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MG MGF Technical - Exhaust is blowing

My exhaust is blowing like mad (not generating a lot of smoke, just making the 'popping' noises whenever I take my foot off the accelerator).

Questions:

1) How much is a new exhaust (standard)
2) Would I be better off replacing it with a performance exhaust
3) If so which one, and how much is it. Also, will it affect my insurance


Thanks
D
Davey

1) How much is a new exhaust (standard)
Not sure, ring a dealer and ask(!) - probably around 250-350 mark.

2) Would I be better off replacing it with a performance exhaust
Naturally :D

3) If so which one, and how much is it. Also, will it affect my insurance
That's a matter of mass debate. Personally, I've heard Mike's Daytona, the Phoenix, SP and Trevor Taylor. For power gains and sound the Daytona I feel wins out. Looks wise, the quad pipes are "love or hate" material, I hated but now I'm lovin'! Rob has the TT and that's not bad, the finish is a bit "industrial" however.

And quite likely it will affect your insurance, as its a performance modification. Best to check with your insurer.

If you read through the "Phoenix Exhaust" thread in MGF General (I think, either MGF G or MGF Tech') that discusses the Phoenix but touches upon other makes as well.

HTH

Steve.
Steve Childs

Personally, the biggest advantage that I can see to a "non-standard" exhaust is the fact that Stainless Steel is available as a construction material. The "standard" is mild steel, so is subject to (much more) corrosion.
SS should give a much longer life...

Powerband/power/torque gains are likely to be fairly marginal. It really depends on what happens on your particular car. Even minor (effective) differences in the lengths of the various header pipes can make the difference between a power gain and a power loss (have seen this on M/C exhausts!).

See if you can track down a copy of the MGWorld item that various BBSers did a couple of years ago for a view of the compromises (noise/power/style/fitting/....). I don't know if Rob has its contents on his website, but he might well...

In any case it might be worth getting some of MikeS' "Catsaver" nuts fitted instead of the standard as it makes any future undoing MUCH simpler!

Neil.
Neil

I was thinking of getting the Miltek supersports myself - makes a lovely throbby noise. Brown and Gammons sell it.

To add to what Neil said, replacing the cat nuts is a good idea whatever you do. I'm going to replace mine even before I get a throbby exhaust. I'm a vet, so I can be considered quite an expert on cat nuts.

BTW folks, what's the exhaust on the Trophy?
David Bainbridge

>> what's the exhaust on the Trophy? <<
AFAIK, its MG's own make. Has anyone stuck a K&N onto a Trophy? I wonder if you get a similar power increase as seen on the VVC...

Steve.
Steve Childs

>>> 1) How much is a new exhaust (standard)
Not sure, ring a dealer and ask(!) - probably around 250-350 mark. <<<

Is this including fitting/CAT etc?

Davey

That was a off-the-top of my head guess ;p

Steve.
Steve Childs

Steve,
Does the Trophy not come with a KN type air filter as standard ?
Mike
Mike

Mike, from what I saw it has the standard airbox, although the filter inside may well be different, probably a performance filter, but one that fits inside the standard box, instead of being a cone type

Steve.
Steve Childs

Steve,
you are right, I've just re-read the parts list in the archive supplied by Roger,:- "Air cleaner assembly is specific to Trophy only. different parts are as follows...
PHB 000230 - air filter assembly (Same element as VVC)
PHD 000380 - air pipe from cleaner to throttle
PHU 000170 - air cleaner mounting bracket
The inference here is a modified air cleaner with larger bore air feed. Note the resonator and cold air pick up are not showing changes against current cars, but there have been recent changes compared to older cars."

So does this negate any improvements from a KN filter?
Mike

hmm, interesting, TBH I don't know. But it would be interesting to add a K&N on and stick the car on a RR and find out :)

Steve.
Steve Childs

Noisey on over-run? Lovely!!! Why change it? ;o) Seriously though, it sounds as though the baffles may have failed. Two options- replace or repair. The latter is possible- afterall Carl was able to cut open his standard system to remove the baffles!

A new standard exhaust is in the 350-400 UKP braket- ie more expensive than any available after market exhaust. This cost does not include the cat, which is an additional 250-300 UKP. The only downside to fitting one of these aftermarket systems is an insurance penalty despite extremely modest power gains. The other option is to buy a second hand standard exhaust- should be a few lying around in folks garages...

