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MG MGF Technical - SURVEY !! ;) What is that silly thing good/bad for ?

Hi to all Trophy and after VIN 1D522572 MGF/TF owners, speacial on the continent.

Had a visit today at a german dealer to look at the new mgtf and found this mad can at the right exhaust tail pipe.

Rob saw it as strang looking at first and wrote to another thread:
>BTW that strange valve on the exhause system with linkage - the loudness valve to get it past EU drive-by noise regs?

ROFL !!! Funny that :)
I heard of this can beeing installed to MGF Trophy and now at the MGTF.
No information currently about thee existance at standard MGF MY 2001.

Would be great if some UK owners of standard MGF MY2001 and also MGF Trophy could confirm that it isn't or is mounted.

Also interesting to hear from non UK owners.

At last the true reason for that vacuum controlled valve would be interesting.

Thanks for your interest.

PS more related pics on
Dieter Koennecke

I also want to know what it is and what it does. I saw it at the TF launch and no-one could tell me!
Ian Walker

Hi all,
isn´t this a kind of "triggered sport exthaust " ?
During emission and noise measurements (for certification) this thing closes one half of the system = the car passes the test !! In order to get SOME "sporty" sound the valave opens (under specific circumstanses only). Probably only under full throttle acceleration. Several car-makers have had to install this weird thing, Lotus as well as Porsche.... Reminds me of the old day´s when exthaust emissions were lowered by dilluting fresh air into the exthaust system..... To the public it was said to reduce NOx content - but that was a white lie !

Regards , Carl.

I didn't realise this was fitted to the F Trophy. I thought the Trophy didn't conform to the EU take the fun out of life regulations and that was why the exhaust was fitted at the dealership and not the factory.

I see that I'm not the only person who spends most of the time at the dealership with my head under the car! An action that usually scares the bloke at the dealership as they have little idea what is underneath and are more interested in explaining the roof now comes in different colours.

Neil Stothert

"scares the bloke at the dealership" lol

Yep that's what happened! Laying on my back looking under the car at mainly the new suspension the salesman called over and said there's 'nothing wrong with it' and 'you wont need to do that, there are no customer serviceable parts only dealers can service and anyway they have a 3-yr warranty......'


I couldn't help myself I told him the sorry tale of my 'Friday Afternoon MGF'....

Salesman 'nil', customer 'one'

Why can't dealers get technically clued up? I guess a lot of potential and current MG customers are technically competent and appreciate the engineering in the car. Have you ever seen a MGF/TF in a dealers showroom with the engine cover removed or mirrors under a car? Thought not!

PS still bought a TF160 though - but from another dealer!

PPS I asked one salesman once to open the bonnet on a MGF - didn't know how to. lol
Ian Walker

Dieter you have my vin # one of the last F's,this car does not have the can and lever on the right side of exhaust.

Neil's got it spot on ref Trophy exhaust

It didn't have this valve, either

Interesting, if this is a valve that opens and closes due to the throttle position then i wonder if it could be modified to open and close a cat bypass tube?


Fit a 'Y' section with a valve in each in front and after the catalyst with the bypass tube in the other branch. During starting, the cat butterfly would be open, after the car warms up, this butterfly would close, opening the butterfly to the bypass tube. This (should) would pass emissions and yet retain the volume level of the bypass tube during normal driving. Maybe it could be manually operated from the cabin, loud on main roads, but quieter (resident friendly) when needed in urban situations?

The best of both worlds?

Just an idea...

Scarlet Fever

So this valve is the solution to the problem of having the exhaust installed by dealers? It makes sense because it was relatively easy to do with the limited number of Trophy cars produced but they could hardly make sense for dealers to have to exchange every TF exhaust.


Interesting collection of pictures. I noticed the one of the MGF with the TF bumbers and lights. Do you know how easy it was to do that? Did it required major modifications?

Spyros Papageorghiou

Andy, had exactly the same idea - have a cat with a tube straight through it, guarded by a butterfly valve. Need to pass emissions? Close valve. Want more noise/ cat bypass? Open valve! Interestingly, Rog had exactly the same idea!!! ROFL!

Dieter, the more I look at this the more I am convinced that this is a noise reduction valve for drive-by noise reduction. UK spec Trophies do not need it as they were sold under low volume type approval rules that are UK-only ;o) EU spec cars will have this noise abatement system when the Trophy was eventually homologated for EU sale. Presumably German Trophy 160s were the true fore-runners to the TF160?
Rob Bell

May be, I'll find out.
The flap in this manner is here known from a 328i bimmer as well. Dirk will own one :))

Is said to 'improve' or provide consistant running of the cold engine ... ROFL !!

Those who ever heard a cold SP or other very open sportexhaust can imagine what happens.
I mean, when you lift the foot from accelerator :))) Rumble, bumble, rumble... Would realy miss it !!

If I'd such a thingy, I'd already removed and sold off.

>Presumably German Trophy 160s were the true fore-runners to the TF160?

Sounds reasonable from this point of view.

I hope some more EC guys will give input.

Dieter Koennecke

Carl and Rob have mentioned the valves purpose and it is for drive past noise compliance. When it stops working, which it probably will after a time it will always be in the open position. The betst way to see when these work is on a cold damp morning when exhaust vapour is clearly visible. You will note that the right tailpipe is open and only under certain throttle conditions will it be closed. It uses a simple vacuum connection to the inlet manifold.

The 160PS ZR uses a similar device, which I believe may be solenoid operated which offers more control for other 'non approved' uses also touched upon!!!

Roger Parker

Thank you !

I think that could be the first option for the MGTF 'sound tuning'-FAQ...
Paul ???

Dooh, what times have that been, when we chatted about add ons.
MGTF makes all reverse.

How to dismantle, then.
Dieter Koennecke

Why remove? You could instead have a lever inside the car so you can manually control the exhaust noisiness ;o)

May be we could call such a modification, using a simple bonnet release cable, a 'Stealth lever' ;o)
Rob Bell

This thread was discussed between 13/04/2002 and 16/04/2002

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