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MG MGF Technical - Great exhaust mod for TF 160 !!

So, here we go again! It won't have taken long for me to do my first modification on my new TF 160... ;-), and it's a great one!

It all started when I was browsing through the forums on , and there was this discussion on the ZR tuning board on disconnecting the exhaust flap on the ZR 160, to make the exhaust note sportier. It would appear that this flap is closed most of the time but opens when accelerating hard above 4000 rpm. However, the rest/default position of the flap is open, so by disconnecting the control solenoid the flap stays open all the time. I thought such a mod would be nice on my TF as well, so I started looking for the solenoid which controls this flap.

On the TF 160, the solenoid is located in the engine bay on the right hand side, just in front of the expansion tank. If your arm is thin enough, you can just reach it through the boot opening. I disconnected it and tucked the plug between the solenoid and the side panel to keep it from rattling about in the engine bay.

When I then started the engine, I was first a bit underwhelmed by the change it made to the exhaust note. It sounded slightly more rumbly, but nothing to write home about.

However, it was when driving the car that the real advantage of this mod became clear: the throttle response is greatly improved and the engine quite simply feels much more torquey and eager to rev. The urge is markedly improved already from 2000 rpm and the whole car suddenly felt much more responsive!

I went on a long drive along small winding roads and the car felt completely transformed, piling on the revs much more easily and making the little throttle blips on downshifts much more efficient, thereby also transforming the perceived quality of the gearchange. Moreover, this mod also makes the car much more driveable when poodling along in town. Tight right-angle turns are now easily dispatched in second gear, where I previously had to go down to first gear!

This mod quite simply appears to be the essential TF 160 mod, turning the car into the real sportster it should have been right from the start. And it doesn't even light up the MIL light on the dashboard.

So, all you TF 160 owners out there, JUST DO IT!! You won't regret it! Your car will feel 10 bhp more powerful than before. It is just amazing!

Per (<-- trying to calm down)

Furthermore it will no longer look like you have only one real tailpipe as they will both steam.
Neil Stothert

LOL Nice work there Per!

Sorry to hear of your disappointment regarding the sound of the exhaust with the flap open all the time - but more than compensated by the improved performance!

Sounds like an easy mod that would be interesting to test on a RR! :o)
Rob Bell

I like the sound of the better response at lower revs. Have you seen any deterioration in mpg (sorry kp100l)? My TF already is really poor in fuel economy - much, much worse than my old VVC, and I would hate to have to get a large bank loan to pay for the petrol.
David Mills

Fuel consumption should not be significantly worse on your 160 over your old VVC, David - in fact, the official figures suggest that you should be getter more miles to the gallon with your new car (see )

A question of higher consumption in a car that is still running-in David?
Rob Bell


Good point about the steam! Every detail counts in this business... ;-)


I don't really know what this mod will do to my fuel consumption, I just did it the other day. If nothing else, at least I suspect that it will get a bit worse from the engine's newfound willingness to rev and my enthusiastic blipping of the throttle on downshifts.


Yes, a before/after session on a rolling road would be very interesting. Presumably, top power at full whack will be unchanged, since the flap is open anyway in such a situation, but I would bet my last € that the torque curve will be much higher with the flap open.


"should be getter more miles to the gallon"

"Getter"? Should be "getting"! On the other hand, ladies and gentlemen, please enter into your dictionaries, the neolism 'getter' - like getting, only better. ;o) LOL

Per - yeah, exactly would I'd be expecting to see too. :o)
Rob Bell


thanks for the report, I have a picture from John T. already on the HD, showing the electric valve. So an easy mod.

Gets on the site soon :)
Dieter K.

Good mod for anyone wanting extra performance and avoiding problems with the TUV, eh Dieter. All you need to do is plug the solinoid back in, in preparation for the test! :o)
Rob Bell

Maybe I'm being a tad naieve (sp??)....but WHY would MGR go to the expense of fitting a solenoid to close/open this flap, if ALL it does is create a DETERIORATION in the engine's performance????!!!!