More information at http://www.mgf.4mg.com/exhaust_menu.htm

Okay- the trophy filter box. It looks standard from above, but the lower half is quite different. Instead of drawing its air from the reasonance box (via a 90 agle pipe), it has an intake trumpet extending towards the centre of the car over the rear cross member of the rear subframe. Thus it has a more direct air intake tract to the coolest area in the enclosed engine compartment. Assuming that it has a high flow filter fitted (a replacement Piper/ITG/K&N panel), it should perform close to the levels observed with the modified air intake that Roger et al have characterised (see Bruno's power graphs on my web site). As standard however, it uses a paper panel- so it should be possible to eek out extra power just by using a panel filter replacement.
Will it perform as well as a K&N 57i? Debateable- especially if you can ensure an adequate cold air intake supply to the 57i...

HTH

Rob
Rob Bell

>> Will it perform as well as a K&N 57i? <<

Anyhow, who cares, does it sound the same?! ;o)

Steve.
Steve Childs

Davey,

Are you sure it has something to do with the exhaust? Think there's a big number of BBS-members that can sell or borrow you a standard exhaust system. Well, if you were living in Belgium you could have a try with mine, or is jus a reason to get a performance exhaust.

My car will go in on Wednesday 11th for such a problem. I thought (together with some BBS-fellows) about the ignition system. Will be fun if it happens on the small treffen on Saturday.....

Cheers,
Erik
Erik

I've been looking for description of fitting front pipe bracket in archives, as the front pipe is rattling more and more, and now leaking (popping noise when lifting off accelerator during cold start.) I'm waiting for new SS front pipe from MS but need pictures/instructions for fitting the bracket to prevent future failures.
Nathan Carnie

Erik,

I am pretty sure that it is my exhaust that is blowing, but then again, I am not very clued-up when it comes to these matters. When I take my foot off the accelerator, I gat a number of popping noises. Also, it has become generally noisier than it ever was.

TBQH, I didn't really want to change to a performance exhaust. I quite like the standard one. But, if it is cheaper to get a third party one, then I will have to go for one of these.

About this CAT business....do you not have to replace this when you get a new exhaust?

D
Davey

1. As already pointed out as much if not more expensive than a stainless steel alternative. Though still best to phone the dealer and ask IMO.

2. If 1 is correct then it does seem kind of silly to replace the exhaust with another mild-steel system when you could get a Stainless-Steel alternative for around the same money. Beware of any extra charges on your insurance though as this would be regarded as a performance mod.

3. Re: Insurance very likely. As for which one that IMO is going to be more doen to personal preference, ie. sound and required performance gain. Although with the relateively small gains a different exhaust will give it seems better to go for the one you like the sound and look of IMO. Getting my Phoenix system fitted next week . <VBG>

>About this CAT business....do you not have to replace this when you get a >new exhaust?

Not unless there is a problem with the cat itself, the cat is a separate piece in the exhaust system hence the availability of a cat by-pass tube. :)
Paul Lathwell

Paul,

Cheerz for the info. What difference is the Pheonix system making to your insurance (if you don't mind me asking)?
Davey

Isn't the standard system stainless as well? No quite the same grade as the 'performance' systems we are talking about here, but stainless none-the-less?
Rob Bell

Very few "standard" systems are SS, Rob. They are normally mild steel, sometimes galvenised or otherwise teated on the outside...

I suspect that the reason that corrosion isn't showing as much of a problem in killing silencers is that the exhaust system is so short (relatively) on the F, meaning it gets hot quickly and thus doesn't suffer from condensation which causes the rust on the inside.

Neil.
Neil

>>I suspect that the reason that corrosion isn't showing as much of a problem in killing silencers is that the exhaust system is so short (relatively) on the F, meaning it gets hot quickly and thus doesn't suffer from condensation which causes the rust on the inside.<<

Which is why it makes sense to buy a mild steel exhaust for your MGF. But I was thinking of the relative lack of corrosion evident on the outside of the exhaust- ie over the pipes and silencer box. As someone who has had a mildsteel exhaust on his F (a piper)- the extent of corrosion is significantly greater than that observed on a standard system.

So from material is the standard system manufactured? Mildsteel with surprisingly effect galvanising or a low grade stainless (they do discolour, but they don't exactly rust...)
Rob Bell

Just wondering what kind of increases performance exhaust systems have made on people's insurance premiums.


Also, FAO: Rob --> Just had a look at your exhaust comparison on the 4MG website. Do the prices include fitting/VAT?


