Outer Limits 4x4 Board

fluid to air cooler or air to air?

I would think fluid to air, due to low air flow in low range and higher engine/engine bay temps but then why do the comp boys not use them or the ones that did have, have now removed them?

not really answering your question but most of the time that you're in low range - and moving slowly 1st or 2nd would you be using all the engines power? maybe in sand???
Ive got a feeling that the air - air intercooler is more efficient, or can potentially be and there wouldn't be as many plumbing issuses as most comp cars don't run air con and would have most unnecessary items removed.

i wonder if they don't use them due to damage from roll overs, the increase in weight and that they usually don't run the motor for very long (depending on type of comp etc)

Do you ever really see the comp boys going slow? they would get plent of air flow...

we have water to air on comp car

air to water typically is more efficient as water will pull heat out of air better than air, but they both have advantages and disadvantages most of which are covered on this site and many places on the net.

Couple of basics.....

Water to air more complexed, air to air less complexed

Water based cooler can end up getting warm if car runs on boost for extended periods and the exchanger cant cool the water quickly enough (too small) air to air will run on boost for hours with no change.

And of course the one that most people look at.....air to air CHHEAPPPPP



Read this its good info

http://www.autospeed.com/A_107760/cms/article.html

NutterGQ wrote:air to water typically is more efficient as water will pull heat out of air better than air, but they both have advantages and disadvantages most of which are covered on this site and many places on the net.

Couple of basics.....

Water to air more complexed, air to air less complexed

Water based cooler can end up getting warm if car runs on boost for extended periods and the exchanger cant cool the water quickly enough (too small) air to air will run on boost for hours with no change.

And of course the one that most people look at.....air to air CHHEAPPPPP




Read this its good info

http://www.autospeed.com/A_107760/cms/article.html

And to present the other side of the argument. Water to air can be done cheep as well, eg suby intercooler. Water to air has a lot less lag than an air to air. A lot less plumbing so less distance to travel from turbo to inlet.

Although heat transfere water to air is betted many of the water to air systems available are rediculously lacking in surface area, the small PWR barrel is not good, we were seeing 120 degrees in the inlet manifold on a large PWR barrel and the water temp out of the cooler was nothing like that(insufficient surface area for heat transfere), we made a much larger heat exchanger and use a VN V6 radiator (rear mounted) at the other end, the hottest I've seen since (in the inlet manifold from the same sensor) is about 75 degrees.
A large water capacity will give cooling for a longer period when air speed is low compared to an air to air, however the air to air has a faster recovery time, I always use a cheap bosch blow off valve after the cooler as this allows cool air to flow from the intake through the cooler reducing heat soak, this must be vented to atmosphere to be of maximum benefit or the heat just recycles(for anyone that has datalogged ab XR6 turbo sitting idling)

Joel

PGS 4WD wrote:... however the air to air has a faster recovery time, I always use a cheap bosch blow off valve after the cooler as this allows cool air to flow from the intake through the cooler reducing heat soak, this must be vented to atmosphere to be of maximum benefit or the heat just recycles(for anyone that has datalogged ab XR6 turbo sitting idling)
Joel

Can you explain this for a knob who has no idea about intercoolers ?

The intercooler is after the turbo to cool air once its been heated by the turbo etc ?

My take on what you have said is that you use a blow off valve AFTER the intercooler to vent excess pressure of the air because of cooling ?

Is this correct or should I head but the keyboard ?

Thanks Nick

http://www.bellintercoolers.com/pages/t ... html#FAQ_5

Heres some more i/c FAQs

Thanks heaps guys this is all a big help

www.are.com.au as well

ARE has heaps of good information.

The thing everyone forgets with water to aire (and ARE covers) is they are actually a

(Air - alloy - water - alloy - air) heat transfer device.
compared to a
(Air - alloy - air)

Now water has much much greater thermal capacity than air, so 1L of water can take a the heat out of several hundred litres of air, BUT, this does not imply efficiency or effectiveness. It does imply a big (huge) heatsink, which for cars only on boost for short periods is very significant.
BUT all those transfers mean REDUCED efficiency, and, as PGS stated, if each interface isn't doing it's job, then it slows the heat transfer. If you are on boost much of the time (many TD engines) then the water heatsink effect is irrelevent, and possibly a detriment.

SO
Water to air has greater thermal mass, but inherently is less efficient, as there are more thermal transfers involved. This can be overcome with careful design. ie. Good W/A beats cheap A/A.

Water to air has 2 major benefits
a) Plumbing - it's can be more flexible and suitable as the pipes are smaller.
b) huge thermal mass, so for traffic light drags, can work really well, as you are only relying on dumping into the water, getting the water cooled happens after you are slowing again.

If those 2 things arent' your primary driver, then it's more complex.

At the end of the day the cooling is done by the thing that dumps heat to the passing air. It's the size of that that counts in a steady state situation. Anything in between is just slowig that transfer down.

Personally I'm putting in a cheap A/A that is way oversized. I'll wear the flow restriction by moving the wastegate sensor to after the intercooler, turbo will compensate. Efficiency doesn't matter so much, as it's big enough.

