I may be mistaken, but I think the 4.2L 06/07 S-type and/or the 09 XF activated a pump and a slow speed heater fan setting for a period after the engine was shut down to maintain some warmth inside the cabin in cold weather. I don't think the later model years have this feature.

 

I can easily test this!

 

It makes sense if you think about it. The intake charge air, even after the supercharger and under load, will be under 200 degrees. The engine coolant is not substantially cooler than that. To adequately cool the coolant/air, the supercharger coolant really needs its own radiator. Most intake charge cooling systems utilize their own heat exchanger for this reason. Think of the air/air intercoolers in you S4. Likewise, most liquid/air systems have their own radiator.

In contrast, the turbos in the S4 are several hundred degrees ... have you ever seen a turbo glow red under load? Its kind of crazy to imagine how much stress they are under. In this case, engine coolant has more than sufficient temperature difference to adequately cool the turbos down.

 

I think you'll find compressed air entering the intercooler is well above 200F.

In turbo supercharged systems there is a difference between the need for cooling the incoming charge and cooling the turbo itself. Turbos are cooled by engine oil. Water jacketed turbos use engine coolant to cool that oil as it passes through the turbine bearing. Mechanical Superchargers are not cooled as the are not heated by exhaust gas ( which can run up to 1000 C). Air to air intercoolers are much more common than air to liquid intercoolers in turbo installations. I suspect this is partly due to turbo flow characteristics, able to fill a large intercooler rapidly. The Lotus Esprit used an air to liquid intercooler but that's the only one I know of fitted to a turbo engine.

Engine coolant should be around 200F when the engine is fully warmed up and this is sufficient to cool the compressed air. I have not seen separate cooling systems for liquid intercoolers.

 

Um dude really tasting a dab of anti freeze isn't going to hurt you. It is poisonous but not extremely poisonous.

Toxicity occurs at 16 mL of 50% ethylene glycol for an 80 kg adult. That is more then a mouthful of antifreeze. Nothing else under the hood tastes sweet besides antifreeze so tasting it is a very quick way to determine what is leaking.

Are we not men?

 

Here is what mine looked like when the headlight washer unit failed.

 

The ring of colour remains from the dye they use to indicate the presence of methanol.

Glycol dries leaving no residue, slowly but surely.

Glycol may not be extremely toxic but ingesting any amount of poison is not too smart. Glycol has a distinctive smell (which is half of what you taste) and is easily identifiable without tasting it. The sweetish taste attracts animals, particularly dogs, who are small enough to be killed by ingesting glycol. For this reason alone one should fix glycol leaks and clean up any residue accessible to animals or children. If you don't know what glycol smells like, or feels like, just pop off the coolant tank cap and have a touch or a whiff, after all if you suspect a coolant leak this is the first place to look for evidence.

 

I come from the world of custom supercharged Audis and a few of the guys installed thermocouples in the air stream after the non-intercooled supercharger to get a better idea of what was going on. Note: I am not one of those people, I merely benefited from their data! Basically, using an Eaton blower, IAT's after the supercharger with no cooling and under steady state boost were approximately 200 degrees Fahrenheit. Normal cruising temperatures were in the 130-140 degree range. Spraying water/meth into the intake stream substantially reduced temperatures (point of the experiment, among other things). I would expect similar temperatures out of the Jaguar superchargers (assuming they use a roots type supercharger - screw type run cooler).

The turbos on your S4, assuming they are stock, are cooled by both engine coolant and oil. Many of the upgrade options are oil only. Like you said, most turbochargers use air/air to cool the intake charge. Most superchargers use water/air on their own plumbing circuit.

 

Normal cruise would be no boost. Jag uses Eaton type twin screw positive displacement supercharging. Wonder where the temperature peaks? This type of supercharger compresses air only in the inlet tract. The supercharger itself isn't a compressor, it's a positive displacement air pump.

My S4 turbos are stock, oil cooled with an oil cooler. The coolant jacket surrounds the oil jacket. The intercoolers are on each side of the radiator and are directly cooled by the slipstream. On my SAAB turbo the intercooler is integral with the radiator,oil cooler and AC condenser all sequentially cooled by the slipstream.

With due respect I think those Audi guys are not getting useful temperature measurements. Stock boost on supercharged systems are low pressure, around 7 psi max. My modified Audi and my stock SAAB are running around 15 psi, or a bit more under ideal conditions.

My point is only that the air to coolant intercoolers themselves are cooled by passing their coolant through the engine radiator. They simply move the point of heat removal from the slipstream directly to to a point closer to the throttle. The heat still has to be rejected to the slipstream somewhere.

 

Jagular everything you said is correct, dipping your finger in the pool of fluid and touching it to your tongue isn't going to do you a bit of harm. If it makes op feel better spit it out after you taste it. If its sweet its antifreeze if its not sweet its washer fluid. We have a two page thread headed all kinds of directions that could be solved in 2 seconds.

 

The part that interests me is how Jaguar rigs up its intercooler coolant system.

Jaguar, from Ford days, adopted the Eaton modified Roots type blower. Eaton rather cleverly improved the efficiency of the lobe Roots type blower by adding lobes and introducing helical screw type shapes to the lobes. The latest has 160 degree helix, which is getting pretty close to a screw type. Higher efficiency results. Also, a vacuum operated bypass valve similar in principle to the turbo hooter (bypas) valve allows the compressor to idle most of the time, drawing very little crank power. Older systems used a clutch drive on the blower pulley. With the air oressure actuated bypass systm boost pressure is available more or less instantaneously, at very low engine rpm and with excellent fuel efficiency at part throttle.

