ok just had a thought, yes it hurt slightly but beats thinking abt work on a sat morning (im at work!! doh)

any hows, does a diesel turbo require back pressure???

ie is that honking big back box actually a nessecary requirement lol

straight thro pipe from turbo??? no boxes will it lose power??

stuart

no it doesnt all forced industion doesnt req back pressure

n/a does req some back pressure

the big back box is a silecer

prob be way to loud with a straight though mind

no it doesnt all forced industion doesnt req back pressure

n/a does req some back pressure

the big back box is a silecer

prob be way to loud with a straight though mind

Actually the VNT mechanism of the fabia vrs turbo uses back pressure to regulate its speed.

Saying that some people on here have removed the cat (particulate filiter) and backbox and although its loud it doesnt sound half bad

Edited 7 August, 201015 yr by Thirdtimeluck

Actually the VNT mechanism of the fabia vrs turbo uses back pressure to regulate its speed.

Saying that some people on here have removed the cat (particulate filiter) and backbox and although its loud it doesnt sound half bad

Can I ask who renamed the cat a particulate filter?

I do know that the 170`s haqve a particulate filter , but who has renamed the cats?

cos I can say for definate they did not have one from standard (pariculate`s that is)

Sarah

Edited 7 August, 201015 yr by TissMe

cat is on a petrol

particulate filter is on a diesel (resembles a cat)

no?

The newer diesels have DPF's (diesel particulate filters), but as far as I am aware as Sarah stated the Fabia vRS has a Cat.

DPF's are a more complicated affair, needing the burn off cycles every so often if they dont get long enough runs

and are MEGA dough to replace - close to 1000 quid on some cars.

DPF's as far as I am aware are only fitted to the newer VW cars.

Lewwy

TDI needs no back pressure which is why I just have a big-bore out the side, and one little silencer to take the edge off the note.

TDI needs no back pressure which is why I just have a big-bore out the side, and one little silencer to take the edge off the note.

Plus the ECU will not allow the engine to over boost , if so , we all know what happens , it goes in to limp mode , so no the engine will not over boost with the decat on

Thank you all for pujtting things right

Sarah

TDI needs no back pressure which is why I just have a big-bore out the side, and one little silencer to take the edge off the note.

Hmm why is it people say they overspool when back pressure is reduced greatly?

I was aware that they rely on back pressure to knw how fast to spin

My turbo doesn't overboost at all with my setup. Anyone who says their turbo overboosted due to exhaust setup simply hasn't been mapped well enough, or the turbo itself needed cleaning out (sticky vanes)

Wat kind of mpg are people gettin with a straight thro??

Jason's right..

The overboosting / de-cat myth is to do with mapping..

When you remove the cat on say a PD130 Fabia, you are removing a restriction. Which will allow the turbo to spool easier at all rpm, but mainly the range around 3000rpm..

Say if the car is mapped with a cat, then you can use quite a bit of injection quantity in the map, however with a de-cat, the vanes open up (to stop boost) but because of the density of the exhaust flow from the injected quantity there is enough drive there to take the turbo past the specified boost.

This is more apparent with smaller turbos like PD130, 115 etc. and gets better as you go larger

Put simply:

Decat on standard ecu = fine

Decat on ecu mapped for cat = not so good

Decat on ecu mapped for de-cat = good..

Kev

Edited 9 August, 201015 yr by Jabbasport

I have a straight through exhaust on mines, I can go through £10 of Diesel on around 45 miles when giving it the boot but driven normally i average about 43mpg going to work and back and 60mpg on the motorways cruise controlled at 70. Any less than 70 and my car returns poor mpg

I have a straight through exhaust on mines, I can go through £10 of Diesel on around 45 miles when giving it the boot but driven normally i average about 43mpg going to work and back and 60mpg on the motorways cruise controlled at 70. Any less than 70 and my car returns poor mpg

So wat ya getting to a tank then??

Dunno don't ever fill my tank to the brim. I stick a tenner in everytime, stops me driving for no reason but it does make me feel like it's costing a fortune to run