Kyosho KT-18 Modifications

[lornecherry]

...
I have also developed some interesting mods to the cars and the transmitter that really protect the cars and allow you to dial in the exact throttle travel on-the-fly without having to use the ICS, which is ideal when you want to let an 8 year-old drive and don't want that annoying "training mode" blinking light - Lorne

[schmenzer]

Originally Posted by lornecherry

I have also developed some interesting mods to the cars and the transmitter that really protect the cars and allow you to dial in the exact throttle travel on-the-fly without having to use the ICS, which is ideal when you want to let an 8 year-old drive and don't want that annoying "training mode" blinking light - Lorne

Also very interested in the mods. I have young kids running Mini-Zs with ECO motors but have not found an equivalent motor for the dNaNo. If I could electronically limit the performance that would be great!

Greg

[-J-]

Originally Posted by schmenzer

If I could electronically limit the performance that would be great!

Greg

You can. If you're using the KT-18, there's a button you can press to enter 'training mode'. Refer to your manual for a more detailed and probably helpful description, but I'm pretty sure it limits the throttle to allow new drivers to get used to the car more easily. If you're using another computer radio, just turn the throttle EPA down some.

Back on topic.

Lornecherry,

The writeup on ozite carpet was interesting and very informative. I've been driving my dNaNo on carpet (not sure whether it's ozite or not though ) and I completely agree with your findings. Cleaning the bearings every couple of cycles is annoying.

I'm also interested in the you did mods, in particular the ones you did to help dial out the chatter. As I've mentioned in other threads, I'm having difficulty getting rid of the chatter and would appreciate your help. Thanks, and keep us posted.

[lornecherry]

Arch, I didn't keep the list of Porta-Trax owners, was very informal cottage business that was more fun than anything, I doubt if there is any 5-year old carpet around anyway. Moreover, I changed the Ozite formulation at least twice, some of it was not very good at the beginning.

Here are some pictures of the throttle mod: It's ever so simple and costs less than a dollar. Works great though. You just dial in the amount of throttle you want. This first attempt was a little messy and you have very little clearance on the battery pack; that's why I installed the "puller" tab at the end of the battery pack, as the pack sticks a bit when you press the release button (planned also, because kids will inadvertently press that button and the penalty for doing so should be power off, not 4 AAA batteries all over the floor!).

I used a brass knurl nut to embedded into the transmitter casing to receive the large plastic screw, which is easy on the fingers (and I don't like metal-to-metal around R/C).

You need a Dremmel tool to cut away the groove for the brass knurl nut and I secured the nut with CA. I also cut away the small protruding plastic piece on the trigger, so that I could still get full throttle if the plastic screw is turned all the way in.



http://img34.imageshack.us/img34/4550/picture005l.jpg

[lornecherry]

J, here's what's worked for me. At this time, I'm purposely only using genuine upgrade Kyosho parts ... (except tires), as I want to be sure that it's not an aftermarket part causing an effect, as the cars are so new.

Differential:
The stock differential is horrible, mine was tight, grindy and inefficient on both cars right out of the box. You thus need to install the Kyosho ball differential and use the two or three ring spacer setting, as per the instructions. Lubricate the differential (there are right and wrong ways to do this, use a very small amount light machine oil or dry graphite ...never grease). Both rear wheels should spin very smoothly with no hint of binding. While you are back there, get rid of the stock bushing and add ball bearings.

Front Suspension:
Next check your front suspension. Out of the box mine was almost non-functional, there was binding and very little travel. Chuck the stock bushings and lubricate the suspension and bearings. There is an article on the Atomicmods site about polishing kingpins; I don't go quite that far, but I do make sure that everything is very smooth up front.

Rear Suspension:
If you've changed to a carbon fiber H plate, I would change back to the stock plastic; you want max flexibility back there. I remember the reason we changed to carbon fiber on the Mini-Z was because the stock plates broke in a day. That is not a problem with the d'Nano, and from what I can see a the only reason to use carbon fiber H plates is for stiffening up the rear; exactly the opposite of what you want to do if you've got chatter (which is equivalent to full scale "axle hop".)

These setup tips will be old-school for those with Mini_Z experience, and I'd be lost on this little car without having setup so many of those cars previously and thus understanding the Kyosho philosophy on quality construction with a few suspect or poorly performing parts. At this price, the d'Nano should come with full bearings and ball differential.

I've tested this setup on both carpet and EVA foam (the smooth side) and it works well. It does take time to settle in and if you take some very sharp corners with full-grip, you may still get some chatter, but it's certainly much more drivable than stock.

