Here's my first stock DTM ..I love it!

[TJFBryant]

I finally got my much needed parts in the mail the other day.
My DTM STOCK version is done...
I have a Novak spy esc,
Futaba standard rx
130 motor (for now)
and a Hitec 55 micro servo
600 mah 6 cell nimh
It all works so well. And honestly it is pretty fast stock.

I still have a ton of parts to install in it to make it FAST.
Mamba 25 esc and brushless system + 180 modded motor
14 t pinion...and 46 t spur gear.
4 silver aluminum rims
and a 1150 mah 6 cell nimh.

With this setup....It'll be sweet and maybe uncontrolablly fast.
Most of the upgraded parts I have already, now I just need to install them
I still have to paint my toyota supra GT body...but the hard part is done.

[TJFBryant]

One more thing...why are these DTM thread not more lively....is it because not many people know about it?? Its a discontinued uninteresting model??? Both??

Or is their another place where the DTMer's hang out to chat.

Personally, I don't think many people have these dtm sp's or x4's.

[cdog4w]

I'm still here and planning to stay :P Gonna try to do some more custom work on mine, but tough since we're completing a move into a new apt. (same city). I'm still having traction roll issues at the track, but I did get my lap time down a bit more.

Be very careful if you dremel out space for a motor on the motor pod portion of the chassis, as I just broke mine. Dremeled too much. potentiality suggests lining the cut portion of the chassis with superglue to add a bit of strength which I didn't try. Certainly can't hurt.

One thing that did help the traction rolling a lot was supergluing the outside edge of my foam tires. Not sure what the stock foam's hardness is, but from what I understand, harder foams = less traction rolling. The superglue just adds a little hardness to whatever foam you do it to.

TJF, what surface do you run on? That Rx needs to come down to lower your CG if possible. Maybe try shrink wrapping it to save some space.

[TJFBryant]

thats funny.. my wife and I are moving out of our old apartment too and into a new one. *moving suxs* sorry had to say it.

Thanks for the heads up on modding the motor mount, I ll look to be more cautious with the dremeling.

I run my car on too surfaces ....one is very very large row of tennis courts perfect for gathering top speeds and drag lines, the other is an actual LHS RCP foam 40' long road track (this is where I do all my competitive racing....unfortunately only for MINI Z's.) a few days ago was the first I tried my DTM on any surface, I am looking to run it on the courts more often than a track.

I do have a 25' RCP in my basement, but this is used mainly when I want to race in the winter time, rainy days..etc.

I haven't run on any of these surfaces yet...just around the kitchen...because I want to finish the body before I really test drive and open the DTM up to performance runs.

I know your right, the Rx I have a way to high and the CG is going to be unstable....I plan on up grading to the smallest rx I can find. Also, I haven't set any of the electronics cables either to the chassis so it looks very disheveled in the pic I posted.

Thanks for the tips again, and especially supergluing the walls of the tires...that is a great idea. ONE thing that makes the handling of any car bad is the amount of tire track and angle of momentum the tires are at entering a corner or straight away. It really is real racing physics.

[cdog4w]

wow, I'm jealous that you have room for a 25' track in your basement, much less a 25' RCP track. I hear they're quite nice. Not sure how much bite they have compared to the ozite carpet I've been racing on at the local 1/10 track, but traction rolling might not be a problem with the things you can do to reduce it.

Since you seem to know what you're talking about, I was wondering if you could clear up this question. I've heard 2 accounts now about what kind of springs to use up front to reduce traction rolling. Most people say hard springs (along with hard foams) to reduce traction rolling, but last time at the track, a 1/12 racer said go as soft as possible to reduce it. I kind of think the former seems more correct, but figured I'd ask anyway.

I'm working on a custom aluminum upper deck (battery box is plain inconvenient for electric placement). I'm using some DRR kingpins as standoffs. Will also be making a battery hold down that will body clip to the upper deck at one point to make it easy to swap my saddle pack. Will keep you posted on results.

