Full Version: How I made my front oil cooler shroud
Here is a sequence of photos showing how I hand made the oil cooler shroud out of fiberglass for the stock aluminum RX-7 oil cooler.....I made the original pattern out of cardboard covered in blue tape. The mold is out of several layers of plaster of paris reinforced with cloth rags. Three layers of coarse matt fiberglass and the finish layer of fine woven fiberglass cloth. I used CUZ body filler to smooth out the outside...
nice.
Nice work. Have you tried it out on track yet?
I've heard that he outlet should be something like 1.6x the size of the inlet. It's hard to tell but it looks like your outlet might be smaller than the inlet? Not trying to criticize at all and I get that you have limited space with the fuel cell in the way. I ran into the same problem with mine. I've made a couple out of aluminum, but am thinking of going the fiberglass route before next season.
I've heard that he outlet should be something like 1.6x the size of the inlet. It's hard to tell but it looks like your outlet might be smaller than the inlet? Not trying to criticize at all and I get that you have limited space with the fuel cell in the way. I ran into the same problem with mine. I've made a couple out of aluminum, but am thinking of going the fiberglass route before next season.
QUOTE(vintage914racer @ Jan 9 2016, 01:26 PM) 
Nice work. Have you tried it out on track yet?
I've heard that he outlet should be something like 1.6x the size of the inlet. It's hard to tell but it looks like your outlet might be smaller than the inlet? Not trying to criticize at all and I get that you have limited space with the fuel cell in the way. I ran into the same problem with mine. I've made a couple out of aluminum, but am thinking of going the fiberglass route before next season.
Very good point........ it is hard to see but the oil cooler is sticking out halfway under the floor board and is wide open to the air flow under the car coming in through the opening in the air dam. The upper half of the cooler is sticking out above the floorboard as shown in the photo. This slit I cut in the floorboard is to allow air from the top of the cooler that is above the floorboard to exit out the bottom. The duct is for this air only.
I have not tried this on the track yet.
The RX-7 oil cooler works fantastic while the car is sitting still and getting hot. I can put my had on the other side of the fittings and it is cool to the touch where the fitting end at the inlet is really hot.
I learned this RX-7 oil cooler trick from my friend who owns the Elliot Forbes Robinson racing 914.
Yes, fiberglass is always better than trying to fab out of sheetmetal.
Just to clarify,
The duct and the windshield valence are made from two layers of matt fiberglass finished off with a layer of fine cloth. The fine cloth makes the inside of the finished part smoother that matt.
Smoke Grey Krylon spray paint from the spray can lays down very nicely and makes a smooth finish.
You can buy the paint, fiberglass, resin, and plaster of Paris from Home Depot. For larger quantities of fiberglass, call Wicks Aircraft Supply at 800-221-9425
I paint the inside of most of my parts flat black.
Work outside or in a well ventilated are or you will kill some brain cells from the fumes.
Bill
The duct and the windshield valence are made from two layers of matt fiberglass finished off with a layer of fine cloth. The fine cloth makes the inside of the finished part smoother that matt.
Smoke Grey Krylon spray paint from the spray can lays down very nicely and makes a smooth finish.
You can buy the paint, fiberglass, resin, and plaster of Paris from Home Depot. For larger quantities of fiberglass, call Wicks Aircraft Supply at 800-221-9425
I paint the inside of most of my parts flat black.
Work outside or in a well ventilated are or you will kill some brain cells from the fumes.
Bill
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