D
Davey

Davey,

The hike in my insurance was 40 to the yearly premium, plus and extra 50 on my excess. However, the ins. company (Peart) did say that other mods to my car previously not charged for had been taken into consideration by the underwriters - Highway. HTH.

If you are lucky and depending on your ins. company you may not be charged if you have no other mods, the only rela way to find out though is phone them.
Paul Lathwell

Make sure that you get the down pipe checked before going to the expense of changing the exhaust. Coz this usually will go before the main exhaust as unlike the rest of the std. system it isn't stainless.

It will cost around 160 to get a UK dealer to change the d/pipe.

Cheers RichieR
Richard Russell

Looking at the rust on the original exhaust off my F today I'd say it's certainly not stainless steel.

BTW, the Phoenix I now have on my car looks and sounds rather nice, though I've found there's a rather throbbing drone at around 30mph and at other times depending on ending revs and load. I've also noticed my VVC now seems to be slightly more free revving, though this could be in my mind. Much the same effect as when I put the K&N on, the performance increase is not mind blowingly obvious, just the engine seems a little more free revving. :)
Paul Lathwell

FAO Paul L, Dieter, ... and those in the know !

I wonder if my car isn't suffering the exhaust rattles and thus is in need of the famous exhaust bracket.

Could you please describe what type of sound/rattles I should hear, and if there's something to look for ?

FYI, I hear a sound from the RH rear (?? not sure). I've got the impression that the sound is more present after starting (when the engine's cold), but it doesn't disappear when warm. Usually, I hear it more when driving at low speed (1st/2nd gear) and when releasing/pushing the throttle pedal.

At first, I was thinking of the suspension, but I couldn't find anything. Well, maybe the gearbox/clutch ??

Thanks in advance,

Fabrice

PS : I've got an SP exhaust and haven't got the strap to attach it to the cat (well, I could maybe modify the one from my original endbox)

Fabrice

Fabrice,

TBH, I think the noise I was suffering from and others have also suffered is not always present in the same conditions from car to car. The noise itself for me occured mainly when the engine was cold and at or just above engine idle speed. As the engine warmed up the noise gradually dissappeared. The noise itself being a kind of buzzing vibration sound that would also dissappear when the engine revvs were increased, but while the engine still cold would return again once the revvs dropped to on/about the idle speed.

The bracket as previously mentioned is not specific to the F but of general used with Rover models fitted with the K series engine. From what I was told at the dealer where mine was fitted there is no guarrantee the bracket would cure the problem and there's also a chance the sound would continue to be present at another engine speed. However in my case the noise was pretty much cured with only a slight vibration sound being present during acceleration, although this is also not noticeable at all since the Phoenix exhaust was fitted. HTH.

http://www.dotcomoff.demon.co.uk

Home of the F'ers Gallery, MG Dealer Guide and new MGF FAQ (one day!). :)
Paul Lathwell

Can say the same from experience of my old NE-WZ77.
Noisy under heavy load while going hills up. Cured by that cheap bracket GEX13002.

It's IMO worth a try in any way. Installing it is a crap job but can be done yourself with help of a second person and good small wrench sockets plus cardan (1/4 inch and 3/8 or 1/2 inch).
One person below the jacked up car and another who can reach the manifold flange from above with long arms.

The heat shields should both be removed and take care on the lambda sensor cable. Dismanteling the oilfilter makes works also a lot easier.
http://www.lame-delegation.de/mgf-net.de/mods/exhaustbracket_2253.jpg
The look of the bracket.

At last if you are not able to get it in, than you still can give in and re-bolt the flange screws and let any workshop do the job.

HTH
Dieter
Dieter Koennecke

is blowing....me
Your bitch

Thanks guys,
unfortunately, it sounds like my car is suffering from something different.
I'm only getting the sound when driving and accelerating/decelerating, thus putting some load on suspension/transmission ...
It's more like the sound (and the feeling) that something's moving in the suspension ...
it's hard to discribe a sound with my poor English !

Fabrice
Fabrice

A couple of comments, not in any specific order.

Fabrice, I have a baffle rattle that is like an irritating kid who has just been given a toy drum. This apparent only when cold and only at idle. Once a few minutes of warming/driving has gone, so has the noise. This is something that is slowly getting worse, but will be removed very shortly when I start fitting various bits I have in the garage.

