Fixing the overboost issues with the MN 2.5HP

[Naff]

Had this same discussion on Facebook the other day. Problem is you get one young blood who hasn't had the issue (yet) and it gives people confidence in the exhausts.

The exhaust manufacturers should be accountable.

[Cowboy Dave]

Or the other old classic which is "i've got X mod and it goes great and has never caused me a problem" - which misses the point and breeds false confidence for those who follow after.

[coughy]

then there is the other side dave in it is stock exhaust and it limps

[Cowboy Dave]

It happens a lot less often though and if it did then you'd be well justified in taking it back to Mitsy with a please explain.

[coughy]

well yer we have done that and the pimple faces apprentice cant find anything wrong with it
they just rest the limp code clear the lights and
say
See what happens now
they are useless and not worth the air they breath
yes ive had a far few run ins with the stealers(wankers) over this issue
hence the reason i went with a tony chip to stop it
well it has limited it done to not much still working on that one

[mattz]

[Jacob]

3" exhausts are to big for a 2.5l engine. There is simply not enough back pressure which lets the turbo overspool/overboost. 2.5 inch system are max recommended for the mn triton and a lot of professionals will say the same.

[RHKTriton]

Its interesting how one manufacturer can have a significant issue with something that others just don't. My old Vito which had VGT never limped in the six years I had it and that got driven like a sports car at times - bugger all lag, lots of torque off idle and no carbon build up.

[hvac guy]

Landcruiser has the problem too

[Tony]

Yes, as hvac pointed out. V8 Toyota can overboost and many others also will such as Land Rover when back pressure is messed with.

The Dubbo Toyota dealer warns customers NOT to fit 3" exhaust as so many have run into problems with towing.


I have a long list here from this forum who have not said anything in public. I'd imagine 8 out of 10 will eventually encounter the issue at some point when change fueling, air intake and exhaust or a combination of.

[Stoneman]

So if a land cruiser does it too does that mean its ok and we should be happy

why does everyone compare problems to other models? as if we should be happy with the issues ( Not that ive had a over boost issue)

That's like putting people down to make yourself look better.

I don't understand it........not that I really care anyway

[Cowboy Dave]

I think you'll find that was in direct response to the Triton being unfavourably compared to a Mercedes Vito van. A comparison that particular poster makes on a frequent basis, presumably since they both have diesel engines, one of which is perceived to outperform the other.

For my part only the people who have the overboost on stock cars have cause to complain about Mitsubishi. If the overboost is from putting on too big an exhaust, or caning the engine with engine chips etc then to my mind you've forfeited the right to sook about it and you have to design or find your own solution in much the same way as you designed or found the cause of the problem. Of course the natural target of angst at that point is the exhaust retailer but good luck with that.

[har05l]

Without my chip but still running a 2.75" exhaust since the new engine install I haven't had an overboost at all. I still want my chip back in though

[coughy]

lol just looking at the taipan webby and this is what it states for a challenger 2.5l

The 3” Mandrel Bent TaipanXP Vortex Exhaust System
Available in either Aluminised Mild Steel or 304 grade Stainless Steel
Dump Pipe with EGT fittings
200 cell High flow Diesel Spec catalytic converter
Flex bellows
Gen 2 vortex muffler
Rear Resonator
Utilises factory mounts and increases exhaust clearance over factory.

and this is for the triton 2.5l

The 3” Mandrel Bent TaipanXP Vortex Exhaust System
Available in either Aluminised Mild Steel or 304 grade Stainless Steel
2.5inch Stainless Steel Dump Pipe with EGT fitting
200 cell high flow diesel spec catalytic converter
Flex bellows
Gen 2 vortex muffler (Keeps it quiet when towing, but noticeable compared to standard)
Rear Resonator
Utilises factory exhaust mounts and increases exhaust clearance over factory

um WTF
the triton and challenger run the exact same dump pipe and turbo and settings and pipe back to the diff there the same 100% so why does the triton need a 2.5" stainless dumpy???? pipe
and the challenger not???
lol im going to ring them tomorrow and ask this question

[RHKTriton]

Are the kits actually different or is it a typo coughy?

I just used the Vito as comparison CD, based on the fact that one is actually of smaller capacity, is a 2003 v 2009+ year build, lugs similar mass and can base on personal experience. Take tech another notch, our old Peugeot 307 had a little 1.6 TD and it was designed to allow about 40Nm over boost for a short burst for better over taking manouvers, so the gingerbeers knew what limits they could away with before meltdown.

My 3.2 has only ever limped when I've tinkered with the waste gate settings which was to be expected - no tears.

Reading through the forum, the 2.5 mitsi donk seems to be a sensitive beast at times. I have several acquaintances that are wrapped with their trucks and haven't had any issues.

The problem with the bigger exhaust causing limps with the 2.5 is probably a result from the ecu only getting inlet manifold pressure to determine the vane settings based on a giving exhaust characteristic. The ecu has no feedback about the larger exhaust parameters and will try to provide boost as usual but can now achieve it far more easily and then overshoot the expected limits. With the output from the MAP sensor the ecu assumes a protective state.

[coughy]

the kits are different as the challenger can have the 3" dumpy
but the triton they say needs a 2.5" dumpy

mmm going to have to ring them if i remember lol

[coughy]

ok so i rang these monkeys and they do a 2.5" dumpy for the chaleenger as well
so it is a typo on there webby
the Aluminised Mild Steel for the challenger is $1565 plus $60 freight
and the 304 stainless is $2250 plus $60 freight

both come with the 2.5" stainless dumppipe then go to 3"
just thought i would let you fellers know

[Dans Tri]

Without my chip but still running a 2.75" exhaust since the new engine install I haven't had an overboost at all. I still want my chip back in though

Is this a beaudesert exhaust?

[har05l]

Without my chip but still running a 2.75" exhaust since the new engine install I haven't had an overboost at all. I still want my chip back in though

Is this a beaudesert exhaust?

From memory yes it is

[Tony]

Without my chip but still running a 2.75" exhaust since the new engine install I haven't had an overboost at all. I still want my chip back in though

You haven't tried hard enough yet. Memory serves me right, you logged overboost not long after the exhaust was fitted and were towing.

[har05l]

Yeah but the new engine isn't reaching the same psi levels so I'm guessing this was the cause

I tried last weekend coming home out of Mudgee where I've had it a few times occur and nothing.

I will have trailer on again tomorrow so will try harder

[Cowboy Dave]

I couldn't get mine over 18 psi last weekend. NFI why.

[alian]

Does anyone know what the difference between the turbos on the 3.2 and the 2.5? I have a cousin in Brisbane who by default (Dealer didn't have the right turbo in stock) had the earlier 3.2 turbo fitted to his to 2.5. reckons it hammers now. He was having all sorts of problems towing (I am sure he was saying it was going out on limp before that.
Cheers Ian

[ag9111]

They may have fitted the 3.2 vgt from the pajero

[coughy]

I don't they would of as the 2.5 has a different exhaust and different set up parameters