V70 P2 D5 exhaust upgrades, are there any ?

**RobbieH** · Monday 2nd March 2009, 18:52

Cleaning the car on Saturday I noticed that one of the rear box mounts is getting rather rusty and material flaking off. I've seen various "repair" kits on flea-bay but, thinking of the future, I'm wondering if there are any options to the standard exhaust system for a D5, certainly from the cat back. Anyone changed theirs or got any ideas on options?

**cornclose** · Monday 2nd March 2009, 19:33

I've been thinking the same thing recently - although mine is a T5 not a D5. There seems to be lots of talk of people putting sports exhausts on P1 850/V70, but I havn't seen much talk of exhausts for P2s...

Anyone ?

**dave stew** · Monday 2nd March 2009, 19:38

How about a Jetex system: http://www.partsforvolvosonline.com/...oducts_id=4604

**Redbrick** · Monday 2nd March 2009, 20:06

Cat backs are pretty pointless without a bigger downpipe aren't they?

The flexi part of my D5 downpipe failed so I got a new flexi welded in and the first cat removed- turbo spools up quicker, definate improvement.

One of the hangers on the back box has been replaced on mine, just got a new hanger welded on.

**v70torslanda** · Monday 2nd March 2009, 20:48

Twin outlets - here

heicosportiv.de

**RobbieH** · Monday 2nd March 2009, 21:43

Originally Posted by Redbrick

Cat backs are pretty pointless without a bigger downpipe aren't they?

The flexi part of my D5 downpipe failed so I got a new flexi welded in and the first cat removed- turbo spools up quicker, definate improvement.

One of the hangers on the back box has been replaced on mine, just got a new hanger welded on.

Aye, I did think of that (bigger downpipe) but that's the point of the query to see what is possible.

Are you saying then that still have the original downpipe before the flexi but a larger bore flexi onwards?
I've seen a picture of the downpipe (attached if I got it right). Am I right in thinking from the left of the picture is the flange to the turbo, then a cat, then the flexi, then a second cat or silencer box and then a flange to the rest of the system (back box, etc)?
If you've removed the first cat, how are the emissions for MOT purposes?

Apologies but my knowledge of the exhaust system is a bit slender at the moment hence any info gratefully received. I've got some long term plans for various "improvements" which also include a remap but in the mean time small steps first, especially when bits need replacing at the same time as said improvements could be made.

**RobbieH** · Monday 2nd March 2009, 21:58

Originally Posted by v70torslanda

Twin outlets - here

heicosportiv.de

Nice, but it's only the back box and outlets. I'm looking more for info on systems that replace the standard system (entirely?) to let it all breath better (if you get my gist).

Maybe a combination of Redbrick's larger flexi, remove the 1st cat (?) and then onto the Heico twin outlet. Sounds tempting although I wonder how much the Heico system is?

Sorry Redbrick, another question - how big a flexi and onwards have you now got (if you don't mind me asking

)?

**RobbieH** · Monday 2nd March 2009, 21:59

Originally Posted by dave stew

How about a Jetex system: http://www.partsforvolvosonline.com/...oducts_id=4604

Another possibility but can anyone confirm if it would be suitable for a D5? Can't find any info on PFV site.

**v70torslanda** · Monday 2nd March 2009, 22:52

If you look at the exhaust system on a P2 diesel ther is only one box and that is under the rear bumper. Modifying the cat could be illegal and may cause you car to fail its MOT.

The reason these systems only replace the back box is because the rest of the system bar the cat is already just a tube. Euro III standard cars have a catalyst in the system but Euro IV cars have the whole 'particulate filter' thing going on which is difficult to modify. We are seeing ever stricter emissions regs especially diesel particulates. These filters IIRC cannot LEGALLY be removed from the car.

In terms of performance gains modifying the cat is going to do very little, likewise a big bore front pipe. What will gain you serious horsepower is increasing the amount of fuel available on each power stroke allied with more air, cooler and more dense. So a remap, bigger intercooler and increased boost pressure is what you need to concentrate on.

It is a law of diminishing returns, however.

Your remap produces, for example, an extra 20% power and 30-35% more torque.
Say this costs half a bag - ish. *
Exhaust costs whatever it is - incremental power gain 2-3%
Bigger intercooler and turbo upgrade could be twice that before fitting cost for a further gain - max 5-10%

A mandrel-bent downpipe and high flow cat could give you another 3-5% max but the downpipe could cost you half a bag on its own!

On the plus side, if Heico's zorst fits petrol and diesel the Jetex must be the same. All the hangers are in the same place on both models. I think I would be more concerned about how much the bumper needs cutting, getting that wrong could prove really expensive!

J

* bag = bag of sand = grand

**thebadger** · Monday 2nd March 2009, 23:39

I have a Ferrita on my P2.

Very subtle tone & not too blary!

Big looking pipe.. I'm told it's 3" down with a 2.5" cat back.

Costly tho!

Happy the last owner fitted it!

Have you looked into a custom setup?

They sometimes work out cheaper for the total job... Also you get more options & advice at the same time!

Look around a bit!

**Redbrick** · Tuesday 3rd March 2009, 00:09

To clarify, the original flexi was blowing. It was chopped out along with the first cat and a same size flexi and additional piece of pipe welded in place. New support bars were made up to the same mounting points as the original down pipe. The first (smaller) cat I'm told is there for emissions when the engine is not up to temp. It smells a bit diesely when cold, once warmed up no difference. Sailed through its last MOT no problem.

I only did this as the repair to the original down pipe was significantly less than the cost for a new down pipe.

Confused, you will be.