Can damaged exhaust cause poor acceleration and stalling?

[SpeedySpeedBoy]

So bought my car back from garage a while ago and noticed that it sounded quiter, less peppy and vibrant and didn’t perform as good.

Checked sparks, compression,dynoed it etc all cane back well. However car got worse over time and performance fluctuates.

Car is lowered and it wouldn’t surprise me at all if garage got carried away and smashed the Center silencer on a speed hump - all garages do unless u take it to a performance specialist who deal with lowered cars often.

Anyway today I hit speed humps twice and that improved sound and performance a little. I’m wondering it it’s to do with the exhaust.

Now obviously I’m looking into other causes for problem(I think the poor running, difficulty shifting, quiet sound, stalling etc I’s part of the same issue) however I am wondering could the Center silencer which gets hit the most have had its insides damaged and could it get damaged to the point that it caused something like back pressure or something else which leads to Above symptoms?

On the other hand I’ve looked at pics of what a center silencer or muffler looks like and it seems to be Just metal pipes and walls - hard to see how anything can fall apart here before the exhaust itself falls off though
I did have a hanging exhaust for a while.

Thanks

Edited by SpeedySpeedBoy on Sunday 15th November 20:30

[Krikkit]

Why don't you jack it up and have a look? Damaged exhaust will be obvious... Unless it's nearly crushed flat it won't be the problem though. Best thing would be to check OBD for any stored issues.

While it's in the air why don't you give it a less impractical ride height too?

[SpeedySpeedBoy]

There is no check engine lights at present.

[braddo]

Does the car have catalytic converters? On a family vehicle this once happened where the internals of the cat collapsed and it really sapped performance. There weren't any obvious external signed that the cat was faulty.

[normalbloke]

What did the dyno say...

[Mave]

Ours did this as well. Changing down the gears and absolutely thrashing it there was no power and then suddenly it coughed, and it got a bit of power back - I guess this was the cat breaking up then moving around.

[swisstoni]

Sounds like there’s a restriction due to damage.

[bobbysmithy]

https://www.pistonheads.com/gassing/topic.asp?h=0&...
OP Has been rumbled.

[996TT02]

SpeedySpeedBoy said:

"...noticed that it sounded quiter, less peppy...."

"... hit speed humps twice and that improved sound and performance "

Also try a side stripe kit.

Edited by SpeedySpeedBoy on Sunday 15th November 20:30

[Automaton]

Apparently being new here I can't be trusted to post in the OPs other thread!
Ha, the irony.

Giving the OP the benefit of the doubt, yes a damaged exhaust can do this, the damage can also not be visible from outside. It happened to me. It might even not throw up a fault code. What is the car in question?

As for continuing to drive it, according to gov.uk "You can be fined up to £2,500, be banned from driving and get 3 penalty points for driving a vehicle in a dangerous condition." and if you know it has a stalling issue I'd call that a dangerous condition.

https://www.gov.uk/check-vehicle-safe

[E-bmw]

The sort of damage that would cause this would be massive & exceedingly obvious to the eye, and certainly wouldn't be erratic.

What could, however do exactly what you say would be the cat internals coming free from the casing & falling down to partially cover the outlet to the rest of the system.

This would likely be accompanied by a rattling noise when you knock the cat from the outside.

The only way you will find out is to remove it.

[E-bmw]

SpeedySpeedBoy said:

There is no check engine lights at present.

That means not a lot, by the way, not all issues that may help you bring the light on, get it read anyway.