Also going to try to dremel out the motor mount to let me use a larger pinion with my TO Elite Mod motor.

[2000-redrider]

Originally posted by cdog4w

Since you seem to know what you're talking about, I was wondering if you could clear up this question. I've heard 2 accounts now about what kind of springs to use up front to reduce traction rolling. Most people say hard springs (along with hard foams) to reduce traction rolling, but last time at the track, a 1/12 racer said go as soft as possible to reduce it. I kind of think the former seems more correct, but figured I'd ask anyway.


I know this was not intended for me but...hard tires and hard springs both reduce traction. As a result, they will minimize traction rolling.

[cdog4w]

Awesome, thanks for the info. Ordered the hardest ABC foams, will try those out on wed. Running the stock springs, not sure how they compare to the "hard" and "soft" abc springs.

[TJFBryant]

Ummm Cdog,
before you go hard springs and tires...I would STRONGLY reconsider!!

WHy?
Because if your running on Ozite carpeting or ANY carpeting the last thing you want is a hard spring set and tire set. Your car will flip and roll like no tomorrow.

NOW..

If you told me you where running on a different terrain like a foam track, or pavement...I would say HARD all the way around tires and suspension.

You may be in big trouble if use the hard setting on Ozite.

FYI, I have run on Ozite before....not with a DTM but with a Z...
I needed to lower the CG and go with the soft to med spring set and TRY med to hard tires.

Also, FYI..its not my basement, its my grandmothers..lol
She's letting my wife and I move in with her to help her around the house. She's 88.
Her basement is 45 ' wide and 20 ' long.

[cdog4w]

TJF, thats what the 1/12 racer told me. Why is ozite so different from other racing surfaces that it requires the exact opposite in tuning to reduce traction rolls?

Anyway, the superglue on the outside of the tires really helped reduce the traction roll on the ozite, and isn't that just simulating harder foams? If what you say is true shouldn't I have traction rolled more?

Thanks for the help btw. I'm still trying to learn about this stuff.

[2000-redrider]

Hey, sorry if I steered you in the wrong direction Cdog. I have never run on ozite and am unfamiliar with it's traction characteristics.

Here's something to consider though. If going "hard" isn't reducing your traction rolls, maybe it really isn't just a traction problem. Perhaps you've hit the speed limit that you cars CG has set. As TJFB has said, he had to lower his CG to stop his car from flipping. Perhaps soft springs result in an overall lower CG while going through a turn by lowering the cars ride hieght. The added traction (resulting from the soft springs) would then have to be counterd by harder tires (TJFB suggests med or hard) or else a traction roll will agian result. Maybe soft springs/hard tires is the way to go.

Let us know if you figure this one out. I think your final set up will be pretty interesting.

[TJFBryant]

redrider

I am not underestimating your knowledge with the physcis of these cars ( I hope you know that)

You are right about vehicular characteristics and what you should use.
But on ozite..its..a lil..(very little) different.

ALso, one thing I ve found out is when driving on hard tires and springs...the car tends to lose grip when corning causing MASSIVE irratating problems...believe me ( I was ready to give up 3 weeks of racing when I couldn't figure out the right setup.)

**The problems all hard setups MAY cause is a pushing of the front tires going around a corner. This causes the car to take a much wider (unwanted, understeer) turn around a hairpin.
Also if you have hards on the back it may cause your rear to slide around all over the place (you would look like a trout fishtailing around corners so much)

-** Note: That is if you are going high speeds and NOT going a proper speed.

You may want to try a combination of hard and med tires.

I know my Z I have (although a totally different monster than the DTM has a Hard front tires ...Med back tires.....soft front suspension and soft rear dampner spring and med roll shock springs.
The car ....is a monster ...sticks to its line like glue with no understeer, tailspin, or roll shock (unless you go into a turn full speed)

I hope this helps...again redrider... you are right about a cars physics. I apologize if I jumped in there without being more polite.

