Let's get back to booming V6 exhausts.
 

This is rapidly becoming the bane of my life entailing many hours underneath my X-plate 2.5 cursing the exhaust, the car and life in general.

The factory fitted rear box disintegrated at around 90k and I've spent the last 12000 miles fitting and removing a succession of replacement boxes all of which produced a loud resonating boom between 1200 and 2400 revs, louder than the engine in many cases which is a shame when the engine sounds so nice.

I've tried fitting additional soundproofing to the boot and that has improved things a little but I'd love to have some suggestions as to how to fix it.

Is it resonance in the boot/rear bumper area?
Is it the result of the pipes being too short and the bumper magnifying the sound?
Are the hangers too short (and if so how to fit longer ones while avoiding the pipe-knocking-on-the-crossmember sound)?

To be quite honest I'm running out of ideas so any suggestions would be gratefully accepted.

I hate that resonance, it's low frequency so the usual sound proofing probably won't help much, it might be transmitted through the body shell.



My V6 has an 'after market cat' and Dave in Fencehouses suggested an original might be quieter. When he reset the engine warning light he suggested it might be caused by the cat or dodgy fuel. But thinking about it I did fill up in Liverpool.


Pete

How about trying something like this?

https://www.ebay.co.uk/itm/4-x-14-CL...cAAOSwvT5dW6sv

Simple really, the aftermarket boxes are just that, something that fits but does not really MATCH the original design requirements, i.e. size of internal pipes and exactly the same construction.

Had a similar problem a few years ago when the company car leasing company insisted (for £ reasons) that an aftermarket final box had to be fitted. It was awful, after a bit of argy bargy they agreed to have the MGR parts fitted, all was returned to normal silence.

:wot:
A forum member was in the process, last year I think, of commissioning a replica of the original MGR clamshell KV6 rear silencer/tailpipe. An excellent initiative but as is so often the case, it's all gone very quiet. :cool:

Simon

Thanks for the replies so far. Purely from a cost point of view, if the answer is to fit a factory-spec rear box or some sort of resonator to the existing ageing system then I may as well wait until the world returns to some sort of normality and have the stainless cat-back that I was quoted around £300 for. When I had one from the same people for the Outlander I was able to specify what sort of exhaust note I wanted and they removed/moved resonators and changed tailpipes accordingly.

However, now I'm obliged to work from home half the time I hope to have the opportunity to continue playing with it. So if I stumble across any undiscovered answers I shall let everyone know.

I had an aftermarket box on my KV^, which was "boomy" at speed, and also at idle. I did notice, at idle, if I lifted my foot up to 1 of the tailpipes, it went quieter. So a spud was stuffed up it, and a quick drive proved it was quieter, though the spud didn't last long! Sadly this experiment wasn't continued, as circumstances changed and I got the present car instead. Maybe there is something about blocking off one of the tailpipes?

Stewart

I also saw something about stuffing one of the pipes with glass fibre, and another one about "manufacturing" an external baffle from an old fizzy drink can. Got to be worth a try I suppose :}

I must have been lucky - my garage fitted an after-market rear silencer to my 2.5 V6 ZT last December, and it sounds just like the original which had lasted 17 years (it still had MG on it!). Didn't use any exhaust centre (like Quick fit etc.) and didn't specify what I wanted as it was just before Christmas and I was desperate to have it done. Labour was not cheap, but the exhaust was about £55 which I thought reasonable, and the result is that lovely V6 burble.

Further to the "spud", when I swapped the car to the present on I thought I'd got another boomer. I tried a temporary experiment (which did look promising) with sound/heat insulation tape off ebay - plenty on there. Basically, I removed the silencer, then wrapped it in this tape. I then covered it in aluminium foil (actually kitchen foil, which was really too thin), for protection; the latter held on by metal cable ties. With it back on the car, it seemed a fair bit quieter, but a week later, it got very noisy. I removed it again, abandoned the experiment, and fitted a replacement (from Euro or CarParts4Less I think). The replacement is quite acceptable. The experimental one had blown a hole btw.

