air to liquid intercooling
Turbo Mini Forums

Just out of interest, does anyone use air to liquid (to air) intercooling? Oh yeah anyone turboed a 16-valve head from KAD? Bet that'd be bloody quick!

Its often called a charge cooler... you have two rads..

the air goes through one that is immersed in water, water being 3 times more heat conductive than air. The water is circulated to a small rad at the front of the car, so that the water can cool.

They work well but do suffer from heat soak, so good for 1/4 miles but not so great for trackdays!

As for the KAD head... WHY?! Is 200+ bhp and lots of broken gears not enough?!?!?!

Alex

AlexF

My Subaru uses a charge cooler. And that's got 200bhp and dosen't break gears.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

ok , keeping this mini turbo only...
has any one actually used a charge cooler , home made or bought , and if so did it suffer from heat soak and is great on the 1/4 mile and crap on the track.

Everyone knows that instructions only have to be read if the thing doesn't work....

My subaru's dont

9 valves, 4 wheel drive, 3 cylinders, 1 turbo, which got nicked

Your Subaru also doesn't have a KAD head does it Wil

I am basing my opions on tests conducted on an RST at Bedford Autodrome So non-mini but the theory should be exactly the same.

alex

AlexF

You still rely on exactly the same cooling medium;
The ambient air.

And are still trying to cool the same thing;
The charge air.

Putting water in the equation makes little difference, compared to the poor heat co-efficient that the air has. (Air being the important factor here - we are trying to cool AIR with a different sample of AIR).

Direct comparisons are only valid if exactly the same ambient air surface is available for cooling, the charge air area on the inside of the intercooler and the overall surface area (from the turbulators) that actually cool the air are also identical.

Brilliant results could be achieved with a charge cooler on a RR compared to an intercooler... By the same analogy, a 'foot to the board' sprint round the 'ring COULD show an intercooler to be superior...

This will go on and on and on I suspect!

The end of the day, both work, but in different ways, and better / worse in different applications / circumstances...

ok , thought that 1/4 would suffer as the water would be heating up as you sit waiting to go and would rise above air temp and it would take a while to cool the charge..

Everyone knows that instructions only have to be read if the thing doesn't work....

Totally agree Dave... I'm talking about applications and circumstances really. The main difference is the time factor, drag racing last very little time, in fact you could say the less the better!!!! On track thou you dont want to have to pull off after 3 laps because your acts are sky high.

The simple idea is that balsting round and round a track heats up the charger cooler to the point were it cant keep up with heat transfer.

1/4 miling is normally better as you have a nice cool supply of water before you set off and you only want one power run.

Alex

AlexF

ok , so its not worth no to the hassle of fitting one then??

Everyone knows that instructions only have to be read if the thing doesn't work....

I've read about charge coolers in the book by Corky Bell called "Maximum Boost" and he says that with charge coolers you can use more boost because the density is increased and so some pressure is lost. On a further note, I would have thought that charge coolers would still would better on track racing (even though the water heats up quickly as a result of could heat conductivity) because you can install a radiator at the front that gets rid of most of the heat before passing back through the core of the charge cooler, and therefore the water would still be below ambient air temperature (allowing further cooling). Anyway I don't really know, any experts on the subject?

why not install both, charnge and intercoolers?? or is that a silly question?

like where

Everyone knows that instructions only have to be read if the thing doesn't work....

I'm sure with some creative pipe work it can be done!

it's possible

My subaru has two 8-vale heads but I don't think KAD made them.

I thought one of the main advantages of charge coolers was space. i.e the charge cooler would be nuch smaller than an air/air cooler. I think a charge cooler would be heavier too.

My mate is thinking of turboing his Imp (he's struggling to keep up with me) and he's planning on running a charge cooler mainly because it's so hard to fit an air/air cooler at the rear. He's also considering just using a header tank with no actual way of cooling the coolant because we mainly run for a very short time. Not so sure about this theory though.

wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

it's a very interesting machine. And for a normally aspirated 998 it's bloody fast (faster than any NA 998 mini). And its grip is immense. see below

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

Now That's a quality car, and a great action snap!

LOVE the imp!


Corky Bell's book is old, out of date and just plain wrong in places!!

Get a copy of A. Graham Bell's Forced Induction, much better, more modern and more importantly correct!


Alex

AlexF

a friend of mine uses a charge cooler BUT only for quarter mile runs.

the water is pumped straight from an igloo in the car that is filled with ice and water

even after three consecutive runs the charge cooler is still so cold air condenses on it

'I swear to use the Boost, The whole Boost'
'And nothing but the Boost..... So help me God'

That's an what's called an ice-chest and is a one-shot charge cooler, and maybe the most effective in terms of heat transfer. However, some dragsters have liquid nitrogen sprayed on pipes to cool it.
As far as charge coolers go, they can have a more direct route to the plenum as they don't need to be exposed to ambient air at the front of the engine bay so probably less boost as a result of friction (even though boost is lost from increased density, the density rise increases power so the effect of boost lost is cancelled out). Thanks for the recomendation on the book! I may buy it.
I think we can all conclude that intercoolers are ace.
P.S. that mini's a beast!

You still want a cold air feed... don't make any cooling system work harder than it needs to!

alex

AlexF

Yes, of course

but on a light car like the mini, would the weight mpenalty of al this gubbins not out-weigh any advantage...

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.