NS/NT Exhaust

[Richo-NT]

Hi everyone, I know this has been covered before but I have done some searches and couldn't come up with anyone who has done an exhaust upgrade on a PDF equiped DiD Pajero. Has anyone found what the story is?

I was looking at my exhaust and I can't work out exactly what the PDF filter is?? The exhaust comes down from the turbo, switches over from the drivers side to the passenger side of the car then goes ito what looks like a catalytic converter, then there is a small bit of pipe before going into a look cylinder which I thought may have been the PDF but there are no wires or anything attached to it, then it goes into a small muffler, then over the rear axle then into another small muffler then exit. It all looks pretty straight forward to replace and I figure if that cylinder is the PDF then how would the electronics not know that it removed considering there is no wiring to it? Or could you leave it on and still get some good flow anyway considering on the NT the PDF is a high flow design??

Pretty keen to do this mod to my car...

[apsilon]

I'm of the belief that that cylinder things is the DPF. All the ones I've seen look similar though I admit I've never looked for any sensors etc.

As to my exhaust I'm thinking what ever the current pipe size is (2.5") as it's a decent size and I'm only planing on doing from the DPF back currently. As to muffler it'll have to be whatever will fit as the aux fuel tank takes up a lot of room. This'll probably mean a canon of some kind. Hope it sounds OK as they typically sound like shite on the cars they're usually fitted to. Turo will at least help keep it quiet regardless of being as straight through as possible.

[Richo-NT]

apsilon - I have heard of people just going a straight through pipe with just a hotdog (resonator) which is a lot smaller then a cannon, and the car is still usually quiet.

[Angry]

What size is the standard NS exhaust pipe ???. 2.5 or 2.75"

Does a larger size say 3.0" make any difference??.

Being involved in turbo petrol engines & race cars I just cant believe the (substandard) size of the standard Intercooler.

Surley the engine would benefit for a larger intercooler, without having chip/tuneup issues.

Has anyone fitted a larger exhaust (on a DPF) car ? or a larger intercooler ??

[apsilon]

Hotdog might be an option but they're usually fairly long aren't they? I'm not sure I could fit one. Other than freeing up the flow I want to keep the noise well below the legal limit but more importantly I don't want it to drone on the highway.

The IC is fairly typical size for OEM. Larger IC couldn't hurt and might be something I do in the future. Not sure of the standard exahust size. I was guessing 2.5 but it could be 2.75 3" I think would be fine on a turbo 3.2 but unless you're going to do from the turbo right through there's not much point and at this stage I'm not willing to remove the DPF.

[CeeJay]

Could I ask why? The NT has loads of power and torque - do you need any more? What can't the car do that you want it to?

[Richo-NT]

I have found that a properly good exhaust on a turbo diesel has a range of benefits including more power, more drivability as the engine comes on boost sooner, better efficiency and therefore economy, it makes the vehcile rev smoother and when done correctly is no louder then stock, however sounds a lot better. It is all about efficiency, if you improve the efficiency of a motor then its always going to be an improvement.

The benefits on petrol engines usually aren't as great, turbo diesels just respond really really well to good airflow.

I think a bigger intercooler would definetly be of benefit but the cost would be up there a bit as you would require new plumbing from the turbo to the intercooler then to the intake

[Richo-NT]

I think the exhaust size is 3" from the turbo to the catalytic converter, then 2 3/4" the rest of the way.

I spoke to one exhaust guy who thought that maintaining that setup was the way to go, just using mandral bends rather then press bends as well as better flowing mufflers, however he had little idea about the PDF which means I probably won't use him, to avoid problems I will be going with someone who understands the PDF

[apsilon]

I've never had a diesel before let alone done an exhaust on one so that's good to hear.

IMO having more power means you don't push the vehicle as hard to do the same thing which can often mean improved economy.

In my case I believe the repalcement muffler from the aux fuel tank is too restrictive and is actually robbing power. It might have been OK on the NS as none of the NS owners have commented but I feel it's down on pwoer/torque and I haven't been able to get near the same economy since fitting it and I suspect it because I'm pushing harder than I was before. It's also a little because the new muffler has an awful note so a nicer sound will be an extra plus.

As for the IC a larger one would be more efficient in hot temps and providing cooler air to the engine can never be a bad thing from a longevity POV.

[Richo-NT]

apsilon - I had a performance exhaust on my old magna but when I grew up a bit I found it too noisy so put the standard muffler back on it, as soon as I did that my wife who knows nothing about cars said "yeah its quieter but is something wrong with it? feels gutless"

a restrictive exhaust does make a BIG difference...