|
Update: I did not get a chance to do the mountain run, but I did take the car to the track as well as some street driving and highway cruise. Also, the highest pressures logged were 13psi. It seems the valve body regulates the line pressure to the cooler circuit and the pressure is typically 8 - 10psi.
Highway cruising at steady state came back with 194 degrees going out of the transmission and back in. Generally, it was very stable and only occasionally varying by a couple degrees.
City driving, however, had a lot more variation in temperatures (as to be expected), but they had a tendency to run a bit higher at 205 degrees coming out of the transmission and 201 degrees returning from the factory cooler. Here you can see the factory cooler actually bringing temps down compared to steady state at idle where the "cooler" was actually keeping the temperature elevated.
For the most part, the factory transmission cooler works great and does exactly what it needs to do when driving Miss Daisy, getting groceries and normal day to day driving.
When you take the FT86 to the track, however, we found that the factory transmission cooler just cannot keep up. At Adams Motorsport Park we ran the 3rd session of the night and it was 80 degrees Fahrenheit ambient temperature. A session consists of 3 runs (3 laps each) with approximately 10 minutes between each run. Each lap took between 51 and 55 seconds.
During the first session, the transmission outlet temperature started at 205 degrees and climbed up to 216 degrees. The return temperature from the factory cooler started out at 199 degrees and climbed up to 214 degrees. OK, no big deal the temperature isn't out of control and there is a 10 minute cool down before the next run.
The second session, however, showed that in 10 minutes, the transmission hadn't dumped the heat accumulated from the previous session and was still fairly warm with temperatures starting out at 214 degrees from the transmission and 212 degrees on the return. By the end of the session, temps had climbed to 228 degrees coming out of the transmission and 223 on the return. Notice that the cooler is only pulling 5 degrees of temperature from the fluid at this point.
Now for the 3rd session, the transmission has really started retaining heat as the outlet temperature remained at 228 degrees and the cooler is not doing so well now that the car is heat soaked with temperatures coming out of the cooler at 225 (only a 3 degree delta). By the end of the run, the temperature had climbed up to 244 degrees coming out of the transmission and 235 degrees going back to the transmission. My gauges were in the red by the end of the last lap and my co-driver called out over 240 as we were pulling into the pits.
Keep in mind that this is just a total of 8 minutes of track time with two 10 minute breaks on a stock car with stock power levels. Most HPDE's at a full size road course are 20 minute sessions. While I would be interested in seeing how high the temps go during a 20 minute session, I'm not really inclined to subject my transmission to that kind of abuse without proper thermal management.
The bottom line here is that if you track your FT86 and you have an automatic, you need a transmission cooler to keep the temps in check.
I'm still going to do a mountain run and log the temps to see how much sustained driving it takes to get the temps to 240 degrees. After that, it'll be time to hook up the cooler and see how it does.
Stay tuned for more.
|