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Discussion Starter · #1 · (Edited)
Now I may be missing something BUT

I may have some interesting information or maybe you all knew it but it's been pretty widely discussed on here and I've not seen anyone answering it

-------------- Keeping the valves shut on cold start...

Post receiving a Top Gear exhaust, I've been figuring out the ins and outs of the vacuum install and I now understand a couple of things that might be of use to everyone. This is specifically for a Gen 1 R8 - not sure of the behaviour of Gen 2.

1. Power
The first thing to understand and you likely already know, exhaust valves are always open by default e.g. with no vacuum. Hence cold start, LOUD, annoyed neighbours!

Most on here I've read up wire the aftermarket solenoid to the 12v power source of the original solenoid E.g. OEM Exhaust Valve controller. Even various aftermarket exhaust PDF install instructions tell you to do this.

Now this does work, I'm not disputing that, however what is not mentioned and I put a multimeter on it to test.
On ignition, 12V is sent to the OEM solenoid and subsequently if you've either replaced the OEM Solenoid of piggy-backed from the OEM Solenoid, then 12V is also getting to the aftermarket Solenoid (2 in diagram above) so now you have either 1 or 2 solenoids with 12V power.

Now you start the car, that 12V is now 0V - unless and until you hit that big SPORT button in the centre console. Now 12V flows to the OEM Solenoid and/or Aftermarket solenoid and subsequently the valves are controllable.
Switch off that SPORT button, No 12V, no controlling the aftermarket solenoid and therefore no controlling the aftermarket exhaust valves.

The moral of the story, if you only want to be able to control your exhausts with the gearbox in SPORTS mode then using the original wiring works great.

I now just need to find an ignition 12V.....


2. Vacuum
A few of asked how it's possible for exhaust valves to open/close on ignition when no vacuum has been generated by the car running for a few seconds - I've seen no answers to this and hold your breath (Literally) this is a big one.....

If you've ever started the car before, vacuum has been created and held in that odd shaped 3 ball cylinder thing (Literally called a Vacuum Reservoir)
Now you turn the key for ignition - Remember I said 12V on ignition - no SPORT button needed.
Well that existing vacuum in the system is enough to open and close the valves on Ignition around 3-4 times before all of the existing vacuum (generated from the last time you started the car) has been dissipated.

You start the car, vacuum is replenished within a 30 seconds or so and repeat.
 

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Is there some difference between V8 and V10 models or R-tronic/s-stronic because I changed my exhaust to this Topgear F1 system for my V8 r-tronic and took power for new solenoid from the existing solenoid and I can use the controller for closing or opening valves even if sport mode isn’t selected.
But I’m not able to close the valves before engine is running so I guess that the solenoid is getting power only when engine is running and then I can adjust the valves (in my case?).
But it would be good to have an option for close the valves before startup when ignition is turned on, so I guess that the power for the valves have to be taken somewhere that is powered when only ignition is on and engine not running.
 

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I'm intrigued by this.
1 Valves are normally open (Loud) unless there is suffient vacuum to close them?
2 Cold start, valves open, Audi software allows them to stay open for 30 secs to warm up the cats?
3 Once running you can 'toggle' using the sport button between open and closed?
4 If you stop and restart the engine while it's still within a operating temperature there is an initial bark from the exhaust before it returns to valve closed (quiet)
5 If you start from cold, run 2 or 3 secs switch off, restart, engine goes to idle with valves closed?
Question, if you have a valve controller will it allow you to go to scenario 5 without the restart?
 

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Discussion Starter · #6 ·
Is there some difference between V8 and V10 models or R-tronic/s-stronic because I changed my exhaust to this Topgear F1 system for my V8 r-tronic and took power for new solenoid from the existing solenoid and I can use the controller for closing or opening valves even if sport mode isn’t selected.
But I’m not able to close the valves before engine is running so I guess that the solenoid is getting power only when engine is running and then I can adjust the valves (in my case?).
But it would be good to have an option for close the valves before startup when ignition is turned on, so I guess that the power for the valves have to be taken somewhere that is powered when only ignition is on and engine not running.
Difficult to say about the V8 vs V10 vs RTRONIC vs STRONIC without testing it, the gearbox not having anything to do with the valves, I can't see why that would influence it but the logic in the ECU certainly would have been refined overtime which naturally would have progressed from RTRONIC to STRONIC given one is older than the other.

