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 Joel
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| posted on December 9th, 2009 at 07:16 PM |
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I'm not gonna profess to being a guru on these engines given the short amount of time ive been playing with them but setting up my cooling system has
given me a fair idea of how they work
basically if the cooling system is setup as per the good DR subaru's original design they wont overcool
with the 'stat being on the inlet side of the engine theres no such thing as an oversized radiator.
you could have a bloody big detroit diesel raditator with a cessna prop blowing through it and it still wouldnt over cool
the engine just keeps circulating the water around itself internally via the heater loop totally bypassing the radiator and will do that untill such
times as the it gets hot enough to open the 'stat.
All that happens then is the waterpump "sips" cooler water from the radiator supply
the bigger that rad the more reserve there is for it
this is all dependant ofcoarse on the original heaterloop working right and the stat not having holes bleeding cooler water passed it
but as Ian says they dont need a big radiator anyway
mines been running all over town this arvo with the temp being 39.8c and even in stop go traffic it sat around 85-90 mark and the fan didnt come on
once and its only a little 1.5L mazda radiator
it has a stock genuine subi stat with no holes drilled in it and only takes about 1-2kms to get upto temp
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pete wood
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| posted on December 10th, 2009 at 02:47 PM |
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the missing link in all this "why does it stay cool question" is mostly likely the amount of heat the long radiator piping sheds as you drive along.
see the steel pipes act as a very ineffient core with a fairly significant surface area. I won't do the maths, but I reckon it would be like adding
about 1/2 and extra core to your rad. My car struggles to get over 90 except on very hot days in traffic and sits on about 91deg on a +35deg day on
the free way. That's only about 1deg hotter than a day in the 20s. Fans come on at 92deg or so in traffic, but not for long.
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ian.mezz
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| posted on December 10th, 2009 at 07:18 PM |
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| Quote: | Originally
posted by pete wood
the missing link in all this "why does it stay cool question" is mostly likely the amount of heat the long radiator piping sheds as you drive along.
see the steel pipes act as a very ineffient core with a fairly significant surface area. I won't do the maths, but I reckon it would be like adding
about 1/2 and extra core to your rad. My car struggles to get over 90 except on very hot days in traffic and sits on about 91deg on a +35deg day on
the free way. That's only about 1deg hotter than a day in the 20s. Fans come on at 92deg or so in traffic, but not for long.
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that's how the fans should work if it comes on at 92 that means thr temp should run below that, hold your hand on the radiator 90 isn't cool, I have
cars running in my work shop for 20/30 mins and fans don't come on, I normally have to hold the revs at3000 to get the fan to cycle and then like you
say it only comes on for a very short time.
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TristanJ
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| posted on December 11th, 2009 at 09:20 AM |
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| Quote: | Originally
posted by Joel
I'm not gonna profess to being a guru on these engines given the short amount of time ive been playing with them but setting up my cooling system has
given me a fair idea of how they work
basically if the cooling system is setup as per the good DR subaru's original design they wont overcool
with the 'stat being on the inlet side of the engine theres no such thing as an oversized radiator.
you could have a bloody big detroit diesel raditator with a cessna prop blowing through it and it still wouldnt over cool
the engine just keeps circulating the water around itself internally via the heater loop totally bypassing the radiator and will do that untill such
times as the it gets hot enough to open the 'stat.
All that happens then is the waterpump "sips" cooler water from the radiator supply
the bigger that rad the more reserve there is for it
this is all dependant ofcoarse on the original heaterloop working right and the stat not having holes bleeding cooler water passed it
but as Ian says they dont need a big radiator anyway
mines been running all over town this arvo with the temp being 39.8c and even in stop go traffic it sat around 85-90 mark and the fan didnt come on
once and its only a little 1.5L mazda radiator
it has a stock genuine subi stat with no holes drilled in it and only takes about 1-2kms to get upto temp
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Theoretically I really tend to agree with you on this one. When I drilled the hole in my thermostat it was not for the reason of bleeding air, but
for the reason of stopping the thermostat slamming open and shut, open and shut as it sensed the cold water and reacted to it. Kind of a smoothing
hole. I drilled it under the advice of a V8 supercar engine builder, and have never run the car without it. Joel, have you noticed an oscillating
effect on your temperature gauge? I notice you are located in Northern NSW, the ambient temperature is probably a lot higher than here in Melbourne
and I suspect the effect I am describing would be a lot less pronounced.
