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Topgear Valved Exhaust Fitting

4 Aug 2016
I've received the above for my 997 and just need a couple of pointers concerning the valve control assembly.
- where is a good position to locate the solenoid and signal receiver in the engine bay
- what 12v should I tap into in the engine bay rather than run a cable all the way to the battery
- what do I connect the pipes 'vacuum intake tube' and 'OE tube' to? I'm assuming they don't connect to anything as they just intake air?


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I suggest giving topgear HQ a call and have a chat with their workshop foreman , they fit lots of these down in Bridport and he will be able to answer all your questions specific to the 997.1 :thumb: :thumb:
Hi Phil, I have twice and they were going to get back to me but still waiting. I have just asked them about the pipe ends. Will try again.
for the valves to work they need vacuum so looks like you are just T-ing into an existing vac line somewhere

If youre replacing PSE boxes then I presume you dont need any of this but if you dont have PSE then you need to get the vac from somewhere. So the top two parts of the T are the existing vac line that you cut and insert the T piece into. then the bottom leg of the T goes to the exhausts via the solenoid
scarletboarder said:
Hi Phil, I have twice and they were going to get back to me but still waiting. I have just asked them about the pipe ends. Will try again.

Try cutting out the office guys and ask to talk directly to the workshop foreman , he's the guy that will be able to tell you :thumb:
I fitted the same system myself last year.
You will need to tee into the vacuum line that originates at the throttle body / inlet manifold. I put the T in the line near the alternator and mounted the solenoid near the engine mount on the passenger side, on the flat surface there.
I mounted the relay box inside the car, again on the passenger side, under the carpet near the suspension top mount. Two reasons for this, easy access to nearby electrical connections and so that the antenna was in easier reach of the remote control, which I mounted in the ashtray.
I didn't think the instructions supplied were that great, downloaded some others from the internet for a similar system which helped with context.
I can take some photos of the engine bay bits for you, bit of a mission to get to the relay box though, would have to pull the Bose Sub out.
Hi Phil, only pic I have of the vacuum line connection, hope it helps!

As Iain above, I fitted the relay next to the relay panel under the rear carpet and tapped into a switched live one of the relay connectors, although I can't remember which one!

Nice one guys. Been through it with the garage and all seems straight forward. Top Gear did ring me back and were very helpful.
Anyone tried to wire it in such that it activates with the sport button?
Won't be that hard to do, I did see some articles on connecting up to the OE buttons, although I didn't pursue it.
Just starting this job. Swapping the exhausts over I don't think will be too difficult (old ones already off) but I don't seem to have any instructions at all in the box!?

Is there a decent how to guide anywhere or a step through of someone's install?

One question - any reason not to install the electronics box in the engine bay also?. Surely that will make the job easier and I would have thought the remote signal would be able to reach that far?

Just finished fitting my top gear valves exhaust.
Big thanks to Iain Warner for his help with a few photos of his install which really helped.
One question I do have - the system seems to default to loud mode and even if I switch to quiet mode the next time I start it it's back to loud mode again.

I seem to recall reading somewhere that the system remembered which mode it was last set to (as opposed to OE which defaults to quiet mode i think).

Is this how everyone else's works or have I done something wrong?

Sound is great - quiet is quieter than gundo hack and loud is louder than gundo - perfect balance really.

I've had both closed and open valves on start up as I've had a few different designs. Doesn't really matter which design you have it will end up with the valves open.

Version 1

If you switch the engine off the vacuum will keep the valves shut for a period of time. After a while the vacuum leaks out and the valves naturally open. When you start up it takes a couple of seconds to build vacuum and close the valves.

Version 2

The version where the valves open when the engine is switched off. Once you start her up the valves then close. Same as above really.

Just one opens as designed when the power is killed , the other opens when the vacuum is lost.

The only advantage with the first option is the valves do stay closed for 2 or 3 days. Which means if you drive it often the car will start with the valves closed as it still holds vacuum, no noise on start up. Sometimes
The Topgear ones have loud as the default setting , I found this out as 8 years ago when I fitted it to my gen1 ,I hadn't told my late wife that I was spending more money on the car so sneaked off to Topgear HQ Bridport to have it fitted ,enjoyed a loud drive home but switched it to quiet as I turned into my road . next morning jumped in the car started it :eek: :eek: "gates of hell opening" :grin: front door opened and she shouted "have you spent more money on the car" oops :hand: so lesson learnt dont try and sneak behind your wives back when it comes to exhausts :grin:

I have found that if its on quiet and you park for an hour or so it will still be on quiet when you restart the car as the air hasn't left the system so the valve is still held closed but overnight the air leaves the system so the valves open . :thumb:
I know it's an old post but

I've just connected mine up and I can here the solenoid click but no change in the exhaust sound.

Have I got a bad solenoid?


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