[2000-redrider]

Hey no offense taken. I have found all too often that what I think should work doesn't (and with good reason). What you found to work on ozite seems to go against the general rule of thumb. I wasn't doubting your setup (sorry if I sounded that way), I was just trying to figure out why it works. That's why I'm interested to see what Cdog finds out. Believe me, I am in no way an expert and welcome any set up tips and suggestions.

[TJFBryant]

definetely....I want to find out how it works for C dog.....what I find also, as a personal thought, is that it matters what type of driver you are also. Are you a cautious driver that stays within the limits of your cars ability when cornering and throttling? Or do you test the cars traction and physical ability at every hairpin?

You wouldn't believe this if I told you, but..

My good friend has such good drivers discipline that he can use his stock engined mini Z and BEAT many racers who have the X speed in the car and tons of hop ups.
He has such good driver awareness, and runs an extremely tight race line that he beats them at every corner and every hairpin.

In general though, your estimates are right on with a cars physics. Personally I hope Cdog can find the perfect setup that works for him.

One last thing I found is that their are different thickness of ozite carpeting out there.....I never really knew that..until the ozite track owner mentioned it to me...maybe I ran on a different thickness of ozite than Cdog does....

at any rate....I hope it works out.....I know it took me over 6 months to find the perfect setup on my track I race on.

P.S.....I am no master of this stuff either...just a really avid micro RCer.

[cdog4w]

Thanks for all the advice guys, I'll keep you all posted. As a side note, its tought to keep track of my tuning because so many things change between race days for me. Last week I broke my rear pod after a nasty hit (my fault). Problem was I had dremeled out the rear pod to accept the TO Elite Mod motor and it weakend the chassis at the screw point to the motor mount (one towards front of car). Luckily someone donated a spare chassis so I'm layed out all my electronics on it, but still need to dremel out space for the motor. Going to try the super glue trick that potentiality suggests and hope it strengthens it enough (that and avoid nasty hits). Aside from that I also switched over to using a custom aluminum upper deck (I'll post pics later). I'm pretty happy with it, even if it isn't the prettiest. We'll see how it runs. I also realized that the one foams I had tried the "superglue on outside tire" wall trick with was a bit torn and was ruined by the last race (along with my chassis :). Tonight I will be getting a new spur (40T) to try to coax a bit more speed, hard front foams and some other random parts.

As for driving style, I do try to ride the line and don't have much in the way of discipline. I'm getting better though, and still working on it. It's great racing with more experienced drivers like potentiality who is rapidly gaining on the lap times of the 1/10 drivers with his 1/18 m18 :P They run 11's and 12's and he runs an avg of 13.5 or so.

This also brings up the track, I'm not sure on the thickness of the ozite, but remember that its 1/10 scale, so understeer isn't nec. a bad thing (I have my dualrate set to 50-60% as it is, helps a lot).

Good to see some real activity and discussion on tiny again!

[2000-redrider]

Cdog4w, not sure what your aluminum upper deck looks like but there's a pic what I'm running at http://www.tinyrc.com/forums/showthread.php?s=&threadid=7114. It looks very similar to your plastic one.

[TJFBryant]

Here's a problem for you. This shows you exactly what I don't know..lol

AS mentioned with my setup earlier in the thread.
I have a 600 mah pack, standard sized Futaba rx, novak spy and a hitec 55 micro servo.
So heres my problem.

When I run the throttle full speed holding it in my hand and I turn the steering servo all the way left and right...everything happens as it should....NOW
When I run full throttle or kick the gas trigger going to full throttle my car wildly fishtails ALWAYS to the right as the steering servo appears locked in that position until I let up on the gas down to a minimum 20% throttle speed. Then I can turn the wheels. Otherwise, my steering remains locked to the right no matter how much I turn the tx wheel.

I am buggered...really confused...now I usually know some $hit when it comes to this stuff...I ve done it for over 18 years...you think I would have run into this problem already..lol

SO anyone have any suggestions??
Could the engine be messing with the radio signals at full throttle?....is the esc disrupting something.

