Tribology

Monday was 100% up.

Headed out to GingerMan for a CGI track day. Paid an extra $50 for an instructor and requested a RWD person. Got a guy with a 600hp Corvette. We did the standard Novice run at my request, minus the classroom. 

Holy ****. I have CAR. 

The instructor (Mark) helped me find a functional line and had me pushing into oversteer in two useful locations on the track. The line is so incredibly different. We spent the whole day talking about the differences and why I was defaulting to certain (FF) behaviours. He actually drove the car for the first couple of laps and said that it is far better than he had imagined and continued to comment on how awesome it is the whole day. That was kind of cool. He said it was a big treat for him to have an experienced driver who knew all the basics and he could just focus on getting me around the track faster. That was really cool to hear.

His evaluation was – my inputs are great, super smooth, and very controlled, and my experience was clear. Once I had a new line down, I was holding it and driving very consistently. He said he could see me moving around a little to try things out. We are both DR people (there is one section of GM that can be run DA or DR) and he said that my path through there was really sweet and that basically from inside of 3 to through 11 I was kicking ass and only going to get faster. I still need to polish 1 and 2 and the entrance to 3. He said the biggest deal of all was that I was pushing into oversteer and not freaking out. I was not oversteering that much, but I guess it was enough to count. I was just countersteering it and riding it out for fun. Because of the placement of the line he recommended, I had plenty of track to use for that. So no stress. 

I ran my last session solo and railed it. 

Met a bunch of 86 people (five cars started, one lost their engine , one runs Midwest 86 Cup) and learned about AIM Solo telemetry. Might need one of those. 

So tons of positive feedback about my driving and met new people and had a blast and started to actually DRIVE my little blueberry.

So. One last note on the PP Brembos. I have way more brakes than I realized. Like OMGHolyCowWTFBBQ brakes. Like Last Stick Brakes. Hmmm. That would be a good name for a friction supplier.

Still catching up on blogging here….

Another awesome day at Waterford Hills. 

Spent time continuing to work on evicting FWD habits. Spent lots of time on not braking (again). Getting speeds up and working on my own brain. 

The Azenis are very good, but I could feel the left front rolling up a bit. I was down to 20psi (cold) in that corner with about 25 RF and 35 in the rear. WHRRI eats up front lefts on all cars. I could have probably dropped the LF even further. The tyre is visibly heat cycled hard – getting a bit furry. Lots of rolls of rubber around the entire circumference of the one solid band of tread. I could feel the rolls building up in certain corners. That’s a super new experience and I love how communicative the car is about what is going on in various places. It was a really hot day (temps 90+°F) and I could feel a bit of greasy trying to come in at the ends of the sessions. But just a tiny bit, not enough to worry about. These will be fine for Gingerman when I head out there next month. I’ll be at the CGI day and have spent the extra cash to get an instructor for the day, even though I got booted from novice. 

One thing I’m starting to understand is that there are no truly bad tyres for this car. There are sticky tyres and not-sticky tyres, but all of them can be driven with the right attitude. I had the Michelins back on briefly trying to track down a noise (Brembo’s crappy PWI!), and found that since my first good day at WHRRI, the lack of grip was far less annoying. I felt a lot more in control of the car whether I had traction or not and was way less bothered by the tendency of the tyres to give up. So basically the driver is the fail, not the tyres. 

ie – the driver needs more training. 

 Must do more track days! Oh, darn. 

Then went home and spent the better part of 30 hours working on my son’s #RustyMR2. Will wrap that up after work today.

I hit Waterford Hills back in June. Here are some notes.

[URL=”http://www.waterfordhills.com/”]Waterford Hills[/URL] was excellent. Ran with the Trackalicious group, well-run day, only one incident involving a new Camaro that was a total loss. Sad as the driver was improving. Waterford Hills is a small track, barely more than a big shifter kart track. It is tight and fun. Very zoom-zoom. I think about 1.6 miles. Elevation change, a wall, some narrow runoffs, and a swamp. And like all of Michigan, turtles. They repaved it for this season and the surface is AMAZING. Considering that the old surface was half asphalt and half concrete, I am estimating that about 20% of my bandwidth was freed up due to no longer having to think about pavement transitions. The company that does Watkins Glen did the work and it was soooo worth it. Track went from thank goodness it’s close to home because that is the only redeeming factor to OMG, need more WHRRI days!!