In my case (and I tested it multiple times) I only got power to my solenoid(s) in 2 scenarios,
1. When ignition was switched on
2. When the SPORT button was pressed while the engine was running.

The multimeter tracked perfectly and repeatedly exactly those 2 scenarios that 12V was present BUT I haven't driven 50 miles and had a multimeter hooked up while driving to analyse whether other scenarios exist where 12V is delivered.

In your situation, if you can't close the valves before the engine is turned on, I believe irrespective of model is explainable by A. Power or B. Vacuum.

A. Power, you are hooked up to a power source that isn't getting 12V until the engine is started but I've never heard of that. In general, car electronics you have permanent live 12V and ignition 12V e.g. Ignition on would always mirror the car running in-terms of 12V delivery. Permanent is of course a continuous 12V feed irrespective of the ignition status.

B. Vacuum, You haven't got independent vacuum feed going to your aftermarket solenoid and instead depend on the OEM solenoid receiving vacuum, passing said vacuum to the aftermarket solenoid before the valves can be closed. e.g. Cars Vacuum > OEM Solenoid > Aftermarket Solenoid

B2. Vacuum, You have a vacuum leak somewhere (could be in the original system or could be at the points you attached tubing) but however gradual, losing the vacuum would result in the little black control box (the solenoid plugs into) sending the signal to the aftermarket solenoid to open up and allow the vacuum through but no residual vacuum is left in the vacuum reservoir to close the valves. Once you start the car vacuum is generated and will grant you the ability.

The little black box (the aftermarket solenoid plugs into) clicks when you press the button on the fob - though you wouldn't hear this with the engine running.

1. If it's power you won't hear it click on ignition alone.
2. If you hear it click but not the valves moving (they are audible when the engine isn't running) then you have no vacuum to be able to close the valves.

Losing vacuum also leads to quite a big difference in BHP - if you watch Matt Armstrong AUDI R8 rebuild on YouTube, a video he did while he was trying to figure out why he was producing approx 50bhp less (on a dyno) turned out to a be a vacuum line he hadn't plugged back in. Plugged it back in, 50bhp restored - that's all it was.

.......
Having now wired mine to the 12V Cigarette socket (centre console) I can confirm (unlike before, irrespective of the SPORT button, my valves are opening and closing, working completely independent of the cars ECU and whether it wants to send power to the OEM solenoid.
 

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Discussion Starter · #7 · (Edited)
I'm intrigued by this.
1 Valves are normally open (Loud) unless there is sufficient vacuum to close them? Correct
2 Cold start, valves open, Audi software allows them to stay open for 30 secs to warm up the cats? All Audi software has to keep valves open is nothing. It's closing them where power and vacuum is required. There is an assumption there is somehow less flow because valves are closed? On stock and most systems I've seen it's just that 1 of the 2 exit pipes on either side (so 2 pipes allow flow rather than 4) it's just forced to take a different route is all. If the exhaust gases were restricted the car would struggle to run.
3 Once running you can 'toggle' using the sport button between open and closed? You can, both OEM or Aftermarket - depending your configuration of the vacuum tubes of course.
4 If you stop and restart the engine while it's still within an operating temperature there is an initial bark from the exhaust before it returns to valve closed (quiet). There is additional volume from the car holding the choke and therefore higher revs for a few seconds. I can't comment in your scenario but depending whether you have residual vacuum in the system to close them. No vacuum - no closed valves which means the vacuum needs to be created which takes a few seconds.
5 If you start from cold, run 2 or 3 secs switch off, restart, engine goes to idle with valves closed? It depends if you had residual vacuum in the system before starting, if 2 or 3 seconds is enough to gather enough vacuum and what the cars ECU deems the OEM Solenoid should do, just because you gather vacuum to close the valves, I can't tell you the car won't release that vacuum and therefore open the valves again upon turning the car off.
An aftermarket solenoid overrides this so if you press the button on the fob to close the valves, the solenoid opens, allows vacuum through, that vacuum has no where to go unless the aftermarket solenoid (Controlled by you) allows the vacuum to escape so the valves stay and remained closed.
From Google:

What happens when a solenoid loses power?
If there's no power to the coil or if power is interrupted, the solenoid will cease functioning and remain in whatever position it was last in.

