Exhaust Thoughts?

[cpinneri92]

Currently changing exhaust and need help removing cat from back of turbo... Need to finish it tonight

[BillMcQuade]

Currently changing exhaust and need help removing cat from back of turbo... Need to finish it tonight

How did that go for you.

[RHKTriton]

3" just sounds too big for a little 2.5l diesel, considering the rev range. Different for a turbo petrol spinning up to 6k or more.

Stainless is better for longevity than mild steel, but corrosion doesn't seem a major issue with diesels, unless you do a lot of splashing around in the shallows at the beach.

2.75" seems a less common, dearer section of pipe to get when checking out some exhaust joints.

Has anyone thought about running two smaller pipes in parallel to give a larger total bore? This would allow keeping the plumbing further off the ground than with 3" setups and more option with bends.

[BillMcQuade]

3" just sounds too big for a little 2.5l diesel, considering the rev range. Different for a turbo petrol spinning up to 6k or more.

Stainless is better for longevity than mild steel, but corrosion doesn't seem a major issue with diesels, unless you do a lot of splashing around in the shallows at the beach.

2.75" seems a less common, dearer section of pipe to get when checking out some exhaust joints.

Has anyone thought about running two smaller pipes in parallel to give a larger total bore? This would allow keeping the plumbing further off the ground than with 3" setups and more option with bends.

A well designed 3" system is acceptable on a stock vehicle, but offers very little gain. In fact, the only reason to go to a larger exhaust is to reduce EGT. It has been proven on the dyno that exhausts offer very little improvement in rear wheel torque.

On the subject of dual exhuast, I can't see any harm in building a dual system, which would be split after the CAT. The downside is that you will be up for 2 mufflers, another set of hangers and 2 runs of pipe. I had a look at the available dual inlet/outlet mufflers, which would be another option for dual piping, but they only seem to offer 2.25" as the smallest pipe size. For example;

http://www.ebay.com.au/itm/Gibson-55105 ... XQHO9RePF9

I feel that in the end, it comes down to cost. With some very well designed stainless 3" systems available, for less than $700, you would be hard pressed to justify the cost of anything else, especially as the gains/losses are so small.

[Sofled]

Ok so i recently purchased a chip from a reputable new triton sponsor. Its fantastic and i run a egt protection system on it and to do that i brought a 3inch exhaust with ports. It was good advice to go 3inch i believ because i wanted to run higher tunes in the sand dunes during summer so generally going to be nice and hot. Issue is i now have the cel code poping up for over booste if im going up big long hills and stuff.
I realise i can fluctuate the throttle and it elimanates it but it would be nice to just over take with my foot to the floor you know.
Can anyone agree with me on possibly getting a sleeve made up for the inside of the exhaust pipe off the back of the turbo that reduces its initial flow capacity to give abit more back pressure on the turbo. But then cause it rather quickly opens back out to 3 inch i still get good exhaust flow getting rid of the hot gases. Essentially i want to restrict my 3 inch exhaust at the turbo and still have all the old benefits. Sounds stupid when i type it out but it could start some good thought discussions?
Shoot me down!

[coughy]

it has been well documented on forums happens all the time not mine anymore tho
i have seen that taipan ehxhuasts use a 2.5" dumppipe to stop this

from there webby

http://www.taipanxp.com.au/models/mitsu ... -5l-wagon/

We run a 2.5inch 304 Stainless Steel (on the aluminised system the top part is 304 and the dump is then heat proof painted) Dump Pipe with 200 Cell Diesel Catalytic Convertor for these vehicles due to from factory this vehicle runs very high boost levels (18-20psi +). If we were to run a 3” Dump Pipe we would not have enough backpressure which would lead to issues with overboosting & premature turbo failure. It also allows for quicker spool up and better drivability.
We make the dump pipe from 304 Stainless Steel instead of ceramic coating due to the fact we can't ceramic coat the Catalytic Convertor as it can damage the substrate inside it.

[srb]

Restricting your exhaust flow by reducing the size of the dump is unlikely to fix it. Plenty have tried doing this with higher cell catalytic converters but still get the limpy. Some still do it with the stock exhaust system.

Tony from Spvi has a fix for it... Though I'm not sure if available for the masses yet.

[Sofled]

Alright doing it with a cat sounds like it would prove it wont work with a sleeve i was just thinking dirrect nack pressure at the turbo might be the difference. Yes i have spoken with tony im waiting on his reply currently. Denius man that bloke

[dieselweasel]

Hi all, not posted here for a while, I've read most of the exhaust posts on the forum and have a couple of questions.

What's the most restrictive part of the standard factory exhaust? (have an 08 ml)

Does the ml require a little backpressure?

I'm keen to upgrade the exhaust but may try and have some fun first by hollowing out the cat and then chucking on a hotdog, if I'm happy with the result then I can put my dosh somewhere else. I don't want a big loud exhaust, I'm happy with a bit of noise increase but I just want no restrictions down there, that's what it's mainly about. I don't want to lose any low end grunt

Triton has a chip for a l200 mk4, I got it in the UK but never been game enough to plug it in. So apart from snorkel, k&n and Tonys mod, the engine is standard. I intend to fit the chip if I do replace/hollow out oem exhaust. Not after a massive increase in power, the chip will be set low just because I'm not after power, like I said, it's more about losing the restrictions. Christ I've waffled on a bit.

[BillMcQuade]

Hi all, not posted here for a while, I've read most of the exhaust posts on the forum and have a couple of questions. What's the most restrictive part of the standard factory exhaust? (have an 08 ml)

I'd say it would be the CAT.