The standard exhaust is found under part number GEX33619 for cars up to VIN AD12534 and GEX33683 there after to YD522573 (2000MY) Current cars using GEX33774. Those wanting to knowhow much an exhaust system is for their cars can now simply contact any Rover parts supplier and ask for the price of the part!

If the downpipe is in need of changing then the Trophy one may release a little extra. It attches to a common manifold and then to the same post 2000MY cat that is common to all these later cars. I don't believe there are any physical differences between pre and post 2000MY cats that would cause any fitting problems of the Trophy parts to the earlier cars, especially as all gaskets are common to all models.

The Trophy rear exhaust assembly (GEX33778) is in stainless, at least the pipes with SS304 stamped over them indicates!! The standard system seems to be aluminised only.

On the subject of Trophy induction I would expect only minor differences if a K&N were to be fitted. The Trophy has significant advances which I believe provide the bulk of the extra power. The K&N would show little difference in my view and require a more advanced induction system. Also remember that the Trophy uses a larger throttle and connection pipe between airfilter body and throttle.

Rog


Roger Parker

>>Also, FAO: Rob --> Just had a look at your exhaust comparison on the 4MG website. Do the prices include fitting/VAT?<<

Sorry Davey for not getting back to you sooner, but prices are ex-VAT and fitting.

>>Also remember that the Trophy uses a larger throttle and connection pipe between airfilter body and throttle.<<

Rog, are you saying that the alloy throttle body on the Trophy has a larger choke? Interesting!
Rob Bell

Thanks Rog, Paul & Dieter...

I'm a bit slow sometimes : I think this has nothing to do with the exhaust or the suspension and that the noise and "play" can be quite probably related to the clutch. I was in an underground parking last saturday and could much better hear the noise. I nearly have no doubt...

Now what to do ?
If it's just the clutch starting to die, well, I could just wait for it to die properly if it doesn't damage anything else (because the noise isn't really noticeable nor annoying)
But maybe something could be made to fix it ??
My F is a 1997 1.8 mpi with 65.000 km on the clock. (40K miles)

The problem is the labour required. If I ask my dealer to have a look at it, it won't be much more expensive to have it changed... I don't know if I could do the change myself at the next oil change... Does this require special skills/tools/equipment ?

Fabrice
Fabrice

> can be quite probably related to the clutch.

Can be heard any change in the noise if you push the clutch pedal ?
A very slight noise can be heard from the 'clutch release bearing' if the engine runs in idle, but it should be very silent an it should disappear if you push the pedal.

>I'm a bit slow sometimes

You're not alone ;)

Dieter

Dieter Koennecke

Sorry Dieter I think you're confused - clutch release bearing will get noisy when the clutch is pressed, as it will not normally be engaged. Noise which disappears on pressing the clutch at idle suggests worn main gearbox bearings as this will stop the mainshaft spinning. If you're only getting noise when accelerating suggests either worn diff bearings - ie remove gearbox, or more likely knackered downpipe. I should know as I had both at the same time.
Nathan Carnie

Err, I'm sorry, you are absolutely right.

Dieter --> missed to sleep in the office, so: confused in the evening :)
Dieter Koennecke

Rob, Rog has given you a slight *** steer on the throttle body dia of later cars in particular the 160. It is made of alloy vs plastic to prevent throttle hang up as much less distortion /wear occurs but sadly the bore is the same size. Looks nice though!
Lloyd
Lloyd

I should test more carefully ...
from memory : no noise at idle (clutch pressed or not).
I'm getting the noise when on the move, and it's more present when pushing or releasing the gas pedal "without care". That's not only a sound, I really can feel some "free play"...
Nathan, by "knackered downpipe", you mean the exhaust pipe with the flexi-joint ?
thanks again Nathan & Dieter,

Fabrice
Fabrice

The down pipe incorporates the flexipipe Fabrice. The exhaust system in total comprises of four sections:
1. Exhaust manifold
2. Down pipe (incorporating flexi)
3. Catalyst
4. Silencer box and tail pipes.

A blowing sound could eminate from a failed gasket at any point. Rattles could be a problem with the flexi pipe or due to damaged baffles in the silencer box. Inspection of the flexi pipe is easy if you can get your car onto an inspection pit.
Replacement is expensive- almost as much as a full performance stainless steel 4-2-1 exhaust manifold that actually replaces the down pipe as well...

Rob
Rob Bell

This thread was discussed between 04/07/2001 and 17/07/2001

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