Temperature management

[#84]

The subject has been disussed in some threads recently, so: Since the temperature managment is so poor in the Q4 and the temperature often goes too high maybe this could be a solution:

http://www.daviescraig.com.au/Electric_Water_Pumps-content.aspx
http://www.daviescraig.com.au/Controller_and_Switches-content.aspx

A digital controller with an electric pump which reduces required power in most cases, do the pump work more efficiently and has the ability to increase flow if needed. If that doesn't help maybe a fan with higher capacity might help. I discuseesd the subject with an alfisti who has worked as an Audi mechanic for many years and he said that the radiators available today are far more efficient than the radiators available 15 years ago. I don't know. Maybe a new radiator from a car with the same power rating could do miracles?

[AlfaJack]

That website has some lovely products on it. I have thought about an electric water pump for the Q4, mainly because the Q4 one might be in short supply and a bugger to change.

Does anyone know about their reliability?

[#84]

I will ask more about them. I found the products on the website from a local tuning company where I am about to some dyno tests on two other cars. So hopefully, in two weeks, I can tell more about the fan and water pump.

I use the fan from an Opel/Vauxal Vectra -96 to have room for the turbo, but the fan itself has wings desgind for less flow, so I should try AGAIN to get the Q4 fan on the Vectra fan motor. Maybe I end up destroying the fan motor .... So, then I need to look for something else.

[arjunior45]

The subject has been disussed in some threads recently, so: Since the temperature managment is so poor in the Q4 and the temperature often goes too high maybe this could be a solution:

http://www.daviescraig.com.au/Electric_Water_Pumps-content.aspx
http://www.daviescraig.com.au/Controller_and_Switches-content.aspx

A digital controller with an electric pump which reduces required power in most cases, do the pump work more efficiently and has the ability to increase flow if needed. If that doesn't help maybe a fan with higher capacity might help. I discuseesd the subject with an alfisti who has worked as an Audi mechanic for many years and he said that the radiators available today are far more efficient than the radiators available 15 years ago. I don't know. Maybe a new radiator from a car with the same power rating could do miracles?



well, thanks for the links #84.

I think it is not a 'plug and play' mod and need some serious job / mods to be done.

With an electric pump like that you can have some 3-4 extra bhp {more power} but you must also consider the ability of the oem radiator to tolerate the increased pressure due to the increased flow. The valeo radiator available today, for the Q4s, is made of copper/plastic and I do not think it can tolerate too much pressure. That's the reason for having the expansion box with a plug that opens at 1,1 bar {I believe}.
I do not know how much more pressure can tolerate the engine?s core plugs too.


Dealing with temperature management in a Q4 is not an ?easy job?, as far as I can say, mostly in countries with hot climate. You see the ?free? space is very limited and the turbine is too close to the engine from one part and the water radiator from the other. Unless you are willing to renounce the air conditioning facility!

From my experience all that can be done is:

1} a front bonnet ?hole? ? not that efficient in city traffic.
This morning I removed the alu inner part too { http://forum.berlinasportivo.org/attachment.php?attachmentid=821&d=1238852456 } without any serious effect, at least so far. Need to test it again in city traffic!

2} a lower radiator?s fan switch.
I?m going to mount the one from FIAT Duna Diesel late this afternoon and I?ll report my results later.

3} move the rad fan switch position to the ?inlet? part of the radiator?s hoses.
This will make the rad fan to start earlier ? as the water temp at the ?inlet? hose is higher than the ?output? hose one. It?s a nice though, but I do not know how lower will be the water temp at the ?outlet? hose.

4} move forward the water radiator for a max of 2-3 cm. More than that it is not possible keeping the air-con rad.
I do not believe this by itself can make any difference.

5} use a wider radiator, taking advance of the radiator?s 2-3 cm forward move.
That might be useful, but do not know if it will be sufficient.

