Tony's Subaru Conversion Thread Options

[Aaron Cox]

badass tony. sounds like you are well on your way to being finished....

[bondo]

Ok, here are some pictures!

[TravisNeff]

What about Scott Thacker's bottom scoop method? It sounded like he didn't have cooling issues, but I don't know if he had a temp gauge or not.

[pfierb]

Tony if your avatar is a picture of you there is a picture of you in the Sunday New York Times with a story about blogs,that I didn't get a chance to read.

Paul F.

[TonyAKAVW]

No, the avatar is not me... thats Napoleon Dynamite from the movie of the same name.

Regarding the direction of cooling... Scott Thatcher uses a scoop under his car and pulls the air through the radiator and up out through the engine bay lid. He made it from Massachustes (I believe) to California and back last year during spring, along with a pretty decent beating at Willow Springs and had no cooling issues.

I'm trying a different approach. I want to have as little as possible (ideally nothing) hanging below the car. To do that I have to draw the air from above the car and out under. Getting that airflow to happen is challenging because of the low pressure zone created behind the targa bar. It is however the direction of airflow that the OEM engines used. As well, it eliminates picking up hot air off the asphault. For now I have sufficient cooling for driving on streets with 4 fans (2 on the engine bay lid and two on the radiator).

However when I take it on the freeway, that low pressure zone seems to be causing me problems. To fix this I am planning on adding a small spoiler behind the targa bar that will shoot air down into the engine bay. Secondly, on the bottom of the car I'm going to fabricate a large diffuser which should help to suck air through the radiator.

I really don't know if all of this will work, but its something that hasn't been done before and if it does work would be yet another option for conversions.

-Tony

[Dr Evil]

More fans, more fans! (IMG:style_emoticons/default/wink.gif)

You remind me of the professor off of South Park, " I have created the perfect 914 with 4 asses. That 914 has only one ass, it is of no use to me.."

[project-914]

haha ^^ that's awesome

also, how about some more pics! hehe

[Crazyhippy]

how about reversing the fans on the freeway?? Let the low pressure work for you when it is there, and draw cool air from above @ low speeds???

Doesn't cost anything to try it

BJH

[neo914-6]

I'm trying a different approach. I want to have as little as possible (ideally nothing) hanging below the car. To do that I have to draw the air from above the car and out under. Getting that airflow to happen is challenging because of the low pressure zone created behind the targa bar. It is however the direction of airflow that the OEM engines used. As well, it eliminates picking up hot air off the asphault. For now I have sufficient cooling for driving on streets with 4 fans (2 on the engine bay lid and two on the radiator).
-Tony

Hey Tony, I am incorporating a roof scoop to break up the flatness of the top. It works well on coupes (Exige) but a challenge on targa cars. A flap will divert the air down when needed and straight through when not...at least that's my "functional" excuse (IMG:style_emoticons/default/laugh.gif)

[fat73]

Tony....

I don't if you've thought of this yet, but have you tried running any of the super coolant additive stuff in your radiator fluid. I don't remember which one it was but I know one guy I talked to at Napa a couple of weeks ago that has a turbo'd Acura that's not close to stock who say's the stuff he uses dropped the coolant temp by 28 degrees.

fyi..jacked the car WAY up and rolled the engine into the engine bay last night. Trying to mount 'er up tonight.

Ed aka fat73 and a few jacks away from W9R1

[Spoke]

Tony,

Very nice job on your conversion. You'll get through the issues. Remember that technical difficulties are something that engineers purposely design into everything made in this world so we need more engineers to figure out the issues.

A question about your cooling issues. Is the overheating due to recirculating the hot air from one side of the radiator to the other? I guess this is why the air cooled engines have the tin and gaskets to keep the hot air from re-entering the cooling system.

Before my red 914 was wrecked, I was going to follow your lead on conversion. I like the placement of the radiator in the engine compartment. Now with the green 914, I'm not sure which direction to go for more power: Suby, Massive IV, or 6.

Spoke

[TonyAKAVW]

BJ: I have thought about doing a reverse fan test. From the experience of the two others (Scott Thacher and Evan) with engine bay radiators, a scoop is necessary on the highway. It would be an interesting test though. A test that Bondo mentioned was to leave the engine bay fans (not the radiator fans) unplugged and put a volt meter on them to see which way the air naturally goes.

Felix: I'd like to see what kind of scoop ideas you have. I've been thinking of using some kind of scoop like racecars use (opening near the windshield, and a tunnel that goes back) or just a simple fin spanning the width of the roof, just behind it.

Ed: I think you might be talking about this stuff: http://www.evanscooling.com/main27.htm
??? Congrats on the engine-in-car. Its the first major step. Firing it up is even more satisfying. Moreso than the first drive even.