My car takes ages to heat up, and in really cold weather sometimes never gets to temp except on extended city driving which I suspect may lead to poor
fuel economy due to the computer still keeping engine on the warm up map. I have tried getting the information about the temperature when the 'warm
up cycle' finishes from Subaru but with very little luck (even after 'borrowing' the engine and VIN numbers from a 92 liberty parked around the
corner).
I know COR advertises milage of about 9.5 - 10L/100km with the EJ22 conversion, mine is in a '74 bay camper, I'd be really interested what milage
other people are getting.
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1303Steve
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| posted on December 11th, 2009 at 09:36 AM |
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Hi
I had a small hole in my WBX thermostat, this was for easier filling without bleeding issues, the hole was really small, the smallest bit in my set,
but it allowed the motor to be filled when cold and end up with coolant on both sides of thermostat before starting. The hole was so small I'm sure
it had no affect on the actions of the thermostat. The WBX from a dry install and fill would usually use most of the overflow bottle on cool down, the
air gets expelled and coolant gets sucked in via the radiator cap.
I'm planning on doing same thing on my STI install.
Steve
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pete wood
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| posted on December 11th, 2009 at 10:10 AM |
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As stated a few pages back, I've pulled the flipper valve out and that's all. before I did that, I drilled the hole out to 8mm as per Brad's
instructions but the car took ages to warm up, I mean like, 40mins idling. I wouldn't do anymore than pull than valve out now. Again, it was to get
around the bleeding issue, but also to stop the thermostat oscilating as I know a bunch of guys in the states have had this issue.
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ElusiveStranger
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| posted on December 11th, 2009 at 10:18 AM |
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| Quote: | Originally
posted by TristanJTheoretically I really tend to agree with you on this one. When I drilled the hole in my thermostat it was not for the reason
of bleeding air, but for the reason of stopping the thermostat slamming open and shut, open and shut as it sensed the cold water and reacted to it.
Kind of a smoothing hole. I drilled it under the advice of a V8 supercar engine builder
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Maybe a question you should ask yourself, "Does the V8 supercar engine builder have the R & D skills and money of Fuji Heavy Industries?"
'Stats have hysteresis, this stops them banging shut like a barndoor in a wind.
Scoobies sup little bits of cold water from the rad when required
My theory why fitting a Scooby/water cooled lump in a bug/bus/whatever is......
Think of the relationship of the engine to the rad in a Subaru is. The water manifold line goes uphill to the top of the rad, the rad has a bleed
built into the cap.
Right, in our set ups (bug/bus/whatever) this pipe runs down, either to the rad or under the floor and back up to a rad.
Oh, oh, air really doesn't want to go downhill unless it's dissolved in the fluid, which in our case it isn't.
So we have to put the bleed bit straight after the manifold.
Once you have the initial air out of the system it should take care of its self.
The heater or heater bypass ensures the stat is seeing the correct engine temp.
Stuff drilling the stat, set it up properly.
The latter's harder than the first. One works properly though.
Appols if I've rambled or gone off at a tangent!
Edit: 28mpg (UK gallons) on a cruise, 70mphaverage. 091 box, EJ20 NA donk
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TristanJ
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| posted on December 11th, 2009 at 10:53 AM |
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Thanks for all your thoughts, I'm going downstairs now to block the thermostat hole. Will post my findings on warm up time and possible temp
oscillations.