I have exactly the same resonance issue. My ZT-T was fitted with a very nice s/s Cybox cat back exhaust by the previous owner which resonated too much for us, so I had a local garage which specialises in S/S exhausts look at it. They recommended to remove it and go back to standard, which I did. The reduction was unfortunately not that significant. (I don't know what they fitted to be fair, but it was nice and shiny). Their comment was it was the correct system and should quieten down after a few hundred miles lol.
I still have the as new s/s Cybox system, but am now actively looking for the source of the resonance. I think the problem is the wheel well, which is resonating badly at 1400-2200 revs under load. The exhaust bracket on mine is welded to the passenger side of the wheel well, and even with a new rubber support, I feel it's not decoupling the exhaust enough from the side of the wheel well. With everything out of the wheel bay, tapping it really does boom like a steel drum. Play from engine mountings may also be another factor. but I haven't properly checked them yet. I'm going to clean up and paint the wheel well properly and then strategically supplement the existing sound deadener strips with Noico 2mm butyl sound deadener. I've a load of other stuff ongoing, so won't be able to report on results for a while until the car is back on the road.

I've got a new Bosal 278-967 which didn't produce any resonation when I tested it on the original factory system (minus its original back box). I enlarged the Bosal inlet pipe a bit so that it fitted the MGR centre pipe, which I'd cut off at the bend.

In the end I didn't use the Bosal because I decided to replace the original centre section as well and the (now enlarged) Bosal doesn't fit the new Klarius centre.

Btw, the Bosal is oval with twin outlets. It has a separate mounting bracket similar to the MGR original.

I'm still very pleased with my full SS MIJ Performance Exhaust line that was fitted in 2018. :D
No distressing or awful sound, looks as quiet as the genuine 19 years old one. :cool:
And icing on the cake for a very fair price. :}
It's a very bliss and being SS I assume it will last at least as long as the V6 2.5 engine... :p:

I think that was Saga Lout (Wigan)

And that very exhaust is fitted to my wife's car as we speak, and it it superb :drool4:

I took no notice of the people who thought £185 was an expensive price to pay to be a "guinea pig"

Here is the write up, read it and weep gents, this exhaust is the exhaust to end exhausts in terms of quality and quietness :drool4:

LINK

Brian :D

P.S. it is of course a V6 pipe, I just chose to fit it to a diesel, and if you fancy one, then take a look HERE ;)

£185 was around 3x more expensive than the non-stainless clamshell type that's still available, so it wasn't a bad price for stainless IMO.

And more to the point Simon, it fits properly, sounds as per original and looks the part ;)

It may be worth dropping Jeremy (Jezzer 1) a line to see if he made any progress in having these imported, email him HERE

Brian :D

Please share any response from Jezzer 1 - I would be very interested in a group buy type proposition. If I recall correctly saga lout was looking at getting a mild steel version made in UK/Lancashire!

No reply from Jezzer 1 to my PM of 9th April.

Send him an email Simon ;)

Will do. :}

Edit. Have done.

Just spotted this - https://www.ebay.co.uk/itm/MGZT-2-0-....c100005.m1851

:eek:

Hello all,
We have supply of a quality backbox available from our SAIC MG supplier - they're meant to be 'the bees knees' (not my words) and avoid all booming etc.
They're an exact replica of the OE item fitted to the MG7; we've been told build quality is fantastic from those who have seen one / had one fitted.

I'm happy to bring a couple over if members would like them - I did ask some months ago, but not much interest was shown so it was temporarily shelved. :)

I'd certainly be interested if it' s quality item and has the "turned down" outlest like the 75 OEM box :}

Cliff

Have you got any photos to show us?