Spoke: I don't believe the problem is recirculation of hot air, but insufficient flow of cool air. I don't think that the radiator exhaust is feeding back on itself, but I think the only air getting to the radiator at high speed is warmed already by a combination of radiative engine and exhaust heat, and maybe a little blowback from the radiator exhaust. What I really need is a good pressure differential across the radiator. At speed I need positive pressure on the input side, and a vacuum on the output. A leading edge flap and diffuser are my tentative solutions for generating a low pressure zone, and a lip/air deflector above the engine bay is my idea for the positive pressure side. The diffuser will aid in isolating the air pressure from above and below the car as well. (the above is pure theory)

-Tony

[Rotary'14]

I don't if you've thought of this yet, but have you tried running any of the super coolant additive stuff in your radiator fluid. I don't remember which one it was but I know one guy I talked to at Napa a couple of weeks ago that has a turbo'd Acura that's not close to stock who say's the stuff he uses dropped the coolant temp by 28 degrees.

I think Ed means Redline water wetter. I've used the stuff in my conversion and I have had a similiar experieance with around a 20 degree drop in temp. It used to cost $6 but now it's more like $10 for a bottle. I have even seen it at pepboys. You should try some Tony,,,,

-Rob

[JPB]

I think you can also get some air flow from the sides of the car if you scoop it. Sail panel scoops would look cool but if you want it to stay stock looking, it would compromise that. Perhaps like a Testarosa with the door skins knocked in for that purpose, there is much room in the rear fenders behind the doors for ducting.

(IMG:style_emoticons/default/beer.gif)

[andys]

Tony,

You being the crafty bloke you are, why don't you get yourself some vinyl tubing and make a couple of manometer columns...Two U shapes (or as many as you like) half filled with colored water zip tied to cardboard (with graduations) fastened to the dash, and run lines to areas you beilieve are the issue. This will give you an indication of where the pressure differentials are and at what speed. Duct tape and cardboard are your freinds...........You need to stop guessing. Someone needs to go through this excersize for the 914CLUB, and put to rest all the speculation. The results will surely end up in the "Classics" section.

Andys

[TonyAKAVW]

I got back Thursday from Italy (gone almost two weeks) and brought with me a bad cold. Today I finally felt good enough to get some work done on the car, so I built a really cheesy spoiler to divert air from above the car to the engine bay.

[TonyAKAVW]

Testing with compressed air shows that it does effectively divert air in the correct direction. So I have some confidence that at high speeds (say above 40 mph) there is now positive pressure above the engine bay.

I took the car out for a test drive and the cooling is still not sufficient. At freeway speeds the temperature still continues to rise, very slowly, but it still rises.

My impression right now is that I am not getting a real pressure differential across the radiator other than that created by the fans, which is not enough to cool the engine. Without some kind of ducting to the radiator I will not get positive pressure on the input side. My initial design was based on creating low pressure on the output side by means of a leading edge flap (as in the rubber 914 flaps) and a diffuser/venturi. I have still not constructed these, so its possible that those two items combined with the spoiler will be enough.

However there are two other problems I have noticed.

1. The cabin of the car gets really warm. The radiator output is blowing against the firewall ad heating it up a lot. Its like a giant heater behind your back.

2. The brake lines and proportioning valve are getting heated up. This could be solved by rerouting the brake lines, but would be a bit of a pain.

So issue #1 could possibly be solved by insulation but then I'd be adding weight...

I'm beginning to think that trying to push the air from the top to the bottom just isn't going to work. There isn't enough room to put ducting on the radiator unless I move the fans to the opposite side of the radiator. If I do this I still only have a small area for ducting (maybe 2 inches of clearance before I hit the alternator or crank pulley). Then I need to get air into the ducting which could mean a huge ugly enclosed area behind the rear windshield.

So my main concern with the scoop under the car is speed bumps, but I have come up with a possbile solution...

-tony

[neo914-6]

Sorry to hear you got sick, I lost several days productivity when I was sick.. (IMG:style_emoticons/default/sad.gif)

Did Jes get sick too, how was Italy?

I found a diverter online similar to your proto.

I bought a roof scoop but probably won't use it. I'd have to cut into the targa band, figure a way to duct the air into the engine compartment and make it all weatherproof. I was brainstorming with a friend the other day and a retractible snorkel sounded interesting... (IMG:style_emoticons/default/idea.gif) (IMG:style_emoticons/default/biggrin.gif)




...yeah we were drinking (IMG:style_emoticons/default/laugh.gif) (IMG:style_emoticons/default/drunk.gif)

[Aaron Cox]

tony... maybe bite the bullet and go front cooling (ram air = good)

not necessarily an off the shelf kit tho.... thought about maybe twin radiators like a 996 or maybe a third one in the middle like a boxster S and TT 996's?

would look just like an oil cooler (middle one) and maybe duct the 2 outer ones into the fenderwell?

could be a slick setup... and if anyone could do it... you could

food for thought
(IMG:http://www.realtime.net/~rentner/Porsche/Radiator/P0001081.jpg)
(IMG:http://www.realtime.net/~rentner/Porsche/Radiator/P0001096.jpg)

996 third rad...
(IMG:http://platz.com/philwatercoolerlarge.jpg)

[JPB]

Shazzamm!

(IMG:style_emoticons/default/beer.gif) BBBBBBbeer cold.