23 intake installs, the exhaust valve will never operate correctly, because the vacuum accumulator that is part of the airbox, is deleted.  With the exhaust valve connected directly to supercharger, the valve will open and close of it's own accord, as vacuum comes and goes with the throttle.

To the OP, if you wish for your exhaust valve to operate as originally intended, plus with use of the button on the side of the column, you will need to reinstate the solenoid, and include a one-way valve and vacuum accumulator in the circuit.  This will ensure that the valve can remain closed, when there is no vacuum present at the engine - and get rid of the annoying valve opening and closing whenever you accelerate gently / change gear / etc.

Dave

Hello, I’m just investigating the valve on my car. I know the pipe was removed some years ago, and I also know that at some point there was an alias intake, however the intake is now what looks to be OEM(I haven’t looked at the internals though). 
 

with the red pipe(which goes down to the exhaust valve) disconnected, the exhaust valve is open/exhaust is loud. With the red pipe attached the exhaust is quiet. Therefore the vacuum valve on the exhaust is moving okay.
 

with the red pipe attached to the T piece, between the air box and the solenoid, the valve does not operate by pressing the left hand steering column button(the red display shows the open or closed status when the button is pressed). I have also noticed that if I rev the engine above 4500rpm the exhaust still doesn’t open automatically. Does this mean there is maybe something missing from inside the air box…..? Or maybe the electrical operated solenoid is not working? 

 

Edited October 6, 2023 by Richlud99

[Richlud99]

[Paul_D]

@Richlud99

I think that your piping arrangement has been messed up by whoever fitted / removed the air intake system.

That T-piece should not be on the outlet of the solenoid. It's basically pulling a vacuum on your exhaust all the time I believe. There should be a black pipe going into the solenoid, and the red exhaust tube should be connected directly to the solenoid. 

I have a 410 which has a different arrangement so I can't check exactly how it should look. But this picture and wording suggests that the T-piece is used to provide vacuum TO the solenoid.