exhaust issues..........please help!!

[john crossland]

hi all,
im in need of some advice/past experience relating to removal of centre box on exhaust.
i have a 2003 a4 quattro sport 1.8t (190 BEX version). 2 weeks ago i sent the car to a well recommended exhaust builders to have some work done.
the stock exhaust had a hole in the y pipe at front of centre box and a couple of holes in the centre box itself.
Exhaust builders assured me that removing the centre box would have no affect on performance.
now instead of centre box there is stainless pipe from downpipe from the cat running towards rear of car and then splits into a y piece to feed the 2 back boxes.
the car ran fine before it went to them and now the power is certainly reduced. the best way i can explain this is before the car would doo 100 at approx 6000 rpm in 3rd gear whereas now you have to pretty much redline it to get 80mph in 3rd and the same in 4th gear to get 90mph. This is not right and the car doesnt seem to pick up as well as it did. also seems to go flat on power like it wants to go faster but cant when your in the higher rev range.
the exhuast people are saying it is nothing to do with the work they have done but i dont accept this.
i have had the car checked out and put on i diagnostic machine and there are no codes stored or pending
has anyone else had this experience or can any of you help me with this.
Please help!
thanks in advance

john

 

[Tobester]

Probably not going to be much help I'm afraid John, but I had my entire exhaust replaced from CAT back with the middle-box deleted and didn't experience any problems like this. And I can't see how changing it would have that effect.

Some things to consider though:

Is your CAT OK? If collapsing inside it will increase back-pressure and that could reduce power (give it a gentle tap when cool and if you hear a rattling then it's days are numbered).
And likewise the back boxes, if the exhaust was exiting through the holes around the y section and it can now only go through the back boxes then have these collapsed internally? If original to the car then they may well have done.

 

[vr6gordy]

Sounds like your cat is knackered .. I have my middle box removed and there's loads more response ..middle box restricts the gas flow loads as its a massive box where the gasses enter then swirl around then eventually leave then has to do it all again at the back boxes

 

[john crossland]

hi. thanks for your input guys,
would the standard exhaust hide a cat problem?
just seems funny that the car appeared to be performing correctly when i took it in for the work but now performance has dropped off quite a bit

 

[vr6gordy]

Have you tapped the cat yet to see if you can here anything loose ??guess when they have fitted the new pipe work they could of moved the internals around a bit when bolting it all up .. Could of been knackered before

 

[john crossland]

yes mate, just tapped the cat and cant hear anything loose at all.,

 

[Ovid]

If you need more revs and getting less speed compared to before then it has to be your clutch slipping.

Unless you've fitted smaller wheels since exhaust repair

 

[john crossland]

I don't think it's the clutch as this wouldn't fail overnight and performance wouldn't suffer as quickly as it has. Car was running fine when it went to exhaust shop and 8 hrs later had the performance issue

 

[jimmcgee]

your car will still get to 100 at 6000rpm in third if it had 2000hp , gearing sees to that , only thing it will do is get there quicker

 

[vr6gordy]

test your clutch .. Try set of in 3rd and if it stalls your cluch is fine

 

[john crossland]

well it only gets to 80 redlining it.
i have now changed the maf after some advice and testing it and it hasnt made any difference except now when in 4th at high revs it starts to judder a little like it wants to go faster but it cant.
going back to exhaust guys tomorrow for them to find an issue or rule an exhaust issue out.
Is it possible that the holes in the front section of the exhaust were masking a problem that has now shown itself after having a non holey exhaust?

 

[john crossland]

hi gordy, that was the first thing i tried after exhaust issue, did the 3rd gear test and it stalled

 

[vr6gordy]

Now it's starting to sound like a fuel problem

 

[john crossland]

or an ecu issue? just seems funny that all this happened since exhaust work

 

[john777w]

My monies on a blocked exhaust!!

 

[Ovid]

Its impossible for the engine to rev higher and the speed be slower unless clutch is slipping or your brakes are jammed on

 

[jimmcgee]

correct !!