the incubus

iTrader: (17)

It's interesting to see how the opinion on the dual slipper has changed now that it comes standard on the V4. Before then, when I was curious about it, the vast majority of folks said its a hit or miss "upgrade" because for 4wd you don't want any slip on the center portion of the drive train.

Personally, the explanation I've gotten on a center diff has been absurd in respect to how it can differentiate (no pun intended) between applying power from front to rear more aggressively and efficiently than a slipper and that you don't want any slip in the center. Having owned the very fist stealth tranny with what is to date STILL, one of the best slippers in history, even 25+ years later, I'd prefer a slipper because it has been my experience that fine tuning a slipper can prove extremely effective in controlling the delivery of power to the wheels which can and does help you drive faster without breaking traction as easily. A center diff can change bias from front to rear a bit but it cannot prevent breaking traction, so I feel a center diff is for the advanced or almost pro level driver who have exquisite and flawless throttle finger control.

I'm not there but I do tune slip on my standard V3 slipper so there's a tad bit of slippage so the heraldry of my 6.5 isn't applied instantly if the car is not in motion. When. Y tracks have been loose and tuning via tires is all but a lost cause, I have loosened my slipper and have gained traction pretty well that way. The adjustment is very minor though because too loose and I wouldn't stand a chance to make triples and quads.

Bman's 3XNT

iTrader: (71)

The whole center diff theory in these cars is not what you would of expected. If you haven't tried it then don't try to explain how it should work. I have been running mine since October and love it. I started with 5,7,10,15,20,30,50,60,100,120. I settled on 100k for my track. I can grab the throttle coming out of the corner with no rear problems at all. I ran the o.e slipper and two way before this. Even though the two way was better it's still not like a real center diff. My motor/esc actually run cooler because before I had to much slip to get the rear to stay inline. I even have faster lap times and better results to prove it. I wish the other V5 guys out there would give their real world opinions in the center diff vs the two way. I could go up further in the center as well because I am wearing front tires 2/1 over the rears. But the car just hooks and goes. These little buggies are grossly over powered!! Why is it that you can run as low as 5k in 1/8 scales? I thought those were overpowered. To each their own, but I'm sure you will here a ton about the Hot Bodies car over the next few weeks as people will surely say it's the best car they drove because of the center diff...

the incubus

iTrader: (17)

I hear you but I've driven a few cars with center diffs in them so I have so e experience with them, just not on the 410 specifically.

I am surprised to hear you're going through tires 2-1 on the front as the front end is a bit lighter on the 410, especially as power is applied. I tend to wear my tires about evenly and I usually wear out a side more quickly than the other rather than front to rear.

I was looking to get myself a 413 but all the copays this month put a real dent in my spare change fund so I have to sell some car stands once my new arms come in so I can by myself one. I figured I'd put it through the paces and then compare to my 410 and then to the XB4 and stay with the car I found to perform the best.

If only there was a 4-5mm CF chassis for the 410 that wasn't ridiculously overpriced.

Bman's 3XNT

iTrader: (71)

This whole project was fun from the beginning. Learned a lot. As you mentioned I too ran cars with center diffs (all 1/8) and this project proved me wrong about a lot of things. The car behaves totally different. I have been driving the 410 since 2009 and didn't give up on it because the engineering of the car is just awesome. The ease of diff maintenance, carbon and aluminum parts standard, etc.. But the car was always ass happy. Coming from on road this didn't work well for me. I always had to be cautious. Turn a fast lap here and there but to be consistent I had to slow things down. I have seen many people at my local track buy and sell these because of that very reason. So I made something that works for me with all the conveniences of the o.e car. I just wish more people could try it or if I was able to produce them cheaper, because it IS that good. As for the tires you would think 100k would lock up the center but it's a good compromise ( there again proved me wrong). Left to right sounds like to light of an oil. Probably light to put the power down. Been there before too. I was also thinking of producing a carbon center section with a front and rear aluminum clip. But haven't had time to even try to design it. Maybe next winter.....

the incubus

iTrader: (17)

My left to right tire wear is due to the orientation of the track. Doesn't matter where you run, or oil weight... if there are more lefts than rights you'll wear out the right side rubber more quickly and visa versa. Happens on my racing kart and my mazda 3 and any car really.

I would like to just a CF chassis for my rig as is because the Khuler body is simply the best looking lid in all of RC. Lol

Dino_D

I haven't tried Bman's center diff, but I think the DESC would be in essence very similar so I will try to explain it from my experiences. Just don't quote me on it.

Well the standard v3 diff just acts like a slipper, so that it limits the amount of power that is applied to both wheels. Most 4WD cars run this type of setup as it removes some stress from the drive train during acceleration and jolts when the car lands from a jump.

For sure having the center diff is better because of tune-ability however, that does come at the expense of added weight which I think is why they went with a 2-way slipper.

A center diff adjusts the amount of power being sent to the wheels with traction. This is controlled via diff fluids or thru dual independent slipper units such as the 2-way. When you get on the gas hard out of a corner, the front of the vehicle may want to lift and as soon as the front tires come off the ground, power to the rear is lost. This loss of power comes at the expense of speed or acceleration but also makes the car easier to control or drive. We can adjust the center diff with thicker fluids or with a harder friction pads in the rear to reduce this power loss and send more of that power to the wheel with traction. That is why when track grip is high, a thicker center diff is better as you can lay more power down, but when grip is low, its harder control.

