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View Full Version : Q & A Thread for car Setup and Maintenance/Build tips


DMALMAD
2015.08.19, 10:03 PM
So I have posted a couple video tutorials along with my setup/beginner guide to racing article and have figured that setup and car strategy have become some of my favorite aspects about Mini-Z. I also have come to the realization that a lot of people (including myself at times) are driving their cars without realizing that their setup or methodology to car preperation is wrong. For example, for the longest time I had a ball diff procedure that I thought was golden but one sunday I travel out to PA and have another racer (MLEEMOR60) point out a flaw in my ball diff. Anyways this was a month or so back and I have adjusted my preperation of the diff and I feel like it has made an improvement (check out this recent video for the quick advice: https://www.youtube.com/watch?v=Fu6I4J9wsBg&feature=youtu.be). I have a much longer (20 or so odd minutes) video guide taking you step by step through building a diff but I am still going through and editing the video so that will be comming eventually.

Anyways, I thought that this could be a thread where you guys could ask me setup questions and advice, and I too will ask setup questions and advice to you guys too. I want this to kind of be a cooperative thread where everybody can impart their little speed secret on everybody else. Over my time racing I have compiled some of these secrets and I will do my best to share whatever information I have.

I am compiling a list of setup sheets and am working on making my own editablle pdf setup sheet too. Since my local track is switching to RCP I will try and test as much as possible (different front ends, roll centers, tire strategy, etc. etc.) and will try and have a list of carpet and RCP setups.

I would also like to talk about electronics and specifically esc throttle settings and radio settings. I will get the ball rolling and say that I hate sensorless motors :p With the Kyosho VE board there is a known problem of the lack of drag brake. I think that in all actuality there are ways to get around this, the issue I have with the VE board is the powerband. As for the drag brake I think the simple answer is to dial in more steering travel, run softer front tires on wide rear rims (like PN 8 & 6 slicks), and dial in more finger brake on the radio to compensate on the straights. Putting some scrub in the front end with a lot of steering and a fast motor makes the braking very manageable. Of course the setup changes and tire prep that this entails is much more complex but I think an all around softer car would help along with more front weight transfer. You can acomplish this by lowering your front roll center. If you run an A-Arm or even a reverse kingpin / reflex of some sort in the front of your 03 (assuming you are running nimh chassis) take the servo cover off, cut off the front part that the two top screws of the front end mount to, and then shave a little material (Using fine sandpaper on glass, checking with calipers to ensure exact symmetry) from the upper bar mounting holes. I would start by taking off 1mm-.5mm and using the .2mm shims to get it close to stock so you can adjust both up and down. Remember, the lower the front tower the lower your roll center. Generally if you have an MRX you don't run the stock servo cover, which is how I came to this conclusion about adjusting the front roll center. When I switched chassis I noticed that I had to run stiffer front springs to maintain the same corner speed as there was more weight transfer to the front.

Well back to esc's. I have tested the X-power esc and so far I am liking it with the 7500kv PN V2. You can dial however much drag brake you want and I have foun 5-20% to be the sweet spot on that ESC. I have not tried the Atomic but I hope to in the future. And you already know my opinion of the kyosho VE, hopefully this ve pro got updated software along with a better reciever system :cool:???

With that over with my first question is what do you guys who have run the atomic bl esc think about its powerband? Locally the ve is starting to prove to be faster and faster and I am personally going to stick with it as I hate changing brushes anyway :p

Also sidenote, on Hobby King there is a (leopard?) 25A 1/18th esc that is very small (especially when decased) and has proven to have more than enough drag brake and programability and is a price performer at like 20$. Anyways check it out if you haven't already.

DMALMAD
2015.08.30, 09:47 PM
So as we all know tire preperation and choice is the most important tuning aspect of Mini-Z. If your tires are not on point your car will not handle well so it is very important to have them prepared properly and have enough tread/sidewall left to perform well.

Typically the go to tire choices are Pn 6 or 5 rears and 15 fronts or kyosho 20R and 30F or even 20. For my video demonstration I used pn 20 which can be useful if you are fighting flipping or oversteer.

I have made a video (albiet poor quaiity) which can be here that explains my methods to preparing my tires for race day: https://youtu.be/MAI0aB-e0y0

One thing I forgot to mention in the video is that once I have finished truing my front tires I use 800 or 1000 grit sandpaper to finish the surface of the tire. Basically I just run the tire once it is fully trued to 22mm on the truer and run the sandpaper on the tire for a couple of seconds to smooth the contact patch of the tire. After truing the tire can be slightly rough and this means that there are high and low spots on the tire due to pitting which leads to less traction. Usually this wears away and the tire gets smooth after a couple of battery packs but I like the tires to be race ready the first time I put them on the track so I use the fine grit sandpaper.