What Teflon said. For my V6 I'd want the OEM style double turned-down outlet pipes, how about some pictures please and maybe an indication of price, I'd be really interested

Very interested in this. I'm happy to give this a try without any guarantees.
What is the price again please? Many thanks in anticipation.

It fits properly, sounds as per original and looks the part ...
 

DMGRS is experienced in purchasing and importing parts, so how about it chaps? :}

Simon

Hello all, sorry - I didn't have any pictures to hand, as these discussions were from a while back.
I've been in touch with the supplier and he's sent over some pictures; here we go:

https://i.ibb.co/zVvBq6z/rear-exhaust-1.jpg

https://i.ibb.co/q1m6tZC/rear-exhaust-2.jpg


Unfortunately for you 75'ers they're fitted with the tips as in the picture.
I've double checked and they're the only type we can source for now - but you can of course swap the tips for something more subtle if you have a friendly local exhaust fabricator. :)

The timing is also quite tight with regards to getting these on our next import order - as some will know we have some SAIC MG Rear Upper Arms due to catch a boat in the next week or so, if there's any interest we'll throw a few of these on the order so we can have a look and supply a few to members for review.

Cost wise we're looking at £155 if anyone would like one to try, including postage and VAT - this is our cost plus a couple of beers for the nightmare of packing such a stupidly shaped item... :D

Lovel has a thread here on the same part, where the tips are removed and swapped for 'downward sweepers' for use on a 75:
https://www.the75andztclub.co.uk/for...d.php?t=283049

Hello all,
The supplier has confirmed the order, so we're good to go.
We've also sourced some of the Original MG exhaust mounting brackets too if you need one - selectable via the drop-down menu.

https://www.dmgrs.co.uk/products/rov...cg000301-oem-q

Delivery is due in June; please order from the link above ASAP to secure yours as we only have 5 coming over. :)

And I imagine Jeremy is more than proficient too.

The silencer I trialled for him had the correct exhaust tips fitted for a Rover 75, not the standard slash cut tips as per the MG models.

Of course you could always fit an MG exhaust cutout trim to the bumper of the 75, quite a nice modification if you are that way inclined :cool:

Brian :D

P.S. irrespective of the supplier, the clamp supplied with the item is not suitable ;)

Apart from your imagination Brian, the fact is that eighteen months has passed with no apparent progress. As DMGRS is a business with an established supply chain it obviously makes sense for them to lend a hand with the project.

Simon

Well I suppose we could wait to see what the MG7 version looks like fitted to your car Simon............oops I forgot it costs more than 50p so we could be in for a long wait eh? :p:

Brian :D

Don't worry - the bracket we've sourced works with these, no panic there. :D
Also, we have a large order coming in June - so makes sense for us to add these to this order, rather than incur additional costs having a standalone batch imported.

Time will tell - thanks to those who have ordered; we'll have them with you as soon as possible. :)

Not the bracket, but the clamp welded on the pipe itself ;)

I minor inconvenience, simply cut it off and use a proprietary exhaust clamp.

I'm sure these will be considerably better than some of the tat being touted by Bosal and Klarius :cool:

Brian :D

Just ordered one for the V6 :}.

It will no doubt be a while before it gets fitted, as I'll need to find someone both willing and able to fabricate the down turned tail pipes. I'd love to try it myself, but I suspect it wouldn't end well :getmecoat:.

Cliff

Ahh, my apologies Brian! Hadn't had enough coffee... :D

I'm really hoping they will be - I've been told they're the best out there, but we shall see. Judgement is withheld for now. :)

Thank you - it's appreciated. :D

Good news about the mounting bracket as the Rimmer ones are quite expensive. But a bit confused (happens quite often) the one Brian fitted was stainless, are these stainless too ?

Regards

I don't believe so - they're mild steel to my knowledge (but I could be wrong).

During talks with the manufacturer we've been promised they last incredibly well in service, as they're made by an OE supplier to other Chinese car manufacturers.

Time to start putting a bit more in the piggy bank if I want one of those!

