Fixing the overboost issues with the MN 2.5HP

[gregned]

I guess borngeek is alluding to the fact that a snorkel is a factory option.

[borngeek]

Because a engine will only suck the air it asks for and can dispose of - and there are sensors that control that, that report to a computer that controls the engine. Many sensors, target voltages, time, and all sorts of things measured and reported and hard coded responses to exceptions. For safety longevity of components.

A snorkel is an raised air intake, not a forced induction system. Makes zero difference.

I know what causes the problem. Been enough hints already. Way so many hints.

When a plug in solution is ready for release, you will hear about it. Being tested. As Tony has already said.

[Stoneman]

I'm not in need of a "fix" thanks

You could just say you don't know. Thanks for your take on it but

Sounds like another product is going to hit the markets.

[borngeek]

I'm not in need of a "fix" thanks

You could just say you don't know. Thanks for your take on it but

Sounds like another product is going to hit the markets.

Never said you did, others have the problem and read here.

Ass ume all you like.

[coughy]

i DONT have a snorkel and i get over boost so snorkel dont do it
simple it is a coouple of other sensors doing it which i believe i have nutted it out as i havent had a over boost since i fixed mine
more testing happening

[hvac guy]

Snorkel wont be the issue as it increases the intake track. In hind sight it should make the turbo less efficient due too the pressures drop. But were clutching at staws here.

[MilkmanDan]

I'm not suggesting I have a special motor or anything else but I've had a 3" exhaust with no cat on my mn for over 100thou with no issues, 10thou with snorkel. Peaks boost at 24psi by the gauges memory and tapers off like I would expect the vgt to do.

A turbo is a mechanical object, a vgt just needs to be manipulated to bleed boost earlier. Don't know why we need to be all cryptic about it

[Stoneman]

Never said you did, others have the problem and read here.

All the more reason to share info

I wasn't assuming, it was just your explanation was very vague and didn't really explain anything

If I'm going to jump off a cliff I would like to know why

[Stoneman]

i DONT have a snorkel and i get over boost so snorkel dont do it
simple it is a coouple of other sensors doing it which i believe i have nutted it out as i havent had a over boost since i fixed mine
more testing happening

That's good news coughy. I know you've put a lot into it so would be great to see what your results are

I just seen it on the pajero forum and I thought I would post it here as some might of been able to share some info to help

Do you think it's faulty sensors?

[Stoneman]

I'm not suggesting I have a special motor or anything else but I've had a 3" exhaust with no cat on my mn for over 100thou with no issues, 10thou with snorkel. Peaks boost at 24psi by the gauges memory and tapers off like I would expect the vgt to do.

A turbo is a mechanical object, a vgt just needs to be manipulated to bleed boost earlier. Don't know why we need to be all cryptic about it

I'm with you

There has to be a logical answer to what is going on

[Stoneman]

.

[Cowboy Dave]

I didn't think he was being cryptic. I thought he was getting at the fact that the answer was already in this thread, at least for those with the bigger exhausts.

[srb]

I'm not suggesting I have a special motor or anything else but I've had a 3" exhaust with no cat on my mn for over 100thou with no issues, 10thou with snorkel. Peaks boost at 24psi by the gauges memory and tapers off like I would expect the vgt to do.

A turbo is a mechanical object, a vgt just needs to be manipulated to bleed boost earlier. Don't know why we need to be all cryptic about it

I'm with you

There has to be a logical answer to what is going on

Are you two serious??
There's nothing cryptic about it!!

It's already been mentioned why it happens a few pages back.

[MilkmanDan]

I know about the vgt operation and why it does it. The fact this place thrives on being cryptic with information, dunno why people need to hide it.

Fwiw other models that use vgt actually have electronic controllers you can tune to work with engine load changes etc, mainly with stationary engines but from memory Cummins engined Dodge trucks in the states utilise a controller for them.

[borngeek]

I'm not suggesting I have a special motor or anything else but I've had a 3" exhaust with no cat on my mn for over 100thou with no issues, 10thou with snorkel. Peaks boost at 24psi by the gauges memory and tapers off like I would expect the vgt to do.

A turbo is a mechanical object, a vgt just needs to be manipulated to bleed boost earlier. Don't know why we need to be all cryptic about it

I'm with you

There has to be a logical answer to what is going on

Are you two serious??
There's nothing cryptic about it!!

It's already been mentioned why it happens a few pages back.

[Stoneman]

I don't think any of you can explain

In stead of being idiots can you link the specific post?

[Stoneman]

I didn't think he was being cryptic. I thought he was getting at the fact that the answer was already in this thread, at least for those with the bigger exhausts.

So what's the difference CD between having an exhaust and not having one

Seems like no one really knows what's going on but it's sure made complicated here

[Stoneman]

I'm not suggesting I have a special motor or anything else but I've had a 3" exhaust with no cat on my mn for over 100thou with no issues, 10thou with snorkel. Peaks boost at 24psi by the gauges memory and tapers off like I would expect the vgt to do.