One NOTE: When my batteries appear nearly dead the servo locking to the right at full throttle rarely happens at all.....what the heck...if you gentlemen have any ideas...let me know. I am glad to see these DTM threads re-invigorated.

[cdog4w]

Redrider: did you custom make that rear suspension mount? Looks very nice if so. Much cleaner than my hack job.

I posted pics of the aluminum upper deck I made. Not pretty, but it seemed to work well. (http://tinyrc.com/forums/showthread.php?s=&postid=176163)

TJFB: I had the exact same problem. What motor are you using? I had a lot of trouble with the stock motor in the same way. Perhaps bad capacitors? If you're using a different motor, check those out. Another thing I did to help clean up the problem was add a 4700uF capacitor, tho that is dual purpose. Gives a nice kick on acceleration, but also smooths out the voltage drops, which will make things happier overall. I think that was the biggest cause, voltage drop on full throttle. You don't need to go so large, but if you're interested, potentiality found the caps which are 10V, 4700uF, low impedance and pretty small for their capacity.

Now on to the exciting bit, I had a fantastic race night tonight. I dunno if it was the non-torn/super glued outer wall front tires or the new aluminum upper deck or both, but the car ran beautifully tonight. New personal best lap time of 16s. As a side note, potentiality ran a 12 flat as his PB, which is 1/10 stock sedan speed (with his 1/18!). So I can vouch for hard foams up front (not sure what I have in back), and I have soft springs up front still I think. I also ran without the upper portion of the damper spring assembly (the long one that attaches to the very top ball/socket). I'll test out the hard fronts (35 whatever) from ABC I just got next time I go, and see how a non-superglue tricked set of hard foams do. Also thanks to the new upper deck, I seem to have lowered my CG. I rolled once or twice, but instead of going all the way over, it sat back down and kept running. Maybe its just that I'm not rolling as hard :P Anyway, I bumped up to a 12T pinion/40T spur and wow can this thing fly. Time to see if they make 14T pinions for the rs4 :P

[potentiality]

Cdog was having somethng similiar happening originally. It was hard to pin down, but we thought it might have been the 130 motor. That or we did add a power cap at the same time..

Try putting some resistance on the rear tires while holding it up, and then punch it. If it does it then its something with amp draw I would suspect.

BTW he did great tonight! (Well except forgetting to peak his battery before the main, gearing up, then dumping in the last minute of the 8 minute race).

[2000-redrider]

Cdog, Yeah I made the rear mounts with sheet aluminum. It works as a mount but I think it allows too much chassis flex. I was thinking of making a deck that went all the way to the front brace, but I like how you used the DRR king pins.

That picture is of my car when I first got it. I'm still using aaa's but not in a saddle pack config. I'm also using a shredder receiver, instead of that dcx.

Good to hear your making progress with you set up.

[cdog4w]

We did an 8 min main again? I guess from now on, cool :P I had geared up for the second heat, but only ran 4-5 laps, which is why I didn't think I'd need to peak for the main. Bah...

Oh yea, and I dumped for the last 2-3 min of the race :P My final lap was 45 sec or so! (compared with a personal best of 16s) It was pathetic, but I made it across the finish line.

EDIT: Thanks redrider, so where do you run your SP? Any tracks? I'm looking for some good SP stories now that I've got a stable racing SP. Also, what kind motor do you run, and which pinion/spur? Your rear suspension mount is amazing, what did you do to cut it out/bend it? I used a tinsnip/vice to cut/flatten my plate, it may not be pretty, but it seems to work. Going to clean it up with a file later when I add the battery mount stuff.

[TJFBryant]

thanks for the reply guys....yeah I have the stock 130..cause I wanted to test out its capabilities....which I might add is fine for running in a small kitchen but crap when running a road course on a large tennis court.

I haven't soldered on one of the caps yet ( 2 are standard on the stock)....but I am going to add a third cap to see what happens.
If it coninues I ll just say "screw it" and modd the DTM the way I want it..

