Sunday, July 08, 2007

Cooling the Cobra

When I first purchased the Cobra I researched as much as I could about it's strengths and weaknesses when run hard at the race track; most of my information came from the forums at SVTPerformance.com.

As is common among relatively inexpensive high horsepower cars, the Cobra runs very hot at the race track. In fact, after hard lapping for about 15 minutes it starts to overheat and when it reaches 245F (coolant temperature), its engine management computer puts the car into "limp mode" which effectively cuts back maximum power; thus reducing the heat generated by the engine. In anything above 70F ambient temperatures, my Cobra, as predicted, overheated in this manner.

The culprit is a wholy inadequate cooling system from the Ford factory. I read about the ultimate solution, called the Evans Cooling System, early on, but it costs serveral thousand dollars (including installation), so I've been playing with less costly changes. None of which helped, so, in the end, I recently had Cantrell Motorsports install the Evans Cooling System.

The two main things the Evans Cooling System addresses are the thermostat and oil cooling.

In the stock system, the thermostat is flawed in a way that allows too much coolant to go through the bypass rather than through the radiator. The kit relocates the thermostat and the bypass routing. Here is a picture of the new thermostat location, the black round thingy in the center.

Relocated thermostat

The stock system utilizes a water-to-oil heat exchanger to cool the oil. The problem with this setup is that it effectively uses the radiator to cool the oil. Add this to the flawed thermostat design, the coolant simply can't be cooled enough.

To address the oil cooling, the Evans system does away with the water-to-oil heat exchanger that is an integral part of the oil filter housing. The oil filter is relocated under the bumper and Cantrell added a Mocal oil cooler just ahead of the left front tire.

This picture shows the relocated oil filter and the new oil cooler (note, this is someone else's car, but my setup is basically the same).

Relocated oil filter

This picture is of my oil cooler.

Oil cooler

And here is Brandon at Cantrell Motorsports, doing his usual magic on my car :)

Brandon at Cantrell Motorsports

The first test of the new system came last Wednesday (July 4th). Ambient temperatures were in the 70's and low 80's and the Cobra was able to run at full blast for 30 minutes with no overheating!! Yeah!!

Coolant temps hit a high 236F, but stayed there. Post-intercooler intake air temp (IAT2) was in the 160's F. Both temperatures are still too high; coolant should be closer to 220F and IAT2 should be closer to 130F, especially to maintain full power.

Stay tuned for updates on future Cobra cooling...

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