Any successful radiator in engine compartment conversions?, Or other than front trunk installs? Options

[Chris914n6]

I crunched some numbers.
Based on a few sedans I have available, the point at which the airflow through the grille surpasses the fan cfm is about 15mph. In part throttle low speed around town normal traffic driving almost anything near OEM design will seem adequate. It's at freeway speeds where a higher engine load and increased heat generation takes it's toll. It's the hours on the highway at 2/3 throttle where you'll see temps creep up because you don't have 5x or so airflow forced through the rad.

My 914n6 is an exception. I have 2x 1390cfm from the fans and my break even point is 40mph. But I also have a little oil cooler on the firewall and the SE spoiler lets air flow along the hoses. The ecu triggers 2 speed fans at 203F and 212F. Cruising at 80mph I'd be toast without the forced air.

[fiid]

It seems doable to do radiators in the engine bay, or at the rear of the car at least. Sacrificing the rear trunk to save the front, esp if you could keep just enough to keep the roof back there would be a win.

Just my opinions, but it makes sense to me that with engine tin and sufficient fans you could make it work. I think an engine driven fan may make more sense. I think you might want to use an upright engine so you can maximise the surface areas on either side of the motor. Maybe a centrifugal fan on the crank wheel that blows in two directions into two radiators on either side of the motor? or maybe a slant motor with a rad on one side so you can keep the radiators away from the exhaust.

Logically, if a 3.6 can work, you should be able to do something reasonably powerful, except an air cooled motor has a *lot* of surface area (all those fins!). I think you'd have to pick something physically small-ish to make it fit, but that could still be deeply entertaining.

[McMark]

Maybe a centrifugal fan on the crank wheel that blows in two directions into two radiators on either side of the motor?

That's a good idea! (IMG:style_emoticons/default/drunk.gif)

[SirAndy]

Logically, if a 3.6 can work, you should be able to do something reasonably powerful

I doubt a 3.6L would work *without* a front mounted cooler. I have yet to see one that didn't have direct airflow over an external cooler.

(IMG:style_emoticons/default/shades.gif)

PS: Hi Fiid! (IMG:style_emoticons/default/bye1.gif)

[sixnotfour]

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[DBCooper]

The question was whether a radiator had been successfully used in the 914 engine compartment. I think the answer is still generally not in a 914, with a lot of discussion of theoretical possibilities. It HAS been done in other cars, for example that Laborghini, or closer to home by Toy-Jet, which put their radiator in an LS1 911's whale tale:
(IMG:http://www.914world.com/bbs2/uploads_offsite/i379.photobucket.com-2618-1418073678.1.jpg)

On the more practical side VW bus guys have been out there actively trying lots of different ways to adapt modern engines to their old air-cooled busses. One that was interesting to our discussion was split dual radiators in the engine compartment fed with large scoops on the sides of a bay window bus, augmented by large fans. This worked reasonably well but still tended to heat saturate after extended time on the freeway.
(IMG:http://www.914world.com/bbs2/uploads_offsite/i53.photobucket.com-2618-1418073678.2.jpg)

Another bus had huge fans pulling air into split window's engine bay, proved not nearly enough. Yet another had scoops across the underside of a kombi gave good airflow and worked for a while, but scooped up a lot of dirt and crap that eventually clogged things. Another was roof-mounted like a luggage rack, which sounds a bit like the targa suggestion.
(IMG:http://www.914world.com/bbs2/uploads_offsite/i53.photobucket.com-2618-1418073678.3.jpg)

The owner intends to camouflage that so it looks like a suitcase or a beer cooler, interesting idea but probably not the best look for a 914. This one actually works really well, it's in direct air flow, but not exactly in the engine compartment.

Obviously these aren't 914's, but it's significant that most of those applications are low to medium powered Subaru engines that are relatively efficient and don't need a huge amount of cooling. A higher powered engine would certainly be more difficult. Basically what's relevant is that the practical experiments indicate that it's really difficult to cool without having access to direct air flow. That means I wouldn't be optimistic about it working in a 914's engine compartment either, but hey, if you think you have a good idea, go for it.

[76-914]

Paul makes a good point re: heat sink. I watched it as I worked thru my cooling probs. And the more efficient your power plant the longer it takes. You think you have it then you don't. It's like chasing your tail. Frankly, I won't know until I've cruised thru the desert @115F w/o a hitch. Everyone of us is running a variation of a variation w/o any "hard" numbers. To Paul's point, you just have to look around to see what works and what hasn't. Good luck (IMG:style_emoticons/default/beerchug.gif)

[Andyrew]

You know what would be an interesting fail safe, If there was a water sprayer in front of the radiator for if the water temp got to a dangerous degree. Obviously you would have to replace the water, but it could avoid a dangerous overheat, and should drop the temps down really fast.

