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Old 3rd April 2020, 22:43   #11
edwardmk
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Quote:
Originally Posted by Lord of Hog View Post
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 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.
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Old 4th April 2020, 09:45   #12
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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.
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Old 5th April 2020, 19:43   #13
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I'm still very pleased with my full SS MIJ Performance Exhaust line that was fitted in 2018.
No distressing or awful sound, looks as quiet as the genuine 19 years old one.
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...
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  • This vehicle was the 7,517th 75 to run off the production line, out of 112,381
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Old 6th April 2020, 13:21   #14
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Quote:
Originally Posted by SD1too View Post

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.

Simon
I think that was Saga Lout (Wigan)
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Old 6th April 2020, 21:55   #15
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Quote:
Originally Posted by SD1too View Post

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.

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

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

LINK

Brian

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
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Old 7th April 2020, 11:27   #16
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£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.
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Old 7th April 2020, 11:32   #17
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Quote:
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£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
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Old 7th April 2020, 13:23   #18
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Quote:
Originally Posted by marinabrian View Post
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
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!
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Old 11th April 2020, 08:01   #19
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Quote:
Originally Posted by marinabrian View Post
.... It may be worth dropping Jeremy (Jezzer 1) a line to see if he made any progress in having these imported, ....

Quote:
Originally Posted by rab60bit View Post
Please share any response from Jezzer 1 - I would be very interested in a group buy type proposition.
No reply from Jezzer 1 to my PM of 9th April.
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Old 11th April 2020, 09:12   #20
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No reply from Jezzer 1 to my PM of 9th April.
Send him an email Simon
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