Yesterday was a success in general. We ended up converting an engine to run on points and a coil, which turned out very good. It looks like the engine that we will use in the final car. We will probably transplant the flywheel and coil stuff to our brand new engine with the new head. The we will port and polish it and do a final dyno run.
The coil set up used a lot of power. While running, it was pulling 80 watts, , which made the coil really hot. We had to install a switch so it wouldn't drain our battery pack so fast.
While running the treadmill dyno yesterday, the key that holds the 3" pulley on the treadmill motor came out. Unfortunately, some of the material stayed inside and jammed the pulley on the shaft. After about an hour of trying various things (hammer, pipes, hair dryer, C- clamps), we gave up and decided to keep running the dyno. After a few more minutes, we sprayed some lithium greese inside of it. Once we got it up to about 4k rpm, she decided to let go and fly off the end of the shaft. The belt didn't fly too far, but the pulley spun on the table for about 20 seconds
It took about 40 seconds for the treadmill motor to stop, since it had no load at the time.
When we got it all back together, we did a couple more efficiency runs using the brand new engine, which yielded 10.1 % compared to the 9.7% for the points engine. Both percentages were lower, probably caused by the bent pulley.
Also, we got the solenoid clutch working. Only about 10 min more work is needed for it to be done. It does take two 14v packs to run it, but as long as it is reliable.
I also did a careful discharge of our lipo batteries to see if they could hold 14v while under load. It turns out that the computer actually needs >14 volts to run, but putting 26v to it would cause too much heat in the voltage converter. I ran the 1350 mah 4s lipo pack at 4 amps. It finally dipped below 14v after 1183 mah, so I deemed it a success. The computer will pull less than 1 amp.
The carbon fiber for the cooled seat fan was finished and the cupholder was also worked on.
Sorry for the lack of photos. My camera was accidentally left on and the battery was dead. Next week, the car should be back from the paint shop and we will put everything in it --> lots of photos then.
EDIT:
I looked at the data from yesterday's dyno runs and calculated the efficiency.
Once I added the # of lightbulbs in, the numbers came out as follows:
The points engine was 10.0% efficient at 1.4 hp. Peak power was a new record of 2.36 hp.
The brand new engine was 11.3 % efficient at 1.54 hp.
Both efficiency runs were done with the same mangled pulley, hence the lower numbers when compared to before. The belt was jumping a quite a bit due to the pulley.
I think next week we should add the coil and points to the new engine and possibly port + pollish the intake and exhaust. I think there is a good chance that the new engine has some differences that may increase the efficiency.