Project 4 Cell

[Yell03SpecV]

Maybe it's just me, but I think 4 cell is the only way to go for racing on a track, to reduce rollover risk, and better the weight distribution.... probably just me. Anyways, the 5/6 cell offers quite a bit more speed for very low cost, but IMO it's just a cheater mod, or rather just a mod for those of you without the know-how to do more advanced things, like proper custom armature winding, etc.

Aaaaaaaanyways, my goal was to beat my friend'd modded mini-z around a short track (i still think a higher RPM motor is in order for a long track, but i'm workin on it ). Obviously, in stock form, it was a no-contest race, with him pulling the lead pretty much everywhere. 6 cells and the SB hybrid motor would edge him in the straights, but flip like crazy every time i had to turn. Sure, the Xmods dont have a great turning circle, but thats nothing some slight oversteer (NOT drifting) can't correct. With my current setup, as viewable in my sig, i hand it to him every time. Sure, it doesnt look the prettiest, without a rear bumper/sideskirts and all, but after spending some time with a dremel and removing unnecessary plastic, it is considerably lighter than a normal AWD xmod, and as a result, gives it that little edge around a corner. No pics for right now (until i can borrow someone elses digicam), but i think you guys get the idea. Weight is certainly an enemy around a track, and this was my push for making it the way it is. Has anyone else followed/contemplated this idea?

BTW, if anyone has any ideas i can use, be sure to let me know

Happy modding!

[theMonster]

You could try to get a mini-z turbo unit (basicly a fet upgrade that uses 6 wires to solder in. Then you could use a low-turn mini-z motor with 4-cells and be on equal ground save for the chassis and steering. If he's just using a not-fet upgraded motor in his mini-z then I'd get a hot 180 motor so you can out-torque him off the line and accelerate harder out of the turns.

[Yell03SpecV]

the only problem with the 180 is extra weight... theres almost no way around that. the FET upgrade would have to be an internal one, to avoid the weight of CAT5 cable and an external PCB. at this point, the motor is good enough for about 26-28mph, which is plenty for this point in time. As far as torque output goes, here's my situation:

1. the car handles plenty well to corner at high speed, placing the car in an acceptable RPM range to apply more than suffcient torque to power through the turns.

2. when the FET upgrade is complete, i will need something that spins 40k RPM or above, top speed is really the goal here, save the low-end torque for you drag racers out there

3. the RSX has a short wheelbase, effectively the best for handling.. anyone who knows real cars should know this.

4. after making a custom upper deck for the front assembly, i was able to add a little bit of negative camber, not enough to suffer on the straights, but still not enough to keep the car stable in a turn where load is placed on the front, aka under braking.

5. the CG is plenty low with 4 cells, and the RSX, being the slimmest body available, helps this only fractionally, but remember that this is 1:28 scale, and a fraction is a lot more than most people think.

6. i want a CF chassis. end of story for this point.

7. i still think there are some other plastic parts which could use a bit of trimming. i guess i'll have to experiment later.


at this point in time, i'm fairly happy with the setup. but i really could use that CF chassis.

[SuPrBuGmAn]

www.atomicmods.com

Get the Li Ion AAs available from above, they weigh less than 4 AAAs and will push 7.2v for about 40min. They should improve your CG even more. Unless your doing some kind of friggin drawn out touring race, 40min should be plenty of time for what you have in mind.

Sounds like you're already on the lookout for CF parts, which would have been my next suggestion.



So have you tried any non-stock or mod'd stock 130 motors?

[Yell03SpecV]

i tried a 12 turn hand wound motor just to see how long the stock FETs would last.


"HOW LONG DID IT LAST, PHIL?"

lol, long enough to get to about 40mph and kablam. fire.


anyways, i am looking for another motor (as specified above), however, i need to do a FET upgrade first. the li-ion seup is feasable, thank you for the link. btw... i just earlier experienced a bit of crappy reception, maybe about 30 feet away, and it would studder real bad. i took apart the reciever and replaced the antenna wire, and checked the resistance of the 2 resistors... (holy redundancy batman.....) and the both of em are fine. my batteries SEEMED fine, although they may have needed a charge. maybe ill be ordering parts soon.

[SuPrBuGmAn]

Once you've upgraded the FETs, you can try a Plasma Dash or Yeah Racing motor. The SO2s and SO3s are supposed to be nice as well, however, the lack of torque on atleast the Plasma is less than desirable(few extra winds or stronger Neos could probably take care of that). Seems like you are looking for a topspeed motor anyway



You could always must build your own motor from the ground up. I'd suggest Neo mags, carbon brushes, BB can, for sure... Number of winds and gauge wire can be changed out to fit anyone's needs.