[EdwardBlume]

You could mount an oil cooler right behind the 914 drivers head, but there's a lot of hot air there too! (IMG:style_emoticons/default/lol-2.gif)

[veekry9]

You know what would be an interesting fail safe, If there was a water sprayer in front of the radiator for if the water temp got to a dangerous degree. Obviously you would have to replace the water, but it could avoid a dangerous overheat, and should drop the temps down really fast.

Sure.
Works great,adiabatic cooling,a pal had a system for his van in the '70s that was fantastic.Took it to Daytona to see Yvon DuHamel and Paul Smart.(With our bikes)
A small 12v motor spun a thin sheetmetal disk,water was pumped to an orifice and the water was centrifigually thrown onto a coarse open cell polyurethane foam tube,on the inside.
As the fan was mounted atop the tube,air was forced through the foam into a tubular plenum,where it was distributed to the interior of the van.
Economical,requires water of the fresh kind.Humidity inside rises to near saturation.A turbo charge cooler can be made that works the same.

http://en.wikipedia.org/wiki/Paul_Smart_%2...rcycle_racer%29
http://en.wikipedia.org/wiki/Kawasaki_H2_Mach_IV
http://www.cycleworld.com/2012/06/12/from-...s-daytona-1973/
http://www.vf750fd.com/motorbikes/H2r1.html

[bulitt]

I would love for the radiator to work in the engine compartment but logic says no. Heat from engine and little airflow work against it. Do you know of any production mid or rear engine car that makes it work- I dont. Again, I'm on your side. If I didn't feel it absolutely neccesary to mount the oil cooler on my gt build or the rad on my suby build up front, I wouldn't.

Ferrari Testarossa.

[mepstein]

I would love for the radiator to work in the engine compartment but logic says no. Heat from engine and little airflow work against it. Do you know of any production mid or rear engine car that makes it work- I dont. Again, I'm on your side. If I didn't feel it absolutely neccesary to mount the oil cooler on my gt build or the rad on my suby build up front, I wouldn't.

Ferrari Testarossa.

I stand corrected. But we are still fighting an uphill battle to make a mid mounted radiator work in a 914 compared to a car that was designed that way.

[timothy_nd28]

Laying a radiator flat in the front trunk?

[Mike Bellis]

I had a radiator built to lay flat in the front trunk on my first conversion. It worked great and gave me back some of the trunk space. Con: the air outlet was straight down and would blow dirt around and add unwanted air under the car.

people keep stating cars like Ferrari and Lamborghini as successful engine bay radiators. Keep in mind these cars were engineered for this. Body panels and air flow direct the heat away. $$$$ have been spent in R&D.

The 914 engine bay has horrible air flow. It was not designed to force air through the tins. The fan forces air through the tins. flaps below help to create turbulent air for the fan to force through the tins.

I think if Porsche thought engine bay radiators were practical, they would have used this method on the 911 and Boxster.

There looks to be just enough room under the 914 headlight bucket to use a pair of Boxster radiators. I am going this route at some point. I may also use the center rad with a matching size oil cooler too. I would love to have a front trunk again.

The design would be to raise the center tunnel, creating a raised void under the car to route the Boxster coolant lines. Oil lines and fuel lines could be routed here as well. A cover would be fabricated like a belly pan to enclose the void. Getting past the front suspension with the Boxster hard tubes look like the biggest difficulty.

[914werke]

Scott Thacher was the guy who showed up in WCR 05 with his "In Bay" NA scooby conversion. He drove it from MD to SoCal and back!
#'s dont always tell you if it will WORK.

Thread

[Andyrew]

I had a radiator built to lay flat in the front trunk on my first conversion. It worked great and gave me back some of the trunk space. Con: the air outlet was straight down and would blow dirt around and add unwanted air under the car.

people keep stating cars like Ferrari and Lamborghini as successful engine bay radiators. Keep in mind these cars were engineered for this. Body panels and air flow direct the heat away. $$$$ have been spent in R&D.

The 914 engine bay has horrible air flow. It was not designed to force air through the tins. The fan forces air through the tins. flaps below help to create turbulent air for the fan to force through the tins.

I think if Porsche thought engine bay radiators were practical, they would have used this method on the 911 and Boxster.

There looks to be just enough room under the 914 headlight bucket to use a pair of Boxster radiators. I am going this route at some point. I may also use the center rad with a matching size oil cooler too. I would love to have a front trunk again.

The design would be to raise the center tunnel, creating a raised void under the car to route the Boxster coolant lines. Oil lines and fuel lines could be routed here as well. A cover would be fabricated like a belly pan to enclose the void. Getting past the front suspension with the Boxster hard tubes look like the biggest difficulty.

With your small displacement I think you can get away with this fairly easily. (IMG:style_emoticons/default/smile.gif)

[DBCooper]

Cool, this thread came back. In the meantime I ran across a thread (titled "Subaru Engine") at www.spyderclub.com that traced one of their car's evolution of radiator placement. The 550's have the same rear transmission mid-engine layout, are going more Subaru, and their owners would also prefer to keep everything in the engine compartment. This is one car's iterations and an eerie parallel to what we've also seen:

Quote

But the basic evolution:
1: Mcrae with an little 1.8lt Subaru turbo engine and gearbox
Radiator mounted above the engine under the rear grills, no intercooler.
Found that I always had a engine temp problems, I never had on the track at that point.
Eventually the overtemp took its toll and the little 1.8 failed.