I spent two sessions sorting out my new line, which was interesting as I was starting to carry some speed. Third session was devoted to the turn at the end of the back straight, which still requires work and braking practice. Fourth session was all about no longer braking for every little wobble in the track. That works great for FWD, but…. So by the end of the fourth I was carrying a lot more speed around the track, which was really fun. I think on my first lap, I probably pulled about 50 in Big Bend, by the end of the day, I was holding 65+ through it. That is a lot of improvement. I also was able to stop braking on the uphill section. This is so new to me and so much fun to be in the learning curve again. Last session, I just goofed off and stayed on my line and relaxed.

The Azenis RT615Ks performed well. They are now making an incredible racket. I thought I was losing a wheel bearing. Nope, tars. My LF was taking all of the load and the temps (hand check) were letting me know that. I did get a cheapo IR gun off amazon for $15 for next time. Emissivity be damned, it will be close enough for me.

The Schroth Rallye3 worked really well, in fact, better than I expected. I conned another driver into pulling my hip tabs for me, which made all the difference.

So, a great day and I am super happy with the car and finally feel like I am getting somewhere with it.

Possibly a strange habit, but I like to take cars as received to a track I know to get a baseline. Also a bit of a baseline for me as I’ve spent my track career in FWD VWs.

Saturday was the day for my bone stock ’18 PP BRZ.

Grattan is a challenging a fun track and is Michigan’s little piece of heaven. If you haven’t been there, imagine those videos of the Nordschleife and cut it down to just over two miles. It is truly a wonderful place to drive. I’ve got a lot of laps there, but the last time out there was about eight years ago. That is a lot of ground to make up.

One thing that helped me was that I was assigned to do the classroom for the novices. I actually love doing this. Club day, so we try to make sure no one gets in the (literal) weeds. No, seriously. The bottom of the track is a swamp, complete with turtles. For a first day out, it was actually really helpful to go through the routine with them and put myself in the novice mindset. I ended up basically driving control (this appears to be a motorcycle thing) and doing lead follow laps with all of the assorted novices. This had the side effect of forcing me to pay strict attention to my lines instead of just screwing around. I found myself able to go much deeper into the turns than I expected and what traction I had was useful for pushing turning.

One new challenge at Grattan is a repave of sections of the track with some very weird tar surface. Grattan is challenging enough dry, but this surface and water did not agree. I experienced something new to me – skittering. I have not experienced a car hopping sideways across the track before. That was rather unsettling, because it was a start-stop behaviour instead of a slide. There was not a whole lot of steering into it as that just caused the traction control (even light) to go nuts. I have not perfected the pedal dance yet, so getting rid of all of it was not an option.

I have to address that being new to RWD (except for about 5 years as a kid) cost me a ton of time. It’s like learning to drive all over again. I have a good feel for pushing the car, but not for sliding it yet. The skittering was really off-putting and once I figured it out, it was a matter of keeping two wheels on the old pavement at all times. I needed a lot of laps to get my reference points back (needed as the track drops away in several places) and I am a lot rustier than I had hoped. I’m pretty good everywhere except turn 3 now. 3 makes the Corkscrew seem like a walk in the park. It’s so blind (downhill and off camber left) that it is now officially the track exit, mostly because people freak out and drive off right there. I think it took me several days to get it the first time, so no crisis. I’m slow, it’s ok. I have the jump, the esses, the bowl, the bus stop, and the valley back in my brain now.

So enough about me and the track, now the car, with a brief weather report.

The day was cold (low to mid 50s) and rainy. Then came the hail. And more hail. Then more rain. Not the best conditions, which contributed mightily to my experience.

Holy hell, the stock tyres are hilariously bad. Forget worrying about brake updates, the first things that need to go are these stupid tyres. I have experience quite a bit of wandering on longitudinally grooved pavement here in MI, and after a few skitters, I was able to associate it with the rain grooves in the tyres themselves. They seem to be folding over and breaking traction, then catching it again. Like slideways ABS? NO. Like driving me batshit crazy. I think a fair amount of this was due to the weather conditions – summer tyres right at the thermal limit of performance. I had one session where the track was dry and this was far different than the rest of the day. The control was there, I was able to avoid ABS, no skitters, etc. That was a good session and instead of learning new ways to avoid engaging TC, I was building speed in the corners. My hope had been to practice entering little slides, but that did not happen.
Brakes never really got tested because I was never going that fast.  ABS is minimally intrusive – I prefer more feedback! It’s useless as a training aid if you can’t feel it. Again, the weather contributed.

Steering was tight and predictable.

