1.9 TDi exhaust upgrade

[MooLard]

Good afternoon

I'm having a subtle but hopefully pleasant upgrade to my TDi quattro in the next few days, I am having the particle filter replaced with a slightly larger bore flexi join and downpipe, and also having the centre box replace with straight pipes.

Is there anything I need to be aware of once this is done, like adjustments to the turbo or adding a manual boost controller to stop overboosting? I will be remapping the car soon too, but should probably own and run it for a while over the festive period...

Many thanks

 

[Gaz!]

It's not a DPF, it's a CAT. On the 1.9's it's not advised to de cat due to surges.

How are you going to fit an MBC when the turbo is a VVT that is actuated via vacuum and not boost pressure?

 

[MooLard]

Hey Gaz! Thanks for the reply I did some research on doing this before booking the car in and have had really mixed findings, some say it's great and amazing while others have said the same as you and that I will get surges.
Look up Dawes Device TDi, I fitted one to my previous mk4 Golf TDi 150 and although it was a bit tedious (start-stop) to set up, once done it capped the car from overboosting and then settling at the correct boost. Potentially a worthy purchase, not sure if I'll get one imported though, there has to be a similar one available from this country.

 

[DieselJake]

Yeah no DPF for the 1.9, personally think it's fine without the cat but as you say there are allot of mixed opinions.

 

[dale86]

Mine has no cat and a straight through stainless fitted no boxes and it's been fine no overboost .

 

[MooLard]

Ah that's good to hear, as an afterthought I think I'll probably replace my vacuum pipes soon as at this sort of age and mileage cracks may appear, which could in turn be giving drivers a bad time after doing any engine tweaks. We will see on Monday eve, I'll take photos of my exhaust and try to learn uploading in this time...

 

[Gaz!]

Hey Gaz! Thanks for the reply I did some research on doing this before booking the car in and have had really mixed findings, some say it's great and amazing while others have said the same as you and that I will get surges.
Look up Dawes Device TDi, I fitted one to my previous mk4 Golf TDi 150 and although it was a bit tedious (start-stop) to set up, once done it capped the car from overboosting and then settling at the correct boost. Potentially a worthy purchase, not sure if I'll get one imported though, there has to be a similar one available from this country.

Yes thats an MBC, manual boost controller. But how will you get it to work on the 1.9? The turbo is controlled by vacuum, not boost.

 

[MooLard]

Morning! The MBC can work either way, the mk4 Golf is a vacuum based system too, the Dawes device specifically has a ball and spring valve in it that you set up to close once the right pressure is reached from the tapped boost side.
That aside though, collected my car last night and I'm really happy with the results! We agreed to do the decat / downpipe section in a very slightly larger bore including a new flexi join, and the twin centre section pipes are just the same diameter.
The sound is very slightly louder on throttle but the response is a bit quicker from low down.
Had a few puffs of smoke from stationary but it's probably just the rest of the exhaust system getting cleared out, or the car adjusting to the boost coming on more easily.

 

[cnut]

Why would you want to amplify the sound of a diesel? :S

 

[dale86]

You'd be surprised how it sounds I'm impressed with the burble mine has it sounds great for a diesel.

 

[MooLard]

Correct Dale! Agreed that a an exhaust system with no backboxes on a diesel sounds very much like a tractor but I've retained the two rear ones and it's quite a nice low and warm note. The main purpose was to remove the restriction of the particle filter though and as it wasn't too much more it made sense to remove the centre box at the same time.

 

[_JJ_]

I've got a 59 plate 1.9TDI A3 to my knowledge its got a DPF as i'm toying with getting the delete at the moment.

As for the noise in my opinion diesels have the ability to sound just a good as a petrol, some of the 3TDI engines sound insane.

 

[dale86]

Mine is a stainless straight through from the turbo not even any back boxes and it sounds like a v8 I think although it is loud on full chat but I don't do much motorway miles so I live with it.

 

[MooLard]

Evening JJ, if your car has a DPF do some research and reading so that you know if the car will throw a fault code by changing the exhaust system pressure by removing the DPF. Some cars you can code it out as part of a remap but I don't know the details I'm afraid.

 

[MooLard]

Good day! Got my exhaust done a few weeks ago now and I'm really pleased with the results. It hasn't created any issues with the car and the torque comes in at lower revs so all good from here.
There is a slight puff of smoke in first or second sometimes, usually when the car is warming up so I can only guess that it is a slight excess of diesel when waiting at junctions etc, I'm not worried, for now.