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TristanJ
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| posted on December 11th, 2009 at 01:02 PM |
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Just pulled the thermostat out and the holes I drilled are too close to the edge to be filled with a pop rivet. So a new one is going in. On making
the decision whether to put in a new 82 degree or a 78 degree, I rang Subaru and although they both fit, the 78 degree is the original fitment for the
EJ22 engine, the 82 degree was fitted only to the later 6 cylinder engines apparently.
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Joel
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| posted on December 11th, 2009 at 03:50 PM |
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apperently 78 is for car with A/C fitted
i dont notice any oscillatation with mine till its up to temp
once it hits 90 on my gauge (which reads about 10c high) i see a bit of variation depending on ambient temp and speed
if its just crawling around town with no real air flow through the rad itll creep upto 95ish but ive still yet to see the fan cut it while im
driving
out on the open road it wont budge of the 90 mark
i left the rattle pin in my stat
i was thinking of cutting it out like pete but it actually serves as a plug when theres pressure on the inlet side
what have you got in the heater loop setup?
mines just a short piece of 16mm heater hose looped back which probably helps keep a stable temp too
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TristanJ
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| posted on December 11th, 2009 at 06:43 PM |
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Okay, just returned from the Subaru dealership with my new thermostat and while I was there I asked about a few things.
According to the tech, the 78 degree thermostat opens at this temp but is only fully open at about 87 degrees, now here's the confusing bit,
according to him (and he was contacting Subaru Tech Dept about it) the 'engine warm up' program is in operation merrily enriching the mixture until
somewhere between 85 to 90 degrees, as between 90-95 degrees in optimum temp for this engine. That means if your thermostat is fully open and you
have a very efficient (or ridiculously large like me) you will never get off the warm up map. Can someone please explain to me how you guys are
running at 90+ degrees consistently when the only thing regulating your temperature (down to the thermostat top temp) is ambient temp and car
speed?
He actually suggested two things, number one put a second thermostat down stream of the outlet pipe (as suggested by Ricola) or a electrically
operated valve of some sort, or secondly, put a variable resistor in parallel with the temperature sense line going into your computer. You then
connect the computer to a diagnostic box. You then get the car to it's normal operating temp (in my case about 80 degrees on the highway) and then
adjust the variable resistor so that the computer thinks that the engine is at 90 and thus stops the 'warm up mode'. This would lead to another
problem though, the fans would come on also 10 degrees too early.
Sorry for rambling, I will post again when I see whether Technical Dept actually give him the information, fingers crossed.
Joel, you say you are running a stock thermostat, do you know whether it is a 78 or 82? Also how is your milage, as you say your temperature gauge
sits on 90 which is about 10 too high. This is the same me (80 degrees on the hwy).
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Joel
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| posted on December 11th, 2009 at 07:10 PM |
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its a 78
its just my gauge that reads about 10c high
i havent actually tested it to confirm but the temp comes up really quick till it hits the 89-90 mark and sits there which i assume is the 78ish area
that the stat is just starting to open
also my fan turns on at 102 and off at 98
im thinking the stock points would be around 92on and 88off which also ties in with it being 10c off
i cant see that being right about the colds start enrichement not turning off till 90
they would make the stat open temp higher than the cut off temp otherwise they would cancel each other out
both my EJ22s were identical to the degree
i cant tell u mileage yet as this motor has only got 100kms on it so far and the first motor got 9.2L but that was only 1 tank with lots of idleing
and hard driving testing the cooling system
a bug will get totaly different economy to a kombi though so its probably pointless trying to compare
do you normally have problems bleeding when you fill?
it would be worth trying the thermostat with the stock rattle pin inplace first before trying it removed
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TristanJ
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| posted on December 11th, 2009 at 09:01 PM |
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I'm not sure your temp gauge is out by all that much. On page one of this thread there is a chart which says the fan comes on at 95. From memory
when I had my computer hooked to a diagnostic box, this is when mine came on too. My dash gauge is a bit open to interpretation...
