make your Puchi Maru faster than any Bit, speed and handling 101

[strakka]

Due to it's fully porportional control, the Yokomo Puchi Maru is my personal favorite of the truely micro cars. But "box-stock" the speed of them leaves alot to be desired. although they are much easier to drive and control, as far as speed goes, my Yokomos had a hard time keeping up with a stock Tomy BitcharG, but that's now a thing of the past. and, it's extremely simple to do.

this mod is actually two modifications. first we'll give the car more power, and then we'll make the car be able to use it by making it handle better, and speeding it up further by, in effect, changing the gearing by replacing the tires with a larger diameter and a softer compound to give it more traction


to offer much more power (33%) to the motor, we'll be adding a 3rd cell. while this can be difficult mod on a Bit, it couldn't be easier on the Yokomo. it took me all of 5 minutes to perform it.

first, remove the body by removing the screw at the front of the car.

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next unsolder the black wire that's connected to the battery on the left side of the car.

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now obtain a 1/3AAA GP12AAAM cell (120mah) Nimh cell. you can get these for only $2.00 ea from:
http://www.batterystation.com/nicads.htm

prepare it by soldering some very small gauge red and black wires to it's + and - terminals, covering the ends with a small circular piece of masking tape and shrink wrapping it to provide insulation. then use a tiny amount of hot glue and attach it to the rear of the PCB.

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picture

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now solder the red wire to the terminal of the battery that you removed the black wire from on the car's chassis. and solder the black wire to the black wire that's dangling on the chasisis, apply some shrink tubing and carefully tuck them under the PCB. be careful as these wires are tiny and will break easily.

when finished with this step, you car will look like this:

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now, for the second part of the mod.

acquire two Takara ChoroQ cars and remove the rear tires from both of them. place two of them on an arbor ( a rod that fits their internal dimension) and chuck it into a drill. while it's spinning reduce their diameter and round their profile until they will fit with a little clearance into the Puchi's rear wheel wells. the stock rear tire's OD, unmounted, measures .535". i reduced mine to measure .500" ( or 1/2 inch).

take two more tires to make the front ones, and reduce their diameter to .480". now simply remove the original tires and pop on the new ones. the larger diameter will yield more speed and more ground clearance. plus the softer rubber will give more traction and offer a lttle suspension to absorb shock to the chassis.

when this step is finished, your car will look like this:

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compare these two pics's tires to the photos at the top of the post and you'll get the idea....


now mount the body, charge it on a charger that's capable of properly charging 3 cell packs ( i use an Orbit for best results), and go race any 2 cell modified bit for pink slips. . you'll beat them in a drag race, and lap them countless times on a road course. This car is now extemely fast, handles awesome and in my opinion, performs the way that i would've expected it to. it's easily my favorite of all of micro cars and now, i like to drive it as much as i do my 4 cell Epoch spec2's.

here' a pic of it completed. an added bonus is, i think that it actually looks alot better now that the tires fill up the wheel wells:

[strakka]

*other notes from the thread*


there's really no need to change gears as it's super fast now (easily as fast as a 2 cell bit with a 2.6 motor). and the larger tires achieves the same purpose as changing the gear ratio. it still burns rubber (has alot of torque) but also has a really high top speed as well.

to me, it's absolutely perfect now, and needs no further modifications. it's a joy to drive and it's extremely quiet too.

i'm cycling the battery pack right now and i'm going to check it's run times, which, so far, seems to have increased dramatically. the instructions indicate a stock Puchi Maru's average run time is for 5 minutes, but mine seemd alot longer than that on only it's second charge.


it's definitely as fast as a stock 3 cell Epoch Spec2. probably faster.

no, it doesn't handle better than an Epoch Spec2 but almost just as well. and better if you consider it's scale. now that i've driven it more, i can tell that it's definitely as fast as any 3 cell bit, about as fast as a 4 cell epoch and faster than a digiQ. the only car that i have that is faster is my li-poly zipzap.

i just timed a run where i was on full throttle 90% of the time (doing ovals on hardwood flooring).i even threw in a few full throttle donuts to pull as much current as possible. it's run time was 25 minutes and 34 seconds!!!!!!! at 24 :15 i noticed it to slightly slow down, but not much.

the batteries temp was 91 degrees F, as was the motor. the servo motor's temp was 92 degrees. i believe that these are very safe temperatures for the batts and motors. (the room's ambient temp is 72 deg) btw, i took the temp readings with a laser-sighted Raytek temp gun, which i have found to be very acccurate.


the more i drive this car, the more i love it!!!

