Suby Air Intake

Very Nice Tom.  In a few years the builders will get it down pat.  My car does not overheat either but I don't drive in 90 plus Humidity more than a few days a year in the summer.  Your car will be a good test mule because of where you live and the fact that you drive your car often.  There is a Subaru Dual Radiator setup being tested now (similar to a Porsche Boxster).  Here is my car from a few years back in the build stage.  

I have a civic dual core radiator on my set-up. No issues and I stay in South Africa, dry weather hitting high 30's no problem. When in traffic the fan comes on, but during normal driving........nadda. I'm currently designing a new set-up that will allow for the radiator to sit further back and lower which will allow for the spare wheel to get back in there where it belongs.

Very nice Greg.

It will go nicely with the SOC badge attached to the grill...if your ticked-off SA postal employees ever go back to work!!

And, speaking of cooling:

Is anyone familiar with these engine cooling fans (TheSamba# 1704989) for a dual port aircooled engine?...Are they effective, and is there room for them in a speedster engine compartment? 

I suspect they're for drag racers, who want to cool their engines down on the way back to the pits after a run.

Carl- As Ron said, they are 12 volt fans used by dragracers who have taken off the fan shroud and generator to free up extra power and cool the engine somewhat between rounds. I don't know offhand how much air they move, but it's not as much as a stock shroud. They're not even close to effective in a street car. 

TRahn...could you please give dimensions of the current rad...length , width and depth  and also , what are the dimensions of the exposed rad shown down below the bumper and again, the width and length of the exposed area of the rectangular scoop below the rad, please ? Also...does the scoop direct air up and into the front of the rad or sweep around to the back of the rad to create suck thru situation? Thanks....we're just trying to learn here.

flatfourfan: I think I have the same rad as you. Does my heart good to hear it works in your car. I've got a big upright grill to feed air through mine so that should not be my problem...

and you have metal fore/aft coolant tubes, Ed...those will disspell heat.

TRahn...could you please give dimensions of the current rad...length , width and depth  and also , what are the dimensions of the exposed rad shown down below the bumper and again, the width and length of the exposed area of the rectangular scoop below the rad, please ? Also...does the scoop direct air up and into the front of the rad or sweep around to the back of the rad to create suck thru situation? Thanks....we're just trying to learn here.

David .... I am sure Carey can give full specs but this is what i see + or -:

side to side: 27"

top to bottom: 16 1/2"

exposed: 4" ... scoop 4" by 27"

small fwd rad: 3/4 " depth

large rad: 2 1/4 " depth

Note picture with the smaller front radiator (obviously I'm not an expert at this)

Thanks for that TRhan...every bit helps us laypersons to become a little bit more educated on what works and what might not.

Now...just to ask for a bit more clarification, please...those rad dimensions above...are they the dimensions of the rad core only ( the little wiggly area with the

fins ) ? or the overall dimensions. The core thickness may be less than the top aluminum plate dimension too...thinner. The little rad in front doesn't matter to me.

Again...about the scoop on the bottom. Does it direct incoming air to the front of the rad or under and up behind the rad.

Thanks for your patience...these dimensions are very helpful.

Regards...

DS

No problem ....

Scoop allows air from the front only the dimensions are overall

and another show-off picture..

Thanks Dood...that's a nice looking rig and I'm glad it's working well for you. No surprise tho' since Carey at Beck did it right.

Eventually all manufacturers will figure out #1 radiator MUST be in the front and #2 the closer to vertical the better.  BTW I have no cooling issues at all with my IM but the fans run a lot in the summer.  Radiator in front at about 45 degrees. 

If you were to make that radiator a dual pass, it would be 21% increase in cooling efficiency without changing anything else on the radiator or cooling system. If you had some more detailed pictures I might be able to suggest some other easy improvements.

Just trying to learn here. What makes a vertical mount rad superior to a horizontal mount rad ? With my setup, a rad mounted about 20 deg nose up from horizontal is a pretty good fit considering the existing obstacles up front. Something configured about like this rad pictured below would be about right. Bleeders would have to be built in at the other end. For clarity, the Ron Davis logo would face up in my application, the inlet and outlet would face the rear of the car and the other end would be up those 20 deg mounted in line with my existing bumper brackets.