From what we've heard and discussed with the supplier, they should be worth the extra. :D

They appear incredibly well-made from the pictures we have, but final judgement will be made when they're here.
I'm keen to see one - the business is now based in Southampton and I'm up north in Southport, but subject to COVID-19 restrictions I'm hoping to be there on the day these land to inspect and provide a lot more detail.

Not sure how likely that is to happen given the circumstances, but I live in hope - these 4 walls are getting rather tedious :o

Hello all, just an update - we had to increase the bracket price as SAIC MG didn't have stock; we have to purchase these from XPart.
The exhaust is the same price as it always has been, and we have 2 left of this test batch. :)

The increase on price of the bracket won't affect orders already placed - apologies again.

Do you have any left? I need one for my KV6 ZT. Thanks.

How are the tests going? Are these new boxes significantly quieter? I just had a new box fitted but it's still boomy, so looking out for something better.
Many thanks in anticipation.

These would probably do it - stainless, various sizes 32-57mm ID - https://www.ebay.co.uk/itm/Curved-Cu...r=431424144581

Hello all, any that were ordered as part of this batch should have landed with you by now.

I've had some excellent feedback from Stocktake regarding these - does anyone else have any for us? :)

Unfortunately not, but we are taking deposits for the next batch due later this year. Please PM if you'd like to secure yours.

We've had Stocktake confirm these are whisper quiet - which is great news.
We're now taking deposits for the next batch, due later in the year.

PM if you'd like to reserve one.

As some may know for many years I have had a powerflow stainless back box fitted to a 60mm standard middle section (with the triangular profile box). My 75 was originally 57mm so to fit the powerflow box I got a middle section of a 190. ( i.8T are also 60mm)

I loved the look of the straight exit oval tail pipe and cut the rear bumper and fitted the ZT exhaust surround. Loved the tickover hum but, although not earshattering there has always been a very noticeable drone 50mph to 70 is around 2000rpm to 2500.

Earlier this year one of the stainless hangers came away on the powerflow. this was about the same time DMGRS advertised the possibility of a OEM with chrome tails so I took the plunge.

Delivered when they said it would be it appears well made, As I have told Mat the OEM bracket came without the bolts which I found annoying and I believe Mat is sorting this for future sales. The box also comes with a clamp to clamp to the middle section, waste of time in my opinion.
Note: it has a cup and is made to fit over 60mm exhaust.

I could not get a good seal with the clamp on the middle section of my exhaust which is 60mm, so I cut the clamp off with the angle grinder as it was attached with a small blob of weld and fitted a 63mm Uclamp. Problem solved.

The tail pipes fill the space inside the cut out of the bumper really well so you have to make sure you have it just where you want it before the tightening of the clamp.

As soon as you start the car you can tell the difference, and I honestly could not hear the exhaust through the rev range especially under load which is where the powerflow was lacking, that said it could also be said the drone was noticeable by its absence.

Are they cheap? No. Would I buy another one. Absolutely.

NB. These are my unbiased findings on my car, Rover 75 V6 2.5 auto. You also have to take into account that I still have the standard middle section with two boxes on it.

definitely going to order one come payday, my work colleagues were telling me today how they always know when i turn up and leave. :shrug: didnt realise how noisy my car is..

Mine arrived safely last week. It appears to be very well made and is a hefty old lump :}.

It's currently sitting in the attic whilst I get my finger out and sort someone who can do the necessary mod to the exhaust tips and fit it for me. Current favourite is Profusion Customs in Slough. I'll report back once it's fitted, but so far I'm very pleased :D.

Cliff

Received mine too. Won't be fitted for a while, but it certainly looks well made and so nice to have the proper correct shape as originally designed for the car.

Thanks all!
And stocktake - apologies, I was meant to update the description to mention the 60mm pipework, but today has been absolutely hectic. :)

Thanks again for your input, it's very much appreciated.