making a water to air intercooler work better

[mudhunt]

I have a nissan patrol that was a 4.2 diesel non turbo but ive put a custom turbo setup on it a td05-16g turbo from an evo 6 and uinfilter, 3" exhaust and a subaru water to air intercooler. The intercooler works well but i would like to know how to makeit better. Has anyone ever used one? I only have a small radiator for it at the moment. Im thinking a larger radiator and a fan anyone know what size i should use and is the standard subaru water pump sufficient im running increased fuel and 10lb boost.

[IcedJohnno]

I have heard from an engine-tuning Guru that these intercoolers really are not big enough for a 1KZ-TE (Turbo-ed 3 litre Toyota diesel). This would make it definitely too small for a 4.2l.

The issue is not how much horsepower the Subbie will produce, nor what revs they will pull but rather the amount of air needed to flow through the intercooler. Bear in mind that the Subbie runs say 9.5 to 1 Compression ratio, and the Nissan about 22 to 1, so that means the air flow would be over twice as much at the same revs, if they were the same capacity.
(I am not sure of these motors Comp ratios however these will be in the ballpark)

Hope this helps

[mudhunt]

any ideas of a change of intercooler mate? front mount seemed like a pain, hard to get thepipes there

[DaveM]

How about a later model GU top mount with fan?

[mercutio]

any ideas of a change of intercooler mate? front mount seemed like a pain, hard to get thepipes there

they also fill up with mud when front mounted

[mudhunt]

yeah i could do that, are they a good intercooler should i consider an aftermarket core and fit that do you mount the fan on top or underneath the core there aint alot of room obviously i will have to put a scoop in aswell

[DaveM]

http://carl.outerlimits4x4.com/viewtopi ... er&start=0

Couple of pics here. There are a few threads on the top mount intercoolers on there, the GU fans are underneath, and the guys in oz seem to get them to fit on the GQ ok.
That, or Bighorn/Mu or GTi-R units, but I like the GU option since it has the fan and they are designed to fit the TD42, but you can mod the others to include a fan easily enough I guess

[Andrew1706]

You can add a tank somewhere in the system and fill that with ice and at the same time plumb a radiator with a decent fan on it.

It depends on where you put the radiator though, if you put it after the ice you'll get super cold water but you'll be returning warmer water back to the ice in the tank after its been through the cooler.

If you put it before the tank then the warmer water coming back from the cooler will be cooled by the radiator and wont melt the ice in the tank.

Read up a bit and find out what other people have done.

Personally I would prefer water-to-air over air-to-air when 4WD'ing because you're always getting constant cooling whereas the air cooler requires air movement which when you're in a bog hole is only causing harm as it starts to become a heatsoak, especially on top mount coolers on a truck.

[mudhunt]

the subaru core will be all good aye? i think just bigger radiator and a fan will help a lot

[DaveM]

Are you going to run a spereate rad/fan/pump for the intercooler?

[mudhunt]

its already in dave and yep running the subaru pump and at the moment im jst running a 15 fin oil cooler as the radiator i want to upsize the radiator and throw a fan into the mix

[DaveM]

its already in dave and yep running the subaru pump and at the moment im jst running a 15 fin oil cooler as the radiator i want to upsize the radiator and throw a fan into the mix

Getting mixed up with similar thread on another forum

I'd just do as you were saying, bigger rad, and a fan, should make all he difference I would have thought

[IcedJohnno]

its already in dave and yep running the subaru pump and at the moment im jst running a 15 fin oil cooler as the radiator i want to upsize the radiator and throw a fan into the mix

Getting mixed up with similar thread on another forum

I'd just do as you were saying, bigger rad, and a fan, should make all he difference I would have thought

Re-read my comments above. Bigger fan will not flow more air thru the intercooler itself, nor will a larger turbo. The restriction for the airflow from the turbo to the motor is the intercooler, which is too small. Find another larger water to air intercooler or add a second one. The restrictive intercooler will work OK at low to medium work but not for high output work.

My comments come from an engine guru who has studied engine airflow for the last twenty years.

[DaveM]

I must have mis-read the original post, I thought that the original setup worked well, but he was trying to improve it, and must have missed the part on trying a bigger fan, I thought he was adding a bigger radiator, AND a fan.

If the setup works well now, and there is a possible chance to improve it by adding a fan and bigger radiator, then that is surely cheaper and easier than buying another larger intercooler, or trying to plumb in a second one?

[NJV6]

Bear in mind that the Subbie runs say 9.5 to 1 Compression ratio, and the Nissan about 22 to 1, so that means the air flow would be over twice as much at the same revs, if they were the same capacity.

Please explain?

I would say the air flow at atmospheric pressure would be identical given the same capacity and same RPM.

[KiwiBacon]

The airflow through an intercooler isn't the biggest concern. The biggest concern is the boost level, which dictates the temperature of the incoming air.

The first thing you need to do is put in temp gauges. A couple of those cheap indoor/outdoor thermometers will do the job if the wires are long enough.
Fit them to the pipes in and out of the intercooler and then shift them to in/out of the radiator.

If the water coming going into the intercooler is warm, then you need a bigger radiator out front.
If the water coming out the intercooler is hot, then you probably need more water flow. Look at the lines to see if you have any restrictions.

You'll get the idea, basically using your two temp probes to check the working of each component, concentrate on fixing/improving the ones that aren't doing the job properly.
If the temp of the air leaving the intercooler is below about 50 deg C, then there's not much to fix. At 15psi boost the air entering can easily be 120 deg C.

[mudhunt]

so change core or not then?

[KiwiBacon]

so change core or not then?

Changing anything prior to testing is just dumb.
Test it, find the bottleneck and fix it. If it turns out to be the core, that's fine. But make sure first.