One of the biggest pains for me was to get the rad hoses to go up and over the front beam with bleeders at the high spots. The location of the inlet and outlet in the Ron Davis example would help in avoiding the beam obstacle nicely.

Kevin....it's always worthwhile reading what you have to offer. How would you feel about mounting two rads in series, one each up in the headlight bucket area? Any guidelines for something like that ? Thanks.

Another one for you Kevin, please. Are all dual pass rads more restrictive than single pass or does it come down to just needing a good dual rad design ? If they are more restrictive, how would one be able to know ahead of time that the stock water pump would be capable of delivering sufficient pressure all the way up to and through the front and back to the rear? Thanks.

I don't think it matters if the rad is angled, if you can get good airflow to to rad.

What happens to the air after it passes through the rad is also important, as is the type of fan(s) used.  I wouldn't use anything but Spal fans.  I had them on my monster (V8) Miata and they worked like a charm.

I really like Ron Davis rads, but boy, are they pricey.  When I redid the cooling system on my monster Miata I measured where the rad would go, then went online and found a dual pass rad that would fit.

    "I don't think it matters if the rad is angled,

      if you can get good airflow to the rad"

The British watercooled Merlin engines in the WW2 Spitfire had radiators parallel to airflow. I recall Flight Leader Michael Caine's caustic remark to ground control in the movie that if they didn't release his squadron soon to intercept the Germans that the idling engines would blow up!

Caine was always given caustically dry unemotional lines when facing life and death in his movies!   

Carl, I imagine the rads on the Spits didn't have fans?

amen on rons comment. I always knew that a civic dual core radiator would be a temporary solution on my car. A local company will custom make one for me based on the jeep size. Nice and long, but not high so that a false floor will be able to fit on top. The angle won't make much of a diffs as long as all the air that is being channeled from the front hits the radiator. 

WRT TRahn's radiator set-up.  The thinner "radiator" in front is actually his AC condenser.  Our smaller dual pass radiator has worked very well for years, but adding up the AC condenser and the hot FL summers, he was running at the upper limits of what I like to see, so we decided to increase everything slightly.

The scoop in front is pretty flat but we built one-off inserts that 1) closed the gaps at the bottom and top of the radiator and 2) directed airflow upwards as it entered but did not allow it to go over top of the radiator either...

When we worked with PWR/Davies Craig on the radiator set-up for an Australian track Spyder they actually liked our horizontal set-up and their engineer felt it would dissipate heat quicker IF we could get proper airflow through it and expel hot air out of the compartment...  and that was the issue. It was difficult getting even airflow through the horizontal set-up at high speed, but even more difficult directing it out of the front compartment.  In that case we wound up going almost vertical, ducted through our custom Spyder shroud, which easily dumps into the low pressure area behind the front beam.

My comment above also brings to mind another point that I have seen missed on some other set-ups that we've serviced.  Big gaps around a radiator only allow for a "path of least resistance" around the radiator reducing cooling efficiency.

"My comment above also brings to mind another point that I have seen missed on some other set-ups that we've serviced.  Big gaps around a radiator only allow for a "path of least resistance" around the radiator reducing cooling efficiency."

spot on with that remark. I've seen many set-ups where the radiator is just fitted there, not built in at all.

We installed vanes on either side of the radiator with a cover on the top and a scoop at the bottom, there is no-where else for the air to go than straight through. The above pic was initial mock up, which has since been made way smaller, but you get the idea. 

I find this thread very interesting having having spent many sleepless nights figuring out a system that would work for me. Now I have the opportunity to tweak a good working system if I want to.

Here are three pics of my rad and it's scoop...out of the car for some reason. The rad mounts up front angled about 15-20 deg. nose up. The scoop was designed after seeing the example shown in the Lola pics attached.

