Driving laps on a race track is considerably hard on a vehicle. The engine, trans, and brakes are a few things in particular that take much abuse. So, it’s crucial to take measures to help reduce the wear on those components. Coolers, cooling ducts, fans, and fluid types are all things to consider adding or upgrading before driving on a race track.
When I first purchased the Cruze, I didn’t intend on driving it on a race track. I just wanted a nice car with specific options. The LTZ trim had all the options I wanted, but the one thing that wasn’t an option was a manual transmission. The LTZ came only with an automatic. At the time, it wasn’t that big of a deal, but after deciding to prepare the car for track use, it was a big concern. An automatic transmission isn’t exactly the transmission you want on a race track. I have no clue if the one in the Cruze is capable of handling that stress or not, so the first thing I investigated was the cooling.
The stock cooler was a little thin, and I couldn’t find any information on what the temperature rating was for the thermostat. Another thing was the transmission fluid passing through the endcap of the radiator. I’m not an engineer, so I can only assume that since there is an external, front-mounted transmission cooler, the trans fluid passes through the end cap of the radiator to help get the trans to operating temperature more quickly. I have seen coolant temps as high as 215 – 220 on the Cruze, and the ideal transmission temp is 195 or below, so I can’t imagine it’s to help with cooling.
Anyway, I decided to upgrade the trans cooler to a larger one and upgrade the thermostat as well. After searching for available options, I came across Improved Racing products. The thermostat was the first of their products I saw, and it looked stunning. It’s made of billet aluminum and has several fitting types and sizes to choose from. They also have a patented design that keeps the bypass valve out of the primary flow path. They offer several temperature ranges to choose from, so I decided on the FSM-165. It works to keep the temperature around 165 degrees by closing the bypass and sending full flow to the cooler at 180 degrees. The FSM-185 was a consideration, but I thought the full flow temperature of 203 degrees was a bit high for the transmission.
The cooler size I determined by measuring the width of the radiator. I also wanted to add a proper oil cooler, so I measured the width of the radiator and selected a cooler half its width. I could then add another cooler for the engine. I went with Improved Racing’s 19-row cooler. They offered it as a package deal with the thermostat, which reduced the total cost. The cooler seemed well-made and looked almost identical to the Setrab coolers. You can also select whatever size fittings are appropriate for your installation. The transmission hard-lines are 3/8-inches in diameter, which equates to a -6AN hose, so I chose -6AN fittings for the cooler and thermostat.
The installation wasn’t complicated, just time-consuming. The trans fluid needed to be drained, and then the front bumper cover was removed to access and remove the stock cooler and lines. After removing the lines, I went ahead and plugged the ports where the fluid passes through the radiator end cap. Since I’m tracking the car, I want to keep the trans as cool as possible, so it made sense not to have the fluid run through the radiator. I only need to make sure the trans fluid is warmed up before the car goes out on the track.
The next task was adapting the new -6AN hose to the transmission. I took the stock hard-lines and cut them with a metal tube cutter a couple of inches up from where they connect to the transmission. I ordered two -6AN to 3/8 tube adapters that use a compression fitting to adapt the tube to a -AN male fitting. I also ordered a tee adapter, so I could install a temperature sensor to monitor the trans temp.
After I installed the tube adapters, I mounted the thermostat and coolers. I mounted the thermostat under the front bumper bar and mounted the coolers on top of the bumper bar. I had ordered the oil cooler along with the trans cooler, so it would make the oil cooler install a little easier down the road. Once all those were mounted, it was just a matter of measuring the hose lengths and installing hose ends.
Once I assembled the hoses, I connected them all to the cooler and thermostat but not the transmission. They needed to be flushed out before they were connected. I just attached a hand siphon pump, with a -6AN adapter, to one of the hoses, stuck the other hose in a bucket, and siphoned a quart of trans fluid through to flush it all out. After the flush, I connected the lines, filled the transmission with fluid, took it for a quick test drive, checked for leaks, and installed the front bumper cover. Installation complete! Now I hope the transmission handles some track time.
DS
