Intercooler upgrade in D40

Hi all
I have been reading the thread about the intercooler upgrade started by 4.8GU but has anyone else done this upgrade?
I have emailed Lindsay from Northside 4X4 and he has answered a few of my questions for me.
Those of you that have done it, was it worth doing? Would you do it again and how?( kit form or just get parts and make it up as you go)?
From what I've read there has only been two or three guys that have done this mod.
Thanks Mal

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Yeah it is easy to think you are dealing with every d40 owner that ever lived when on a forum but in reality it is only a small percentage.

As far as intercooler kit goes... I really like mine but not for any massive power gain. ( I am yet to add any extra fuel in the form of a 'chip')
I am just comfortable knowing that no matter how hard I push the car it is still safer than a factory set up and will maintain intake temps for longer.

I see this mod as a necessary thing when someone is going to put a chip on there d40 as they run so hot from factory. Any extra cooling ability you can give it is going to help longevity of the motor.
Coupled with the hard pipe upgrade it has certainly been a good thing for me.

Brian

Northside 4x4 said:

I have sold well over 100 of these upgrades on just the early model D40's alone. I think there is more navara owners not on this forum, than there is on it.

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there's the sales pitch...how can one argue with that

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Northside 4x4 said:

but the fortunate few have a piece of mind and a longer lasting engine.

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is that a fact?

and in which way is this acheived?

Sure is a fact.

Less temp going into the engine means lower combustion temp. Less heat going into the pistons and cooling system.

Why else would everybody be so concerned about EGT if it wasnt a benefit to engine longevity?

Northside 4x4 said:

Sure is a fact.

Less temp going into the engine means lower combustion temp. Less heat going into the pistons and cooling system.

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less heat in combustion also is less power..

besides that,
you mentioned in another thread that a "refridgerated IC" would be of no benefit/ wouldnt cool the air flowing through it,
so
how will an IC that has only ambient outside air passing over it cool the intake air and even more so a front mounted IC that has a longer path/tubing to the engine and also being reheated in the engine bay due to its length.?

Krankin & Lindsay,
You both have got me thinking a bit more and now and I have a new question. I know how a diesel motor works (needs heat to combust) but isn't cooler air more dense than warm air? Isn't cooler/dense air going to cause more of an "explosion" in the cylinder? Or am I not understanding something?
Thanks
Mal

The entire reason for turbo/supercharging/nitrous is to provide more oxygen molecules for a more complete combustion. The cooler air is definitely more dense and is the exact reason for the manufacture of an intercooler (as well as the refrigeration-driven variants).

Coupling turbo/superchargers with intercoolers is just good sense. The act of compressing the air which the turbo/supercharger does causes the air to heat up - and thus there will be less air molecules per unit volume. The intercooler reverses this to a degree - the difference being dependent on the internal/external interface surface area of the intercooler and the temperature differential.

The intercooler relies on getting as much air close to the inner surface of the device as possible, so that heat energy from the air can be absorbed by the metal of the intercooler and then dispersed by the passage of cooler air over the outside. Cooling the outside creates a larger differential and thus greater cooling, so wetting the surface is quite effective (and low cost - you can do this for under $20).

This is the reason why front-mount intercoolers are in front of everything else - so that the coolest air goes where it's needed most. This does cause heat issues with everything behind it - airconditioning and radiator - but those are designed to cope. Adding a mist system will benefit both of these devices too, because they're working on the exact same principle - trying to exchange or transfer heat from the inner liquid/gas to the outside air.

This is the reason why your diesel performs so well in the rain and in the snow. When it's that bloody cold outside, the intercooler can drag the temperature of the charge air (that's the name of the compressed air between the turbo/supercharger and the intake manifold) down dramatically.

As for how it affects combustion, it does it in two ways. A certain amount of diesel is introduced to the chamber and this amount of diesel requires a certain amount of air to combust completely. If it doesn't combust completely (over-fuelling, or "rich") then your power is down (compared to what it could be) and you're blowing black smoke (diesel or petrol, actually - they both work the same in this respect). If you're getting MORE air (running "lean") the fuel will combust completely AND the remaining air is heated rapidly, causing it to expand as well. While this isn't a huge gain in power, there is SOME, plus the bonus of getting every last bit of power out of the fuel used. The drawback is heat. Providing ample air means the fuel will burn better, and hotter. If you design the system to USE that heat - like drive the turbocharger harder - and make it from materials that aren't adversely effected by that heat - then your engine is going to produce more power for its size than comparable engines.

That's probably why the Nissan 2.5L TD produces 140Kw and the new Mazda that produces 147Kw has to be a 3.0L engine - Mazda haven't produced an engine that would run as hot as our Renault-designed Nissan engines. That said, of course, you could probably raise the Mazda's output to much higher proportionally than you could the Nissan, but then what else do you expect from having more cubes!

Misting the intercooler sounds like a good idea although you wouldn't want to do it on a dusty road. Yuk

Well said Tony, Thanks. But if I now go and put on a larger cooler what will then happen to the radiator heat? Obviously the motor will run hotter as there is more heat and slightly less flow in front of it, so saying that will the EGT's still come down or would they stay around the same? What if I added a bigger radiator to compensate?

Don't worry about the radiator. There's so much air flowing over the outside that the ambient temperature rise won't be significant enough to worry it. As long as the air passing over the radiator is under 90C it will cool the radiator (not as well as it could, but it will still do it).