[Shane]

so change core or not then?

I would put a pressure gauge(boost gauge) on either side of the intercooler and see how much pressure drop there is at full boost,could use one gauge and just test each side of intercooler at a time.

If its the suby intercooler i'm thinking of more than likely would be to small(esp once the boost gets up higher,may work fine at cruise 3-4psi)

did fitting the intercooler make much differance?

Shane

[mudhunt]

ive always had it fitted we did when we turboed the saffy, dont know any different

[PigFmr]

saw this turbo setup yesterday well impressed nice tidy job,makes me want to get my arse into gear and fit a hairdryer to mine,jase you should posts some photos up,

vince

[KiwiBacon]

If its the suby intercooler i'm thinking of more than likely would be to small(esp once the boost gets up higher,may work fine at cruise 3-4psi)

The surbaru engines are half the size, but work at twice the rpm and similar boost.
So the total airflow required is similar and the inlet temps will be similar too.

[mudhunt]

yeah i should aye thats a good idea, Ill get on to it this week

[darinz]

The issue is not how much horsepower the Subbie will produce, nor what revs they will pull but rather the amount of air needed to flow through the intercooler. Bear in mind that the Subbie runs say 9.5 to 1 Compression ratio, and the Nissan about 22 to 1, so that means the air flow would be over twice as much at the same revs, if they were the same capacity.
(I am not sure of these motors Comp ratios however these will be in the ballpark)

Hope this helps

Compression ratio has absolutely nothing to do with the amount of air and engine uses. All it does is tell you the ratio between the cylinder size at bottom dead centre and top dead centre ie cylinder capacity vs combustion chamber capacity. ie how much the air is compressed once in the motor.
If the effeiciency of the motors is the same ie same head design, valves cams etc then a 4l motor at 4000rpm will flow the same amount of air per minute as a 2l motor at 8000 rpm.
A DOHC engine is far more efficient than I6 so again the Subbie IC should work OK in theory. But there is more to it than that!

Things to check are what Kiwibacon has said. Get some base line reading so you know what the problem is. It sounds like the rad is too small. I'm in the process of fitting a very large rad with twin fans on to mine as the water is getting too hot and my inlet air temps were hitting 60*c and the ecu reduces timing at that point which isn't what I want.
It is very very important that you get some pressure drop accross the IC 1/2 to 1psi is a bout the best compromise. Too little and the air doesn't cool, too much and while it is getting really cold it is also sucking power!
The other thing is water speed. The Subbie has a dual speed pump so this also needs to be taken into account. The water must be moved fast enough to keep the IC cool but not too fast or the rad won't cool the water. I have a 7l per min pump fitted but I suspect this is too small for my application, but my cooling requirement are a little different to a TD42!!

As far as the Subbie setup goes. I thought this would be ideal for a TD42 with low boost. ie They are too small for a subbie with big boost so that gives you an idea of the cfm they do. At 14.7psi the effective capacity of the motor is doubled. A TD42 at 20psi is doing some seriously big cfm so custom is the go. ie as much as a 10l motor!!! At 10psi I would think a standard Subbie IC is about good enough.
Adding water volume will make it work better but that is because it is adding a heat sink. It will mean at full noise for a short time it will cope but once the water is warm it will then take longer to cool down.

All of the above is why air to air is favoured. ie air to air is simple and easy to setup but a water to air will work better is working properly. Simple physics tells you this! ie what feels colder. water at 20*c or air at 20*c?

If the above doesn't make sense then I blame the home brew rum I'm drinking!!!!!!!!!! Sorry!

[tweake]

All of the above is why air to air is favoured. ie air to air is simple and easy to setup but a water to air will work better is working properly.

not quite.

air to air works well at speed due to huge amount of cooling air and direct cooling. only thin bit of alloy between intake air and cooling air. water to air has a longer parth, much more alloy and the water itself inbetween intake air and cooling air. so at speed water-air is not as good as air-air.
however at low speed air-air is quite poor as it dosn't have a lot of cooling air flow to work with. in that situation water-air can out perform air-air by a sizable margin.

[KiwiBacon]

At 14.7psi the effective capacity of the motor is doubled. A TD42 at 20psi is doing some seriously big cfm so custom is the go. ie as much as a 10l motor!!! At 10psi I would think a standard Subbie IC is about good enough.

[/quote]

You'd need perfect intercooling to get twice the air in at 14.7psi boost. With no intercooling 15psi boost gives you 60% more air. Pick a point in between depending on how good you think your intercooler is.

[pagar]

best inter cooler I have seen was an after market one fitted into the back of an aircon unit instead of the outlets into the vehicle, air con dam near freezes the air coming through. and more than makes up for the lose of hp from running the pump. bit of work though I recon plumbing into cab.

[KiwiBacon]

best inter cooler I have seen was an after market one fitted into the back of an aircon unit instead of the outlets into the vehicle, air con dam near freezes the air coming through. and more than makes up for the lose of hp from running the pump. bit of work though I recon plumbing into cab.

Was that on a petrol or diesel?
On a petrol the turbos don't work as often so the aircon has a chance to cool it all down between boost sessions.
But on a diesel which boosts almost all the time it'd need to be a massive aircon unit to keep up. My 3.9L diesel at 2500rpm and 15psi boost needs to shed 7.3 kilowatts of heat to get the engine intake temps down to 38 deg.

7.3kw of cooling is two decent size household heatpumps running on full cooling power.

[mudhunt]

thanks for all the info altough most of it is gibrish to me i do get the drift, I havent had a chance yet to do any tests on water temps and inlet temps . I am running a pyro but i need to test the cooler to see what i need to do