The air to coolant intercoolers drop the intake charge temperature by moving heat fom the compressed air in the intercoolers from there to the slipstream. Incidentally, direct fuel injection significantly drops intake charge temperature by cooling the compressed air charge directly inside the combustion chamber. Fuel cooling is the holy grail of gasoline and methanol or ethanol fuelled engines.

The original poster asked what fluid was used. I have always assumed the fluid was engine coolant drawn from close to the radiator outlet which would be around ambient air temperature at best and depending on radiator efficiency and as high as say 190 F if the engine were working hard at relatively slow speeds, a pretty rare event in reality.

This engine coolant would be pumped through the intercooler matrices and returned to the hot end of the radiator for heat rejection to the slipstream. Another poster says this process is assisted by an electric pump. My query is whether Jaguar also fits a separate mini radiator for the intercooler coolant?

My guess is no, that the intercoolers draw their coolant from the radiator lower hose. Why a separate pump would be remains required a mystery.

 

Ford used a separate cooling system for their roots blower on the 03-04 Cobra Mustangs. They had intercooler expansion tanks from the factory. See image below. Lower left tank is for the intercooler and the lower right is the normal overfill coolant tank. I'm not sure why.

 

Yes, just checked Wikipedia and this system was also used on the Lightning truck. Advantage would be a much cooler intercooler for more effective charge temperature reduction. Since Jaguar and Ford shared this technology maybe the XF uses it too.

Anybody seen the XF cooling system diagram, or actually checked their supercharged Jag?

And here's the answer, at least for S Types:

https://www.jaguarforums.com/forum/s...ficient-73789/

Separate radiator for intercooler coolant, located in front of the engine radiator. The coolant is the same and both circuits are connected at the expansion tank, but there's little or no flow across the connection. This may be a good reason the expansion tank is in a different location on supercharged cars.

To answer the initial post, any coolant leak would affect the level in the expansion tank. There would be no reason to suspect the intercoolers as the source of a fluid leak under the passenger side of the engine compartment.

 

My engine is encased in plastic can't see anything

 

[QUOTE=jagular;679293]The part that interests me is how Jaguar rigs up its intercooler coolant system.

Jaguar, from Ford days, adopted the Eaton modified Roots type blower. Eaton rather cleverly improved the efficiency of the lobe Roots type blower by adding lobes and introducing helical screw type shapes to the lobes. The latest has 160 degree helix, which is getting pretty close to a screw type. Higher efficiency results. Also, a vacuum operated bypass valve similar in principle to the turbo hooter (bypas) valve allows the compressor to idle most of the time, drawing very little crank power. Older systems used a clutch drive on the blower pulley. With the air oressure actuated bypass systm boost pressure is available more or less instantaneously, at very low engine rpm and with excellent fuel efficiency at part throttle.

The air to coolant intercoolers drop the intake charge temperature by moving heat fom the compressed air in the intercoolers from there to the slipstream. Incidentally, direct fuel injection significantly drops intake charge temperature by cooling the compressed air charge directly inside the combustion chamber. Fuel cooling is the holy grail of gasoline and methanol or ethanol fuelled engines.

The original poster asked what fluid was used. I have always assumed the fluid was engine coolant drawn from close to the radiator outlet which would be around ambient air temperature at best and depending on radiator efficiency and as high as say 190 F if the engine were working hard at relatively slow speeds, a pretty rare event in reality.

This engine coolant would be pumped through the intercooler matrices and returned to the hot end of the radiator for heat rejection to the slipstream. Another poster says this process is assisted by an electric pump. My query is whether Jaguar also fits a separate mini radiator for the intercooler coolant?

My guess is no, that the intercoolers draw their coolant from the radiator lower hose. Why a separate pump would be remains required a mystery.[/QUOTE]

---------------------------------------------------------------------------------------------------------------------------
Yes, I have been saying all along that there is a dedicated radiator for the supercharger intercoolers located in front of the engine radiator.

I have bolded the statements in each of my posts, please take a look.

 

I understand your frustration. I sometimes take a while to figger things out, even when explicated more or less clarifyingly. Sorry to try your patience but appreciate same nonetheless.

 

Exactly. What I was trying to explain was the rationale for this. IATs, even under sustained boost, are not that much higher than the engine coolant temperature. See, e.g.:

Tech - Supercharger Intercooling
APR B8 3.0 TFSI Supercharger Coolant Performance System

The second link is useful in that it shows the benefits of running a dedicated radiator for the coolant. Evidently, the 3.0t Audi engine runs a combined circuit stock that can be upgraded to a separated circuit with aftermarket parts. To achieve best cooling of the intake charge, there really needs to be a separate loop for the intercooler coolant.

 

No problem, I went back and reread my posts cause you had me wondering if I was being clear.

We are all here to share information with like minded individuals.

 

You were clear. I failed to correctly read what you wrote. The giveaway was your statement that you'd taken one apart!

 

on my 2011 S/C, there are 2 side coolers behind the cats eye grills below the headlights. You can also see the corresponding perforated slots in the wheel wells to let the exhaust air out.
I assume these are the heat exchangers for the SC liquid charge coolers?

Also, I'm told this configuration was change mid year , and in 2012 models, there is only one of the above side cooler, and the other cat's eye is closed-fake like on the NA models.

Am I correct, or these coolers have other functions?