opamps
‘Opamps roasting on an open fire’…
CAN
Since my GTR is getting close to done, I need to get my Analog-to-CAN boards done. I added some auto-calibration routines (since the resistors in the sampling filter are only 1% accurate) to get the channels equal to each other. Endpoints are pretty close, but a tad off in the center. With the input at 5.001V, the channels all get 5.001Vs in the average, but a few have more noise than the others.. and the maximum noise is +- 12-14mV. That noise is almost certainly because the 5.001V input is from the power rail. If you look at the zero input (all 8 channels grounded) most channels are +/- 1mV, which is not bad considering the board layout and the very inexpensive 12 bit ADC.
Right now I sampling at 400hz and decimating to 100hz, but I’ll up that to sample at 1000hz and decimate to 100hz. Doing 8 channels at 100hz over a 1 mbit CAN bus is pretty easy, as that amounts to 200 messages/sec, or about 3% bus load.
Since this is for automotive sensors like pressure sensors and temperature sensors, 1mv noise is sufficient. With a 100psig sensor in the typical 0.5-4.5V output range, 1mv represents .025psi, smaller than the physical variations I would be measuring.
GTR
Progress! Beautiful job notching the frame rails. Lots of sensor goodness coming together.
House
So we continue to make progress on the new house design. The picture attached is my re-drawing of the actual architectural drawing of the basement. There is significant slope from the front to the back of this drawing, and the ‘shop’ floor is 6 feet lower (same ceiling level) as the garage. (Thus the shop has 15′ 6″ height, and the garage only 9′ 6″).
The driveway will come around the right side of the house, sloping down to the first garage, then around to the shop. It is difficult to make the driveway or area behind the shop much bigger as this is at the top of a peak and the falloff is all directions is hundreds of feet.
The question is where to put the garage door on the shop. If it is close to the right side, it would make it difficult to turn into it. There are also 4 pillars (the red boxes) 20 feet back from the end of the house. Those hold up the exterior decking above them. Having the door near the center means less risk of bumping one of those pillars, but makes the lift placement a tad more difficult.
Comments and thoughts appreciated and welcomed!
GTO
I finished up the fuel system as well as the turbo replacement in the 06 GTO. In 3rd gear it spools to target (about 11psi) around 3200rpm, which is about 250 rpm slower than with the smaller .64A/R housings.(now .86A/R) 4th Gear spools around 2800rpm.
1st, 2nd, and 3rd are still limited by the lack of available traction.
Next up is the enable flex fuel and switch to E85.
ID
Since I have my ID2000 injectors out of my 08 STI for service, I thought it would be worthwhile to take a look at the backsides of the intake valves. With about 10k miles of mostly E85 and E98 they look pretty good. I’ll pull the spark plugs next and check out things on the other side.
Drag
So here is a thought for my automotive friends – I like drag racing, road racing, autocross, rally, and pretty much any other form of motorsports.
Drag Racing has a certain popularity in part because it has a comparable benchmark. There are dragstrips all over the world that can measure the same time/distance. There are differences in track condition, but at least the fundamental measurement is the same.
Road Racing, Autocross, and Rally suffer from the problem of uniqueness. Each road course is different, each stage different, and it makes comparisons challenging.
The downside of pure drag racing (and even roll racing) is the singular focus (just accelerating) creates an environment where the compromises to the car become very focused and limiting. You often hear ‘I wonder if that car can turn’ in reference to some very fast 1/4 mile funny cars. There is nothing wrong with specialization and optimization, as that is the nature of competition.
The recent popularity of airstrip racing has a similar property. It is comparable, and somewhat singular in focus. It is cool because of that. It is also a bit dangerous as we have the ability to make car much faster than the safety gear can protect.
What ideas do people have to something similar to drag racing/roll racing/airstrip that would have elements that encourage a broader array of performance characteristics, but is still comparable across sites?
It has to be something that can be replicated, measured, compared, and has balance.
You could have a 1/4 drag race that involved stopping and turning around, or perhaps something that involved a slalom either at the beginning or end, or in the middle.
Other ideas?
MSP
Home away from home.. I hear there might be a little bit of snow in Minneapolis?