Air to water cooler.... why don't i see a lot?

TribesMan

Active member
Joined
Jan 31, 2010
Location
Slovenia
TDI
AR JTD :)
I didnt read all thread into detail, but I have not seen anyone mention that VAG TSI engines use air/water/air intercooling...

My friend bought a nice little VW Polo 1.2 TSI (105BHP), and this car has water cooled intercooler, that is integrated into the intake manifold. Very compact package the path from the turbo to intake manifold is around 50cm... also this reduces the need to use any rubber flexible pipes that are prone to splitting from time to time. The Pipe from turbo to manifold is hard plastic, that looks more reliable to me than 2 metres of rubber piping to air intercooler and back.

And then the water is cooled down by quite big water to air radiator (around 12x60cm frontal area) mounted in front of the engine coolant radiator. Also the turbo is cooled by this water.

It looks like a very good setup to me. The only problem that I can see is the "stop and go" traffic. Where there is probably not enough airflow to keep the water temperature down, and that adds some delay in cooling because of the huge heat capacity of the water.

Here is a nice review of the system in TSIs...

http://www.rx7club.com/showthread.php?t=932402
 

D_Bat

Veteran Member
Joined
Jun 25, 2008
Location
Melbourne, Fl.
TDI
1998 Jetta TDI
I know about heatpipes, all my Thermalright heatsinks use them and have been for years. How do you expect to design this? How are you going to take the heat out of the air in the charge pipes? You'll use some sort of device that filters the air into the heatpipes..... kinda sounds like an intercooler to me. Then you've got the pipes that extend from that to your heat dissipation device which is made out of what? The only thing that is really changing in that whole equation is if an intercooler of sorts made from heatpipes would be more efficient at taking away the heat out of the charged air more efficiently than the best current a/w intercooler cores can. If they can then awesome but a/w already gets but a few degrees away from ambient. Not to mention the cost and complexity of running hard copper pipes to a free air source.
 

nicklockard

Torque Dorque
Joined
Aug 15, 2004
Location
Arizona
TDI
SOLD 2010 Touareg Tdi w/factory Tow PCKG
DBat,

Following the thread, you can see the conversation has been about the appropriateness of various layouts. A\W allows for remoteness and compact packaging, but has obvious, high-consequence failure modes.

Heat pipes give constant-temp heat rejection which makes tuning and managing airflow much easier. They also allow for remoteness and compactness. The heat transfer coefficient of them is higher than anything else. Copper isn't hard. Where do you get that? It can be bent with finger pressure. It is a very soft metal. Nothing could be easier to route and fabricate.

I think your knowledge of heat pipe technology could increase. The wiki entries are a good place to start learning.


Sent from my iPhone using Tapatalk
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
You can be among the first to try it out, Nick. :) I think you might be looking at using propane or butane as the phase change fluid, though...
 

sardo_67

Veteran Member
Joined
Feb 15, 2010
Location
CT
TDI
2015 Golf SEL 6spd
so...... back from the dead, anyone make progress on one of these?
since my car blew 4th gear up i stuck an O2M 6 speed in it last night and am now going to finish building it.
 

shakescreek

Veteran Member
Joined
Oct 14, 2005
Location
B.C. Canada
TDI
18'6" welded aluminum jetboat with pd160, gtb2056vl, and tuning by rub87, 2003 chev blazer with bhw swap, 2000 jetta alh with gtd1752 vrk, .240 injectors, 11mm pump, fmic, 6 spd manual
Awesome. I run the same style of intercooler only about twice as big on my boat, now you have me thinking of integrating it into the intake manifold like you have done.
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
You going to run that through the cooling system? If so you'll get materially more-stable intake temperatures but for many parts of the operating paradigm they will actually go up.

The stability, however, may be well worth it and allow optimization of combustion to a degree that is much better than you can achieve with a more-common air-exchange IC.