2: EJ20T and stock 2WD gearbox
Stock radiator mounted in front of the engine and about 3" gap to the fire wall.
Never going to get the cooling but good try.
Stock intercooler mounted under the rear grills.
Stock ECU rechipped to remove the speed limiter. 12.4 ET @ 180kph

3: Small 2" chin scoop behind the radiator under the car, still not engough cooling and now super sprinting the car.
Aftermarket ECU
Still overtemp after several laps, intake temps would also increase due to poor heat transfer between the stock intercooler and grill airflow.
Stock 2WD gearbox with open diff goes bang but it took 2 seasons of hillclimbs and lots of passes at the strip.

4: Add 2 cutouts behind the seats with ducting to radiator to increase the air flow, still kidding myself, that's just not enough.

5: Ring lands failed on several pistons.
Rebuild the 2ltr but now use a NA 2.5 block with new 2.5ltr STI rods and pistons and 2ltr heads, replace original auto turbo with a manual turbo 13lbs boost.
Convert an STI CR gearbox to 2WD using the 2WD rear casing stock and STI LSD.
Move the new alloy radiator to the front of the car, use 1 1/8" aluminium tubing and silicon bends etc, cut out the oil grills, alloy ducting enclosing the radiator.
Mounted a large alloy front mount intercooler in the front of the engine in the place of the old radiator used stock aftermarket front mount alloy intercooler pipework.
Turbo inlet via a CF box above the engine taking in air from one rear grill.
10.4 ET @ 125mph.
Radiator outlet was just flowing into the hood area, after 20 or so laps the temps in the hood area and the fuel tank would increase, fuel surge pot would be red hot.

6: Enclose the rear of the radiator and duct out the front wheel wells.

7: Super reliable, go out and run at full boost all day, scare the locals.
last time I was out we were lapping 2 up (wife likes to drive but not shotgun) with a second level V8 super car, he had much better corner speed but we would pull up to him on the straight and poke our nose out as if to pass, had his pit crew hanging over the pit wall wondering what the hell this little car was. :-\"
Only thing I think I would do now is convert to an air/water barrel intercooler with front mount radiator, just a lot more compact and would restore the firewall to stockish.
Photos to follow. Cheers from downunder.

Unquote

[DBCooper]

Unfortunately a lot of rear-mount cooling projects in all kinds of different cars get started and then either don't work or the threads peter out and disappear. I'd assume that to mean they didn't work out either. Scott's gone too, but does anyone know what happened to his car? I think his is the only I've heard of that was reported to work well. I don't remember seeing any photos, though, does anyone have a link?

Not the same, but there are these vasserboxers in VW's:

(IMG:http://www.914world.com/bbs2/uploads_offsite/images.thesamba.com-2618-1421686704.1.jpg)

(IMG:http://www.914world.com/bbs2/uploads_offsite/i33.photobucket.com-2618-1421686705.2.jpg)

Both said to work, both bring air in over the transmission through a big cutout in the firewall in front of the engine. Even so the consensus in the VW community (shoptalkforums.com, Conversion Perversions and thesamba.com) seems to be the same as here, that front mounted is foolproof, rear remains unproven.

[3d914]

OK, here's mine. Not done, but in process. I have two plans to locate radiators for the SHO V6 - the example here in the engine bay and an atypical up-front method that doesn't eat up the trunk.

This engine bay method (similar to 904's approach) provides the 200 sq.ft of surface area and same volume as stock by running dual (smaller) radiators in series (not parallel). The radiators are positioned and will be fully enclosed from the engine lid down to the radiator. Fans will be below the rads and draw air down, so hot air exists out the back.

Here's some pics:

Engine with lid
(IMG:http://www.914world.com/bbs2/uploads/post-1191-1388356682.jpg)

Engine lid cutouts for cooling air
http://www.914world.com/bbs2/uploads/post-...-1392609342.jpg

Layout graphics:
(IMG:http://www.914world.com/bbs2/uploads/post-1191-1327545657.png)

(IMG:http://www.914world.com/bbs2/uploads/post-1191-1327545667.png)

[Mueller]

Laying a radiator flat in the front trunk?

Got a link to that? Looks cool whatever it is!


I forgot about Scotts subaru powered 914 way back at that event...I was there!

There was also a 4 cylinder Dodge conversion that I think the guy was from the Bay Area that did the radiator in the engine bay, saw it one time at a event and never saw him or the car again.

The radiator was mounted I think on the drivers side of the motor with a fan that pushed hot air towards drivers side.

Those lines for the Boxster are neat, 1st time I've seen those.