What do you guys do to prepare your tires? I know some just use the tape in both the front and the rear but I think that gluing the tires to the rim makes the tires more consistent and lets the rears have a little longer life time and more consistent. Also what diameter do you all usually true the fronts down to? I was recomended 22 by other racers and tried 22.75-22.5 and did not like it so have stuck with the 21.75-22 and have had good results.

byebye
2015.08.30, 10:54 PM
My tires of choice are Kyosho 30 round front tried flat and kyosho LM rears again tired flat but the outside edge is cut at a slight angle.

I prepare the tires by running both the inside and outside of the tire over masking tape to pull any loose debris. I prep the wheel with a light sanding and remove any glue residue. I wipe it clean with a damp towel and use Kyosho tire tape of appropriate width.

Once the wheels and tires are ready I wrap the tire on the wheel and work the edges and spin the wheel to check for evenness around the inside and outside of the tire. I also,check for bulges and pic he and smooth to get an even amount of tire wrapped around.

Second to Last step I've started doing is glueing both the front and rear tires on the inside and outside of the wheels. Kind of like making a bead. This is somthing new I've been doing and noticed a lot more consistency.

Last prep left is to true the tires. I don't measure diameter but I will just to have a reference. I don't sandy the tires afterwards to smooth them out but I usually get a handful of hot laps in to do the same thing. I usually bring my car in and again run the tires over the sticky side of the masking tape to clean them up.

Iced ordered some foam tubing and hope to do the same but for outside use.

DMALMAD
2015.08.31, 12:29 AM
I also run the wheel alone and sand it slightly to get rid of residue and high/low spots, but I have never heard of sanding the tire with masking tape. Are you using the blue masking tape and are you running it on the wheel and the tire or the tire alone? Does this give a notciable increase in consistency? Just curious as I have been struggling to make it so that the tires work from the first couple laps instead of the 2nd half of the race. When the tires are new they work immediatly for the first few battery packs but then I notice it takes longer and longer for them to come in after that. You notice that too, or is that just me? I think it is partly my fault for not cleaning them off with wd-40 before I go to run them and there is a little stuff on the tire but I would think that that stuff would go away after 2 or 3 laps.

DMALMAD
2015.08.31, 12:40 AM
Another tip that I think is important is to keep some sort of race journal or some sort of record of setups and finishing positions/hot laps. Basically for me i keep a medium sized notepad at home and after the race when I go home I will right all setup changes I made, the effect, the final setup, the finishing position and the hot lap. I will usually add notes like how one setup gave more lap times but was harder to be consistent or how same lap times and consistency setups had different characteristics and so on. Usually when I get to the race track I don't make any radical changes just usually spring rates or oils and camber. I don't even usually touch RH at the front just at the back. I do this so I can spend more time racing and less time worrying about setup because usally if I am close it will just come down to tires but if there is a major problem Like I want to switch from brushless to brushed or change my front end (have 3 different options) then I will save that for when I get home and have time to get everything right.

This won't make you go faster but having a record of setups and notes will help in the long run spend more time using the car when you are at the race track. 9 times out of ten I can make signifgant or small adjustments at home without testing the car and notice the difference that I was aiming for without testing until the next raceday.

Anyways just something I do that I think could help some people, especially those with limited track time and budget constraints not being able to use up a lot of tires.

byebye
2015.08.31, 06:31 AM
I also run the wheel alone and sand it slightly to get rid of residue and high/low spots, but I have never heard of sanding the tire with masking tape. Are you using the blue masking tape and are you running it on the wheel and the tire or the tire alone? Does this give a notciable increase in consistency? Just curious as I have been struggling to make it so that the tires work from the first couple laps instead of the 2nd half of the race. When the tires are new they work immediatly for the first few battery packs but then I notice it takes longer and longer for them to come in after that. You notice that too, or is that just me? I think it is partly my fault for not cleaning them off with wd-40 before I go to run them and there is a little stuff on the tire but I would think that that stuff would go away after 2 or 3 laps.

Sorry, I gave a terrible description of the tape thing. I take masking tape and pull a strip off a flip it so the sticky side is up. I run my tires on the sticky side and the tape pulls any residue a deposits off the tires. The tires start out clean and have great grip to start but pick up any loose residue on the track. We typically vacuum the track before every race day.