Some Detroit 2-strokes use this arrangement with what they call an "aftercooler" physically present in the airbox under the blower. It works well.
 

sardo_67

Veteran Member
Joined
Feb 15, 2010
Location
CT
TDI
2015 Golf SEL 6spd
if you have a good enough heat exchanger with the proper air flow you can keep the water temp down. this system may head soak but only when the car is sitting still, traffic possibly idling or in warmer weather. i bet this system is gonna run pretty cold come fall or winter when the temp starts dropping, although that may be too low.

my set up is going to need more monitoring and tinkering with at first but once everything is figured out i'll be set.
dieseleuxhttp://forums.tdiclub.com/member.php?u=52721 what are you running for the rest of the system?
 

dieseleux

Théoricien -TDIClub Contributor
Joined
Nov 14, 2006
Location
Pas assez loin pour vider ma tank!
TDI
Jetta TDI 02
If you see post #80, i buy a complet kit, finaly i change my concept en buy another intercooler to weld directly on intake.
For first run, i use original tdi air-air intercooler to cool water and make a water tank.
Later, i will install a big water-air radiator, i saw the project of another person that places this on driver side.
This intercooler need a modification, because i run horizontaly and two side inlet are place at center, the air trap and need to drill a hole to install small valve.



Dieseleux
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
You going to run that through the cooling system? If so you'll get materially more-stable intake temperatures but for many parts of the operating paradigm they will actually go up.

The stability, however, may be well worth it and allow optimization of combustion to a degree that is much better than you can achieve with a more-common air-exchange IC.

Some Detroit 2-strokes use this arrangement with what they call an "aftercooler" physically present in the airbox under the blower. It works well.
They get run through their own dedicated radiator and pump, so it adds a bit of weight to the car, but depending on the application it can be well worth the trouble..
 

dieseleux

Théoricien -TDIClub Contributor
Joined
Nov 14, 2006
Location
Pas assez loin pour vider ma tank!
TDI
Jetta TDI 02
For daily use weigth problem is marginal.
I select water to air because air volume reduction between turbo and intake (spool time), no big piping to bumper and bumper cut, is possible to turn off pump in winter for better mpg and for dyno and 1/4miles is a possibility to use ice!



Dieseleux
 

The Shootist

Veteran Member
Joined
Aug 21, 2006
Location
Hixson, TN
TDI
2002 New Beetle GLS TDI
No need for 4 gallons of water. Volume of IC+volume of Radiator+volume of hose=Maybe a gallon total. Pump weighs maybe 2 pounds.(cheap 12v marine pump)

I plan to mount my IC to the firewall behind the engine eliminating all the tubing that gets in the way in a Beetle engine bay.
 

sardo_67

Veteran Member
Joined
Feb 15, 2010
Location
CT
TDI
2015 Golf SEL 6spd
ok even if you add 33lb to the car, unless you are competing in 1/4 mile or some type of racing where 0.0X is the difference between 1st and 2nd it's not going to matter.

on my jetta i was looking at the same idea, bolting the A/W to the firewall behind the motor and above the turbo but i won't be able to use a large enough IC.
still not 100% sure on how i am going to run the pipes.
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
I would end up heat soaking an air/water setup.. They're great for short spurts but I tow quite a bit with my car on a regular basis.. I'd need a 3-5 gallon system capacity and a radiator half the size of the engine's radiator to keep everything cool going uphill at highway speeds with 2000lbs behind me..

There's a reason why all of the heavy duty applications use air-air..
 

