Took my BL HPI PRO 4 Racing last weekend

[OptimaMan]

Hey guys, I took my HPI Pro 4 racing last weekend. Instead of using the Lipos, I stuck with some beater 3300's. I'm using a Basic 3100 with a FDR of around 6:1 in it and running each qualifier, I've only used up approx 800 mah per race!!!!

They only run stock motors so I was running with the stock motor guys. RPM wise, they actually have higher RPM, but I have WAY more torque and even adjusted for equal top speed, I'll get to that top speed in much less time/distance... so yeah, I heard some whining around the pits.

The stock motor specs I've been looking at says max output of around 60 something watts at 5.0 volts and a max efficiency of 44%. The Basic 3100 is 86% or higher from 10 amps up. I guess that can easily explain why I can run over 2x longer than the stock guys and why my batteries and motor ran sooooo cooool. Those guys were all saying things like how I got a plane or boat motor in my car.

Then the local guys were impressed that I did absolutley NOTHING to my motor the whole night...

Then I impressed them by putting in the 1515 6 turn motor and 6 cells. In my car, with the smallest pinion that would fit the stock spur, the top speed is 45 mph. In a small indoor track, that's way too much speed... and in a shaft drive TC, I had massive torque steering. Not to mention the sound a motor makes as is passes you at 70,000 rpm... At 2 minutes into the main, my whole right side suspension was busted (front and rear). I guess it was fun... until I had to repair it.

[howielong]

Cool you beat there butts.

[OptimaMan]

NOOO, I didn't beat their butts. They're much better drivers than me. But I had the cooler car.

[DaFF]

Awesome, can't wait to get mine !

DFF

[OptimaMan]

I went racing again this weekend - but this time I was using Lipos. I tried TP 1900 11.1 packs. With the Basic 3100 geared about 10:1, I was out accelerating and outpacing the stock guys easily. I have 4 of these packs so I used all four. I wasn't sure how many mah I would use up.

I just got home and charged three of the lipos already. The first one only used up 375 mah!!!!!!!!!!!!!!!!!!!!!! Second and third were 575 and 620 mah used up. Fourth race I DNF because the spur gear worked loose.

The first pack I just drove smoothly just to make sure the battery woulnd't swell/overheat and when I noticed it was just warm, I went for it in the second and third heats hence the higher usage. These numbers are indicating that my average amp draw is only about 9 amps or so or approximately 90-100 watts during race conditions. It's insane to see how light the pro 4 is with on 11.1 volt 1900 mah pack! My car, when it hits a barrier or get hits just bounces around and nothing gets bent out of shape or breaks because it's a good 3/4 pound lighter!

[Strike 4]

Awesome man! Now did you win? Didn't anyone fit about it being illegal?

[DaFF]

It's pretty good that you can race with only one 1900 mA 11.1 v pack (hence lightweight setup)

Is that the Thunderpower pack with 6C ?

And what would be your estimated top speed and run time out of a fully charged 1900 pack ?

BTW, how does your 10:1 FDR translate into the ratio HPI is using in their ratio given at the end of your manual... Like when I look at Atshusi Hara setup sheet on page 43, it say 98 spur / 32 pinion = 7.46 FDR.

Tks

DFF

[OptimaMan]

I actually changed the spur gear to 48 pitch because I have like 20 different 48 pitch gears and not much 64 pitch. A 75 tooth is pretty much a drop in. So, using a 75 spur and 18 pinion, my FDR is 10.15:1 which translates to a top speed of about 25-26 mph. This is fine at my local indoor carpet track due to the small size.

Threre are usually about 8 heats of stock class touring and because not enough run mod. Now, being a "novice", we're allowed to bring anything. Just yesterday, I raced against a bunch of TC3s, XXXSs, and even an RC-10L!!

In the lower ranks, there isn't much griping about being illegal. It's race what you brung. Most of the guys are running foam tires while I run rubber so it's all fair and square. The main difference is setup and especially driving anyway. Now, if I were to move higher up to the mains, then I'm sure there would be some griping.

With a single 1900 pack, I could probably run somewhere between 12-15 minutes at this track with this setup. I'm not sure if it's 5 or 6 C, but the batteries were a bit warm, but definitely not hot and in no danger of swelling. Next time, I'll get the temp guage. The motor and controller were probably under 110 degrees. But I'll have actual measurements next week.

Last question, did I win? Well, I'm in the second to last main (which pretty much puts me 1 level above complete beginner) and I am able to win consistenly w/o much trouble at all. I don't get much track time, and I still have yet to figure out the ideal setup. My setup is BOX STOCK minus the anti-roll bars. I'm going to play around with droop and shock springs next time.

[DaFF]

Wow, 12-15 minutes with a single 1900 is awesome...

I heard the stock setup runs pretty good anyway !

DFF