Question, if you have a valve controller will it allow you to go to scenario 5 without the restart?
I have an aftermarket valves controller with my Top Gear exhaust and I can confirm, if the aftermarket solenoid can get vacuum independent of the OEM solenoid (As the instructions say) and power is sourced from an ignition 12V, I can go to scenario 5 now, skipping the starting for 2 or 3 seconds of running, hot or cold, irrespective of idle.
The vacuum is the vacuum and it's inevitably there from the last time you ran the car (whenever that was). The exception to do this is if I pull a vacuum line off an exhaust valve for example or do anything with the solenoid then you can hear the vacuum escaping.
 

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Thanks for the write up! And sorry for the hassle, I tested now on my R8 that I can close and open valves even without (or with) sport mode enabled.

I wired my new exhaust solenoid like this:

-Cutted the red/green wire from the existing oem solenoid.

-Soldered the new red+ wire from the new solenoid between the wire above

-Grounded the black- wire to chassis from the new solenoid

And this way I can control valves on my exhaust with remote when engine running (with or without sport mode), but it’s not possible to control the valves when only ignition is turned on and engine not running.
I checked that vacuum is ok, and there is no leaks, vacuum recervoir is holding the vacuum etc.
Automotive tire Electrical wiring Bicycle part Cable Gas
 

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I wanted to test it prior to commenting. But I have the valvetronic solenoid kit for my Armytrix Ti, and confirmed you can activate it prior to starting the vehicle.

Car sat after a 12 hour shift, key on, hit my programmed garage door button I use to activate the valves, and started the vehicle with valves closed for the cold start. Obviously holds vacuum long enough to do so. Will try it again tomorrow morning.

 

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Discussion Starter · #10 · (Edited)
Thanks @satnav. I’ve now had chance to test out the
I wanted to test it prior to commenting. But I have the valvetronic solenoid kit for my Armytrix Ti, and confirmed you can activate it prior to starting the vehicle.

Car sat after a 12 hour shift, key on, hit my programmed garage door button I use to activate the valves, and started the vehicle with valves closed for the cold start. Obviously holds vacuum long enough to do so. Will try it again tomorrow morning.

That’s awesome.

Yup, any third party solenoid kit, any exhaust with valves.. it’s all about using the residual vacuum.

I went away for the weekend recently and my current setup didn’t skip a beat. Opened/closed on cold start, 5,10,15,20 sec after start, half way through a journey etc etc.

To be honest I’m still unclear what the confusion was around valves and cold starts on the forum but it seems to be working for all.
 

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Thanks @satnav. I’ve now had chance to test out the


That’s awesome.

Yup, any third party solenoid kit, any exhaust with valves.. it’s all about using the residual vacuum.

I went away for the weekend recently and my current setup didn’t skip a beat. Opened/closed on cold start, 5,10,15,20 sec after start, half way through a journey etc etc.

To be honest I’m still unclear what the confusion was around valves and close starts on the forum but it seems to be working for all.
I believe it also depends where you take the power from to the new solenoid so that you can control the valves before engine is running. Because the way I took power to my new solenoid, it isn’t working when only ignition power is turned on. I can’t hear the solenoid clicking or anything when only ignition power on.
 

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Discussion Starter · #12 ·
I believe it also depends where you take the power from to the new solenoid so that you can control the valves before engine is running. Because the way I took power to my new solenoid, it isn’t working when only ignition power is turned on. I can’t hear the solenoid clicking or anything when only ignition power on.
It does.

I tried to explain the power situation in quite a lot of detail above and most exhaust/valve guides suggest to piggy back off the original solenoid wiring which at least on my Gen 1 Facelift, my multimeter shows there is 12V on ignition, 0V on engine on and 12V again only when SPORT button is activated but obviously what the instructions say and what garages are doing could be 2 different things.

I ended up wiring to the cigarette lighter, going through the firewall because I felt it gave me the ultimate control of the solenoid with the ignition power.
 

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Worked over night like a champ. Key on, push button, valves close, turn ignition to start vehicle.

The Armytrix Ti is still quite loud even with valves closed so the wife would still prefer if I could get a tune that eliminated the cold start haha.
 
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