ArturCosta

Veteran Member
Joined
Dec 8, 2003
Location
Portugal
TDI
Audi A4 Avant 1996 Silver
Check out how the new BMW M5 engine works... it has 4 air to water coolers working with 2 pumps ;)
 

ArturCosta

Veteran Member
Joined
Dec 8, 2003
Location
Portugal
TDI
Audi A4 Avant 1996 Silver
Yep.. Overly complicated system to accomplish a very simple task, and it's not designed for high load for an extended period of time either.. What's the tow rating for a new M5? :D
Dont know.. but have here a test of one with remap driving at WOT with 49ºC outside temp... 640hp and it is always towing 2Tones at least :D

System is really complicated but do you think it is worse in terms of intake temps then a standard air air cooler? In this case they say they make this in order not to have lag and the engine feels like a NA ;)
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
I say it again: Run the calculations as to the gains available if you have stable IATs that are right around engine coolant temp. Your first-blush is probably that this would be a big lose but that may not be true because the variation will go way down and this means you probably can run a higher boost level. Remember that you're after two things with an engine -- number of molecules of oxygen to burn the fuel and the delta between the combustion temperature and exhaust temperature.

If I get some time I'll sit down with my HP calc and some paper and see if I can quantify what you give up with this strategy. I know what you get -- a highly-stable IAT and little (if any) additional mass since you already have the cooling system. The question is the trade-off.
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
Dont know.. but have here a test of one with remap driving at WOT with 49ºC outside temp... 640hp and it is always towing 2Tones at least :D

System is really complicated but do you think it is worse in terms of intake temps then a standard air air cooler? In this case they say they make this in order not to have lag and the engine feels like a NA ;)
how long can it stay WOT? no more than 15 seconds before you let off the throttle.. Try hooking a trailer to it, put another car on that trailer, and drive down the highway at 65mph for 3 hours.. That's where an air-air system shines..

I usually see intake air temperature readings about 10-15F over ambient even with extended periods of time pulling a trailer in hot weather with the A/C on.. My ALH gets VERY smoky, unresponsive, and has a noticeable decrease in power when my intake temperature goes above about 130F... No way, no how I would want intake temperatures up at 180-200F... If the goal were fuel economy then yes hot air helps, but for power it does not..
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
My ALH gets VERY smoky, unresponsive, and has a noticeable decrease in power when my intake temperature goes above about 130F... No way, no how I would want intake temperatures up at 180-200F... If the goal were fuel economy then yes hot air helps, but for power it does not..
That's because your fuel and boost mapping is designed for lower temperatures. Remember that the power extraction from the fuel depends on (1) the number of molecules of oxygen available to burn the fuel and (2) the difference in degrees Kelvin between the combustion temperature and exhaust temperature. (The number of molecules of oxygen [density] is also ratably related to the temperature of the charge air.)
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
Who says anything about A2W IATs doing to 180-200F? :confused: They can be every bit as cool as A2A and even more so because you have fewer constraints on how big, how many and where you place the heat exchangers to the ambient air.
 

TDIJetta99

Top Post Dawg
Joined
May 17, 2005
Location
Port Jervis, New York, USA
TDI
03... Faster than yours =]
That's because your fuel and boost mapping is designed for lower temperatures. Remember that the power extraction from the fuel depends on (1) the number of molecules of oxygen available to burn the fuel and (2) the difference in degrees Kelvin between the combustion temperature and exhaust temperature. (The number of molecules of oxygen [density] is also ratably related to the temperature of the charge air.)
Yes it is mapped for cooler temperatures because it makes more power that way. Mainly because there are more oxygen molecules in cooler air for a given (edit) volume... You know how it gets mapped for higher intake temperature? You reduce fueling which reduces power... There is a finite amount of boost/airflow a turbo can move, and I'm at about the pressure limit for my current turbo at 35psi, so my options to reduce the smoke at higher intake temperatures are to fit a larger turbo or reduce fueling.. Any larger of a turbo and there won't be anything resembling throttle response OR low end torque capability which is unacceptable for the way I use my car.
 
Last edited:

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
Genesis is saying to regulate it with engine coolant...
I see. Why TH would anyone do that?! I guess most of the engineers in the world are stupid for putting intercoolers instead of interheaters. :rolleyes:
 
Last edited:
Top