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Discussion Starter · #81 ·
I know this this thread is about Air Dynamics and its effects, but it doesn't hurt to discuss all the other bits for understanding the whole system and the relationships.

Fair enough, i am hoping to only hear people come back with stories of success given that better aero will help any vehicle.

i found when playing with waterflow and other aspects of cooling systems it was much harder to consult people successfully in understanding what's happening in total when we make changes and why we would even bother in the first place.

aero seems to be a no brainer to me no matter the vehicle.
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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Mike if you have followed any of my ramblings in countless cooling threads over 16 years here you will see i references to this very important aspect of your "Aero" many times. I tried to insight experimentation many times, and at times an inventive smart dude comes up with something different that might make a difference. The best ideal solution fixes rarely come from engineers.

Air damming the radiator and with better low pressure deflectors is a great solution. There is more too this behind radiator low pressure solution and more can be had by multi deflectors in different positions as well. But sadly its only part of our problem. I stated a Math old school rule for radiators above for a reason. So now i will give evidence to this, our GQ radiator size to cubic inch is 2 sq inch of radiator surface area to 1 cubic inch displacement, we have twice as much radiator surface area than is needed. Actually our GQ radiator is sized for 450+hp. So logic suggests our problem solution of the kettle is elsewhere, not that this aero stuff doesn't help expediently, it does and credit to you for having a go..
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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It is not my intention to rail road this thread or this important aspect of cooling. That is not my way. But maybe its time to discuss some real engineering aspects or water dynamics to find a stable temp solution for this issue. I have theories with a lot of evidence from testing that is pointing me in a different direction for cooling stability on a TD. I am happy to discuss these theories here if you feel inclined.
 

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GQ Dual Cab. TD42Ti with fruit.
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It is not my intention to rail road this thread or this important aspect of cooling. That is not my way. But maybe its time to discuss some real engineering aspects or water dynamics to find a stable temp solution for this issue. I have theories with a lot of evidence from testing that is pointing me in a different direction for cooling stability on a TD. I am happy to discuss these theories here if you feel inclined.
It is Mikes thread, so its up to him, but the other cooling threads we have give everyone a headache to read because they are so big and go off topic constantly. It is very difficult to find anything.

My vote is to start a separate thread, given that these topics are important.
 

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Today I removed my spotlights before driving down to the beach. Ambient 32 deg, A/C on, 93 deg on the flats and from memory none of the hills put me up past 97, which is my usual cruising temp.

While it's only 4 degrees, I will take it. I will be replacing the spotted with a light bar across the top of my bullbar. I'm now 8 degrees away from my stats 'opening temp'... I would like to relocate my winch control box as well in time.
 

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Today I removed my spotlights before driving down to the beach. Ambient 32 deg, A/C on, 93 deg on the flats and from memory none of the hills put me up past 97, which is my usual cruising temp.

While it's only 4 degrees, I will take it. I will be replacing the spotted with a light bar across the top of my bullbar. I'm now 8 degrees away from my stats 'opening temp'... I would like to relocate my winch control box as well in time.
Many years ago I noticed my big Cibie lights made the GQ run hotter. Then they fell to pieces (as Euro stuff does) and temps went back to normal. These days I have a modest size light bar that's more than adequate and doesn't seem to affect airflow as much as those big round spotties.
 

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It is Mikes thread, so its up to him, but the other cooling threads we have give everyone a headache to read because they are so big and go off topic constantly. It is very difficult to find anything.

My vote is to start a separate thread, given that these topics are important.
I agree the subject deserves a thread of its own.
 

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Discussion Starter · #88 ·
Happy to participate in a new all things cooling system related thread, the old "engine running hot" thread has got quite alot of evidence of "learning" from many of its participants from over the years. and its a bit of an overwhelming read.

in saying that, i am 100% not knocking it as its been a learning tool of mine also and there is some great content in it, its just a bit crazy for the average dude to piece together.

I fully agree with OldMav and GQShayne on the waterflow stuff, particularly on the TD and for the sake of full disclosure, my waterflow on my TD is definitely not standard. When we start leaning on these motors they quickly run out of cooling system in terms of the way the water moves in my opinion.

is this as important as aero? In my opinion, sure is.

Knowing what i do now days, would i start with elaborate waterflow re works and custom built impellers?

nope. Id get the air flowing right first. A lot of dudes are probably wanting to just be able to tow their van at 100kph without risking a domestic with the misso because the aircon keeps turning off.

airflow (done right) will likely get them there, and as Shayne pointed out - sometimes for less then the cost of a carton of beer.

anything that makes over standard power however and especially something a bit more up there in its tune (lots of "big power" TDs around these days)

Id be doing both.

some engines don't need much done with the water flow to get it all working properly for example the 6.5 H/O impeller was not terrible in its geometry and performance however we opted for a hand built impeller and it did marginally improve things over all.