Mamba esc and 180 brushless system..
creating own upper deck using CF.

[cdog4w]

Yea, give the third cap a try, but I'm waiting for your latter suggestion :P

I thought you'd already ordered the mamba? I can't wait to see that thing in action, its going to be RIDICULOUS on a car this small.

So do you know how to work with CF? Are you doing it somewhat professionally or you attacking it with a dremel? :P

Regardless, good luck on getting the 130 running properly, but unless you're stuck in your kitchen, you'll have it working for 5 min before you start installing the mamba.

[TJFBryant]

hahaha,,yeah I have the mamba and all the items I need to mod this DTM up the wing wang. I just wanted to see it run stock first. Now that I know it runs faster than a stock Z but just slightly slower than a X speed Z.....I think it'll be time soon to add a little punch to her system.

I do want to try the 3rd cap...so I ll solder it in a few minutes and give you my results.

Otherwise...its mamba 25 time.

As far as CF goes....I know nothing about the stuff...I just know where to get it, and what I want to shap it like... so I am dremeling away at it probably.

[cdog4w]

Cool. Yea, I guess I never tried stock on mine. Then again, I can't compare to a Z since I've never seen one :P Good to hear some perspective.

/me chants "MAMBA MAMBA MAMBA!"

I didn't have the nerve to plunk down $25 on a sheet of CF to play with, I got my aluminum sheet for $1 :P From what I understand you should get a face mask as the CF powder from cutting it is bad for the lungs, like asbestos.

What I really want to find is a 2mm drill bit for my dremel so I can put real holes in my aluminum. Right now I don't have any bits that small so I use, ahem, more imprecise methods. Aside from that, its tinsnips and a set of hobby files. Rocket science here I come :P

[TJFBryant]

sounds good thanks for the tips about CF....

Well, here's another major problem.

I soldered the cap on the motor...
assembled everything....and apparently...
the reason why my servo locked up is because the motor is shot.
I tried everything to get power to the servo I have....its a no go.
So I have to put more money down on another (perhaps) more powerful servo.
I just don't know what caused burn out of the servo.
Maybe it was the lack of the 3rd cap on the motor...but somehow I doubt it.
So, I am back at square one temporarily....which micro servo motor do you prefer.

BTW...I think I know what happened...I installed a Hitec HS 55 servo (JR, RCD). I have a FUTABA receiver...and should have put in a Hitec HS 55 servo (FUT). Do you think is was the problem....incompatibility? I think maybe

[2000-redrider]

Cdog, I basically only run my sp on my drive way and the occasional parking lot. Unfortunately I haven't been able meet up with other SP owners that often. I did meet up with MicroRCEngineering once and all I can say is that his car is FAST!

I'm runnig a 12T/40T gear combo with a GPM high rev motor.

TJFB, it could be an incompatiblity thing. Just check that the wires are in the correct order. I had to switch mine since I use an airtronics receiver and use a Hitec servo.

[cdog4w]

I'f you're using the Rx from your 2PL, I think the manual has instructions on wiring for the dif. servo types, you can always check that. If not, mayber your spy manual does?

I'm not exactly clear on how you burned it out though. It was working fine with the stock 130 motor and the HS-55, but after you soldered on the new cap it burned out the motor and took the servo with it? Had you changed the wiring into the Rx before it burned out? Try unplugging the motor from the ESC and test out the servo that way. (I'm sure you've tried already but...)

As for which servo I have, its the Hitec HS-56HB, got it at servocity.com. Another cheap one that I've heard good things about are the bluebirds: http://www.av8hobbies.com/blue.html

Some people use hobbico cs-5's (which are futaba servos in this case from my understanding, and slightly higher qual than normal hobbicos).

red: Yea, I don't have any other SP owners to run with either, last night it was 2 M18's and a MRS4. So did you get to look under the hood at MRCEngineering's car? I've heard good things about the GPM high rev. I'm hoping I can run 15/40 with my Elite Modified :P I need the speed to keep up with those damn M18s! One is running a speed 300, the other a "beast" which I *think* is a dyno tuned 280.