In my mind, it doesn't make sense to have the warm up map finish higher than the fully open thermostat temp, hopefully next week I will have a more
conclusive answer, although the technician says Subaru Technical are quite cagey about that sort of thing.
I'm going to install the new thermostat with the rattler intact and see how things go.
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Joel
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| posted on December 12th, 2009 at 09:07 AM |
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it would be around the same temp as the chart, but that chart is for later OBDII engines which also use vehicle speed to determine fan operation as
well
most cars with thermo fans generally bring the fans on somewhere between 88 and 95c
the tridon website is good as they list all the specs for there fan switches
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TristanJ
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| posted on December 12th, 2009 at 09:56 AM |
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It's probably in another thread but here is a link to the original 1992 Subaru manual
http://www.driftquebec.com/legacy/1992_legacy.pdf
In it (along with some other research in a Gregory's manual) I found the following information.
The standard 78 degree thermostat starts to open at 76 - 80 degrees and is fully open to 9mm at 91 degrees.
The correct nominal operating temperature for the EJ22 is 91 degrees.
The ECU engages the fan at 95 degrees.
AND (although it's just a graph) the richening due to the 'warm up program' finishes at 60 degrees (figure 22, page 14 of section 2.7a)
I will still be very interested to hear back from Subaru regardless, as the graph is only an indication.
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pete wood
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| posted on December 17th, 2009 at 05:25 PM |
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well, thought today's journey was worth a post. I drove up to Kurrajong today in something like 43degC heat. And the car worked hard. On the way out
there as long as we were moving the car was ok and didn't need the fans. The way back it was a little hotter but survived ok. The top temp I saw was
somewhere near 97 I reckon.
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JVLRacing
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| posted on December 30th, 2009 at 01:40 PM |
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| Quote: | Originally
posted by tassupervee
| Quote: | Originally
posted by Buggy Brad
| Quote: | Originally
posted by ricola
An 8mm hole in ther thermostat will effectively render it useless, Rich
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Can you explain why this is so ??
The purpose of the hole is to stop the air blockage they will often get without it. I can happily say from experience that an 8mm hole will not make
it useless. I am guessing from your comment you have of course run an 8mm hole in an EJ series thermostat and found that it was useless because you
also ran it without a thermostat at all and it was the same as one with an 8mm hole it it ... yeah ??
If not you would be basing your comment on what exactly ??
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Ummm...........well actually, I actually fully agree with Ricola.
Back in the V6 Capri days, we were chasing overheating issues and tried this approach after being advised to, along with the nafarious practise of
removing the thermostat altogether!!! Which BTY, caused the engine to overheat even further!! And experimented with different sized and number of
holes in the thermostat flange ranging from a single 3mm and up to many 6mm holes around the flange.
Basically, it all achieved nothing apart from causing the engine to run too cold when not run hard, say, down long hills and experience very wide and
savage temp variations and seriously slowed the engine from initial heating up.
However, it did make filling the system pretty foolproof!!!
This is because so much of the water pressure differential, created by a closed thermostat, necessary to force the water thru the internal bypass
system, including a heater core, was lost.
The water made its way along the path of least resistance which was the holes in the thermostat and went out into the radiator, introducing relatively
cold water into an already cold engine, rather than forcing water around and around the engine sans radiator making warmup a really looooong process.
The heater didnt work properly either after that.
Air only requires a suprisingly small orifice to bleed thru and a single 3mm hole right at the top of the flange is more than adequate to allow air to
pass by that point without compromising the operation of the thermostat.
The operation of filling/bleeding the system out becomes a little more complicated and time consuming to get right but the results are well worth it
in terms of faster warmup and less variation in water temps whilst running along with a fucking hot heater!!.
Careful attention to the setup of a de-airation/header tank will just about cure any air issues in the system regardless of the positioning of the
radiator.
Ford, for one, solved the drama of a radiator below the top of the water system a long time ago.
L8tr
E
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