[-J-]

Thanks again for the help Lornecherry.

Differential:

I've added ball bearings all around, so I can check this off the list. I've sanded the diff plates smooth with high grit sandpaper (it was HIGH, just can't remember the exact grit rating), which is definitely worth doing, just be sure you use a ultra high grit sandpaper so you don't increase friction. Anyway, I rebuilt my diff and only lubricated it with a little, light bearing oil. Seems to work well. Both rear wheels spins and work freely, but I'm still not happy with the Kyosho diff. I don't think it differentiates very while, but that's for another topic. I'm gonna keep playing with the provided spacers and may try to find other springs that may work.

Front Suspension:

Again I've added bearings all around so we don't have to worry about that. After buying numerous spring sets, I've finally found a set of each hardness that seats properly within itself with compressing and is nice and smooth. I've just double checked and the front suspension seems to be working properly.

Rear Suspension:

The past couple weeks I've been playing with the Atomic h-plate set. Almost all the h-plates in the Atomic set are softer than the Kyosho plates, but like you said, the stock h-plate works the best on the carpet of anything I've found so far.



Again thanks for all the tips and tricks. I look forward to your next writeup. The only thing that I haven't tried that you suggested were the atomic tires. They're on the list for this weekend's trip to the track. Then again it could be the surface under the carpet, which is quite rough, and my malicious driving. :P

[arch2b]

due to my mini-z experience, i've always perferred soft h plates vs. stiff. for mini-z, i actually use custom made lexan h plates that vary in stiffness and are nearly indestructible. they will tweak if left bent but easy enough to flatten out.

stock mini-z h plates are very succesptible to breakage due to force and angle of impacts and amount of exposure of the rear end. i find it very hard to believe the dnano will have the same problems unless you get nailed just right on a rear wheel.

thank you for sharing the throttle limiter mod! i recall this being done to the old kt-5/2's way back in the day as well. the training mode is slow enough for my kids but this mod is very useful to keep in mind
if you could, please start a thread in the parts subforum detailing this modification it will be much easier for people to find it there and it's worthy of sharing!

[lornecherry]

arch, if it is easier, feel free to move these two threads (the one on the transmitter and the one on the suspension) to the hop-up or mod category.

[arch2b]

done

[RealTracks]

That’s a great limiter. Since I am new to the forums I don't know if this method has been covered. It is what I used when my girls were very young learning to drive a RC car. I just did the KT-18 to see if it would work as well as it did on the KT-2, It Did. These are just bicycle inner tubes cut to different lengths. You can cut them on a angle if you need a narrow but larger diameter section. I like the feel of the grip especially if your hand gets sweaty. These stops were cut with scissors from discarded clear plastic packaging. I have used popsicle stick sections in the past. The inner tubes are only a few dollars each. As their skill progress you just remove a shim piece. I used to keep one set up for a crawl for when their friends would first want to try it. It works well for first time adults also. They just mash the throttle and the car just putts along and they only have to worry about steering. There is much less frustration and less for them to think about. It’s kind of like learning to fly a RC heli by sliding it around on the ground before you add the vertical dimension. While not very hi-tec it does work well.

KT-18



And the KT-2

[arch2b]

thanks for adding to the ideas! indeed, this was one of the simplest means to limiting the speed done way back in the early days of the mini-z i had never thought to try a tire inner tube... how do you secure it to the handle?

what i had always wanted to try but never did was tennis racket handle tape. it's offers very good grip, nicely padded and very comfortable. i would image that a couple winds behind the trigger would work just as well.

nice thing about this stuff is, it comes in all kinds of colors.

[RealTracks]

No need to secure it with anything. It's just like a big wide rubber band. Once its on it does not move at all. If you did not notice there is one on the whole handle of the KT-18 in the pic. Your right, rather than putting a shim you could do a few layers under the trigger, but it does build up the back also when you do that. (Not Good for kids small hands) . The shims also keep the back clean where it contacts the web of your hand like a pistol. The 1.75" tube fits the both the KT-18 & 2. The shims are solid under the pressure of the inner tube and never budge. Get a few different sizes and you will find a ton of uses for them. The U.S. Army is held together with old inner tubes and duct tape. I have used them for everything from attaching a big mag light to the side of a M-4. (in the early days before surefires and fancy mounts) to securing my parachute static line during an in-flight rig. (a big no-go) The KT 18 only needs it if you want to go slower than the min. electronic adjustment allows. You don’t get the power curve to your selected max throttle setting with a shim that the electronics give you.