oh, and by the way, peak charging has nothing to do with how many cells are in the pack. the delta peak charger that's in the gun's voltage is set to charge the pack that is made up of two 120mah cells. that's why i use my Orbit, since it'll charge anything, and do it perfectly.


i thought about putting the cell where the sticker is but it really is too big to fit there without it sitting up even higher, since it would have to sit on top of some of the smd components. plus it would be more on one side than the other so the CG concerning it's height, and being offset to one side might do more harm than good (the servo motor is also on that side). it actually handles awesome the way that it is.


could use one 145 but the Nimh way to do it is much less invasive, plus the 145 doesn't really fit in the battery compartment without folding it.

btw, i just made it handle twice as well as before. i'm now using some wheels from a Precious Racer, with the Precious tires up front and zipZap treaded tires in the rear. Traction is awesome and i can now harness it's power completely. now it handles easily as good as an Epoch spec 2. i can make super tight turns, or wide ones. the fronts are wide and soft and the steering is 10X better, and with the rears being treaded, it doesn't spin out as easily.i saw some rims that i really liked yesterday (5 spoke mags) so i think i'll get them tomorrow and replace the precious ones with them. it's alittle noisier since there's more rim and less rubber, but the handling is soooooo much better, i doubt that i'll go back to using the stock rims with the ChoroQ tires. these have the same OD front and rear, as the custom cut Choro tires so the gearing has remained the same.

the axles on the Yokomo are smaller than on the bit type wheels, so i made stainless steel inserts that have the correct ID to fit them. then i bored the rims to fit the inserts. i can now use slicks, or two different tread patterns on the rear, depending on how i want it to handle (loose or tight).

here's some pics of them:

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here's the new 5 spoke rims that i was talking about earlier.

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not only do they improve performance, but i think they look alot better than the stock wheels and tires. here's a photo of the stock ones for comparison:

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on these 5 spoke wheels, the hole was the correct size so i didn't have to make inserts, however, they didn't have a center rib to support the tires so i had to modify them alittle.







now i can't decide whether i like the Precious wheels or these new ones as they both work great with the Precious front tires and the ZZ rears.




the wheel wells just fit without any trimming at all. Bit tires in the rear would've rubbed, but the ZZ tires are a little thinner and lower profile, so although it'svery close, they don't touch the body at all.

i think that i will enter it in the COM contest as you suggest as i think that the Puchi's could use more exposure.

[strakka]

i just recieved my warranty replacement Puchi from Yokomo today. the first one's steering was locking up so they replaced the whole car with transmitter. i feel that this is excellent customer service! (fast turnaround with no questions asked). however, they sent me the wrong body style and i really don't like the Toyota "Fitz" body all that much. i called them today to see if they'll just send me back my original body so i can put it on the new one's chassis. ( i hope to hear back from them tomorrow).

anyway, i added the third cell to this one and made up a new set of microsizer wheels for it to run it for now, until i make a new set of DuB wheels for it.

here's some pics of the car as it came stock. i think the small stock wheels & tires really look goofy on this body style:

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i drove it a few times in it's stock form to remind me of how they perform. they actually drive very well, but it's hard to go back now that i have the other one so tricked out.

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compare it to these pics of it with the MS wheels:

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and here's a pic of my 3 cell Puchi's together:

(some pics were cut out cuz it'd be just a waste of space, but if you want them i can post them up for you. there just different angles.)



so yeah this is about all of the important stuff from the thread..........changing rims is continued in another thread so i think i'll do the same here......... there you go kwikbb

[chelboed]

That was the most exhaustive tutorial I've seen in a long time. (in a good way) Man!!! How do you get the wheels on straight enough to not wobble. I have done this with Bits and mine are on with epoxy. Is that what you use? Mine don't wobble very much, but on a Pooch, I would be frightened to mess them up. You're a brave soul to cut into such an expensive car. BTW for repl. car did you call a US dist. or Japan?

[strakka]

yokomoUSA, there phone # is (949) 252-8663, anyways.....

ONLY on the BCG were stell inserts used to stop the wheels from wobbling, the Jada Dub City rims (made by Jada Toys incase your wondering) fit on the axle no problem, i suggest using a bit of epoxy of super glue to make sure that the rims stay on.

[Racer9]

Buy Zip Zaps SE and use them for only 24.99!:)

[cu_333]

Problems In steering
Hi, I examine some problems with steering and I wonder if that starts after the 3rd cell you installed. I also install a third cell as you describe. Could this happen? Did you also install a 3rd cell in your new car.

Please advise:(