Exhaust back boxes on 1.9 tdi quattro

[MooLard]

Good afternoon
Just wondering if there is a technical or given reason as to why my car's exhaust system splits from one pipe to two, and then to two separate back boxes? Is it to balance the car's weight, or to make the engine sound quieter, or both and some other reasons?
Cheers

 

[ruffrida]

It would most liley have something to do with producing the right amount of back pressure fr the engine, and to go round the diff lol.

This is where a lot of people who have custom exhausts made go wrong, my mate stripped his down to the bare min, it lost all its guts and was like a wet fart, no power at, re-added silencer / box, back pressure resumed, back t full power !!

 

[MooLard]

Backpressure?! You don't need any of that on a turbo car! Well a bit probably helps protect the components from accelerating past their top safe speed, backpressure is only needed for naturally aspirated cars! Anyhows, that's a debate I'm not fussed for.
I was more interested to know if anyone has read anywhere more directly from Audi as to why they chose to do two backboxes on a small 1.9 engine.
What car was that on that lost power from no silencers?
If anything I would be temped to simplify my exhaust system and keep the pipework the same as my larger downpipe and put one box on the rear passenger side to save weight and to balance my weight out. In theory an aftermarket backbox would be quite a bit lighter than standard anyway.

 

[ruffrida]

Nah also applies to high powered turbo cars aswel, as the car in question but like ya say that's another debate all on its own,the car was a pd130 a4, all the bells and whistles but no go,wasnt even pumping out 200bhp with big turbo remap etc. If ya serious about a stainless back box,got another mate who has 2 universal 1s for sale, not cheap crap either,bit they have spent the previous life on a civic vti,so may be a little loud

 

[MooLard]

Cool dude, if I do anything further with my exhaust I think I will keep a single backbox rather than removing all of them, and just up the pipe bore by 1/2 inch at the most as I'm not going for mega HP in the future. Thanks for the kind offer of the backbox but I'll get a customer fabricator to supply all of the hardware for the least joins possible.

 

[ruffrida]

Yeh cant fault ya for that,seemless the better

 

[DieselJake]

Go for a straight through 2.5" pipe.

 

[jbcalvin]

I may be incorrect here, but does it not have something to do with the quattro system? I don't think the normal route/size/shape of the non quattro exhaust gives enough room to clear the driveshafts/rear diff… it is the one way of differentiating between quattro and non quattro cars, non quattro only have one pipe….

Having the twin outlets makes it look better if you are doing say a S4 rear bumper conversion….

 

[Cobra88]

Im pretty sure no 1.9 tdi B6 Avants have twin pipes as standard.
Only the B7 2.0 170 comes with twin pipes as standard.

So someone has retrofitted yours

Im just doing mine if Audi can send the correct sport rear vallance
Have sent 3 non sport so far this week
Different parts man now on the case.

 

[ruffrida]

Nope. All fwd 1.9tdi's are single pipe. All quattro 1.9s are twin,hence the 1.8t bumper conversion we all do!

 

[Cobra88]

Are you sure ?
the Quattro I looked at had single pipe and descreet valance (No cutouts) just like my FWD one :/

 

[Welshquattro]

Ruffrida is right,the 1.9tdi quattro with avf engine has twin pipes

 

[Cobra88]

Well I never

I thought they where same.

 

[ruffrida]

Yep defo twin pipes,just Hidden by the big *** back bumper,release the beast and fit a twin pipe bumper,or if ya got plenty of wealth like Rick lol, you buy the lower valance from Audi,well ya do when ya get the right 1 eh rick lol

 

[Cobra88]

Ha Ha

not wealth mate
Kids moved out last year as im a lot older than you
50 now (but if you reach 50 without growing up you don't have to)

 

[ruffrida]

Hahhaha like it rick,sorry forget ya an old man,not like the rest of the whipper snappers on ere,can you send me the link from where you had ya wire from for ya clocks,cheers

 

[Cobra88]

Cheeky Boy PMd link

 

[Icarus83]

Nope. All fwd 1.9tdi's are single pipe. All quattro 1.9s are twin,hence the 1.8t bumper conversion we all do!

Agreed, mine is a Quattro, has twin boxes at the back. They are discreet tips pointing at the ground.