VIR with SCCA TNiA: July 2023
HOT day, and testing plans derailed
Newly installed hood vent - newly found unrelated problems.
It was HOT. 90-95F ambient all day.
Track Night in America was fun and I would definitely do it again… just not in 90F ambient temps. There was tons of free space in the advanced group and traffic was never an issue. I was hoping to be able to test my recently added hood vent, and play around with brake adaptations which I have been diving DEEP into research-wise (article[s] coming soon), but I encountered problems from the PCV ingesting a ton of oil in every session. I burned through 1.5 quarts over the course of only (3) 20min sessions - far more than ever before.
I was getting TONS of timing pull - all oil-ingestion related. Per one of the other drivers I was blowing smoke quite often…
Screenshot of a buddy’s camera - smoking through South Bend. Thanks Arul!
I was adding 0.25 to 0.5 liter of oil after each session. I went through about 1.5 liters total.
Between the heat and the timing pull, best I could muster up was a 2:18.something in my first session... it was miserable with sun beating down. I had some flashing of the CEL light (on my tune it does that if timing pull exceeds 1.5deg avg or 3.0deg on any single cylinder), but did not get the EPC light until the second and third sessions. Session 2 it actually cut all power/boost entirely. Before session 3 I flashed back an older tune (more conservative, less boost and less timing), but still popped an EPC light, though there was no power cut involved.
What about temperatures with the hood vent?
As far as the temp logs go... temps were not as good as I had hoped they'd be, BUT considering the ridiculous amounts of timing pull (which adds heat), and the fact I could never exceed 276F even beating on it for 12 min straight once up to temp (min 258F indicated on the MID)... in 90F ambient heat I'd call the hood vent a success, but doesn’t seem like it’ll be an end-all solution (as far as oil temps are concerned).
I need to get the oil ingestion thing figured out and reassess. The hottest I’ve ever logged temperatures in before was about 70-75F heat where I was still able to get the car to 270F+ in a couple laps. I was pleased to see that coolant temp was never remotely an issue at a max of 233F. I’d prefer to see a bit lower, but considering it was 90F ambient I’ll take it.
Temperature logged from session 1 (my only “full” session run). While it was my first session, it was still the afternoon, and I’d just driven ~3hrs to get to VIR. You can see the min/max/average (highlighted between the 2 white vertical lines where temps were elevated) in the lower right corner, and what all the temps started out at the beginning of the session on the left side bottom of each graph.
Note in the above screenshot I have included both the oil temps on the MID (which has been confirmed to be as close to accurate as one could hope), and the calculated "toil" which is used internally in the ECU (and what most people log themselves). Interestingly the "toil" (labeled as “Oil Temp”) is actually lower than the Oil Temp MID, which it almost never is on the many different logs I've seen (once up to temp).
Next steps
This entire oil ingestion problem led down a DEEP rabbit hole on the MK7 PCV system, which is heavily documented here for further reading.
I overlaid my first session on video with some notation throughout - MOST of the knock encountered is following RH turns.
The day wasn’t a complete loss at least…
One little bit of testing that WAS successful was purchasing some temperature indicating paint to find out what my rotor temps were getting up to, which I went over here in a pretty quick 3.5 min video.
What was learned is that stuff gets hot. No real surprise, BUT the peak temp data found (1470F+ for front rotors, ~680 to 800F for the rears) will be helpful in brake pad compound selection, and to evaluate brake cooling solutions in the future.
Also related: here in an article about getting the most from your Performance Pack brakes if you haven’t seen it yet or are interested in seeing what works for me, which also includes all the parts info on the setup run in the video above.
