The Yusa Project - What's the point?

Prior to 2007, a lot of us had heard about "the guy with the 1/8 scale brushless buggy" but we had never really seen one in action.  In 2007 that changed.  A number of guys all over the US were running and doing well in Nitro Mains with their brushless conversions however everyone had a different idea about voltage, motor brand, motor KV, ...etc. and especially the style of conversion itself.  With the Yusa Project, the goal is to figure out what works and what doesn't in based on real facts from my Medusa Products Oracle Data Resorder and in a head to head to a good old tried and true Nitro powered buggy. 

The Point Revised
Nitro against Direct NTB (Nitro to Brushless) conversion against a plate style NTB conversion.   Why two styles of NTB conversion? The update is I proved my point with a direct brake retained conversion already and won't be doing further testing unless something changes - I guess I have a spare buggy already. 

Retaining brakes lowers heat and stress to the motor and ESC, however you will only need brakes in large scale conversions like truggies and monster trucks.  A Medusa Research 2200Kv 540 sized can brushless motor passed a 5 hour endurance test I put it through while also handling braking duties in my Yusa buggy and wasn't even breathing heavy, so unless you are running some mongo rig it really isn't necessary.  If you need to shed some heat, add the mechanical brakes and your ESC and Motor temps with probably drop by 30%-40%.

Conversion Flavors
There were and are two main flavors of conversions.  A direct conversion uses an L bracket (aka the Novak conversion) that mounts up to the existing engine mounts which allows the motor to be mounted with a regular or extended MOD1 pinion. This conversion allows the brakes to be retained and makes things very simple and easy however hard impacts and chassis flex can FUBAR the gear mesh and shred gears. 

The other conversion is a plate style conversion made popular by my good friend Mike at RC-Monster.com.  RC-Monster has brushless motor mount plates that replaces the rear diff mount but are intended to use the motor for braking duties. 

There are other flavors, Bob Novak was everywhere running around in 2007 with a structurally weak looking direct style conversion that didn't retain the brakes - no offense Bob, it just looks like I could break it in about 10 minutes. Jim at Tekin has spent the last part of 2007 driving nightly and racing every weekend with his fleet (yes fleet) of brushless converted buggies & Truggies using RC-Monster's plates, Tekin's new R1-8 ESC and Tekin motors and Neumotors. 

Sounds like we have it all wrapped up, so why test?
Well, part of the problem is that we now have enough people out there that have driven one of these things that we now have feedback.  Some people say the old disk brakes offer better feel, others say the advancement of brushless ESC flexibility outperforms disk brakes any day, and others like myself have concerns that we are dumping a ton of stress on the ESC and motor to handle both those duties.  Based on testing already done I used a fan cooled Mamba Max ESC ($125), a Medusa Products 2200Kv motor ($100), and a couple 3S MaxAmps.com LiPo packs and I ran it all day, now that is something anyone can afford to go brushless on 1/8th scale.  For instance would one of Castle's new Sidewinder Brushless systems work if we could reduce the stress on the ESC? One thing we all agree on is that 1/8 scale electric is nutty torquey and freaky fast.  For example - my Losi 8 running a Neu 1515 and 6S A123 packs will wheelie all the way down the street - that's less than probable with any nitro system I know of.

Highs and Lows
Brushless conversions are getting easier and easier.  Pull all the Nitro crap out, buy a electric motor mount plate from RC-Monster.com along with a Mod1 pinion with the appropriate shaft diameter, drop in a Castle ESC with a big Hacker or Neumotor motor or one of the new Novak HV systems. Power it with MaxAmps or A123 lithium packs and go.  Tekin, Losi, Novak, and Castle are all working on drop in system specifically for buggies and truggies, so it's going to get even easier. Brushless systems deliver huge nitro stomping power.  The reality is knowing how to dial down the power to a useable level and learn trigger control - it's guaranteed that Nitro drivers will flip the car at least once in the first 5 minutes. The power is there, however each method has it's advantages and disadvantages.

Direct Conversion

• Highs

  • Same analog disk brakes you are used to.

  • Lower motor and ESC Stress - perhaps we can use a less powerful ESC and motor.

  • If there was some universal bolt on plate this would be a super easy conversion.

