SVX Engine cooling "Again & Again"

[smc]

Originally Posted by Dessertrunner

I think the airflow through the engine bay is bad.
See results.
Tony

It is quite bad. Those vents I installed in the hood Drastically dropped under hood temps. When the fans fire up, you can see and feel a great deal of heat being pulled out of the engine bay. At speed while driving, even more so.

[Dessertrunner]

Do you have photos of the vents please?

[SVXRide]

Tony,

Check out the vid in this thread http://www.subaru-svx.net/forum/showthread.php?t=59965

Bill

[teamilluminata]

Originally Posted by SilverSpear

??? $$$ ???

$65 each. Send me your core.

[smc]

Originally Posted by Dessertrunner

Do you have photos of the vents please?

here ya go.

http://www.subaru-svx.net/forum/show...4&postcount=12

[Tireiron]

So using an upper thermostat housing like this, would there be any issues with pressure on the hose from the top pipe to the housing? I would hate to have the hose burst. Obviously I would have a small hole in the thermostat to get flow past it and allow it to heat up and function properly, any recommendations on the size of the hole? Going to be running a 170 degree standard chevy (what the housing takes) thermostat to start with.

[1986nate]

Originally Posted by Tireiron

So using an upper thermostat housing like this, would there be any issues with pressure on the hose from the top pipe to the housing? I would hate to have the hose burst. Obviously I would have a small hole in the thermostat to get flow past it and allow it to heat up and function properly, any recommendations on the size of the hole? Going to be running a 170 degree standard chevy (what the housing takes) thermostat to start with.

There are already the factory bypass pipes in effect allowing coolant to bypass the tstat and flow directly to the water pump. Same as before.

[Tireiron]

Originally Posted by 1986nate

There are already the factory bypass pipes in effect allowing coolant to bypass the tstat and flow directly to the water pump. Same as before.

Yes but if you don't have a small hole in the thermostat to allow some flow to it you run the risk of the thermostat not getting warmed up and seeing any of the hot water until it is way overheating and makes it to the thermostat. Especially if it is halfway up the upper radiator hose like that. If all the hot water is bypassing the thermostat it won't heat up properly.

[Dessertrunner]

Originally Posted by Tireiron

Yes but if you don't have a small hole in the thermostat to allow some flow to it you run the risk of the thermostat not getting warmed up and seeing any of the hot water until it is way overheating and makes it to the thermostat. Especially if it is halfway up the upper radiator hose like that. If all the hot water is bypassing the thermostat it won't heat up properly.

100 % correct any one that tells you it doesn't happen, is on drugs or from a different planet.

Some news as a result of moving the thermostate to the top of the engine and resulting in a lower engine tempreture we have a major side effect,

"we use less FUEL"

Yes, and I don't know why, when I did my car first I had a really cold thermostate 71C and I noticd that the amount of miles I was getting had greatly improved. From what I read I was concerned that the engine might be running to cold so I change to 77C and noticed a decrease in fuel comsumption to before. It was still better then the standard car.

So I figure I might be getting old and have a wild imagation. 10 days ago I installed a top mounted thermostate on my wifes car and a 77c thermostate. Never mentioned a word about the fuel saving. At the dinner table last night she said "When you fixed the cooling what did you do to the fuel consumption", in short her's is saving fuel as well.

We will play with this and see what we fined but the quick and dirty guess is between 5 to 10% less fuel on a 77c and more on a 71c. When we know the exact number on the 77c we will change her car to the 71c and get some numbers.


So guys why is this happening??????????????????????????


Tony

[SilverSpear]

Don't mind yourself with the reason, as long as the results exceed expectations

Ok Tony, what's next on the cooling menu?

[SVXRide]

Has to be the result of a more favorable thermal balance and a related improved efficiency in atomization of fuel and resultant combustion

Bill

[Dessertrunner]

You could be right Bill,
I was wondering is the O2 sensors are now more accurate for some reason.