I believe now that airflow is the better place to start when we are trying to sort "cooling issues" so staying on track as best we can in this thread should help people do things in stages that make sense for any level of desired outcome.

moneys allready spent on water pumps fans and other is not wasted at all in my opinion even if they didn't change the ECT at all (if i had a dollar) they are likely having positive effects on other important parts of how the engine behaves like temp gradients and they will likely come into their own once the airflow is then right on top of the waterflow changes.

The reason i think aero tends to be left to last when it should come first is that: applying a proper method of problem solving without access to the tools of the OEMs like wind tunnels and CFD requires an outside of the box approach for you to be able to move forward with things that "work".

I fortunately have the method and means "sorted", and the evidence of that is in the good results so far.
 

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Discussion Starter · #89 ·
Today I removed my spotlights before driving down to the beach. Ambient 32 deg, A/C on, 93 deg on the flats and from memory none of the hills put me up past 97, which is my usual cruising temp.

While it's only 4 degrees, I will take it. I will be replacing the spotted with a light bar across the top of my bullbar. I'm now 8 degrees away from my stats 'opening temp'... I would like to relocate my winch control box as well in time.
I don't run spotlights on my car, when testing another S4 patrol, i believe i found 50pa more air pressure at the front of the stack with the spotties removed.

I am of the opinion that if you are removing them and getting substantial gains, the airflow problem is likely elsewhere and once its sorted you should be able to put them back on and not have it cause you issues.

given that if you are chasing the best aero possible like me, eliminating them is the obvious move.

I just have a little rigid industries hyperspot light mounted on the drivers side antenna mount, between S4 headlights, that and the TJM fog lamps, i am sorted for my lighting needs at this point in time.
 

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Today I removed my spotlights before driving down to the beach. Ambient 32 deg, A/C on, 93 deg on the flats and from memory none of the hills put me up past 97, which is my usual cruising temp.

While it's only 4 degrees, I will take it. I will be replacing the spotted with a light bar across the top of my bullbar. I'm now 8 degrees away from my stats 'opening temp'... I would like to relocate my winch control box as well in time.
So that is evidence of not enough pressure differential. You could remove lights, winch control and even the bullbar to get a better differential, but the better result would be to work on improving the low pressure in the engine bay. If you get that right, then your lights should make no difference.
 

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So that is evidence of not enough pressure differential. You could remove lights, winch control and even the bullbar to get a better differential, but the better result would be to work on improving the low pressure in the engine bay. If you get that right, then your lights should make no difference.
Not too sure what more I could do to be honest. My big intercooler and oversized scoop probably doesn't help, but when I look in nothing else is obvious. Have you done anything in addition to foam/air dam to improve low pressure in the bay? My mudguards are intact also (I actually made some new ones out of the excess rubber I had, but only the smaller passenger side one needed replacing)
 

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Discussion Starter · #92 · (Edited)
Not too sure what more I could do to be honest. My big intercooler and oversized scoop probably doesn't help, but when I look in nothing else is obvious. Have you done anything in addition to foam/air dam to improve low pressure in the bay? My mudguards are intact also (I actually made some new ones out of the excess rubber I had, but only the smaller passenger side one needed replacing)
My inner guard mod helps to "drop the pressure in the bay" or create another path that induces a flow of air from bay to outside.

So on the gauges, the pressure doesn't actually drop a lot but the amount of air moving through the bay increases a fair bit, which is exactly what we are chasing.

I would also verify your gauge is accurate, and just from a distance and at a glance i think you may have other issues elsewhere - but by all means, these aero mods are not gonna hurt.

Go rigid on the air dam and make it wider, - as wide as the radiator. make sure any air entering the front is guided into the stack, and cant go left or right, up or down.

will post a bit more about that stuff tomorrow if i get a chance (guide strips or diverters or what ever we want to name them) that help to do ensure the air goes thru the stack instead of around.

also, if you think you are forcing to much air in through the intercooler at the detriment to the stack, use a bit of fly screen mesh on the intercooler core to slow down the flow of air going through it.

monitor ECT and EGT and see how it likes it, they are after all a heat sink, so if it has some physical weight to it, it doesn't necessarily need as much active cooling as a lighter counterpart core under full load conditions, as full load doesn't generally happen for long periods.
 

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Not too sure what more I could do to be honest. My big intercooler and oversized scoop probably doesn't help, but when I look in nothing else is obvious. Have you done anything in addition to foam/air dam to improve low pressure in the bay? My mudguards are intact also (I actually made some new ones out of the excess rubber I had, but only the smaller passenger side one needed replacing)
I have only done what I listed and put pics up of at the start of this thread. Apart from an undertray/deflector underneath which I have not done yet. But of course, I have other non-standard things apart from my airflow mods, so it is not really a fair comparison.

On a previous vehicle I had years ago before the Patrol, I did the light test same as you. Take the lights off and the temp went down. So I made up an air dam for the front, and then the lights being on made no difference.
 

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SUI GENERIS UTE
GQ Ute 1990 Silvertop
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Getting air through the radiator/cooler/condenser etc is not really about the front side its about what's behind the cooling stacks. Example a VS V8 commodore which have very small frontal openings actually they are tiny compared to a patrol even with winch and control box, bar with huge lights. They don't over heat and they have electric fans no mechanical fan either.
 

