[sg335]

I had an opportunity to drive my car at Cal Speedway on Monday with very little traffic in a controlled manner at close to race speeds. We did not run the weekend Roval layout, but the standard Infield course. Average air temps were mid 80's with a high of about 89 degrees and low winds. Oil temps stayed at 270 degrees with factory oil UNTIL I tried using second gear for entry and exit of all the turns.

Given the stock gearing of the tranny and rear end, third gear (for this track) is a little to low and does not provide enought torque to pull out of the corners strong, and second gear a little to high which forces the car to run above 6000 rpms. Second gear is faster and requires significantly more work with the gearbox and downshift/braking coordination but worth it for I believe an additional .5+ seconds per lap.

I had no problems with engine limp home mode as long as I did not shift into second gear. Third gear in all the corners provided a constant oil temp of 270 degrees (6 speed manual with oil cooler). However, when using second gear for all the turns, oil temps hit 290 within three laps and the car shut down. One cool down lap and the car was back to running fine. In the following sessions, I experienced the same thing. Run in third gear and the temps are fine. Try second gear for the turns and the car shuts down at 290 degrees. During the last session, I ran in third gear most of the time and only ran second gear for a few corners. Oil temps hoovered at around 280 but did not shut down.

Conclusion: The extra heat generated from second gear extended operation at high rpms will put the car in the "danger zone" of limp home mode. This was repeatable on several occations and and symptom curred by staying out of this high rpm zone. I believe most drivers of the 335 are not experinecing this problem because most drivers will be satisfied with driving in third gear through these corners (Infield road course, not Roval). I believe if we took a poll of those that drive the Infield road course, most would rarly use second gear, and if they did, they would not not use second all the way around the King Taco building section which can be up to six corners long. Third gear through these sections will be satisfying to most and is definately easier to drive. Plus this Infield road course track is short and tight, allowing second gear downshift and track outs, whereas longer road course have more cool down time between each turn. Last month at Buttonwillow, I had no problems with limp home mode simply because there is not an opportunity to use second gear extensively through multiple sections at a time.

This problem must be fixed and a solution found ASAP. I have driven my E36 3.0 at this same track under same conditions in second gear for the same corners all day long (over three hours of track time per day) and never had a problem with oil or coolant temps as they stayed in their "normal" range on the guages.

So is this an oil issue only? I am not sure. There is discussion within the forum of three possibilities; oil, coolant and AIT's. There is also a list of factory shut down numbers for these values, and 290 degree oil temps should not cause complete limp home mode. Therefore I continue to believe that coolant temps are playing a very large role in this overheating problem. I ran stock oil and it looks like my oil temps are the same as those who ran other oils here at Cal Speedway and S4to335's analysis in the other current thread. So I don't think it is the oil so much anymore, but the engine is just putting out too much heat to quickly when running at extended high rpms that all systems are getting too hot too quickly. I am sure a larger oil cooler will help as well as a larger radiator. Better oil and water wetter is a must for now and I will try both next time out. I am very disappointed with this car and its overheating issues to the point that I may just sell the car and get a NA engine vehicle. Anyone want my TCKline suspension?

To address the brakes system, I found them very good for stock brakes, but could not push the car to where I wanted to. The brakes got soft and I needed to back off of them the whole day to conserve there ability to stop the car. The pads held up pretty good for stock pads but an upgrade is needed if you drive your car hard. I still have my race pads I have not used as I wanted to see how the stock system performed. RBF600 or similar is also highly recommended if you are planning extended heavy braking in this car. Again, most drivers will find this stock system fine as most driver schools have lots of participants and it is rare to have no traffic each lap especially in the B C and D groups and therefore one cannot explore the limits of the braking system. The suspension drove great at the track and have no complaints there, as did the R compound tires.

Thanks for listening.