I am thinking of mounting a radiator flat on the rear decklid for my "Baja Fiero". I will be dropping the cradle 2.5", so I will have plenty of room. I have been taking some considerations into account (based on previous questions answered by y'all), and want to relocate my radiator out of the danger zone (up front and in harms way). Has anyone done this and what do you think the airflow will be like? This would also move most of my weight back over the rear wheels (Baja perfect), and give me a place to mount my 3 batteries (where the radiator was, one main, two 6V aux.). I will be running a 4cyl S-10 "Duke". Chime in with all input please, Crazy ideas often work the best, and negative feedback is positive food for thought....

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carpe diem

You will have the electric fan on it also?

Since it is higher than the motor be sure and put some way to bleed the air out.

Will it also be seperate from the hood so it does not move. That is if you have a hood at all.

I suspect you're going to need a Huge rad and a ton of air flow to compensate for the heat of the engine rising up into it. You're talking about putting it where all the engine heat not removed by the rad goes.

Mounting it back there isn't a bad idea, but I'd keep the decklid (or something) between the engine compartment and the radiator.

What kind of rearward visibility will you need? The radiator would work better at an angle to catch air coming off the roof. You might even want to consider some type of scoop and fairing for the radiator to force cold air into it rather than just bolting out in the open over the engine.

The angle thing is a good Idea, I'll look into that. As far as bleeding out the air, it will be the highest point at the neck of the radiator, so burping will be instant. There will be an electric fan, THE LARGEST I CAN FIND for it. As far as the airflow, that is my dilemma. The cradle will be 2.5" lower, aluminum diamond plate will cover the bottom, and the front will be enclosed(where the rad was). I will be making a custom header that will follow the stock lines, NO CAT, and header to muffler will be wrapped. If I put a small air deflector on the front of the cradle, do y'all think I can get enough airflow up through the radiator, OR, put a larger scoop over the roof and put the air deflector on the backside of the cradle for suction? Does the airflow from the vents (engine bay), suck or blow? I am looking to have this as my DD and only want to do city driving and MAX HWY speed of 85MPH. I live only 4mi from work, but 4hrs from my drill base one weekend a month. I also will beat up the trails in between, but speeds will not exceed 40MHP, but it will be driven like I stole it at that time (Baja Mode).

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carpe diem

The temperature is controlled by a few things...thirmistat,fluid levels.out side temperature and the fan switch.The fan switch kicks the fan on at a specific temperatur,so no matter what modifications you do that fan wont kick on untill a specific temperature.There is such a thing as running too cool,causeing the engine to run rich and the motor wont kick down (bad gas milage).Order Rodney Dickmans Low Temp fan switch and thirmistat.(Im not flameing on anyone,just my 2 cents).If this is an 84 order a bigger oil pan.

I've always wanted to take a Fiero chassis & build something that looked like it came out of a Mad Max movie.

So I'm all for it.

Archie

out of curiosity...are you basing it on a Pisa Jalapeno kit?

[This message has been edited by dcfox (edited 04-18-2007).]

thinking.... could you mount it further up the hood where the spare tire compartment is? that would get it out of harms way?

"The fan switch kicks the fan on at a specific temperatur,so no matter what modifications you do that fan wont kick on untill a specific temperature"

not true, you can ground the switch (mine wasn't working, now it's on all the time, even when the engine isn't running but the auxiliary power is on)

I have many pics of the PISA Jalapeno, but it is just a pretty toy. All of that fiberglass would bust on contact with a small tree. As far as mounting it ON the decklid, it will also rise up WITH the decklid. I am really thinking the air from the engine compartment will blow upward, but I am unsure of the airflow for fiero's now. As far as moving the radiator back towards the trunk (front) I am trying to put most of my weight in the rear. Also I will need that space up front for the batteries, air compressor, recovery gear and tools. Since I can go with probably a 3" thick radiator, large WILL be the case. As far as a bigger oil pan, where would I find such a treasure? I was going to mod mine to 7qts, but if I could find one even just a little smaller, it would save me much headache, and yes, there will be an oil cooler with fan. How do I get air to the radiator though? Has anyone even seen this on ANY other vehicle? If so I can research it. Thank you for all your help so far, I can't wait to show up at a meet with this. Hopefully I can shake hands of all of those who have provided me with some wonderful ideas!

