A brushless MRX-4 or Evolva 2005
 

Excuse me, friends,

I'm thinking of a very fast brushless 1/8 on-road machine.
Speed I want to reach is not really something big.
100mph or so is the norm.
I've found these two machines to be my ultimate candidates.
What recommendaions do you people have as for what brushless system should I use and how many lipos?

Thanks,

Alawi El-Jifri :dft009:

I would choose a 10S LiPo setup with a CC HV110 ESC using the mechanical brakes and probably a Neu 1515...

Well, 10s is waaay too much. 6s seems good.
Dont make the size and look of these cars fool you, they're quite light actually.
How about a 1930/9( already have it) and my current 149.18 controller with 5 or 6s?
It might get me to 100mph or atleast high 80s, right.

i am doing a serpent at this moment. it's one of the nicest conversions to do IMO. The cars don't use a rear diff, i updated mine with a ball-diff, no idea how it goes, but i like the idea of having a diff in it.

I will do some testing with 5S, it will weight about 5 - 5.5 lbs, and 100 mph is completely useless. aim for the 60-70 mph. It makes more sense. 6S is not needed. since it weights almost half of an e-maxx and 6S for a maxx is too much already.

My plan is to try a 7XL/XL2400 and see what it does. i thought about getting a Neu 1512 with 2000 or 2600 kv.

Since it's lightweight, i think a small motor (such as the 1930) would do great.

Here's a tip for you regarding the ball differential:

USE CERAMIC BALLS FOR BOTH THE DIFF AND THE THRUST BEARING. YOUR DIFF WILL KISS YOUR HANDS FOR THAT. TRUST ME!

Thanks for the tip, Where to pick them up?

The thrust bearing is doing fine. it's an SKF bearing

The balls are FAT, so is the entire bearing kind of thing which is used. It's got a nice 'slipper' on the diff as well! it's made by Hudy, a true piece of engineering art..

Hudy ROCKS!
If you go to towerhobbies, type acer racing in the searching engine and it will present you to a large list of ceramic ball sizes and bearing kits for different cars.(They're not in stock, yet).
Boca bearing got a very large selections of ceramic ball sizes, too.

It's using 3/16th thick balls, would be about 40 bucks..

acer doesn't have such large balls..

I currently have 2 Hpi Super Nitro BRUSHLESS cars.These are 1/9 scale chassis' but with Wolfpack Radicals wheel conversions I can run 1/8 onroad wheels and tires(Serpent,Mugen,Proceed)same as Evolva,MRX-4.With this setup I can run an 1/8 scale body and fill it out nicely.I run a Feigao 12xl and 36120 ESC.With 6 cell lipo I run 60ish mph pass after pass at 130 degrees.I am currently testing this setup with 8 lipo cells

Captain, the reason I said 10S, is well, A. I'm a HV freak and B. You said you wanted 100mph. It's just not possible without a super HV setup. Like 8S or more...

Now it makes sense, Squee.
Okay, my mind is set on the MRX-4 with a 1940/8, 6s Evo20 and my 149.18 controller.

Being around the sixties, rcjmaxx, isn't really cool for an onroad machine, but then again, the super nitro is not dialled for hi speed applications like the Evolva or MRX-4. Those two machines with a .21 or a .28 engine made some amazing speeds at the worlds over 100mph. I guess it would be at least at the hi 80s with the 1940 motor.
Its costy, but I'll try to make it my ultimate rc project besides the Phase.2 SuperGorillaMaxx of mine.

Serum, your Serpent is 1/10 scale, right? Those are 1/8 scale, FYI.
And, if you are still interested in the ceramic balls( 40% lighter than steel balls and countless times as hard), go to www.bocabearings.com and probably you'll find what you need.

Yup, found that size at Boca. $4 for each ball, but the outcome is surely worth it.

No, the serpent is 1/8th fyi.

100 mph is redicilous and completely useless. Shoot for yourself, but what's the use of a car that you can only run straight. If you want pure speed another model can be picked as well.

