OCRC Saturday Series, Mid-Series Recap

I've been running the OCRC Saturday Series, put on by OCRC Raceway. It's halfway done with round #5 coming up tomorrow and the final race on the last Saturday of July.

I did alright in round 1, making the A main in both Stock Truck and Buggy, qualifying 4th in both classes. I remember being really tired the entire day, since I didn't get much sleep the night before, and I had no coffee to wake me up in the morning. The only time I felt "awake" was when I was driving! LOL! I did really well in Stock Truck moving up from my 4th place qualifying position, and finishing 3rd :) I blew out in Stock Buggy though :( I got a bad start and made too many mistakes, finally dropping down to 6th.

Round 2 would be held at Hot Rod Hobbies, the only round of the series to be run at another track. I was able to make both A mains for Stock Truck and Buggy, but I was in the back of the pack (7th in Buggy and 6th in Truck). I finished each race where I started :( But, at least I made the A main.

Round 3 was back at OCRC, and was the last race of Block A. In the next 3 races (Block B), the points are doubled, so I wonder how the series positions will play out. Competition at this round was much tougher and I was only able to make the A main in Stock Truck, qualifying in the 7th position. I was in the B Main for Stock Buggy, qualifying near the bottom of the main :( I moved up 1 position in the Truck main, finishing 6th, while I was able to finish 3rd in Buggy (still the B Main though).

Round 4 would be the first race in Block B. I qualified really well in Stock Truck, getting the 3rd position on the A Main grid. My showing in Stock Buggy was not a good though, as I was near the bottom of the A main in the 6th position. In the Stock Truck A main, I held my starting position in 3rd, and was gaining on Brian Halverson in 2nd. I kept reeling him in, then he made a mistake in the big double-double jump in the center of the track, and I was able to jump over him into 2nd place! I held on till the end, finishing in 2nd :) I didn't have such a good result in the Stock Buggy main though, qualifying in the back, then finishing in the back :( Owell :(

So, after 4 rounds I'm sitting in 7th place in the points for Stock Buggy, with the Block A throwout. I'm doing much better in Stock Truck though! I'm currently 3rd in the points, only 2 points behind 2nd! Thus, I will be concentrating more on my Truck than my Buggy for the last 2 races of the series.

I will be heading out to OCRC to race the Club race tonight, to get some practice in for Saturday!

More action pics!

These are from Round 4 of the JBRL Series held at Pegasus Hobbies in Montclair :)

New charger!

I decided to replace my trusty CE Turbo35 charger with a more compact one to use at the track. While the Turbo35 works great, it's overkill. It's big because it has a huge heat sink and fan in the back to dissipate the heat created when discharging batteries and needs a 12v power supply, thus taking up a lot of room in my pit space. I will still use it at home to rate my LiPo batteries as it can measure average discharge voltage and internal resistance.

When looking for a new charger I wanted it to have a built in power supply and be capable of charging up to a 6S LiPo. The 3 chargers I considered were the Electrify EQ2. Hyperion EOS 0606i, and Muchmore Platinum Silent Charger. I picked the Muchmore charger as I already had an Electrify charger and wanted something different, and didn't like how the Hyperion didn't have a detachable DC input cord.

So far I've used it at the last OCRC Sat Series and JBRL race, and it's been working great! Easy to program and use. The only thing I don't like is that it takes forever to get up to the maximum charge rate, as it increases the amp rate at 0.1 amps every 20 seconds. So it takes nearly 18 minutes to reach a 5.0 amp rate. My CE charger reaches the max amp rate in less than a minute. I tested some batteries to see if this impacts its performance, but it doesn't seem to. The battery charged on the Muchmore charger had about the same IR and Avg discharge voltage, but about 144 mah less capacity or 26 seconds less run time, which doesn't make much of a difference anyway.

Car diet

So, I've put both my B4 and T4 on a diet! Both were overweight and I wanted to get both as close as possible to the ROAR minimum weights of 1499g for buggy and 1701g for truck.

The buggy was easy to get under weight, by installing Lunsford titanium screws and ball studs. I would have rather used aluminum screws, but AE doesn't sell an aluminum screw kit anymore :( They used to for the B3. Thus my final setup is:

Factory Team B4 Kit with all carbon parts
Factory Team aluminum in-line front axles
Factory Team titanium turnbuckles
Lunsford titanium hinge pins
Lunsford titanium shock mounts
Lunsford titanium screw kit
Lunsford titanium ball studs
Airtronics 94157 servo
AMB personal transponder
Futaba R604FS receiver
LRP Sphere Competition ESC with heatsink attached
LRP X11 17.5 motor with optional thin cooling plate
Reedy 35C 5000mah lipo battery
14g lead weight in back of chassis
AE wheels with JConcepts Bar Codes with standard inserts
JConcepts Illuzion body and wing
Race weight is 1500g, 1g above the minimum weight :)

The truck was a bit tougher to get close to the minimum weight. It has all the same equipment as the buggy except for the following:

LRP Sphere Competition TC with heatsink and fan
Orion 17.5 motor
Orion 30C 3800mah lipo battery
Race weight is 1724g, 23g above the minimum weight.

I was originally using my Reedy 35C battery, but the truck was 1785g, a whopping 84g overweight! (nearly 3oz!) Thus, I switched to the Orion battery. While lighter, the Orion battery felt as if it didn't have the punch that my Reedy pack did. I confirmed this at the last JBRL race at Hot Rod Hobbies. I ran the Orion battery in round 1 of qualifying, then the Reedy in round 2. The Reedy pack had noticeably more punch! And my lap times proved it as I was nearly 0.5 a second a lap faster! Unfortunately, my laps weren't as consistent, as I needed to get used to the increased punch.

My friend purchased an SMC 40C 4700mah pack in the Hot Rod Hobbies shop. I weighed this pack and it was only 24g (0.8oz) heavier than my Orion pack, but 37g (1.3oz) lighter than the Reedy pack! With its 40C rating, it should have close to the punch of the Reedy pack, but only weigh a little more than the Orion pack! I went into the shop and picked up 2 of these packs for myself! My truck's race weight with this pack is 1748g, 47g overweight. (1.7oz) To lose this extra 47g, I'd need to change to a lighter ESC or receiver or find more lighter parts, or maybe modify some parts myself! I have also found that the weight will change a lot, depending on what tires I'm running.

I tested the Reedy, Orion, and SMC packs on my Turbo35 charger at a 20A discharge rate and 6.6V cut-off. The results were:

Reedy 35C, IR=5.1, avg discharge voltage=7.54
Orion 30C, IR=9.0, avg discharge voltage=7.33
SMC 40C, IR=6.8, avg discharge voltage=7.48

The lower the IR (internal resistance) and higher avg discharge voltage, the more punch and power, the pack should have. Thus, the SMC pack has similar punch and power to the Reedy pack while being lighter! It also has more punch and power than the Orion pack, while only being a little heavier. I will be racing the SMC pack this weekend at round 4 of the OCRC Sat Series, comparing it to the on track performance of the Reedy and Orion packs.

Stay tuned for the results!

Awards!

Stock Buggy A Main, 3rd Place

JBRL Round 1, Hot Rod Hobbies, 5/24/09

Stock Buggy A Main, 5th Place (Left)

Stock Truck A Main, 3rd Place (Right)

JConcepts Wave Race, OCRC, 5/17/09