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carpe diem

when i read your first post i envisioned a radiator mounted onto the decklid with a couple of inches of clearance and a really big fan to top it off. go for it.

Actually I am hoping not to see the fan, only the armored grill on top. When you said big fan though, it made me think. I will have alot of room for the radiator, but I forgot about the fan clearance. If I can figure out airflow, I can cant the rad front or rear to accomodate it. Angling it forward would bring in air from the top, vice-versa the engine compartment. Air flow is in question here...

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carpe diem

I don't know if this is new info for you. This was on ebay a few months back. I have no idea if it is correct, but it may be a starting point for Google. As Follows:
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This is a DUAL ELECTRIC FAN that was taken out of a 96+ Ford or Mercurys.

IF YOU REALY WANT TO COOL YOUR HIGH OUTPUT MOTOR, DO WHAT CORVETTE, FORD TRUCK AND DODGE SUPPER DUTY DOES. (USE A DUAL FAN FOR MAX AREA.) WHY GUESS AT WHETHER THE FAN YOU BUY ON EBAY WILL HAVE ENOUGH CFM. THESE FANS ARE PROVEN AMERICAN MADE FANS BY A PROVEN COMPANY. THE MOTORs ARE MADE BY SIEMENS, THE LEADER IN THE FIELD, DON’T GAMBLE. KNOW THAT WHAT YOUR GETTING WILL WORK.

These are excellent upgrades for Fox body Mustangs Hot Rod Land Rover, and Jeeps 4x4s and many other modified cars and trucks. If you have limited area to work with, and can’t use a single fan due to water pump clearance, these smaller shroud fans may work for you. These fans more than 4000 CFM on the high setting. The setup has two 12 inch blades giving a total area of 24 inches for measuring cfm. !!WOW!! The shroud measures 15 inches by 24 inches and is only 2 1/4 inches deep in the center and 3 1/2 at the motor center. The shroud is equipped with a heat coil that turns the second fan on at 225 degree. This set up will reduce the drag on the motor and free up some extra Horsepower. These are the strongest electric fans available. The fans can be wire for several different fan speeds depending on your need. Please email me for further questions. (This will beat aftermarket electric fans that claim over 3000 by leaps and bounds) Unlike those expensive cheeply made fans, the setups housing is a shroud. The shroud covers more than 90% of most of today’s radiators, and can be altered to cover 100%. A fan without a shroud allows air to flow erratically, creating resistance. The shroud allows the air to be concentrated on the radiator only and disperses the air evenly, cooling the entire radiators antifreeze at once.

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HTH

That fan sounds great! the only thing though is at HWY speeds, if the air is blowing over the top of the rad, and I have it set to suck through the engine comartment, the air will buck itself and I will overheat.

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carpe diem

So tell me your NOT limiting yourself to just the Fiero Radiator There are different styles, shapes,and 4-core, ect.

Maybe even TWO radiators !......wait CAN that be done?? like one on the driver side and one on the pass. side

Maybe even a huge one like on the back to the future car.....

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88 GT, 3800SC, Getrag 5sp. 12" Vette Rotors,Custom stuff done

I should have asked before, can you rig a rad to the rear of a buddies Fiero? Carpet, tape, wire, whatever it takes to mount it w/o damage. Tie or tape yarn or ribbons to the rad to see if you have air flow through it at speed. It may take a good friend, but if you think you want air coming from the engine compartment you could remove the original lid and make a plywood facsimile. Cut a hole, mount the rad, use a remote sensing thermometer to check temp coming from engine compartment. With the ribbons and temp gauge, I would try it at all speeds you think you may encounter.