6} use a fan with higher 'capacity'.
I believe there is not any one better than the oem 7 blade one.
I use the V6 rad fan and definitively can not do the proper 'job'. I?d like to test a fan motor with higher speed {in 1st and 2nd speed as well} and that will be my next move. Something like your next move maybe?

7} wrap around the coolant hose that goes from the radiator to the thermostat with a {asbestos} heat-sealing tape.
Another guy here in Greece did that, as this hose passes too close to the turbine.
I believe it?s a clever thought and I?m going to test this one too!

8} use a thermostat with lower ?opening? temp.
The oem one start to open at 87 degrees C and it is completely open at 92 degrees.
I do not know if a lower than 87 degrees temperature can have a ?negative? impact to the engine! In any case, I believe it will be wiser to keep engine?s running temperatures close to these 87 ? 92 degrees, don?t you agree?

and

9} remove the oil thermostat and make that oil goes always {regardless its temperature} to the oil cooler.
Someone did it and has oil temps at max 87 degrees at city traffic and 60 degrees at highway. But what will happen during winter time ? low temperatures?



If you remove the air condition there is much more space to take advance off and, I believe, a wider water radiator, with 30% more capacity, will be enough!!!

[#84]

By keeping the temperature lower the engine will not work at optimum and the cooling capacity will decrease. Cooling capacity is proportional to temperature difference between incoming air and radiator - don't forget that. The bonnet hole is mayge one of the best modifications, but it is difficult to do it elegantly. The lower side of the bumber slopes downward and you could easily alter the shape upwards and gain minimum 3 cm x radiator with, which is 5-10 % of the radiator area.

I use a turbo with no water cooling, that does also help the radiator since it doesn't have to take som aditional heat.

All new radiators have plastic sides and the cope with higher flow and temperatures, so I doubt that would be a problem. ABout the plugs, I don't know.

As I see it. To increase cooling capacity:
* More air flow
* More water flow
* Higher engine temperature
* Better heat transfer (Water wetter?)

[arjunior45]

4 degrees lower 'working' temperature {that's the difference between 92 and 88 degrees} does not effect the engine efficiency at all, in my opinion.
What is important is to keep this 'working' temperature close to the 'optimum' range. That's why there are the thermostats for {water and oil thermostat}.
Increasing cooling capacity makes easier to maintain this 'optimum' temperature - if you do NOT remove those thermostats of coarse.
So, increase air flow is ok with me. As long as this air quantity does not remain in the engine compartment resulting a higher temperature in the end.
Increased water flow is ok with me too. But even the new water radiators {like the one I mention earlier} can NOT tolerate too much pressure. If you go for a custom all alu one is a different story.

I can not understand how a 'higher engine temperature' can increase the cooling temperature. Maybe I missed something.
Increasing engine temperature you just loose power, as far as I recall from the physics at school.

Better heat transfer? You do not mean the intercooler, do you?

[#84]

Q = Heat transfer [Joule]
k = Heat conductivity [W/m/K]
A = surface area [m2]
DeltaT = Temperature difference between cooling liquid and air stream [K or C]
t = Time [s]

P = Cooling power / Heat dissipation / etc. [Watt = J/s]

P = Q/t = k * A * DeltaT

k: Cooling liquid, Air humidity, Air pressure
A: Radiator size, Radiator design (fins)
Delta T: Ambient temperature, Coolant (Engine) temperature, Air flow (Average temperature through radiator gets higher with lower flow)

So, by increaseing the operating temperature of the engine with 10 % you get the same result as if you increase the radiator size with 10 %.

Another thing to do is to insulate the exhaust manifold; more energy to the turbine, far less heat to the engine compartment. I have been working with marine and industrial engine development and it is very obvious in the engine laboratory that you loose power when you have to use the water cooled turbines that are an absloute customer request for pleasure crafts (plastic boats - you want a cold engine room ...). The difference with insulated/ not insulated is not that big - but remember it also affects the heating of the inlet air in a positive direction.