The seat (which is outstanding for everyday driving) was ok, but a proper high seat and harness are going to be necessary. I’m spoiled in that all of my VWs have had harnesses, and some have had seats and cages. Trying to track a car without being attached to it is uncomfortable and less fun. I was seriously sore everywhere at the end of the day. Except my legs, which was nice. My upper body was feeling it from being in motion so much. I ordered a CGLock and then forgot to install it. It would not have helped with the upper body movement, though, and might have made things worse.

The best part of the day was that another BRZ driver was among my novices and he improved greatly throughout the day.  The second best was discovering that my old endurance car still lives and is actually the west side track rat for our VW club. I got home and found the title, we are going to plate that sucker. It is a beast – ABA swapped with GTI brakes, and caged with two seats and harnesses. It even has window glass now! It weighs all of 1820#. It is soooooo much fun to drive. Pure point and shoot.

There are no bad days at the track if you can drive home. It wasn’t a great day for me, but it was a great (new) start.

I’ll be browsing TireRack now…. 

emojis courtesy ft86club.com

I mentioned that I’ve been riding the Sherpa a lot lately due to a shoulder injury, and it’s been a total blast for the most part. Just not the grooved pavement part.

Last year, I fitted the little green bike with IRC TR8 tyres front and back. They are a good medium duty knob that is regarded well for its on-pavement performance and durability in addition to its very good dirt and gravel chops. I like them a lot on gravel and on grass (yes, I ride on the lawn), and find them to be pretty decent on asphalt.

Unfortunately, a large amount of Michigan seems to be grooved concrete, and knobs and grooves do not seem to get along well.

I initially played off the serious instability of the bike on the tyres being knobs, but the truth is, the TR8s are not a particularly squirmy tyre. If they were, I’d notice the issue on all roads. I finally traced it to the grooves when a colleague noted that my rear tyre was “moving around an awful lot” after following me on I696 one morning. Another day, I had a braking “incident” where I locked the rear while stopping for a red light and the little bike became extremely squirrely. I revisited that lane later and found that it was not only grooved, but the grooves were full of silt and sand. My guess is that there was just enough low traction material to keep the knobs from biting the grooves, and that led to the lockup. I rode it out and did not hit the car in front of me.

I suppose that the lightness of the Sherpa is interfering with me feeling how much the bike actually is moving under me. Apparently, I’m becoming rather used to it and no longer bothered at all by the extra motion. This is a big step forward for me as a rider – I’ve had some fear about handling low traction surfaces and now I find out that I’ve been living with an entire low traction bike for the last two months.

The role of traction* in the stability of a motorcycle is interesting. Too much at the wrong time, and you are flying over your bike in a high-side dismount. Too little and you are hitting the ground in a low-side fall. Somewhere in between (and a pretty big section of in-between, thankfully) is enough traction to stay upright and move forward. Control of the traction force is up to the rider – one can spin up the rear in a nice, smoky burnout, or manage rolling at just the right speed to keep the rear tracking around a hairpin. That burnout is a roost in dirt, where the surface determines more of the traction characteristics than the tyre does. The knobs on knobby tyres allow the tyre to dig into the surface and grip more of it, trying to catch it and lock into it. Roosting occurs when the surface is torn up and thrown into the air. Obviously, this is a bit challenging to do with concrete, so the tyre gets torn up and thrown into the air instead. You can think of the difference between street and dirt riding in terms of which surface is the primary sacrificial one – while dirt tyres do wear (and quickly!), the surface takes more of a beating than the tyre does. This is why motorbikes are often banned from outdoor recreation areas – too much damage to the trails.

Riding in a situation where the traction is not at the operator’s complete beck and call can be unsettling, at least until it is ingrained into the rider’s personal physics. The old term “backing it in” refers to breaking traction at the rear while sliding the bike around a turn. Done properly, this is a very controlled use of traction (or the lack of it) to the rider’s advantage. It requires the rider to have significant comfort in the lower traction environment. One needs to feel confident that they can successfully hook back up and ride it out, without hopping over the line on the track that leads to a high-side. Where better to learn this than on knobby tyres in the sand or loose dirt?