Xovonob
2015.11.02, 01:16 AM
Anyways, I thought that this could be a thread where you guys could ask me setup questions and advice, and I too will ask setup questions and advice to you guys too. I want this to kind of be a cooperative thread where everybody can impart their little speed secret on everybody else. Over my time racing I have compiled some of these secrets and I will do my best to share whatever information I have.


Note: I bolded my questions below if you want to skip the exposition.

This is a great thread and much appreciated. I followed a good deal of the advice in your beginner's tuning guide. I figured out how to prep and true tires. That made a HUGE difference. Now, I'm looking for more / better handling. I ended up getting the double a-arm suspension, the lcg v4 motor mount, and a PN dps.

The double a-arm was a tinge challenging to install correctly, but I ultimately figured it out. However, when I installed the body, the ride height was too low and I couldn't get it to come up until I put in the stock springs I just removed from the Kyosho front-end. I couldn't get the green springs that come with the kit to work.

Question 1: do you use PN springs on your front-end (I'm assuming it's a double a front-end)?

Question 2: what is your approach to choosing the proper spring limiter and shimming it?

Question 3: what is your procedure for setting droop?

I'll hold it to three questions for now, only focusing on the double-a arm. Thanks again for a great thread.

DMALMAD
2015.11.02, 08:40 PM
Note: I bolded my questions below if you want to skip the exposition.

This is a great thread and much appreciated. I followed a good deal of the advice in your beginner's tuning guide. I figured out how to prep and true tires. That made a HUGE difference. Now, I'm looking for more / better handling. I ended up getting the double a-arm suspension, the lcg v4 motor mount, and a PN dps.

The double a-arm was a tinge challenging to install correctly, but I ultimately figured it out. However, when I installed the body, the ride height was too low and I couldn't get it to come up until I put in the stock springs I just removed from the Kyosho front-end. I couldn't get the green springs that come with the kit to work.

Question 1: do you use PN springs on your front-end (I'm assuming it's a double a front-end)?

Question 2: what is your approach to choosing the proper spring limiter and shimming it?

Question 3: what is your procedure for setting droop?

I'll hold it to three questions for now, only focusing on the double-a arm. Thanks again for a great thread.

1. Yes, you should only use pn double a-arm specific springs with that front end. In specific the teal/green a-arm v3 spring seems to work best on RCP

2. The spring cups that come with the A-Arm are fine, for setting preload PN sells a shim kit that works with the spring cups. These are neccesary to get proper ride hieght and preload.

3. For droop it is simple, take your 1.5mm driver on the bottom and the .09mm driver on top and loosen/tighten the set screws until you get desired tension or droop. Next the most important step is to place your car with wheels and tires on a piece of glass. Measure rideheight with a rideheigth gauge (start at 2-2.5mm) and make sure it is equal left and right. Next take 2 pennies and place them on top of the 2 front tires. Then lift the chassis from the center of the body clip with your screw driver. If the pennies drop at the same time then droop is equal left and right. You can also eyeball when the tires leave the ground if you dont have pennies on hand. If droop is unequal the car will handle eradictly so this is critical to good handling.

Xovonob
2015.11.06, 12:09 AM
3. For droop it is simple, take your 1.5mm driver on the bottom and the .09mm driver on top and loosen/tighten the set screws until you get desired tension or droop. Next the most important step is to place your car with wheels and tires on a piece of glass. Measure rideheight with a rideheigth gauge (start at 2-2.5mm) and make sure it is equal left and right. Next take 2 pennies and place them on top of the 2 front tires. Then lift the chassis from the center of the body clip with your screw driver. If the pennies drop at the same time then droop is equal left and right. You can also eyeball when the tires leave the ground if you dont have pennies on hand. If droop is unequal the car will handle eradictly so this is critical to good handling.

Thanks for the response.

My ride height gauge is in the mail. I'll give your droop technique a try after I receive it.

Cheers.

Xovonob
2015.11.15, 04:16 PM
2. The spring cups that come with the A-Arm are fine, for setting preload PN sells a shim kit that works with the spring cups. These are neccesary to get proper ride hieght and preload.

3. For droop it is simple, take your 1.5mm driver on the bottom and the .09mm driver on top and loosen/tighten the set screws until you get desired tension or droop. Next the most important step is to place your car with wheels and tires on a piece of glass. Measure rideheight with a rideheigth gauge (start at 2-2.5mm) and make sure it is equal left and right. Next take 2 pennies and place them on top of the 2 front tires. Then lift the chassis from the center of the body clip with your screw driver. If the pennies drop at the same time then droop is equal left and right. You can also eyeball when the tires leave the ground if you dont have pennies on hand. If droop is unequal the car will handle eradictly so this is critical to good handling.