If the result of disconnecting it causes an improvement in response/poer et NO extra fuel consumption or whatever....WHY FIT THE THING IN THE FIRST PLACE?????

Why not leave it off...get better performance ...and fit better (ally or chrome) door lock pins/heater controls/speaker surrounds instead???

Is it me......???



>>but WHY would MGR go to the expense of fitting a solenoid to close/open this flap<<

Simple: drive-by noise regulations. Ferrari use a similar system to circumvent these regulations as well.

What I find interesting is that the default position is 'open' - I wonder if this was done on purpose by a car-enthusiast engineer, with the intention of providing MG-nutters with a quick and easy Dark-side mod? Knowing a little of the MGR board's background, this would not come as a huge surprise ;o)LOL
Rob Bell

Guys I'm thinking about trying this mod, I've got used to my 160 already and wouldn't mind a bit more response. Has anyone else tried this awell and if so what did they think? anymore details on how to do this mo would be really appreciated as I'm about as novice as they come when it comes to cars!!

> Ferrari use a similar system to circumvent these regulations as well.

I'm sure that the vantage has a silencer that incorperates a straight thru section which opens under command- or at least it did have on the first test drives!

I doubt it adds much, but it's free, reversable, simple, why wait!

Will Munns

Is this mod exclusive to the TF or can it be applied to the F. And if it can how?

n stretton

>Is this mod exclusive to the TF or can it be applied to the F. And if it can how?
The Flap is only fiotted on the TF, on the F the noise is not so bad you need this flap, except on the Trophy, which has an 'aftermarket' exaust fitted at the dealership to get around this problem

Will Munns

Hmmm, think of all the nice things that the "above 4000 revīs" signal could be used for. Water injection, nitrous,fuel enrichment, electric turbo (the new ones seen at "electronica" ,not the toy ones currently on sale.

BR, Carl.
Carl Blom the solenoid the white coloured plastic moulded plug with black wires entering at both sides? A bit more description would help me to try this interesting mod...hope that you can help with this!
Bob (aka The Blue Max)

ROFLMAO Carl! I too was wondering what that redundant signal could be used for!
Rob Bell

See the pics dieter referred to at:
shows connector
the valve itself.

I'd heard that disconnection would cause a warning light to come on tho.

I'll have to give it a go.

Cheers, John
John Thomas


The connector to unplug is shown on John's first picture ( It is the one with the blue and brown wires. Just press the top of the metal clip down with your thumb and the connector will slide off fairly easily. On my car, there was just the right amount of space between the solenoid and the panel to wedge the connector in there, to keep it from rattling about.


The MIL light has not come on on my car, and I don't think it will, since this flap is not supposed to have any influence on emissions.


Thanks, Per, for clear explanation!
Bob (aka The Blue Max)

OK...but what is the FUNCTION of this flap???

What does it close when it's closed??? And, therefore, what is opened above 4000 rpm???


When the flap is closed, it obstructs the right hand side exhaust pipe, which allows the car to pass current stringent noise regulations. Noise is only measured under certain specific conditions, which I don't know in detail, but which appear to be something like "driving-by at constant engine speed of x % of max engine speed". Outside these mesurement conditions, a car can get away with being more noisy.

This is probably not what the legislator had in mind, but it's a loophole which sportscar makers like Ferrari, Aston Martin and MG have used to provide efficient and nice sounding exhausts which still comply with the law.

So, let's enjoy it while it lasts!


>>When the flap is closed, it obstructs the right hand side exhaust pipe, which allows the car to pass current stringent noise regulations.<<

Exactly as Per says, Simon. See JT's picture of the location of the flap:
Rob Bell

Would this mod work on the TF 135 ?
Graham Dean

>Would this mod work on the TF 135 ?

why not try yourself ?

