The Shelby American (Fall 2021)

the car was effectively preventing any air from exiting from the radiator out- let, damping back down radiator exit and preventing any air flow and thereby raising the temperature. The changes to correct this were very minor. It was attention to detail. Which you can’t do empirically. You’ve got to check to find out where the air is actually flowing. You can’t look at the thing and say, “ The air will come out here, ” because it doesn’t. SMITH: This may be an embarrass- ing question for you, but do you feel that maybe your British compatriots were falling down in that respect? MILES: No. They didn’t have the fa- cilities. I think they probably they took the original design figures too much at their face value. They didn’t have a big area at the front of the car and a big area in the top. The thing actually ran with the area in the front and ran after the area on the top. But alter- nately what has to happen, in fact it doesn’t. You look at the car and there isn’t any reason why it shouldn’t. SMITH: Had they ever done any test- ing after the original work which I guess was done at the University of Maryland – and I don’t guess that even involved the internal ducting. Had they ever done anything with measuring pressure points on the car or flow? MILES: We were able, for example, with the radiator flow, by raising a small spoiler – a little, tiny spoiler on the front of the radiator exit – chang- ing the air pressure over the exit, we got the water temperature down 40 degrees. Because we let the air come out. SMITH: There is also, at the rear, an oil cooler and a differential or transaxle cooler. MILES: This was essentially part of the weight reduction program. We looked at the car and we said, “ We have to get some weight out .” The car was just too heavy. Quite obviously one source of weight was the front oil cooler and the dry sump system. The dry sump system was obviously very heavy and used a fair amount of space, the oil tank is up front and lines which carried oil up from the back of the car to the front. SMITH: How many quarts of oil were carried? MILES: I don’t know. It was an enor- mous amount. SMITH: And now it’s down to... MILES: Now it’s down to about eight quarts. SMITH: Is that stock for the Cobra? MILES: Yes. Actually, we’ve done a good deal of work with the Cooper. The Cooper we originally planned to dry sump. But we established that we could manufacture a pan within the limitations of the ground clearance, which worked better than satisfacto- rily on the Cooper, so we had to make a decision. If it worked by extension on the Cooper, it should work the same on the Ford GT. The crankshaft center- line on the Ford GT happens to have been the same distance from the ground as the crankshaft centerline on the Cooper. So the Cooper pan was fit- ted on the Ford GT as an experiment and it worked. It enabled us to gut-out the dry sump system, oil tank, lines and reservoir. Now the question was having gutted the oil tank out of the front, do we want to send the oil to a cooler in the front or do we go to the back? So we put a cooler in the back and it did two things for us. It enabled us to cut down the size of the apera- ture in the front of the car for cooling, and saved the weight of the lines and oil traveling from back to the front of the car. So we mounted the cooler in the back. We were getting adequate air coming into the side scoops, more than we needed. So we decided what we would do is split off some of the air coming into the side scoops, so some of it went to... SMITH: Which scoops are those? MILES: The uppers. What you’ve got on each side of the car are two scoops, one high up and one low down. The upper scoops are split with part of the air sent into the carburetor area. Part of it is sent down into the engine com- partment, particularly the exhaust area, to regulate the engine compart- ment temperature. The bottom scoops again are split, part of what comes out of the bottom scoops are fed into the oil radiator on one side and the trans- mission oil radiator on the other side. The remaining air from that scoop is fed into the rear brakes. By doing it this way we were able to use the air much more efficiently. We also cut some big holes in the back of the car to let air out. The side scoops, I believe, were not related to the original speci- fications.We made very minor changes to them. SMITH: The upper scoops were right behind the side windows, and the lower scoops were below and slightly aft of the door. MILES: The lower scoops we didn’t The SHELBY AMERICAN Fall 2021 45