I will ABSOLUTELY NOT run a fiero radiator. A custom design needs a custon radiator. As far as the fabbing up a mock to find out what the airflow will be, that is a no go, too many custom parts and cooked engines cost to much. I was thinking of using a fiero model and making a wind tunnel, but the model isn't very correct. Back to square one, airflow for an actual fiero...

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carpe diem

I was thinking of a dry non functional rad. My thoughts were to test for air flow and air temp coming up from the engine compartment. No sense checking for cooling if you don't have the air.

Couple of options to consider:

(1) Do you care about the rear trunk. If not then mount the radiator vertically (or slight angle) as far rearward as possible and vent it through a rear grill between the taillights. You can have a forward facing scoop that catches air and channels it into the radiator.

(2) You could mount two smaller radiators under the current grills (with fans) and use a snorkel style air scoop that faces forward and over the rear of the roof. It would then exit into the engine compartment, down and out, giving the engine compartment needed airflow. Exhaust pipes do release a lot of heat. Radiator heat is not much of an issue...look at all front engine cars/trucks.
If you use a light bar over the roof raise up 3-4", the scoop could run the length under it and run along the insides of the sail panels. The center 20" or so I would make actually a flow through oil cooler. That would keep the center of a full width roof scoop from being a useless air brake, with the benefit of cooling the engine oil improving its life and that of direct cooling the engine's bearings and bottom end. Don't forget to seal off the center section on both sides to retain the "ram air" effect of the scoop forcing air into the radiators.
This option requires a front mounted battery, which you were going to do anyway.

(3) Another placement option is to make large side intakes (ex. Ferrari Testarossa) and mount radiators in them, venting down or into the engine compartment.

(4) Options 1 and 3.

(5) Options 2 and 3.

For my Fiero, I plan on large side intakes. These two will eventually feed an the engine, oil cooler and inter-cooler. Turbo is a much later project. The inter-cooler needs may be too large for a side scoop though. If that is true then air one side and big oil cooler n the other side.

Starting to ramble...must go... :-D

I like the way you ramble Knight... I originally thought of the dual radiator, but I haven't been able to find them that small. As far as the scoop under the light bar, that sounds good, but I am still wondering what the natural flow of air will be. Exhaust heat will be minimal due to wrapping the header, so I could dam the air in front of the cradle to blow up, or, I could shunt the air in the front and angle the radiator and dam the back of the cradle for suction.

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carpe diem

Look here.

I don't know if that will help you much though, if you will be changing the body lines dramatically. I think the trunk space is a good bet for you, duct air in from the top and blow it out the back of the car...

Good luck.

Ryan

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86 Fiero GT
-Stage eleventy billion...(pieces, that is!)

04 Mustang "Terminator" Cobra
-K&N FIPK
-DiabloSport Performance Tune
-MGW T-56 Shifter

Thanks for those air flow test results, helped alot. I need to take some measurements now and brainstorm a little, It is looking promising...

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carpe diem

OK, here is what I'm thinking. An Isuzu NPR radiator (the Isuzu cabover trucks that are very common now), is about as wide as the center part of the rear decklid (so I won't lose my engine vents). It is about as long as 3/4 the length of the decklid. I was thinking of making it kinda like a spoiler, bottom of the radiator to the front, and the top of the radiator about level with the roof. Build a fiberglass shroud on the sides and keep the rear open. Put the fans under the radiator and put a small wind deflector on the light bar to direct the air over the roof, through the rad and out the back. I know my ideas are crazy, but that is why most of us drive fiero's anyway, so give me some input people! I am hoping to create a venturi effect with the open end. I hope no one is offended by the Isuzu parts on my GM, but it is actually from a GMC W3500 (GM knock-off), so I can actually say the parts are GM!

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carpe diem

[This message has been edited by frankenfiero1 (edited 04-30-2007).]