Having driven the DESC, you kinda want a thicker center diff, somewhere between 15k to 120k depending on track conditions and grip level. For some reason the center diff needs a lot thicker oil to get the bias at 50/50 unlike the 8th scale cars, probably due to the housing size and gear mesh which plays a big part in your oil selection.

What they did on the v4 (2-way slipper) was a compromise, having somewhat of an adjustable power bias without the extra weight. Does it really feel like a center diff with a slipper like the DESC? The best answer would be sort of yes and no.

When power is applied, both diff halves slip a bit. If the pads are equal the power comes in approx the same time and it tries to equalize the power via slip. If the rear has grip, it will slip more at the rear, allowing the front wheels not to wheelie and continue to accelerate your car via front drive out of a corner. However, some power is lost via slip, also the length of time the rear slips and overall slip is byproduct of the overall slipper tension which equates really to a couple of feet out of the corner. Any less tension and its gonna slip too much, and too much tension basically almost locks the diff after 2 feet making it a handful out of a corner, so you need to spend some time tweaking it on the surface you are running.
On high bite tracks, I would recommend using a friction pad with more resistance like the AE b4 high torque pads instead. Or you can drill a few holes on the front pad and tighten the slipper down a little harder. See which works best for you. Although its not the same as having a real center diff, it's somewhat close. I think Bman explained it best, that its still slips more than a center diff would, and if you cranked the slipper down then its like locking the center.
On a Med bite track, equal pads is preferred.
On a low bite track , Using a heavier pad in the rear will make the car twitchy and harder to drive coming out of a corner, so I prefer take 2 equal pad and drill a few holes in the rear pad thus reducing rear friction, allowing it to be a bit more front wheel drive coming out of a corner which makes it very easy to drive at the expense of a bit of acceleration. Its almost the same as using a lighter fluid.
You can adjust which has more friction or less by drilling holes in the pad or changing the pad material.
The difference is that the whole unit still slips, whereas in the DESC I can run the slipper tight or loose and still control bias via fluid weights, with the 2-way I can't. The bias needs to be controlled via the pads, and overall slippage via slipper tension.

Bman's 3XNT

iTrader: (71)

Excellent explanations! That one thing I haven't tried is playing with holes in the slipper pads. Now knowing what the car feels like and being able to achieve it, I will play with the TD two way slipper in my chassis to try and mimic that exact feel. If I cannot simulate it I can always go back. All is true about the added weight but I am not concerned because temps are all acceptable. As more cars come out with center diffs the options will also be greater for adaptability. I used the DESC diff because that's what I had available. @ Dino if you could recommend a starting hole setup for my two way I will try it and report my findings. Sure if I can achieve the same results with less weight/rotating mass I would surely be a believer. If not, then having something different is way cooler.....

TLRrunner

iTrader: (9)

Hey guys, I have been out of town for a bit but I'm back now and I just saw this. I have the v5 designed by Bman and I absolutely love it!! The car was fast before but now its glued to the track! I took it with me while I was away and got a chance to race against retired Indy car driver Rick Mears! I was only on the track for about 4 practice packs and I started putting down close to track record fast laps. I too have used the stock slipper and the 2 way, the center diff give an added amount of control that I didn't have before.

Dino_D

Wow, I didn't know Rick Mears plays off-road..

TLRrunner

iTrader: (9)

He sure does! He was running 3 classes the night I raced against him.

Bman's 3XNT

iTrader: (71)

I guess the real question is did you beat him???

these_savages

i need to get those alu rear gearbox inserts, as those plastics are breaking just lookin at them.

should i go for team durangos? http://www.amain.com/product_info.ph...ox-Insert-Left

or are there any better ones out there?

TLRrunner

iTrader: (9)

I did in 1 qualifier. He took the other and just barely out qualified me. In the main I had a turnbuckle pop off due to a rough landing and that caused me to loose 3 or so laps.

13Maschine

iTrader: (1)

@Bman: is it possible to do a 3rd eye (center diff) upgrade on the regular chassis? Did you also create a longer chassis with the packs in the center? Thanks for going into all the detail here guys on center diff ideas.

Are any of the Team guys doing 3 diffs?

I wonder if we should try to get a group buy going with DragonPlate for a CF chassis. I'd want to see aluminum front and rear plates though so we could keep the chassis flat and more durable.

What's the favorite CAD software for car designs? Solidworks?

Thanks!

13Maschine

iTrader: (1)

back to the wiring and component question someone had earlier….here's my Spektrum, Speed Passion setup. Taking your time and doing it right makes the car so easy to work on. You can take out the entire ESC/Motor setup with a few screws. Running the wires was a bit time consuming I'll say! Especially since I upgraded to 10AWG and I blame incubus for having to do it over :P Just kidding!

Is anyone using an aftermarket CF radio plate? I'm not sure how I feel about it being flimsy…my ESC bounces a little. I thought it would stiffen up after mounting my components….