A turbo is a mechanical object, a vgt just needs to be manipulated to bleed boost earlier. Don't know why we need to be all cryptic about it

I'm with you

There has to be a logical answer to what is going on

Are you two serious??
There's nothing cryptic about it!!

It's already been mentioned why it happens a few pages back.

Another I can't explain it either

[borngeek]

What do you need explained?

It's simple the ECU believes the turbo is overboosting and causes a limp mode.

WHY?

Because it's a VGT turbo and it measures the amount of air it consumes over a period of time under full load/100% throttle position and has a built in safety measure to stop the turbo from self destruction.

It's really quite simple.

Those that fit bigger exhausts encounter the problem more reguarly, and in a shorter period of time, because it can expel gas quicker and the limit is reached sooner.

Various sensors, as I already explained, are involved in the ECU making that decision.

It would be stupid of me to tell you what voltages, which sensors, how we unlock it, until it is fully tested.
ie. We risk engines of people that have a clue what they are doing, have extra monitoring equipment in place, as well as know what the risk is.

//I suggest you go find a nice long hill and go hold your engine flat out (do not take your foot off the throttle hold it down)
You will discover yours does it too. They all do it. Once you discover the time it takes, you can then use a throttle blip method to avoid the error from occurring. This may be annoying to some but is an effective workaround until the long term solution is finished.

Real cryptic.

[Cowboy Dave]

I don't think any of you can explain

In stead of being idiots can you link the specific post?

Okay so people who couldn't be arsed repeating themselves for people who couldn't be bothered reading the answer are idiots now? Reckon I'll try cryptic instead if that's the quality of feedback available.

[borngeek]

It's amazing, CD, how many idiots continue to be lazy and not want to actually read answers already given....

Living in a world of spoon fed morons, that call themselves adults, imho...

[MilkmanDan]

I'm sorry my post may have been misinterpreted based of my misinterpretation.

I get the Dawes valve fix and why the vgt does what it does and why it goes into limp mode. I read a bit of maybe intentional or not play on words to something.

My apologies gents, did not mean to ruffle feathers.

[MilkmanDan]

What do you need explained?

It's simple the ECU believes the turbo is overboosting and causes a limp mode.

WHY?

Because it's a VGT turbo and it measures the amount of air it consumes over a period of time under full load/100% throttle position and has a built in safety measure to stop the turbo from self destruction.

It's really quite simple.

Those that fit bigger exhausts encounter the problem more reguarly, and in a shorter period of time, because it can expel gas quicker and the limit is reached sooner.

Various sensors, as I already explained, are involved in the ECU making that decision.

It would be stupid of me to tell you what voltages, which sensors, how we unlock it, until it is fully tested.
ie. We risk engines of people that have a clue what they are doing, have extra monitoring equipment in place, as well as know what the risk is.

//I suggest you go find a nice long hill and go hold your engine flat out (do not take your foot off the throttle hold it down)
You will discover yours does it too. They all do it. Once you discover the time it takes, you can then use a throttle blip method to avoid the error from occurring. This may be annoying to some but is an effective workaround until the long term solution is finished.

Real cryptic.

Curios and I assume it's been done but without owning a copy of ecutek software, I can only speak of experience with GM/ford tuning software but has anyone logged what it is doing whilst driving before falls over to cel?

What's fuelling doing, what lambda is it pushing out the pipe?

I only ask as I would find it unusual that the ecu believes it's overboosting over a longer period, has it got a dwell that it accounts for the vgt spiking but can't account for prolonged wot?

[Cowboy Dave]

It wasn't you calling people idiots mate.

Yes logging has been done by not by me.

I think you'll find it will tolerate short boost spikes but has a setting for how long it will put up with it.

Mine used to spike at 25-26 psi but only briefly. Then it would settle to 22 ish where it was content.

With the 3 inch the flow is higher and it's not as easy for it to work back down to the level it finds acceptable.

Obviously the cheat is to lie to the ECU about the boost but you still need to bring the vgt back under control again. Tony has been able to set them up running 25-30 psi and more all day long.

[MilkmanDan]

No worries CD...

The Dawes to me is a fix but not a good one, it changes the whole way the vgt works, now I'd base assumption the the ecu may only just have enough to account for it. It's obviously running SD tuning but with no o2 sensor how does it adjust, algorithms based off map to anticipate a hypothetical egt range to add more or less fuel?

So the problem is to me the vgt actuator can't keep up, hence asking how it is operated earlier. I'm being 100% I've hit limiter in 4th and no problem, hence why I find it strange. If it's actuator related maybe the pump it uses (assuming a pump like most do) can't keep pressure to it so boost creeps again to over the limit set in ecu as the vgt bleeds boost quite well when all is working