mini at the track - part 4

Last track day Mini broke the header so we had to call it a day halfway through.

Yesterday I took the Mini to a BMW club's high performance driving education. It was a full day event. I woke up at 6 AM and arrived there just shortly after 7 AM. I packed a light lunch and brought plenty of drinking water. I have been packing light and this time is no exception. Starting next year I think I would bring a set of well chosen tools. I only brought a tire pressure gauge and a IR thermometer so I can rough-check the tire temperature.

There were 4 groups - novice, intermediate, advance, and instructor. The run starts at about 8:00 and ends at 16:00, so a lot of track time.

we started bright and early

tech inspection station

this GT4 is from Idaho

this guy that has a GT3 RS is the most unfriendly person that I ever met at PIR

my friends that I have not seen for 10 years

I think this is a 930 Turbo

a Cadillac racecar

Early that day I noticed the vacuum/boost gauge was not working. The most likely cause of the malfunction is a fitting or connection has failed. It rattled me as it is a mechanical gauge just that the oil pressure gauge. As both gauges share the same routing of the pressure lines this very well can happen to the oil pressure gauge. A leak undetected immediately can be catastrophic to the engine.

vacuum/boost gauge ceased to work

I suspected that the boot gauge rubber tubing that I installed at the intake manifold must have simply been blown off the circa 15 PSI of pressure during full boost. There is very little I can do as I carry no tools to the track. To rectify it will require the removal of the intercooler. Even then to reattach the detached vacuum/boost line will require a long locking forceps to reach into the crevice.

locking forceps

In retrospect, I later realize this has occur a few days ago as I have notice a slight increase of high pitch whining sound.

Also half way through the day the brake indicator illuminated. It took me a moment to adjusted to the idea that it is not a false alarm. It is most likely caused by the front brake pad wear indicator. What surprised me is in the spring when I inspected all the brake pads there was a lot of lining left on all pads. I did a quick peek at the outer pads on both front brakes and saw the little thickness left. This assured me the wear indicator is doing its job. There are enough pad linings left to last the rest of the event.

As I have been braking harder and later on the straights I really abused the stock brakes. By the last session I could feel the brake fade significantly, as well as very spongy pedal. Spongy pedal indicates the brake fluid boiled. I was a bit concern about outright brake failure which can ruin the day.

brake indicator illuminated

There were 4 sessions. I was very lucky that my friend who organize the event offer to ride with me. This is my 5th track day ever and I can use some coaching.

I have no experience what impact to the ECU engine management with the leak at the intake manifold because of the vacuum/boost gauge fitting. My assessment is running it for the rest of the day is unlikely to cause any harm to the engine.

As I review my lap times I was surprised that they are not better. I then begun to ponder the possibility the not so good lap times is due to the leak. For both front and back straights I have begun to accelerate earlier and brake later and yet the top speed is a bit lower than my previous track days.

Looking the the muffler tips the appearance suggests the Mini has been running lean - hence supports my suspicion that the vacuum/boost leak has caused me lap time.

In the last Instructors' session a highly modified Miata peeped all the engine oil between turn 10 and 12. Two cars after him at the turns including the Porsche GT3 RS spun out, but thankfully no car was damaged. We thought they will just call off the remaining two sessions including mine. The crew spread oil absorbent material and sweep it on the affected arc shaped area of the track and reopen it. My group the first to run. I asked aren't they going to use a road sweeper to sweep up the material. Someone joked that our group of cars is the sweeper.

normally the inside of the tailpipes should have a slight black soot - but it is light grey even with a lot of WOT

Everyone took it easy there and no one spun out. Many drivers did not run, but I did. By the 4th lap you can hardly tell the track is any different. I am amazed how effective the oil absorber.

By the end of the day braking at the end of the straights I could feel front suspension shakes. It felt as though something has worked loose. It was hard to tell what it is, as I know the hard braking that that have been very hard on the pads and the rotors. I could tell the grabs on the rotor was no longer smooth, so the vibration can simply be induced by it.

As soon as I got on the highway to return home, I notice the fuel tank reserve indicator has came on. The Mini burnt through a whole tank in the track day at approximately 10 miles a gallon. We managed to get off the next exit to a gas station to refuel. Based on the tripdometer the Mini accumulated 100 miles at PIR. Checking the lap timer record confirms it.

Like I have wished. I wanted to use up my all stock brakes before installing the Wilwood front brake kit. The only problem is I still need the stock brake to get me through the fall and winter. Next season I will install the Wilwood brakes.

the front stock brakes took a bad beating

Last night I looked into where the vacuum/boost gauge has come loose. Before I remove the intercooler I immediately notice the outlet side rubber boot has shifted again. The oil make the boot very slippery so it can easily slip from any horizontal pressure. I slid my index finger along the oil coated aluminum air horn to wipe off the oil. Big mistake. The ridge left by the machining and the rough aluminum casting has left a sharp serrated knife edge and I cut my finger.

As I suspected the vacuum/boost line has came loose at the intake manifold. The Gates vacuum rubber hose that I used has slipped off the small metal nipple from the boost pressure of 15 PSI. In the presence of engine oil vapor it should be no surprise the rubber hose popped out. It was getting dark fast and I have to think of a quick and effective fix. The obvious fix is to add a small cable tie, but the problem is it is in a crevice and one cannot reach it with even a finger. I managed to make a tighter fit by adding a cable tie pre-tightened to the hose before slipping it onto the nipple. This work as I utilize the elasticity of the very good quality Gates vacuum hose.

It seems that when I reinstalled the intercooler it was slightly bias towards to the inlet air horn. By adjusting the two leading steel brackets I even out the split between two side, and hope this will correct it.

I recorded all four sessions of video but I ran into some problem with the Harry's Track Timer app, and I want to be careful not to risk losing the video and data overlay.