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Possibly.

Keep in mind the engine isn't completely sealed to the tin work. There's about a 1/4" gap all around. I was expecting some air to migrate in from below as it is higher pressure underneath (relative to cabin pressure). I'd guess I'm spilling air downward around the engine instead of through the radiator.

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That gap definitely doesn't help force air through the radiator, but having some ducting from the side vents might. It would be a bear to build and seal, not to mention you would have to remove the ducting to work on the engine unless you have a larger access hatch in the rear deck.

 

My guess is the area ratio between the gap and radiator relative to the side vent drops the velocity to near zero at the rad. Would be interesting to get a pressure reading in the vent relative to sealed engine bay. You could then figure rad velocity based on the areas.

Edited by ctc

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Them Hippie Scoops were not friendly to,the Air Cooled engines when Gene Berg Tested them...

 

Perhaps like the race taxi, you could turn the last window on each side into a giant, yet subtle NACA duct for the radiators?

 

Ever been next to a city bus when the fans kick on and you get blasted by a stream of hot engine bay air coming OUT of the side of the bus?

Edited by Tony D

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     We’ve lost a few posts from the server crash, but I think I had left things with “I have a plan”. Well after 11 weeks of waiting, my ‘plan’ finally arrived. I ordered a second radiator from Ron Davis. Its 24” x 6” x 3”. I’ve mounted it vertically between the frame rails and I’ll plumb it in series with the first radiator.

 

     Using two radiators in this fashion is admittedly unconventional, but I think this will be a fair compromise between maintenance and functionality. As I mentioned I have been avoiding belly mounting (due mostly to maintenance), but doing it this way allows me to clean it easily since the downwind side is conveniently exposed (flushing reverse of airflow) and there are no fans in the way. I should be able to do the job without jacking up the Bus or disassembling anything.

 

     Ground clearance is 5 ½” – an inch higher than the oil pan. I still need to build an inlet screen and finish the plumbing, but here it is as of today…

 

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     Hopefully this will allow me to run the same water temps as before with less dependance on the fans.

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I machined a new thermostat neck and finished plumbing the radiator in.

 

EJ22ThermostatNeckA_zpsd9762993.jpg

 

EJ22ThermostatNeckB_zps733643cf.jpg

 

Filled it up and took it out for a drive. Spent about a half hour driving it in anger on our twisty hilly roads. The highest temp I saw was 183, with no fans running. Spent about an hour at freeway speed and the temps stayed between 180 & 185, with no fans running. The caveat is that it was around 50 deg. ambient. I’ll have to wait until summer to see how much fan I’ll need, if any. But, on an average Oregon day, it’s doing great.

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We’ve had a pretty good heatwave here in the Pacific North Wet. Hotter than usual for longer than usual. I haven’t been driving the Bus much. Either the air-conditioned car or the dual-sport has been the preferred commuter for the last few weeks. But my wife and I decided to do a small road trip up Mt. Hood with ambient in the 93 deg. range. That’s about as hot as it typically gets here on the west side of the Cascades.

 

I figured this would be a good time to lean on the cooling system to see if it could handle the heat and the climb. So that’s what we did. We maintained 4000-4100rpm for the majority of the climb - we’ll just call that “highway speed” :wink:. Water temps hovered around 195-197deg. On the steepest climbs, passing people at 4500+rpm, brought the temps temporarily up to 200-203. This is the hottest I’ve seen the temps under any driving conditions with the new cooling configuration, and certainly acceptable.

 

 

 

Bus%20Only_zpsdt5j2zzd.jpg

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I'll still hoping to get away with just one radiator behind the engine, like your original setup. 

It seems like that setup was sufficient for all standard situations.

 

If I were to stick to my original radiator configuration I would want more fan(s) and or ducting air directly to it. A quick easy improvement would be to mount three more fans on the top side of the radiator just like the bottom side. Configure them as pushers. That should help get more air through the radiator and also give you some redundancy if one or two should fail.

 

I'm wondering if a radiator mister system might work for those extreme situations?

 

Possibly, but I'm not crazy about the extra maintenance. Just a personal preference.

 

A penny for your thoughts?

 

That's twice as much as they're worth :-)

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New guy here!

 

I'm in the early steps of reconstructing a 68 bay, and I love your rear mounted approach for the radiator. There's a lot of planning to be done before I even get into body work and reconstructing the ej22 engine in my garage.

Question here, and it might sound super noob but I still feel like asking: What is considered an adequate temperature range?

 

Obviously you got cooler temps with the second rad belly mounted, I get that. But If you were to add the extra fans to your singular setup, could you get cool enough to say "that's more than sufficient"? I'm in Southern California, average 75 degrees temps, but our summers can be over 100 degrees if God hates us enough. I plan on road-tripping after completing the build, but it will mostly be used to drive about 20 miles daily (with a few 100 mile drives on school breaks).

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Question here, and it might sound super noob but I still feel like asking: What is considered an adequate temperature range?

 

 

The stock Subaru thermostat is 172 degrees and not fully open until somewhere around 195 (and they are also cold side control). It seems stock EJ22 Suby’s typically run at right around 190-205 degrees. I don’t generally start worrying about an engine until it breaks 250.    

 

Obviously you got cooler temps with the second rad belly mounted, I get that. But If you were to add the extra fans to your singular setup, could you get cool enough to say "that's more than sufficient"?

 

 

I’d say “maybe”. I believe the radiator is big enough for stock horsepower, so it really becomes about getting enough airflow across it.

 

How much hotter did you get during stop-and-go traffic on those hot days?

 

 

Not any hotter. Stop and go traffic runs the fans, but maintains the temperature, much like a ‘normal’ car.

 

Good luck with your Bay and keep us posted on your progress.

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Thanks for responding. I'm really avoiding belly mounting if your approach can be refined. I'm going to try and keep your setup on top of the inspiration list. I'm probably still going to relocate the battery to a hidden compartment inside the cab so I'm thinking of creating ducting/that pulls in air from the side vents directly onto the radiator (like a manifold type design)... instead of radiators on those side vent spaces, I'll consider having extra fans for redundancy... not there yet, though.

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