Myths and fairy tails about the VM TD

[Deezelweazel]

Wow, great compliment to both of you sfedek + antiferret! You, gentleman start thinking!
It is the right way of improvement.
I'm working on it right at the moment.

Let me tell you what happened so far.

I had the same thoughts like you:
An intercooler decreases intake temperatures. Every degree less intake temperature it degrades in the same amount exhaust temperature.
So: 1 degree less intake equals 1 degree less exhaust temp.
I ordered a custom Intercooler for the radiator front. Worked fine with one exception:
In that moment I increased speed above 90Km/h the coolant temperatures exploded. I blocked the radiator!

VM rule no1: Do not block the radiator!!!
1100€ wasted for a useless intercooler.
It has areason why the intercooler is located below(behind) the
bumper.
If you look closer you find out that the intercooler is vented by the visco fan.
That means during offroad use the visco draws the heat out of the intercooler.
For that reason make sure the fan shroud is sealed( But I mentioned that way earlier in this thread, do you remember?
So there are ways to improve flow:
Just have a look:
This is how the front cross member looks stock


And this is how the cross member looks after increasing air flow about 1/3

It is an early try - so it is not perfect.
Do not remove the complete front- you influence the front cross member stability.
Also the front bumper has to be modified to increase flow. The factory unit is a double staged unit and has good heat absorbent abilities if air flow is enough.
Clean it from the outside- mine was almost closed with mud in the beginning. So it acted as a useless device( maybe possible head failure cause???)



An air water cooler is great- but where do you want to place the heat exchanger? If never recognized so much space problems as in the Jeep.

You have to make a decision- An offroader with no compromises- or a daily usable vehicle? I choose the DD with offroad abilities.

Carvesdodo mentioned it already!
You can't transform your Jeep into an offroadmachine without keeping elementary parts of the engine on the same level!
As I remember Carves said the Jeep is designed as an "as is" on a stock level. So keeping it reliable means to have at least original performance.
Now you start to throw bigger tires on it which give the engine a bigger load too. So you have to keep up the same level!

[The Smiths]

One of the things I'm looking at with the intercooler is putting one on the top of the engine, and a bonnet scoop (as per some others) - that way it is completely out of the mud - as it needs clearing after every trip (also thinking about dumping the aircon rad as never had overheating problems on my old sport one - even though cooling radiator had lost most of its fins.

This is down the list of to-do items though and needs more thought - so what do others think?

[Deezelweazel]

Mitsubishi is doing that in their Pajero's -they have also a small fan which activates at speeds below 60Km/h to assist during offroad speeds and to maintain the torque.
But be warned-fans are expensive, if they are possible to assist the air flow you will need.
a hood scope alone only delivers air flow during speed conditions.
Long intercooler lines and huge cores do also cause response lags.
Thought already about using the hood scope of an Mitsubishi B200, because it could be a direct bolt on at an acceptible price.
But the space below the hood...

[Antiferret]

Originally Posted by Deezelweazel

Mitsubishi is doing that in their Pajero's -they have also a small fan which activates at speeds below 60Km/h to assist during offroad speeds and to maintain the torque.
But be warned-fans are expensive, if they are possible to assist the air flow you will need.
a hood scope alone only delivers air flow during speed conditions.
Long intercooler lines and huge cores do also cause response lags.
Thought already about using the hood scope of an Mitsubishi B200, because it could be a direct bolt on at an acceptible price.
But the space below the hood...

Modern patrols in australia have a dedicated fan for the top mounted intercooler (interheater) that switches on once the ic hits a certain temp or low range is engaged.

water to air ic's are better at soaking temp spikes than an air to air one.
water has a far greater latent heat than alloy.
its fairly straightfoward to knock one up. guy across the road put a toyota GT4 turbo water to air (from a pre 94, cheap as chips from wrecker)on his mitsubishi starion and plumbed it up. i believe earlier subaru libertys (legacys to non aussies) have one as well.

just hook it up to a motorcycle radiator with electric pump and hey presto.