In the background Barry & I are working out the set up for the dyno interms of monitoring gear and software to run the unit. Bazza has done some good work on O2 sensors etc.

Given that Barry had air build up in his engine during his last race day we want to find out what the fix is. Given he ran up around 6k rpm and I want to run up to 10k we need to confirn the best approach to make this issue go away. Its seems Matt had air build up as well. Pretty sure both guys had no thermostate, I know for sure tha tis the case with Bazza but don't know about Matt.
Tony

[Dessertrunner]

Here is a suggested answer from a different forum,

"Factory ECU's standard answer to anything out of the ordinary seems to be 'add more fuel'

If it was running hotter than desired before, it may well have decide to ignore the 02 sensors readings and go in to open loop mode - which generally results in a richer mixture in an attempt to keep temps under control and protect itself from detonation etc.



Now that temps are back under control it may be staying in closed loop mode more often, and running as lean as possible.

SR20's seem to do this a lot, as soon as you turn the boost up a bit the ECU freaks out and it just pumps in as much fuel as it can - mine went off the scale rich on the dyno. After a tune to fix the problem (no sensors etc replaced, simply fiddling with the factory curves) I gained over 40kW, and cut my fuel consumption drastically....


Its a little hard to believe, but my 200kW s14 with an after market ecu was still the most fuel efficient car I have ever owned - including my wife's crappy mirage (lighter and with about 1/3 the power), and her SX4 that replaced it - 15 years newer, similar weight and again about half the power. "

This one makes sense.
Tony

[Tapani]

Hi all,

I read thru the whole thread... almost 1500 posts. Extensive and impressive work you all have done.

A few questions and observations:

Does anyone know how the aircraft guys with EG33s have solved this? They must be able to run at full song for quite a bit and very reliably.

http://www.canardaviation.com/Philli...g%20System.htm

http://www.youtube.com/watch?v=1nK8bc-GUyc

This guy lives close to Houston, but I have not been able to find an e-mail address.....

Under normal commuting my EG33 runs between 1500-2500 rpm, rarely goes up to 3000. I trust a WRX or any other four cylinder runs maybe between 2000-4000 rpm - yes? The six banger will produce more heat at a given engine speed, but probably app the same under same road / driving conditions, right? So maybe the cooling flow at a given engine speed had to be designed higher to cope high ambient commuting - and also high load low rev uphills with the TCC locked in.

If the water pumps look very close and the pulley is about the same diameter has anyone measured the crank pulleys? Maybe the EG33 is bigger? Naturally the cam pulleys must be bigger too

With the thermostate in the radiator outlet (at the pump) could the engine reach local boiling (at higher vehicle speeds) because the water flow the thermostate sees is too cool and it stays almost closed? Maybe the radiator has excess capacity under these conditions? Maybe Subaru had to design both the flow and the radiator capacity "too high" to deal with typical user conditions in high ambient slow operation under very low engine speeds (heat soaked). Also the air flow thru the radiator and under hood conditions maybe very different to Imprezas, as Bazza and Boxersix have implied.

I know moving the thermostate above the engine tries to fix this, but maybe it sould be at the engine and not too far in the upper hose. Also, the increased pump inlet may shift the flow rate related issues to higher rpms.... having said that, maybe reducing the pump capacity should be tested. What do you think?

Just tossing around thoughts aloud. My car spits coolant sometimes even under spirited driving on an ice track - if I use manual second. All is well if I use manual third - this keeps the revs down, but the engine is loaded much higher under boost to get the same performance.

Tapani

[BRZCory]

aircraft guys generally only spin them up to ~3000rpm.

For reference my EG swapped impreza runs 3200rpm on the highway for hours with no problems. Stock cooling on the motor, but a griffin radiator.

Also, the aircraft guys are under less load, and they are pushing less air through the motor usually (due to altitude and whatnot). So the engines should run cooler.

Also, the crank and cam pulleys are nearly identical to the EJ equivalent.