Paul

PGS 4WD wrote:Although heat transfere water to air is betted many of the water to air systems available are rediculously lacking in surface area, the small PWR barrel is not good, we were seeing 120 degrees in the inlet manifold on a large PWR barrel and the water temp out of the cooler was nothing like that(insufficient surface area for heat transfere), we made a much larger heat exchanger and use a VN V6 radiator (rear mounted) at the other end, the hottest I've seen since (in the inlet manifold from the same sensor) is about 75 degrees.
A large water capacity will give cooling for a longer period when air speed is low compared to an air to air, however the air to air has a faster recovery time, I always use a cheap bosch blow off valve after the cooler as this allows cool air to flow from the intake through the cooler reducing heat soak, this must be vented to atmosphere to be of maximum benefit or the heat just recycles(for anyone that has datalogged ab XR6 turbo sitting idling)

Joel

How big a barrel was this Joel?? I'm running a 600hp unit and looking into upsizing the inlet and outlet water hoses. The water coming out of mine gets "HOT".

mud80 wrote:fluid to air cooler or air to air?

I would think fluid to air, due to low air flow in low range and higher engine/engine bay temps but then why do the comp boys not use them or the ones that did have, have now removed them?

Water to air is always good for crawling applications... or a front mount with a thermo fan attached to it .
Main consideration would be the room you have to work with.

And on a side note, Air IS a fluid, so too Water... just to clarify that.

PGS 4WD wrote:Although heat transfere water to air is betted many of the water to air systems available are rediculously lacking in surface area, the small PWR barrel is not good, we were seeing 120 degrees in the inlet manifold on a large PWR barrel

What sort of boost/temp did you have going into the barrel?

I've had almost 150 deg C at 15psi, but that was with a turbo with a rough compressor wheel (dust erosion). I got 120 deg C with 15psi from a good turbo.

HotFourOk wrote:

mud80 wrote:fluid to air cooler or air to air?

I would think fluid to air, due to low air flow in low range and higher engine/engine bay temps but then why do the comp boys not use them or the ones that did have, have now removed them?

Water to air is always good for crawling applications... or a front mount with a thermo fan attached to it .
Main consideration would be the room you have to work with.

And on a side note, Air IS a fluid, so too Water... just to clarify that.

I thought it was gas

It is but in flow design it can be called a fluid. But in this topic calling air a fluid is just someone big noteing themselves on a trivial matter.

What other Water air coolers are there. As I have been thinking of using a Garret core for mine. Others I know of are ARE and PWR.
In my case it will be a GQ TD42 with a 50mm BL for abit more room under the hood.
As i was going to go a big front mount. but I want aircon and to keep the grill sorta looking like a grill.

I understand one may be more efficient than the other, but in a mild performance situation (say your average DD turbo diesel), will one be far ahead of the other?

I'm considering using a smaller PWR water cooler on my 4L diesel, running no more than 13psi.

for the record air can be referred to as a fluid

frp88 wrote: I thought it was gas

Yes, but is also referred to as a fluid.

turps wrote:It is but in flow design it can be called a fluid. But in this topic calling air a fluid is just someone big noteing themselves on a trivial matter.

No it isn't, a number of people would generally be mislead by the terminology. There's no need to be a knob about it.

Sorry I brought it up. It was only for future reference if he asks any 'professionals' about it.

turps wrote:It is but in flow design it can be called a fluid. But in this topic calling air a fluid is just someone big noteing themselves on a trivial matter.

What other Water air coolers are there. As I have been thinking of using a Garret core for mine. Others I know of are ARE and PWR.
In my case it will be a GQ TD42 with a 50mm BL for abit more room under the hood.
As i was going to go a big front mount. but I want aircon and to keep the grill sorta looking like a grill.

mines a 600X300X75 with air still working and stock grill

DanielS wrote:

PGS 4WD wrote:Although heat transfere water to air is betted many of the water to air systems available are rediculously lacking in surface area, the small PWR barrel is not good, we were seeing 120 degrees in the inlet manifold on a large PWR barrel and the water temp out of the cooler was nothing like that(insufficient surface area for heat transfere), we made a much larger heat exchanger and use a VN V6 radiator (rear mounted) at the other end, the hottest I've seen since (in the inlet manifold from the same sensor) is about 75 degrees.
A large water capacity will give cooling for a longer period when air speed is low compared to an air to air, however the air to air has a faster recovery time, I always use a cheap bosch blow off valve after the cooler as this allows cool air to flow from the intake through the cooler reducing heat soak, this must be vented to atmosphere to be of maximum benefit or the heat just recycles(for anyone that has datalogged ab XR6 turbo sitting idling)

Joel

How big a barrel was this Joel?? I'm running a 600hp unit and looking into upsizing the inlet and outlet water hoses. The water coming out of mine gets "HOT".

It was the biggest of the shelf from PWR. Our Zook makes 280 rwKw on 37 inch tyres through an auto and 2 transfere cases, we have 660 cc injectors at 90 percent duty running 65 psi fuel pressure which equates to about 600 HP assuming .65 brake specific fuel consumption (turbo).
The current cooler was made by Race Radiators and is about the size of 3 shoe boxes laid back to lid.

Joel

Talking about air to air coolers, the diference can be in the type of mounting and requirements ..

You can fit a front mounted cooler with reasonable plumbing that with you turbo setup make rasonable small lag .. or bad turbo selection and the same front mounted cooler with lot's of lag ..

It also depends your front space and important your enviroment conditions ..

If you are in hot climate could be a issue with your cooling system ( for the engine ) and top mounted cooler gonna be your option ..

In a top mouted cooler a nice idea for low speed off road, could be a electric fan under the cooler ( top mounted ) and water mist over the cooler ..

You caan also have n a more complex setup a propane injection on your throtle body to help or replace your intercooler ..