You did not get the point. It can run at 100mph, but you wont loose control over the vehicle like you would with the other cars. You probably know better than me, you have one in your hands already, these are similar to a formula racing machines. If 250-300mph is rediculous for a Nisan Skyline, it is very reasonable for a Toyota GT-1 24hrs endurance race machine.
I'm not trying to talk big, but I'm just trying to point out my view of these 1/8 onroad vehicles. There's no comparison between a racing horse and a wild shita. The shita would run at a frenetic pace of 60mph without tearing it's muscles while a racing horse can't go over 30-35mph.
Once you finish the Serpent and give it a run, you'll realize that there is a huge gap between it and a touring car. I've seen the Evolvas in action in front of me at my local track, and their speeds at the first gear are simply out of discription.:)

Yeah, i've seen a few in action, but the difference between 60 and 100 mph is HUGE.

My idea was to mount a thin carbon fibre plate underneath the entire chassis, to get less air-resistance. and to suck the car on the road. perhaps this is an idea for you too.

How about a chassis protection tape?
You get a transparent sticky tape which can cover the chassis completely from downunder and then you can cut it according to the shape of the chassis.
I think AE sells them.

Here are a few pics of the build up.

Still deciding on what to do with the lipo's and the motor.. It's impossible to get the lipo's in the centre without having the motor mounted a little higher (need to hight of the lipo cells to lift it)

No it's not about protecting the chassis, it's about the flat surface. the ae tape would be of no use. it's not rigid the aero-dynamics of a flat surface as a bottomplate are better.

Yeah, I just noticed that.
How are you gonna make a motor mount for it?
Probably you can make me one?
I would like to ask Mike for that, but I dont know if he can do it? He did not own a 1/8 onroad machine befor, did he?
Also, the lipos I might be using are very thick. 60mm of thickness. I dont think I'll be able to use the upper deck this way.
Your machine looks cool.
I'm very interested to own an onroad rig anytime now.

I haven't decided on what to use for the motormount. i am leaning towards CF at this time.

The space which is between the motor and the front part is not enough to hold most of the lipo's. Perhaps you are better of with taking two 3S packs and put them next to eachother. i think i will do so. I also was thinking about restyling the upper plate, and make it from one piece, since it's got no high nitro engine sticking thru.. arh well.. Need to order some CF and see how it goes.

How much did the Serpent cost you?
Probably I can go for one, too, and work with you to make it brushless.

Serum, any updates on your 950?

I've found a Kyosho Evolva 2005 for $266 only. Its my friend's and in good condition. It only needs a set of tires, though. What do you think, should I go for it?

Yeah, i finally decided on how to put the batteries/steering servo.. Now it's time to order some CF for that baby!

A used 1/8th.. Do you know the state of the drivetrain? tires are not that expensive..

Well, the thing that is really worrying me is the condition of the belts.
I should take a closer look at it.

Belts are not expensive Captain.. Any progress on your project? mine is waiting for me to cut her the CF...... SPeaking of which.. What am i doing here behind the computer.. LOL..

harlock, not sure if you've seen my thread or not, but might help you out:
http://www.rc-monster.com/forum/showthread.php?t=3489

Yeah, I've seen it, my friend!

How is your project doing lately? any major speed records?

eh i'm keeping updates in that thread.. right now, 55.1 is my top speed w/ the gps...
i ran it today at work on my lunch, and being a straight road, and in the daylight, i'd say i was right in the low 60's. no gps this time though. and i just broke the CA that held the spur gear to the 2-speed clutch.. so i'm gonna get a replacement piece machined, so i won't have that problem anymore.
these 1/8 cars are great for high power setups, because the stock drivetrain can withstand the power. i've never driven a nitro 1/8 onroad, so i don't know how much the handling is suffering w/ the packs on the outside.. after i get solid numbers on what's what, i'll take it to a track, and have an experienced driver test it out on the track.. the car's quicker than anything i've seen run before, and traction seems to be my biggest problem. with WOT, wheelspin up to around 30mph