• Lows

  • More weight with the brakes and servo retained

  • Added complexity

  • Reverse is out of the question

  • Chassis Flex and cause gear mesh issues and stripped gears

Plate Style Conversion

• Highs

  • Without question the easiest conversion.

  • Bolt in a plate that replaces the rear diff tower, add motor, ESC and batters and go.

  • Very clean install.

  • Lower overall weight - no brake stuff

  • You can use reverse

• Lows

  • ESC/Motor braking functions transfer a lot of stress to the ESC and motor.
     

1/8 Scale Brushless Brake Questions

How do you do a direct Nitro style conversion that retains the disk brakes for feel?
I have talked with tons of Nitro guys that just love the feel of their mechanical disk brakes but really want to try out brushless.  The first thing I would say is that electric ESC technology and electric braking feel has come a VERY long way in a short period of time. The Castle Mamba Max and Tekin's new R1 offerings provide more brake programming/tuning options than you have with your disk brakes and definitely way more power. The weak link in the equation is that a typical brushless conversion relies on the center differential to distribute the stopping power which comes across as an equal four wheel ABS feel that changes your driving style - pick a line and drive.  No more slamming tight into the turn, crunching the brakes to pull the back end around and then slamming on the gas. If you want to retain that heavy front disk brake feel to pull the back end, you'll need to do the Direct Brushless Conversion I outline below with reverse and brake disabled on the ESC.

What are my braking options - Hybrid brakes?
As noted above you can use the motor to do the braking or retain the disc brake system, however there is another option.  Use both. Simply retain the front disc brake for those times you want to pull that back end around and tune the ESC's drag brakes to handle general braking duties.  There is plenty to play around with on any of these three braking ideas.

Is the brake "feel" as good as actual front/rear proportional brakes when using the motor for braking?
The best analogy I can come up with is to ask have you ever tried to force a car equipped with traction control and ABS brakes to loose it in a turn or have you fought against those automated systems?  It's kind of like that - it's just a different driving experience. With the equal four wheel ABS feel you can't hot rod trough turns - you have to drive like the traction control and ABS brakes are turned on.  If you let the system do it's job you will be faster in turns. Some have said it's easier because you can just drive the line you want, others say they find themselves fighting the brakes.   If you still want that nitro brake feel you will need to do the Direct Brushless Conversion I outline below with reverse and brakes disabled on the ESC to retain that heavy front disk brake feel to pull the back end around.
 

1/8 Scale Brushless Battery Questions

What kind of batteries do I really need?
That really depends on a number of things. Type of cells NiMh vs. Lithium power, expected runtime, ease of change while pitting, speed, ...etc, the list could go on and on.

I think lithium power (either LiPo like MaxAmps or Lithium Ion like A123's packs) is the best way to go.  Lithium based packs deliver more power, super high current, and longer runtimes over NiCd/NiMh packs with far less weight.  I have run A123's indestructible and grossly underrated 2200mh (4400mh like) cells in both 3S1P, 4S1P, and even 6S1P configurations all with great results.  A123's packs consistently delivered 10+ minute runtimes with dual 2200Mh 2S packs for 13.2V. Dual 3S packs consistently ran for about 12-15 minutes on my Losi 8. My various MaxAmps LiPo packs in 11.1V (3s1p) 5000Mh, dual 7.4V packs, and even one 14.4V 10,000Mh pack were equally excellent but with higher current and longer runtimes.

I recommend:

• 4S (13.2V) in A123's packs - dual 2S1P packs

• 3S (11.1V) in typical LiPo packs such as MaxAmps.com or Kokam

• A123's 2200MH packs (10 minute runtimes) or a 4000+ LiPo pack for similar runtime.

• Just like Tesla, aim for high voltage and low current draw.

• High current connectors of course such as Dean are a requirement.

• Up the voltage and the power and speeds get crazy. 

• Keep in mind the more Voltage the more heat you are going to have to deal with at the ESC.  The newer very high voltage ESCs coming out should displace this problem.

1/8 Scale Brushless Motor Questions

What motor and KV should I buy?
These heavier 1/8 scale buggies and truggies require very torquey single large motors or dual 570 motors just like the E-Savage and E-Maxxs.  2000-2600Kv seems to be the perfect range for motors to power 1/8 scale buggies and truggies.  Although you can order the Neumotors in any configuration - make sure you are running a 5mm shaft vs a 3.2mm shaft.  I think there is just too much stress for a smaller 3.2mm shaft to handle, besides you have to buy a Mod1 pinion anyway since your 32P pinions won't work.