Do and report

Looking forward to your experiance.
For sure less improvement then at the VVC.

Dieter K.

Well....I've done it...disconnected the relay, that is!!...and.......................................................................Well, nothing, really!!

Have noticed no difference in noise OR performance (yet!!). But am off to work on a longer journey, maybe something'll show up then.

(UNLESS, of course, my flap was installed late Friday afternoon and has ALWAYS been open!! ;-D )

OK..yes..a longer journey has revealed a DIFFERENCE in the exhaust note. Not so much LOUDER as more of a growl between 2000 & 4/5000 under load (i.e. part throttle).

Still can't detect any PERFORMANCE improvement/difference.

Anyway, hasn't cost anything and can easily be reversed!!

Nice one Simon :o) Thanks for the feedback.

Anyone else done this yet to their TF?
Rob Bell

My TF 160 goes into the dealers next week for some warranty work. As soon as it is returned, I will be doing this and give some feedback then. I will then be arranging a trip to Mikes Satur's so will hopefully see what it does to fuel economy on a run.
David Mills

Have don this and the effect is as Per described.
Ian Walker

I've just done the mod and haven't noticed hardly any difference.... I've taken it for a long run too. There is a slightly more enhanced growl but def no extra performance and the extra growl/noise is really not that much of an enhancement....

Spot on, Darran!!

The curious thing is that the extra growl (very vaguely similar to a 'B' but without the hollow resonance) ONLY seems apparent above 2,000 revs and on PART throttle??? Flooring the throttle appears to lose the growly element.....and the sound appears to go back to normal....hard to REALLY tell above the increased induction noise. No, I haven't got an induction kit, just the Pipercross element.

Still can't detect any performance difference. Throttle response has NOT changed, in spite of what Per & Ian have discovered on THEIR cars, which is curious, as I would've thought the metaphorical clearing of one "nostril" would have improved the breathing more than, say, a K&N or PiperX fliter element!!??'s early days yet and it's hardly been the best of weather!!!

(1) Any further experience of the effects of this disconnection? Previous postings and another thread suggest the jury is still out.

(2) I can just about reach the connector with the fingertips of one hand and push the metal clip down - but cannot manage to unplug the wires, which have to withdrawn on the further side of the plug, all at the same time. What was the "knack" in doing this?
John R

I finally did mine last week (TF135)

I can't say I've noticed much real difference but it's just been commuting since.

Nice to use the rh pipe though.

One small concern is that the flap mechanism will probably seize up through lack of use - heck so what!

I depressed the wire clip and eased the plug out on third attempt, after fully rolling sleeves up - you need to have fairly long thin arm :-)

John Thomas

I wouldn't mind finding out if there's def no damage caused by doing this.. I did it and then put it back on again... wouldn't mind using the rh pipe all the time!

First fill-up since mod....there SEEEEEMS to be a slight improvement in consumption....will report on this again next week.

Ditto, JT, took me three attempts...Gawd knows how I'm gonna get it back on IF we all decide it's not worth it...OR if it's gonna cause some kind of damage!!!

I can't see HOW it could damage the car - after all, having both pipes working is exactly how the standard exhaust on MGFs work!

Interesting that there is such a split in opinion with this mod! Jury definitely still out.
Rob Bell

Simon... pop it over to mine and I'll hook it back on again for ya!! haha I knew not going to the gym would come in handy for something!!

I agree that it's interesting that some people don't seem to notice any difference on their cars. With my experience, I actually find that completely baffling!

However, I noted that SimonKE had a replacement panel filter fitted on his car. I don't have that (yet). Maybe the breathing of the TF 160 can be improved just a little bit, but the various mods on the induction and/or on the exhaust side may not be cumulative. In other words, if you have already fitted a more efficient panel filter, the disconnection of the exhaust flap may not yield any additional benefits, and vice versa. Since I have now received my new Green panel filter, I will fit it as soon as I get a chance to take my hardtop off, and I'll see if it makes any difference.