EGTs are largely governed by the combustion process itself. There's only a small variation by the temperature of the charge air and a smaller variation due to the water temperature. The water temp is so insignificant that you can discard it (although in an engineering equation you'd have to account for the coolant at a higher temperature not evacuating the combustion heat as effectively - but for our purposes, this aspect would be safe to ignore.

A cooler charge air temperature would lower EGTs if there were an abundance of this air. Remember that once the fuel is fully combusted, the remaining air is heated up - but it only has a limited amount of time for this to happen, so the temperature rise of the excess air is finite. If you introduce air at 80C (poorly intercooled) it will reach combustion temps faster than air at 50C (nicely intercooled - assume a typical Aussie summer day). Because of the limited time involved, the cooler air won't reach the same temps and thus goes out the exhaust - affecting the EGT - at a lower temperature.

I should add something important about intercooler cooling (and the same is true of any heat exchanger like your radiator).

The intercooler only transfers a small amount of heat per unit distance across the device. At the start, your charge air temp might be (say) 120C. After the first centimetre, it may have only lost 2C - so the ambient temperature rise OUTSIDE the intercooler will be similarly small over that area of the intercooler.

The air passes across the next centimetre and loses a little more heat, transferring it to the outside. This continues across the entire intercooler.

What this means is that the actual temperature rise behind the intercooler is marginal at best - and certainly not worth worrying about.

Hi Domainmal, a couple of things that I have learnt over the years:
1. For every degree you cool the intake charge air, you get a corresponding amount of cooling in the exhaust air. That is one of the reasons why when you 'add' an intercooler to a forced air inducted internal combustion engine, you can get more power out of it. As the exhaust is cooler you can add more fuel to take the exhaust gasses back up to the 'safe limit' temperature.
2. As a rule of thumb, I use a formula that for every 10 deg F you cool the intake charge, you can get 1% more power out of the engine.

I used to have a 2.5 Litre TDI engine (in another brand 4wd) that was double intercooled. The original air to air i/c was followed by a water to air intercooler. I used to monitor the input and output air temps of both. (god I must have been bored back then). In addition I tweaked the injector pump and added LPG. The LPG conveter cooling water was the same circuit as the water to air i/c thus providing cooler than ambient air water to the i/c. (So the theory goes). The result was 3 burnt out auto transmissions in a year while towing a caravan. (Obviously the old Land Crab brand had crappy transmissions and that's why they were gutless to start with).
My point in all this is a good intercooler is a great addition and 'performance' comes at a price, but do it right the first time. A larger i/c will have a longer turbo lag (for want of a better term) and thats ok if you dont want racing car but there is a point where you can go too big (ask my wife) or too costly to achieve what you want. Proper intercooling is a specialty field and my advice is to ask the experts.
Another form of cooling is known as 'chemical' intercooling or also known as water injection. Good performance increase for the price especially if you add a bit of alchohol in to the mix. but don't go above 50% - it then becomes a flammable mixture.
Good luck with your endeavors. I will be following this thread.
Foxy

Maybe I should of said why I want to drop the EGT's? I have a Chip-it chip and they cut out ( go into safe mode) at around 700deg. By cutting out I essentially lose power (goes back to stock). I want to keep the power there as long as possible there by introducing the upgraded intercooler.

Foxbat, Your right as in cooler air in cooler air out and it's a D40 not a race car.
I don't think it's worth going down the road of chemical cooling or anything like that.
I have learnt that bigger is not always better and more is not always more.

Tony, Maybe I was over thinking the radiator heat. The only place I could see the heat rising too much would be pulling a boat over the beach through the boggy sand. Low speed hi revs... Around town or open road the radiator should be able to handle it. Right?

I just wanted to add that extra lag because of a larger intercooler is neglible on a diesel in general and on a D40 in particular. You are pretty much boosting all the time, and there's no boost purge and repressurization after throttle closure on up shifts etc.

Without doubt.

Even on sand, the car will turn off your aircon before it gets too dangerous, but your fan will be running flat out by then (it comes on full song at coolant=105C).

I would imagine that extended soft sand driving could actually become a problem though. Fraser Island on New Years Day with a boat in tow would be somewhat of a challenge for the cooling system. I'd be inclined to do that in spurts, and not run the air con at all to reduce heat production. I'd also make sure my tyres - and the trailer's - were at 18psi.

Sorry,Bluenavara you are right, the small diesels are on boost pretty much all the time and the lag I spoke of doesn't come into it.
Domainmal, if you tow on the beach a lot, a water to air i/c has a great advantage in that the i/c water supply is cooled by a separate electric fan which runs all the time. This keeps the i/c working even at low revs like on a sandy beach when the vehicle speed is too low for effective air to air i/cooilng. Just my thoughts.

Foxbat said:

Sorry,Bluenavara you are right, the small diesels are on boost pretty much all the time and the lag I spoke of doesn't come into it.
Domainmal, if you tow on the beach a lot, a water to air i/c has a great advantage in that the i/c water supply is cooled by a separate electric fan which runs all the time. This keeps the i/c working even at low revs like on a sandy beach when the vehicle speed is too low for effective air to air i/cooilng. Just my thoughts.

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Well if thats the case, Why can't I just add a small thermo fan to the front of the Air-Air cooler to help? I know the liquid-air will probably be more efficient but also more cost and alot to change over.