[#84]

Nick, could you post a picture showing tha hole in the bonnet from above? It is interesting to hear what you say about it. I would expect it to do some real difference.

[arjunior45]

I'll post it the day after tomorrow - do not have any right now and tomorrow is a very 'strange' day.
With the fan running and the car stopped, you feel the 'forced' air coming out from this hole.

[jimnielsen]

I have used the craigdavis EWP water pumps (in racecars) for years without problems. I am going to use one in the Q4 when I put it back together. I can get them here for approx $180. AUD.

jim~




That website has some lovely products on it. I have thought about an electric water pump for the Q4, mainly because the Q4 one might be in short supply and a bugger to change.

Does anyone know about their reliability?

[arjunior45]

Nick, could you post a picture showing tha hole in the bonnet from above? It is interesting to hear what you say about it. I would expect it to do some real difference.

All I can say about this hole is that you can see {literally} the hot air coming out from this hole and with radiator's fan working you can also feel the hot air at least from a distance of 25 - 30 cm.
Can not say if there is any real difference, as I had replaced the thermo-switch at the same time.
With 37 degrees C, in the Athens's traffic and with both of them {switch and hole open} engine temperature never went over 92-94 degrees - at least so far.

[#84]

Ok. quite good solution. And it is clever to use the Fiat Coupe gasket with the heat shield. I do not understand why it hasn't replaced the old one in the part catalogue for the Q4. Most people don't know about it.

I consider to a similar hole in the bonnet, but only if I can cast it into a carbon fibre bonnet. The problem is I always consider it to be too expensive so it never happens ...

[arjunior45]

does anyone ever tried to mount the double rad fans from the FIAT Coupe 16VT?
Can be done?

[AJ]

does anyone ever tried to mount the double rad fans from the FIAT Coupe 16VT?
Can be done?

This is what I have in the 145, although I took the engine from a Coupe 16vt. I also wired them into the lowest speed switch (there are 2 speeds, at a lower temperature it spins at a lower speed, then when it reaches slightly higher it spins at the higher speed).

So I wired the high speed into the lowest threshold (I forget the values for what temperature it comes in at), and I have no AC. It keeps the temperature very controlled, it will not creep above ~95C on the gauge when stationary in the middle of the summer.

Sometimes the fans do come off/on a few times if the water temperature is around the lower value, so I might add a small timer delay to stop it from going mad sometimes.

[na15575]

if the engine runs at 100 celsius when is stationary
is it a problem?
why the oem works so hi if there is a problem in that temp?

why im ask?
with some mods i try to drop the engine temp when stationary and very hot amb 40+
to 90 celsius
the mods is ,lower switch and i start the hi-speed of the fan 10sec after the low speed is on
but now i change the coolant and i use the evans racing

http://www.evanscooling.com/main25.htm

those never boiling in the engine etc
when i put them the engine temp when stationary went to 100 from 90
is this a problem?

[arjunior45]

I do not like high temperatures at all and 100 C are too high for me. Do not know if there is a problem in short terms but if you had 90 degrees before {with normal antifreeze liquid} why do you want to keep this 'evanscooling' stuff?
Oil temperature will go higher than 100 C soon if you keep that and oil pressure will be lower too!

[na15575]

the big advance with evans is that the cooling system dont have pressure any more
i open the expansions tank tap and i dont hear the ffssssstt from the vapor-air going out
espasilly after hard drive of the car

when the car is on road the temp is 85 cel
100 is only in the traffic
evans recoment to have a bigger pump pulley to have more rpm to the pump and more
circulation becauce the evans coolant have bigger viscosity than water
i must increase 25-50% in pump speed, providing improved cooling at low rpm

[mindus]

when the car is on road the temp is 85 cel
100 is only in the traffic


I would check thermostat unit or replace it... sounds like it's partly open all the time and stuck in that position...
The replacement of cooling liquid and increase of temp. could be a coincidence...

M