This worked. You were correct, the PN shim kit is necessary. Thanks a ton for the advice.

I've been playing with getting the servo precisely adjusted. Two things I've noticed:
1. When turning right, the servo is smooth to a point, then "jumps" over a spot before continuing travel to the endpoint. My stock vehicle (both are MR-03VE Pro) doesn't do this. Do you suspect this something common after installing the double a-arm, or something in the servo?

2. The servo will allow greater travel at the rightmost endpoint, before it binds / buzzes, than it will in the leftmost direction. This seems to be common to both vehicles (stock and double-a). Have you observed this on your mr-03's?

Hopefully our conversation here will help others.

Mike Keely
2015.11.15, 04:50 PM
Do you have the metal third gear in the servo? That gear is easy to get messed up. I have a metal third gear in all of my cars.

DMALMAD
2015.11.15, 06:19 PM
If you feel that the steering is skipping or binding then usually it is the third gear in the servo as already mentioned. As for the unequal steering balance that is usually due to the radio settings. If you have a digital radio than you can adjust the left to right balance but if you have a kt18 than you would have to look into the manual to determine how to change the balance.

Xovonob
2015.11.15, 09:24 PM
Do you have the metal third gear in the servo? That gear is easy to get messed up. I have a metal third gear in all of my cars.

I don't have a metal third gear, but I have a feeling I will soon ;). I just did a quick search on Kenon and I only found a metal 4th gear - part MZW417 (there is an aluminum one, as well - MR3056M). Is that the same thing you're mentioning?

Xovonob
2015.11.15, 09:30 PM
If you feel that the steering is skipping or binding then usually it is the third gear in the servo as already mentioned. As for the unequal steering balance that is usually due to the radio settings. If you have a digital radio than you can adjust the left to right balance but if you have a kt18 than you would have to look into the manual to determine how to change the balance.

My radio is an EX-6. My procedure for setting up steering through the radio is to mess with steering sub-trim to get the wheels centered properly, then set the travel endpoints. When I do this, I notice that I get servo buzz much more quickly on the left than on the right. When I'm done adjusting so that neither the left nor the right buzzes on full-lock at the radio, the wheels on the car will turn further to the right than they will to the left.

DMALMAD
2015.11.16, 01:17 AM
I never mess with Sub trim. I would reset the model and then just adjust with regular st trim. Then I would use the st Balance adjustment to make it so that it buzzes just slightly both left and right at the very end of the steering wheel travel on the radio.

Xovonob
2015.11.22, 08:30 PM
I've been playing with getting the servo precisely adjusted. Two things I've noticed:
1. When turning right, the servo is smooth to a point, then "jumps" over a spot before continuing travel to the endpoint. My stock vehicle (both are MR-03VE Pro) doesn't do this. Do you suspect this something common after installing the double a-arm, or something in the servo?

2. The servo will allow greater travel at the rightmost endpoint, before it binds / buzzes, than it will in the leftmost direction. This seems to be common to both vehicles (stock and double-a). Have you observed this on your mr-03's?


Updated
I performed surgery on the servo gears today and installed a metal 4th gear from Kyosho (MZW417). I never found the metal 3rd gear mentioned above; not sure it exists.

When installing the metal 4th gear, I had to take apart a good deal of the entire servo mechanism, so I decided to take it all apart and examine what was going on. I'm glad I did. Part of the original plastic 4th gear shredded and the debris was nicely munged into the 3rd gear. Need the old magnifier to clean it, and then I inspected the other gears. I found some debris in the 2nd as well. After doing all that and putting everything back together, which is a bit of a pain, everything is working well.

The steering is much smoother with the metal gear. Despite the laborious installation, I recommend this upgrade.

Xovonob
2015.11.22, 08:44 PM
I never mess with Sub trim. I would reset the model and then just adjust with regular st trim. Then I would use the st Balance adjustment to make it so that it buzzes just slightly both left and right at the very end of the steering wheel travel on the radio.

At first, I didn't agree with this because rather oddly written instructions in the ex-6 manual indicate the proper sequence is to set sub-trim first (pg. 13). I tried your method anyway, and I now disagree with the manual. Sub-trim moves the endpoints in the adjustment direction, which results in having to chase endpoints when using regular trim while on the track.

My sub-trim is now set to zero.