Exhaust issues!

Colin.TinkerR75 · 11th February 2023, 16:28

HI. About 10 years ago the flexible part on the downpipe failed on my 2 litre diesel estate. I bought a replacement downpipe with flexi joint and catalytic converter. This has now just started blowing. Thankfully the noise isn't too bad at the moment if I accelerate slowly.
I still have my original downpipe and catalytic converter which I kept after discovering the flexi part can be bought and welded onto the exhaust. I also have an exhaust from a scrap yard that has a silencer installed immediately after the catalytic converter which my car has never had.
My questions are... Should I repair my original exhaust or use the one from the scrap yard? I like the idea of a quiet car and having an exhaust with two silencers sounds appealing. Would the two silencer version be restrictive?

bl52krz · 11th February 2023, 16:43

If it only had one silencer, why do you want two on? This would restrict the gas flow and your mpg would only go one way........down. If the flexi is ok on the one still fitted, why not get that put on the one that is broken. Simples.

Colin.TinkerR75 · 11th February 2023, 18:57

My thought was that the silencer next to the catalytic converter would have minimal restriction being so close to the engine. Rover must have deemed it a good idea at some stage to fit one there. Since my Rover is a 2004 reg it might have been part of Rovers cost cutting exercise. Remove a silencer and save a few pennies. Just guessing!

another_clean_sheet · 11th February 2023, 19:05

Quote:

Originally Posted by Colin.TinkerR75

My thought was that the silencer next to the catalytic converter would have minimal restriction being so close to the engine. Rover must have deemed it a good idea at some stage to fit one there. Since my Rover is a 2004 reg it might have been part of Rovers cost cutting exercise. Remove a silencer and save a few pennies. Just guessing!

The distance of the silencer from the engine does not affect the restriction effect.

daveo138 · 11th February 2023, 19:05

I suppose that if the scrapyard exhaust can just be bolted on, it’s an easier fix. You could try it and see what difference it makes.

Colin.TinkerR75 · 11th February 2023, 19:34

It would be nice to fit the scrap yard exhaust on and see how it performs against the one silencer version. There's currently a snag... the flexi joint is bust on that one too.
I'll need to buy two flexi joints. Fix both exhausts and then do a test comparison.

Any one aware of the two silencer exhaust system? Maybe it was originally installed on the lesser powered pre facelift versions.

planenut · 12th February 2023, 06:39

Colin, if you have that original cat, and especially if you don't use it, put it in for it's scrap value, which will give you cash to make decisions.

slovcan · 12th February 2023, 08:41

Colin, are you sure the box right behind the Cat is a silencer? I have one on mine, too, but mine is a German aftermarket lifetime DPF. It has boosted my car's rating from Euro3 to Euro4.

Ducati750cc · 12th February 2023, 12:27

Quote:

Originally Posted by slovcan

Colin, are you sure the box right behind the Cat is a silencer? I have one on mine, too, but mine is a German aftermarket lifetime DPF. It has boosted my car's rating from Euro3 to Euro4.

Interesting, seeing as how 75's have no re-gen function, what happens when the DPF gets blocked ?

Would the driver have to notice a lowering of performance being that 75's don't have a DPF pressure differential sensor ?

When it does get blocked, or partially, enough to affect performance, what then ? does it need to be replaced or taken to one of the companies that now provide Cat and DPF cleaning ?

slovcan · 12th February 2023, 12:33

Quote:

Originally Posted by Ducati750cc

Interesting, seeing as how 75's have no re-gen function, what happens when the DPF gets blocked ?

Would the driver have to notice a lowering of performance being that 75's don't have a DPF pressure differential sensor ?

When it does get blocked, or partially, enough to affect performance, what then ? does it need to be replaced or taken to one of the companies that now provide Cat and DPF cleaning ?

Duc750, I don't know. The original owner in Germany had it installed to the tune of 1500 Euros or something. The car came with a big manual about it. It apparently doesn't get blocked and doesn't regenerate. Doesn't make sense to me, either, but it has always run great and I haven't touched it. On the car registration and inspection papers it is marked Euro4.

11th February 2023, 16:28	#1
Colin.TinkerR75 Newbie Rover 75 Join Date: Oct 2021 Location: LINCOLN Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Exhaust issues! HI. About 10 years ago the flexible part on the downpipe failed on my 2 litre diesel estate. I bought a replacement downpipe with flexi joint and catalytic converter. This has now just started blowing. Thankfully the noise isn't too bad at the moment if I accelerate slowly. I still have my original downpipe and catalytic converter which I kept after discovering the flexi part can be bought and welded onto the exhaust. I also have an exhaust from a scrap yard that has a silencer installed immediately after the catalytic converter which my car has never had. My questions are... Should I repair my original exhaust or use the one from the scrap yard? I like the idea of a quiet car and having an exhaust with two silencers sounds appealing. Would the two silencer version be restrictive?

11th February 2023, 16:43	#2
bl52krz This is my second home Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008 Location: Birmingham Posts: 11,394 Thanks: 6,587 Thanked 2,262 Times in 1,729 Posts	If it only had one silencer, why do you want two on? This would restrict the gas flow and your mpg would only go one way........down. If the flexi is ok on the one still fitted, why not get that put on the one that is broken. Simples. __________________ Great Barr, Birmingham.

11th February 2023, 18:57	#3
Colin.TinkerR75 Newbie Rover 75 Join Date: Oct 2021 Location: LINCOLN Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	My thought was that the silencer next to the catalytic converter would have minimal restriction being so close to the engine. Rover must have deemed it a good idea at some stage to fit one there. Since my Rover is a 2004 reg it might have been part of Rovers cost cutting exercise. Remove a silencer and save a few pennies. Just guessing!

11th February 2023, 19:05	#5
daveo138 Gets stuck in Rover 75 Tourer Join Date: Mar 2022 Location: Chesterfield Posts: 675 Thanks: 206 Thanked 69 Times in 53 Posts	I suppose that if the scrapyard exhaust can just be bolted on, it’s an easier fix. You could try it and see what difference it makes.

11th February 2023, 19:34	#6
Colin.TinkerR75 Newbie Rover 75 Join Date: Oct 2021 Location: LINCOLN Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	It would be nice to fit the scrap yard exhaust on and see how it performs against the one silencer version. There's currently a snag... the flexi joint is bust on that one too. I'll need to buy two flexi joints. Fix both exhausts and then do a test comparison. Any one aware of the two silencer exhaust system? Maybe it was originally installed on the lesser powered pre facelift versions.

12th February 2023, 06:39	#7
planenut Regional Secretary Rover 1.8T Tourer Join Date: May 2007 Location: Heathrow Posts: 6,955 Thanks: 1,551 Thanked 2,036 Times in 1,264 Posts	Colin, if you have that original cat, and especially if you don't use it, put it in for it's scrap value, which will give you cash to make decisions.