In any case, I think this disconnection should be done as a matter of principle, since the flap is designed solely to interfere with a very efficient, nice sounding and nice looking (see second message on this thread) exhaust, because some kiljoy legislator said so... ;-)


Per, it is possible that the gain on Simon's car is there - it just isn't noticible because it is largely masked by the replacement panel filter, as you noticed. It may be a question of proportionality - ie the flap mod gains are small compared to the panel filter, and as a result, it simply not as noticable.

A RR session should thrash this question out! :o)
Rob Bell

I'd really like to see if there def is a difference and if there is then why didn't I notice it on mine....I'm gonna do it again this weekend and drive it around all weekend maybe second time lucky..


Now been on a "long"ish journey....noise level is definitely higher...Annie and I still deciding if we can live with it...STILL no noticeable performance difference other than a definite fuel consumption improvement...

OK, so, I agree with Rob (see my earlier reference to "nostrils"), there would appear no reason why the disconnection should cause any damage...but, what about Warranty (you KNOW what the bas**rds are like) and, perhaps more importantly, MOT???

Hey Darran, what specific exercises do you DO @ the gym to get long thin flexible fingers???

....BTW, adimittedly I only read a few of the posts on the X-Power site that Per referred to, but it seemed that all they were after was an increase in noise...I don't recall any of the posts I read talking about any performance enhancement!!

ALTHOUGH, you'd have thought that the better breathing would've lead to SOME!!

Simon read my post again!! I don't actually make it to the gym!!!!!!
Darran're right Darran!!! Too much Absinthe (+ empty stomach), I'm afraid!!!!

There shouldn't be any issue with the MOT Simon, but warranty might be an issue - but it is easy (for those with long, thin arms - so that'll be Mr. Tickle then) to reverse before the car next goes for a service :o)
Rob Bell

Performed the mod at the weekend, and can't say I've noticed any difference, apart from more noise between 3-4k. I'm generally able to detect changes in performance of vehicles (I drew a rev/power curve on my bike which was spookily similar to a future dyno plot) so I suppose this is one for those wanting the noise, not extra power. It's currently using std induction setup also, so it's not because of previous breathing enhancements.


Oh well... it's a free world I suppose, everyone is entitled to his/her opinion.

In any case, even if some people only notice the noise difference, that is reason enough to do it!! Unless, of course, they like their sportscars silent, in which case they shouldn't drive a sportscar at all... ;-)

Per (<--- just kidding, before anyone starts a flame war)


You're right, everyone's entitled to their own opinion, though I think the majority agree on the added performance benefit (or not, as the case may be), 2-4 to the non believers (not counting the other boards contributors)! Hopefully, we'll get a TF on a rolling road one day and find out for sure! The TF certainly isn't silent, and one could argue those that keep the revs <4k (where the flap opens) all of the time should not drive a sports car either ;)



Rob...Just thinking that (if it doesn't include a noise test at present), when my TF comes up for an MOT in three years President Blair's boys might've dreamed up such a test!! Still, if THAT's the case, then it's all round to Darran's (Essex Darran) to have it hooked back on again!! <bg>

Simon in three years time you can forget about hooking that voavle back on I'll be getting myself a hoover conversion so I can take to the skys!!! you've seen back to the future 2 !! lets make it happen!!!!


I've done this mod, in my opinion it improves the bottom end performance slightly. It's well worth doing, in any case it's free!!

John Wilkes


You don't live within stiking distance of Chesterfield do you? If so, why not pop along to Mike Satur's rolling road day and do a before and after run to settle the debate.

See his thread on the general board (cut and paste)


Just done it,slightly more eager bottom end,and it's summat for nowt so can't be bad.P.S. Car is 135. REGARDS.
Roy Bridge

This thread was discussed between 06/01/2003 and 29/01/2003

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