[Deezelweazel]

Just be warned to put the additional radiator into the front of the main radiator.
Yes, a water cooled unit maybe great.
I do like the stock layout because the viscofan ( still have problems to say clutch fan) that automatically supplies the heat transfer of the intercooler with fresh air if the fan shroud is sealed to support air movement.

I do look at the grashopper problem. anything that can block air flow is not a good solution.
Ok, mud can also restrict flow.
Water/air coolers are cool as long as the water gets not heat soaked.
I was allowed to watch experiments with ice fillled tanks and radiator fluid to provide better cooling for 1/4mile races. Can you imagine that the ice is completely melted after one single pass?
What an awesome heat exchange!
It will be difficult to support that in Australia.

I have always difficulties with an added coolant circuit. It will develop itself to an additional circuit to watch and to maintain.
KISS!= Keep it strictly simple!

I know that these solutions are commercial sold in Australia. Stumbled over these aftermarket solutions in the past...
It is an interesting thought- where would you like to place the heat exchanger?

I'm asking these questions with one common background in mind.
Will all the countermeasures sum up to prevent engine overheat and head failure?

I'm pretty sure that lowering intake temperatures are beneficial.
We can assume intake temperatures at the turbo outlet of up to 200°C.
If we are able to drop them down to 80°, we have an average intercooler with an efficiency of 60%, an efficiency of 70%, which is very good
(top brand)for an intercooler drops the temperatures down to 60°C.

Water/aircoolers do operate in this range!

[Deezelweazel]

One topic I almost have forgotten to mention!

The low coolant level sensor.
This tiny device should prevent engine damage when activated.
Should? If you watch closer you recognize it is located with in line level with the heads! That means when this light activates it is already to late!

Coolant can dimish very slowly due to radiator leaks.
A warning light at the right time can save you a couple of hundred bucks!

The solution that gives you time to react in advance is very cheap and simple.
Just raise the height of the coolant expansion bottle 2 cm with a thick rubber mat and use of longer bolts to tighten it again!
These simple 2cm height increase will save your butt before it is to late.
The heads are now still safely surrounded with coolant and you know in advance something is wrong.

Take this low coolant warning light as your very last hint something is going wrong. There is nothing that will help you behind this line.
If it lits- all other topics are non important.

[MattP]

Originally Posted by Deezelweazel

One topic I almost have forgotten to mention!

The low coolant level sensor.
This tiny device should prevent engine damage when activated.
Should? If you watch closer you recognize it is located with in line level with the heads! That means when this light activates it is already to late!

Coolant can dimish very slowly due to radiator leaks.
A warning light at the right time can save you a couple of hundred bucks!

The solution that gives you time to react in advance is very cheap and simple.
Just raise the height of the coolant expansion bottle 2 cm with a thick rubber mat and use of longer bolts to tighten it again!
These simple 2cm height increase will save your butt before it is to late.
The heads are now still safely surrounded with coolant and you know in advance something is wrong.

Take this low coolant warning light as your very last hint something is going wrong. There is nothing that will help you behind this line.
If it lits- all other topics are non important.

Can you post of picture of how you mount the expansion tank? I think I know what you mean but it would be nice to check. I've had the low water level light come on once after I refilled the cooling system and there must have been an air lock, the engine had just come up to temperature and I guess once the thermostat opened the level dropped quickly in the expansion tank. I had it standing on a slope while filling as you suggested so that the rear wheels were higher than the front. I squeezed all the hoses to move the fluid but it still got an air lock. Any suggestions? What sort of angle do you need on refilling to prevet air locks in each of the heads? Also, does that fill vent cap on the top right of the radiator unscrew completely or only move a quarter turn? If it's the former then mine must be partly seized. That may also be the reason I can get rid of the air lock. The manual says to "remove" it on refilling but I don't want to break it off trying.