I recommend:

• Hacker C50 11L - 2215Kv - Great all around motor

• Neumotor 1512/2D-Finned - 2600Kv - Applications under 15V

• Neumotor 1512/2.5D-Finned - 2000Kv - Great for all buggies

• Neumotor 1515/1Y-Finned - 2200Kv - Heavier buggies and Truggies

• Novak HV 6.5 - 3100Kv - This is a bit high KV and may require some re-gearing.

• Another option is to use an Emaxx plate for the conversion and run dual brushed motors.
   

Universal 1/8 Scale Brushless Buggy Direct Conversion
The direct conversion is a little tougher for those that can't live without their disc brakes.  You will need to do some metal fabricating.  I used 1/8" 3mm T-6 aluminum plate - I would recommend a little thicker if you can find it.  The idea is to make a mount that positions the motor just like the nitro motor while still clearing the rear disc brakes.  This brushless conversion also requires an extended long shaft pinion from MegaMotors.com so the motor can reach the spur gear.  You can of course set up the brakes in hybrid fashion and let the motor/ESC handle drag brakes and braking or not, and setup a front disc brake only conversion to get you in and out of tight corners.

The only real tricks to this conversion, aside form the talent to create the motor mount, is disabling reverse, braking (for disc brake only setup), and purchasing a servo output splitter so the braking servo and esc share the same 2nd channel port on the receiver.

As you can see on my Direct 1/8 Scale Brushless Buggy Conversion on my Yusa, the dual A123 packs fit perfectly in the wings and gave me 10 minutes of runtime.

With this setup I consistently saw over 10 minute runtimes.  I post more data once I have everything pulled together.
 

Universal 1/8 Scale Brushless Buggy Standard Plate Conversion

Again pretty easy, pull all the Nitro crap out, buy a electric motor mount plate from RC-Monster.com that is specific to your buggy.  Choose a couple Mod1 pinions (12T & 15T are good options), drop in a Castle ESC with a big Hacker or Neumotor motor or one of the new Novak HV systems. Power it with MaxAmps or A123 lithium packs and go.  This modification does require that you modify/remove the brake servo mount and remove all the disc brakes since we need the room for the motor - the motor and ESC will obviously handle braking duties.

The RC-Monster.com motor mount plate replaces your buggy's rear diff mount and allows you to mount your choice of brushless motor.  As far as ESCs go, I have done a couple conversions now with the Castle Mamba Max and it seems to do just fine on 14.4V with these lower Kv motors, in fact I run a Hacker C50 Maxx motor with a Mamba max on my brushless Revo. You may want to add a fan on top of the heat sink as a little insurance. In some situations you may need to flip the differential around (as I had to do on my Losi 8 Conversion) so the spur is at the rear. Mount the electrics, batteries, and go.  It's that easy.  I would say the toughest part is making it look factory installed and getting creative to securely mount the batteries.

Mike at RC-Monster runs 5S Lipo packs with his Castle and I have used a 6S A123 pack configuration that works well in some Castle Mamba Max ESCs (it's not a version thing, you are right at the limit of the ESC input power and amounts to variances between units - some work with 6S some don't).

Yusa Buggy Setup Sheet

I finally got my butt in gear and started some testing.  First up was some chassis tuning on all three Yusa rigs.  I copied all the settings off my Losi 8 Race Roller onto the Yusa's and that netted a HUGE performance improvement - go figure.  Below are the suspension setups I used with about a 3-4 toe out on the front wheels and zero degree camber on all wheels. I clipped in 1/4 shock pre-loads on all shocks and yes the cottonwood trees were shedding.

UPDATE - The Novak 4.5 HV Test

The results quite frankly pissed me off in more ways than one.  I tracked Motor and ESC Temps, Motor RPM, Throttle Level, Voltage, and AMP draw using my with my Oracle Data Recorder.