[Yell03SpecV]

UPDATE:

Removed CL light harness from board, beginning to think reciever is fried, although individual components test to standard. Hrmph.

[neurokinetik]

Originally posted by Yell03SpecV
Maybe it's just me, but I think 4 cell is the only way to go for racing on a track, to reduce rollover risk, and better the weight distribution.... probably just me. Anyways, the 5/6 cell offers quite a bit more speed for very low cost, but IMO it's just a cheater mod, or rather just a mod for those of you without the know-how to do more advanced things, like proper custom armature winding, etc.

I once thought as you do... However, once I figured out how to run six cells without putting them on the roof, I found that I could go even faster, even on a road course. Project drag Civic was never intended to do anything but drag, but I found that it is capable of turning as well. It also makes the custom motor work better, as it is geared too high and not torquey enough for good acceleration with four cells.

I also once thought that the RSX was the way to go, due to the short wheelbase, but I've found that all that short wheelbase does is limit my upgrade options. I've since converted to long wheelbase and don't run the RSX bodies anymore.

[pacificwarriors]

You should lock your differential. it improves, acceleration, and top end. plus it dosent ruin cornering, i have tried it

[Yell03SpecV]

Originally posted by pacificwarriors
You should lock your differential. it improves, acceleration, and top end. plus it dosent ruin cornering, i have tried it

wrong: it decreases rear end traction by keeping the wheel with the most grip spinning. the coefficient of grip on a small lightweight rwd RC car is not enough to warrant a posi-trac mod. i tried this once.... awd is much better, the added traction is made up for by cornering power. plus, it stresses the plastic components beyond acceptability. ill stick with awd. thanks for the input though, i know people are just trying to help.

[Yell03SpecV]

Originally posted by neurokinetik
I once thought as you do... However, once I figured out how to run six cells without putting them on the roof, I found that I could go even faster, even on a road course. Project drag Civic was never intended to do anything but drag, but I found that it is capable of turning as well. It also makes the custom motor work better, as it is geared too high and not torquey enough for good acceleration with four cells.

I also once thought that the RSX was the way to go, due to the short wheelbase, but I've found that all that short wheelbase does is limit my upgrade options. I've since converted to long wheelbase and don't run the RSX bodies anymore.

i havent run into an upgradability problem yet... and the entire point of this project is to have the lightest car possible.

Project drag Civic was never intended to do anything but drag, but I found that it is capable of turning as well.

"drag" is the key word here. despite the fact that it may still turn WELL, the CG is still raised to a point. 6 cells are all well and good for drag... but straight line racing bores me with anything, thats why i stick to autocross and road racing in my spec-v.

i guess to sum this whole project up, i'm following guidelines set by my experience in real world 1:1 racing, and things seem to be working out quite well. thanks, though, i might consider a longer wheelbase if i can offset the decreased handling response with a more noteworthy improvement elsewhere.....hmm.....

[SuPrBuGmAn]

Generally, when you burn your reciever out, the L2 inductor near the CL output has been fried. It can be replaced and fixed, if thats your problem. You'll need to do a bit of disecting to get to the inductors, its not visible by just looking down after removing the body.

[Yell03SpecV]

hmm... it just worked fine from like 30ft away... maybe my damn computer was messing with it. oh well, thats one less thing i have to replace.

[spitty12]

Neuro: Where did you mount the 2 extra cells if they are not on top of the electronics?
I've got my 5th cell out back in the bumper but I'm bothered by having the weight overhanging the back but flipping isn't a problem.

Posts some pics when you get them specV. I'm working on a light weight Rwd car that will run with my friends AWD cars. Lots of stress on the drivetrain though and so much power that throttle modulation is difficult. I've always believed that there is rear wheel drive and wrong wheel drive so I would be a hypocrite if I went awd even though I want to be able to drift well. To shave some weight from my car I removed the body screws and glued the body together, used a dremel to remove excess plastic. Li ion will be a big weight saver if you can get your hands on some.
I'm using an LSD which did help a lot with power out of corners and acceleration. The inside wheel was spinning out of turns just like on my open diff cars. The friction needs to be low though, I'm using bicycle grease packed into the diff.

Good luck taking down the mini Z

[newbitowner]

Neuro: Where did you mount the 2 extra cells if they are not on top of the electronics?

Between the bumper and the rear body clip.

In a Supra, a little shaving would have to be done to the car and/or the holder.