Does the ml require a little backpressure?

Not after the turbo.

I'm keen to upgrade the exhaust but may try and have some fun first by hollowing out the cat and then chucking on a hotdog, if I'm happy with the result then I can put my dosh somewhere else. I don't want a big loud exhaust, I'm happy with a bit of noise increase but I just want no restrictions down there, that's what it's mainly about. I don't want to lose any low end grunt

My 3" exhaust is quieter than stock. Don't hollow out the CAT, apart from being illegal, you don't gain much.

Triton has a chip for a l200 mk4, I got it in the UK but never been game enough to plug it in. So apart from snorkel, k&n and Tonys mod, the engine is standard. I intend to fit the chip if I do replace/hollow out oem exhaust. Not after a massive increase in power, the chip will be set low just because I'm not after power, like I said, it's more about losing the restrictions. Christ I've waffled on a bit.

I don't think you really need a 3" exhaust. Invest in an EGT guage instead. They are reasonably priced, and are mandatory fitment if you are going to play with the fuelling.

[dieselweasel]

I got one of those gauges off eBay when I brought the chip back over, was intending to fit it with the new exhaust, (haha, been intending on getting one for a while), I'm sort of almost keen not to lose the size of the current pipe as I don't want to sacrifice the low end, I've been reading about how bad hollowed out cats sound so may just do what another member did here and just buy the catless dump pipe from eBay and I'll get a hotdog chucked where the muffler is, I'd rather keep the length of the exhausted unless there's no need too, I'm sure that'll make the ole girl breath a bit better

[dieselweasel]

Didn't realise other photo was so dark

[jerrah]

Exhaust tuning for turbo motors is different to n/a motors. Turbos work off a pressure differential. By lowering pressure behind turbo it makes it spool easier I.e lower on the rev range. That is why people fit 3" exhausts. You don't lose low end on a turbo motor by going big. Back pressure kills spool. The factory exhaust is fine for performance reasons. I don't recommend getting rid of your cat however for legality and emissions reasons.

[Jacobie]

Does anyone have one of these installed?

http://www.ebay.com.au/itm/122011207294 ... EBIDX%3AIT

If so how was the installation?

[dieselweasel]

I'll look at some other options for the old girl then, I wasn't looking forwards to knocking all the guts out of the cat. I foresaw some skinned knuckles and extreme use of profanity

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[Jacobie]

I'll look at some other options for the old girl then, I wasn't looking forwards to knocking all the guts out of the cat. I foresaw some skinned knuckles and extreme use of profanity

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I'm thinking of doing this myself. Ill give it a crack and let you know the results. I was going to buy an old cat so I can change it back if I get heat from it.

[dieselweasel]

I read on a couple of random car forums that emptied cats get a loud tinny sound from the hollow space, it annoyed some people but not others? It's the kind of thing I'd spend a morning doing just for curiosity, if you're going to attempt it, some dude on this thread recommended getting some new bolts before needing some when you've got no pipework underneath, might be worth preparing for some broken bolts

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[catchya]

Hi all, not posted here for a while, I've read most of the exhaust posts on the forum and have a couple of questions.

What's the most restrictive part of the standard factory exhaust? (have an 08 ml)

The first bend off the turbo on the dump pipe itself. Who ever designed this from factory must of been on crack!!

Rest of the system is fine.

[catchya]

Exhaust tuning for turbo motors is different to n/a motors. Turbos work off a pressure differential. By lowering pressure behind turbo it makes it spool easier I.e lower on the rev range.

Spot on. Performance gains is not just purely measured by torque and Hp gains!

[BillMcQuade]

Just to be clear; you will gain no additional torque or power from punching out the CAT (highly illegal), or changing the exhaust size. Even after a tune and other mods, the standard exhaust is not a restriction for most driving conditions.

If you tow very heavy loads, or have significantly altered the fuelling, you may benefit from the lower EGT.

Spend your hard-earned on other bling that will give you some return.

[dieselweasel]

Thanks Bill, looks like I get to spend the money on my guitar habit. All I was after really was less- to no restriction to keep everything breathing well. It all depends if I decide to fit the chip I suppose

[ag9111]

Even with a chip there is no noticeable gains.
Bigger turbo, savage remap maybe.

[borngeek]

To backup the guys above that have posted informative information...

There are gains with exactly that - massive amounts of boost and a lot of fuel. This requires turbo upgrade, increase of rail pressure, modification of rail limiter, changes to injection duration and timing- using more than what remaps are capable of anyways. You need to know what you are doing. And be prepared for the risks associated with going this extreme. These risks range from dead clutches, auto, diff, injection pump - to a bricked engine, which is not cheap to fix.

Without advocating the removal of the cat, I can confirm it makes a large difference to the amount of fuel you can run with lower EGT. Is a big difference. Unless you are doing above its pointless.

A mild chip or tune (20-35% power increases) will not benefit from any changes to the exhaust in terms of performance. Just sounds different.
Invest the 600+ dollars on something else, unless you enjoy the different sound as a personal preference

//ML upgrade per first paragraph running mild too hot with cat.. fuel trimmed out a little

[dieselweasel]

When you drop just the muffler, do you get that crazy howling woooooh sound when you change gear? Tractor sound is cool to me but I can't say I'm keen on the gear change sound. Can it be stopped?

[kdan3]

When you drop just the muffler, do you get that crazy howling woooooh sound when you change gear? Tractor sound is cool to me but I can't say I'm keen on the gear change sound. Can it be stopped?

I had just a muffler delete on the stock MN system and to quieten it down i added a small resonator which has almost eliminated that sound from within the cab.