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Discussion Starter · #95 ·
Wood Automotive exterior Composite material Gas Tints and shades
Wood Gas Machine Engineering Auto part


here are some more bits of plastic that do things. . .

Rather then use foam to seal around the radiator, we can also do it this way. See as air enters the front, its going to want to go anywhere but the stack, as the stack is a restriction.

so the air can tend to go left and right, up and down to the nearest low pressure area where it can escape.

see if we use foam, the air can still go left and right, up and down.

if we use a bit of garden edging, it cant really do that any more, so it helps to focus the high pressure on the stack area, weather or not you chose to seal every gap around the stack also.

same goes for bottom of bar, if its open, the air will most definitely bugger off out the bottom instead of doing work across the stack .
 

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Discussion Starter · #97 ·
Just love the bauxite dust stain on everything.
must have taken you years to get all the red back out of your car OldMav, lol Its a full time job for two trying to keep the 6.5 clean. Lets just say its likely the best test rig and test owner for helping me solve the problem of not enough power and too many numbers on the ECT gauge at the same time

. It has also kept me humble, honest and taught me some more patience. U need small hands and big spanner to work on 6.5s in patrols, and that is the same reason why getting the aero as good as possible is crucial on these things. flat out getting wet underneath it if you tipped a bucket of water on the motor.
 

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Thought I would give some "aero" a go.

First this thread has prompted me to replace the radiator cowl bottom BOW insert section. Has been missing for the last 12 months since the auto electrician busted it when with a breaker bar on tensioner when installing new A/C compressor. They were going to repair it but thread prompted me to chase him up and told him that I would buy a new one and he agreed to pay(y) .

So for "air dam" . Have a Billy Goat bash plate that I removed a couple of yrs back as the drag link was touching it sometimes (2" lift). Modified it today, cut off 70mm of the bottom drop section so to ensure clearance and have got hold of 12mm thick rubber laminated conveyor belt (w-nylon / fabric weave) _ slight flex(be good),

Automotive tire Motor vehicle Track Plant Bumper


Bolted up bash plate and secured a cardboard dam mockup. Will run the rubber belt thru to the radiator bottom tank and length to fill up between the chassis rails.

Tire Wheel Automotive tire Vehicle Tread


Unsupported dam rubber drop below steel bash plate of 180mm(some diff pumpkin will show - ground clearance consideration .
Consider this dam drop should adequate as the bonnet is fitted with a 600x300 mm louver vent. Run a 600x300x76mm FMIC (crd).

Vehicle Car Motor vehicle Hood Automotive design


Progress as time allows and will be looking at front of cooling stack (step by step).
 

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Discussion Starter · #99 ·
Thought id share my first lot of pressure testing numbers i did on an S4 TD42T Leafy Ute. (yes i know that doesn't sound right but it got an s4 front put on it like mine did)

It had a TJM bar exactly like mine, but the leafy ute also has TJM siderails. mines got nothing at present.....

It also has an upgrade TMIC "big o 4x4" - a thicker more solid version of the factory size, and its being fed air via a Colorado scoop. Its running a standard stack with genuine 35mm thick wide radiator and his free air section on his shroud is unmolested.

At the time of testing the young bloke had allready made him self a bit of an air dam out of checker plate 6mm ally, but it was not the best as it didn't seal to the bottom of the radiator. This car has about a 2 inch lift and is running 33 inch muds. it does have dual battery setup and a little bit but not a ridiculous amount of bay clutter. Was interesting to observe how these numbers changed between cars.

for example my own TD42ti Ute has much more pressure in the back corners of the bay, weather this can be attributed to the much larger top mount intercooler or the fact that the stack flows much more air then the leafy TD42t Ute is the interesting part.

the reason i am pointing this out is to help people understand that while we are expecting to have a high pressure in front of the stack and a lower one behind it to induce air flow (in theory), it is not necessarily a bad thing getting a higher pressure in the bay, as this could indicate the stack is actually of very little restriction to air flow. see the thicker the stack, the more pressure drop you will get across it, and this could leave you to believe that your bay pressures are sweet as, because your low side is really low, but its not the case at all.

What we are chasing is clean smooth a flow of air thru the stack and TMIC, and to get that we need mores passages to low pressure areas in/on and around the vehicle, From the engine bay area.

although these tests were only done at 3 speeds, some of these areas on the vehicle develop substantial pressure differences at as little as 20kph. substantial enough to justify looking into anyway.

done plenty more testing since, just came across this while looking for something else.

Keep in mind, we do not need a positive to negative pressure to induce a flow, only a difference in 2 pressures, anything around 50pa difference is worth having a look at IMO.






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Great thread.last year was towing light trailer east of Dalby triton started over heating couldn’t understand why.fairly likely I didn’t replace bottom plates.so I have a questio,does it make a difference if the bottom plate (or plastic/ rubber) go’es all the way to the diff/axel centre.not real practical for a patrol but anyway
 
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