My thought was that since the Novak HV 4.5R ripped it up pretty well on my E-Revo it should be able to handle a freaking buggy - that would be a big NO and a disappointment in so many ways.  First the massive Novak motor heatsink had to be ground down on the mill to allow for driveshaft clearance and my rear support had to be moved to the other side of the driveshaft (that part was easy and required just a countersunk hole.)  I fabricated a ESC mount to bolt up to the diff tower and mounted the GINORMOUS fan cooled Novak HV ESC. and spent the better part of an hour getting everything hooked up to the Oracle data recorder.

Basically I beat the hell out of the system until it thermaled and boy did it thermal a lot.  Turns out that temp seems to be around 155 degrees however I would imagine if I could have mounted the temp probe inside the ESC instead of stuck in the heat sink that temp would have around 160 degrees (a typical termaling temp).  RPM topped out at just over 10,000 RPM with the 3S 5000MH MaxAmps Lipo pack with current maxing at around 100 AMPs, and a 12.2V peak.  The motor really wasn't the issue, it was that freaking decade old ESC.  Come on, let's at least move into year 2000+ technology.  It's fan cooled for God's sake, it can't even keep cool with a 1.5" fan blowing on it.  The kicker was it was also pretty damn slow, not like I can gear the thing down a ton from the 14T pinion.  I didn't have a GPS strapped on however, eyeballing it I would say in the low 30's. 

I am going to gear down a bit if I have the clearance, otherwise I may give the 4.5R motor a spin with a Mamba Max or Tekin R1Pro and see what happens.

Above the Novak HV 4.5 brushless system.  I also tested driving the Novak 4.5HV motor with a Castle Creations Mamba Max ESC. Yes, you can run a sensored motor with and sensorless ESC.

I thermaled out in about 5 minutes of run time... and it was again pretty slow.  Dropping from a 14T to a 12T pinion helped extend thermaling intervals a couple minutes, however not enough for me want to keep it attached to a buggy.  A fan cooled Mamba Max did about the same.  The reality is that the Novak 4.5R HV motor is just way to fast for a buggy.  If you are dead set on Novak, go with a 6.5 Novak motor and you will be worlds happier.

Medusa Research 2200KV 540 motor

I tested this with both a stock Mamba Max and also a fan cooled Mamba Max and this combo worked much better. Medusa's brushless afterburner motors are proof that you don't need a big ass Hacker or Neumotor to get your buggy moving. 

The Nitro Powered Yusa Project Buggy

Of course we needed a nitro powered buggy control for our little experiment. Just to assure I didn't have any screamers in the group complaining that I used some under powered mill, I installed a beast of a motor.

Obviously a .21 is the standard buggy, but I used a factory .26 Hot Bodies motor to give the Nitro version quite a bit more extra power and HP.  Some will notice I swapped out the spin to start adapter for a pull start.  No, I am not a masochist, the mill turns over pretty easily and I hate caring around a spin start unit or starter box everywhere I go.  I found a Sportwerks Buggy body on clearance for around $10 and made the modifications needed to make it fit.  The steering servo was the same Tower Hobbies eBay special that was installed on the other buggies and a Hot Bodies unit takes care of throttle and braking duties.

Initial testing showed that this is a freaking screamer of a buggy. The .26 is loud as freaking hell and will certainly give the big dog brushless setups a run for their money.

Poorman's Universal 1/8 Scale Brushless Buggy "Brushed or Brushless" Conversion

This conversion is just like the above Universal 1/8 Scale Brushless conversion with at the very least the rear brakes removed. In this case an EMaxx motor mount plate is screwed to  the rear diff mount with two EMaxx motors and your favorite no-limit brushed ESC.  Sure you could also use the Emaxx mount as is, modify it, or even mount you brushless conversion using this idea.

The Brushless Wrap Up
Brushless buggies/truggies/monster truck (or in my case currently eight) are a blast and get driven more than they every would with Nitro.  I can spend an hour after work tooling around the neighborhood without anyone screaming and my total post run maintenance involves throwing the batteries back on the charger.  There are more than a few hard core nitro guys that have noted that it sure would be nice to only have to cart 2 8000mh batteries and your rig to the track and just drive all day instead of all the nitro junk and worry about tuning. I had a few Pro drivers run my Losi 8 setup at ihobby 2007 who raved about both the power and the brakes.  Knowing what I know, the next two years are going to be very interesting from an 1/8 scale brushless perspective.  It could be that electric power is witnessing a renaissance.  Hopefully my notes will help you get on board with brushless 1/8 scale electric.