All of this musing here is about me coming to terms with low traction. I’m finally starting to really get a feel for it. The baby GS has great Metzler Tourance tyres on and they are profoundly stable under many conditions. Add in the bike’s rudimentary ABS (it’s fine, quit bitching), and the bike is rather insensitive to traction condition transitions that would send the Sherpa and its knobs into orbit. Me along with it, too. Logging more seat time on the little bike with its little traction is helping me understand what low traction feels like and how to not only manage it, but relax and enjoy it. I’m not sure I’m ready to slide all 425# of the Beemer around, but I find that I’m getting less and less freaked out by the wandering rear end of the Sherpa each time I get on it, and what I used to consider frightening wobbles and stepouts are now just situations that require me to moderate my control inputs. I’m thinking less about everything associated with low traction now and riding it all more. Grooved pavement is no longer a navigation avoidance parameter.

Yikes. I might actually become a decent motorcyclist one of these days.

*Traction is friction in the presence of rolling, and is related to friction by the differential speeds of the two surfaces as described by the slide/roll ratio. I’m happy to pontificate on that, it’s kind of my thing.

Everyone who knows me knows that I am a big fan of Hawk Performance brake linings. Ever since my first set of HPs pads on the B5, I’ve been running various Hawk compounds for various purposes. I usually match the compound of the brake linings to the tyres I’m running, so HPS with my winters and HP+ with my summers.

Recently, I needed to repair a leaky power steering line and in the process discovered that I had a loose pad on the front axle. Further investigation found that the lining had separated from the backing plate. This is pretty much a catastrophic failure for a brake pad, so I’m glad I caught it when I did. Considering what the car has been through, I wasn’t too upset with the situation – the car sits for longer periods of time in the summer when I don’t really drive it at all. Add in all the winter salt and who know what’s going on there.

We do some brake bonding at my employer – designing the adhesives used to hold the linings on the back plates, so I was curious to hear what Hawk had to say. I reached out through their customer service contact page. A few days later, they came back, asking for photos, which I gladly sent in. Almost immediately, the answer came back – “we can warranty those for you.”

img_3482.jpeg

So, I have to say, I’m pretty darn pleased with Hawk. Not only for the performance of their linings, which I really like, but also their Customer Service team, who took care of this issue. No doubt there will be some sort of work on their end and hopefully my pad set was an anomaly. It’s refreshing to know that they stand behind their product even when things go pretty wrong.

Thank you, Hawk!

Germany has a rule-based culture, and a fair chunk of life is spent figuring out how to get around the rules while still obeying them. Spirit vs letter of the law. In the US, we prize the Spirit of the Law. In Germany, it is the Letter of the Law. Once I figured this out, my life in Germany got to be fantastically easy. Just figure out how to get around the rule while creatively applying it, and you are fine. VW’s emissions control defeat programming would put the cars in compliance with the Letter of the Law, which specifies the testing conditions, while violating the Spirit of the Law, which says “don’t pollute”. 

I am totally guilty of this, and I think the statute of limitations is up by now.

My wonderful MkIII Golf GT TDI (up top there) was not really in compliance with anything. It was low. It was leaky. Very leaky. And it sort of stopped. However, it was only a few hours of work away from passing the TÜV.  Just like every other modified car in Germany – I had a procedure to get my car ready.

This is what it took:

  1. Porous head gasket. Several cans (ok, close to a case) of engine cleaner, a lot of rags, and two toilet brushes. Over the course of several hours, I removed enough oil and coolant residue to power a small nation. I also ran the coolant mixture down to about 10% glycol. Arrive at testing station just in time so car is hot.
  2. Badly worn summer tyres. Swap on winter wheels with good snows. Same thing if I was running too-large wheels, but I wasn’t.
  3. Lame brake pads. While I was in there swapping wheels, pull off all of the calipers and rough up pads and rotors.
  4. Barely clearing the 10cm bar. Leave car up on jackstands for 24 hours and drive gently to testing station. Bring certification letters for suspension with me with setup that passes circled. I had considered removing the front valance, but this risked failing the obviousness test.

When I arrived at the testing station, the car was solidly at 11cm and my coil count matched the paperwork. Braking was acceptable. I got some dirty looks for my snow tyres because it was May. I earned a comment on how clean the engine was. I noted it and realized that I should have cleaned it a week earlier to look less obvious. And the emissions check was thankfully in spec with no weirdness.

I failed on a broken reflector lens.

When I went back two weeks later, the lens was all they could check. So my clearly leaking (it was dripping) and obviously too low Golf was cleared for driving, because I passed the test as it was written.

I feel kind of funny saying this, but the “pass the test as written” is a cultural thing. With regard to #Dieselgate, I am willing to bet all of Internal Combustion knew exactly what was up and didn’t really think it was that big of a deal, because they passed the test. Oops.