I think my rad is over sized at 19 x 13.5 x 1.25 = 321 cu inches. I have a Jeep rad on hand and it is a whopping 10.75 x 31 x 1.25" coming to 416 cu. inches. I do get some benefit on my car from the two long aluminum 1.5" dia. coolant tubes running from back to front and back again. Having said that, my rad scoop's front opening measures 19.5 x 2.5" or 48.75 square inches. I have run various times experimenting with scoop opening size by blocking of one and two of my three openings. Interestingly, with two blocked off I am left with only 16.25 square inches working. On a 75 deg F day, I can easily drive around town and cruise at any speed and the coolant temp coming out of the engine does not exceed 140 deg F. These trials were done without a thermostat installed and we must remember that the Soob thermostat is situated on the "coolant IN " side of the engine, not the coolant OUT side like most cars.

Interestingly, those little air inlets beside the turn signal lamps total 22.5 square inches. Hmmmm.

David, I had to smile when I looked at the photo of two fans mounted to the back of your rad.  I had an almost identical setup on my monster Miata.  I didn't have enough room for a really big single fan and also couldn't fit a set of duals, so I ended up going with a one Spal medium sized fan and one small.  They worked great together and the car never overheated.  I also spent many hours sealing all the gaps and holes.

Yeah, Ron...I probably went a little overboard but I wanted to err on the safe side.

What I'm seriously guilty of though is doing stuff on the cheap because I'm not sure it will work then finding it does work and not going back to make a nicer looking, more professional job of it. I can only write it off as patina for so long I guess.

David, I personally admire dudes who can accomplish things on the 'cheap' with ingenuity. Please keep detailed notes on components and procedures 'cause I'm squeaky cheap... but lack the 'ingenuity' attribute! 

Hey David. How do you expell the hot air from the radiator? Do you have any pictures of the floor in the trunk area?

I think this is actually the first pics I've seen of your rad set-up. Shame on you. 

Giday, Gary. The entire rad is technically " just under the car" and not up inside the trunk at all. It is more or less slung between the two bumper brackets which run off the front suspension beam. Therefore the hot air expelled just heads backwards under the car. Inside the trunk there is a rectangular bucket at the front which contains the full sized battery, some tools and such and the rad is just about right under it.

Another feature that I learned from the Lola setup was to employ vanes inside the scoop opening. The vertical vanes have an obvious purpose but there are horizontal vanes in there too and they force some oncoming air up into the front section of the rad rather than letting it all compress straight to the rear of the rad. It made sense so I did that too.

ok, so there is a gap between the radiator and the bottom of the car?

as in it's not butted up right against the body?

Do you have any channels or anything that divert the hot air away once it's gone through?

yep, there's bound to be a gap there because there's really nothing flat underneath the car in that area. We're ahead of the axle beam and just about under the front of the trunk.

It's not butted up against anything. The top of the fans are about an inch lower than the bottom of the battery box at the front of the trunk.

You don't need any channels to divert hot air away. It takes care of itself, especially at speed. One could argue that my fans should be shrouded in on the top of the rad to be more effective but this would also prevent that area to "radiate" heat normally. This system works for me so that's the way it will stay.

I found a rough sketch of my cooling system that was in place last Spring. This system did not have a thermostat in place ( which is not ideal ) but I didn't have time to test a different system before we left for Carlisle via Florida again.

David, my dual Setrab oil coolers are mounted in the same place as your rad.  Heck, with a bit more fiddle-farting around I could have put in a radiator and gone water cooled, since I had to run lines to the back anyways.

As I said much earlier, I'll be very happy to show how I did it, but I won't tell you how you should do it.

Phil, I know your comment is way up above, but RE: radiator vertical comment.

The radiator can be in any orientation, as long as air bubbles are not a factor and there is sufficient airflow. I took a close look at a Lotus Elise and the radiator is horizontal. Air flows from the front of the car under the rad then up through it and venting onto the hood and then over the windshield. Dual purpose I imagine as it provides cooling and some front down-force. Crafty engineers!

Danny

I understand.  Air like water can be forced to do anything with the appropriate duct work.  Guess my point is that if radiator is vertical little duct work is needed.  The closer to horizontal the more the air will need to be coaxed through the radiator.  All car builders including Porsche will try to keep radiators vertical as much as design allows.