[TJFBryant]

sorry I need to clarify...

umm.. Before I soldered anything and did my first full range test run yesterday. My servo motor kicked the bucket after the batteries died out. I thought it was because of the batteries, but when I charged them up again to test out the reason for the servo locking....it didn't do anything. No start up glitch, no movement nothing.
So I looked at the box I purchased it in and it said Futaba Hitec HS-55 (JR, RCD). I didn't switch around the wires or anything because I thought it was the servo I ordered correctly. I wasn't.

SO I am going for another servo, hopefully this time the right one.

Its totally shot.

I also thought maybe it was the heat. Remember it was 95 degrees yesterday and probably about 125 on the tennis court surface. I dunno.

On another topic, it appears I am the only one in my area that has a DTM also (NY), I check with the track owner I go to, and he said only one man he knows of owns one of these...and he is in NH. Its all good though because I feel priveledged that I have something not everyone has.(a.ka. mini z)

[cdog4w]

Sucks that your servo is shot. As for the racing situation, you should check with your track and see if they'll let you run a micro class if you can get 3+ people. Thats what our track did anyway. Then its just a matter of drumming up support. When we started out it was only two of us seriously racing, not to mention different scales. We'd have one or two mini-t's run with us, but the drivers weren't serious and were just having some fun away from their 1/10's. In the meantime, potentiality has been constantly dropping his lap time and has earned some respect, we're getting more serious competition to show up. Some people are starting to bring in more m18's and we had the guy who announces the races run an old MRS4 last night. So if you work at it, you will hopefully be able to drum up some fellow racers :P

[TJFBryant]

Your right , the only problem is the track owner only allows Z's on the track. No xmods, no DTM (yet heehe), no clone Z's like the Iwaver. Only Kyosho products. Which personally for me and alot of other people are very disappointed in that idea.
Why not open up other classes and races.

The track is an Indoor 40' RCP track modded to look like a road course. It really is quite good, but again, disapointing because us hardcore micro hobbiER's can't enjoy the RC the way it was meant to be.
What can I say NY sux. :-)

although I think I ll drum up my own interest in the area by telling other racers about my 25' RCp track in my basement. They can race as much as they want for free, (as long as I am there to supervise...:-))

One more thing...While I am waiting for my next servo to come...I successfully modded the stock motor mount to gently hold a 46 t spur and a 15!! t pinion gear...man oh man....I cna't wait to put in that Mamba.....pics, then videos to come if I don't crash it first. :-)
Ginve me a week or 2 to get this modification panned out..lol

[cdog4w]

heh, 46T spur, why not go lower with the mamba, I'm sure it can handle it no problem. I'm running 12/40 and havent lost any acceleration compared to 10/42, or at least not much.

[potentiality]

My rule is if they dont support you, then dont support them. If he wont run a class even if you get enough people.. find a different place to shop.

Anyhow by cap I meant a POWER cap. not a cap for the motor. (Cdog break out the pics).

JR and futuba plugs are intercompatible The fut are nice as you cant plg them in backwords because of the flange. But even if you plug the jr in backwords in wont fry it as its not the positive and negative leads that are switched.... now if you had a airtronics servo or receiver, I can see a problem.

[cdog4w]

http://cstanleyw4.home.comcast.net/rc/dtmsp.htm
power capacitor pics there.

[TJFBryant]

oh...my apologies I didn't know you meant a power capacitor.

Where is the best place to snag one of those...Radioshack?

Also..(sorry for the newbyish question, I never worked with these caps before) Do I mount it between the ESC battery wires and the battery or the ESC motor wires and the motor??

Thanks again for all your help...

Its nice to see these DTM threads still active.

[cdog4w]

I got mine from potentiality who got his from digikey (they have a minimum order of some kind, so he got 5, I picked up 2, he used one and he sold the others). Not sure on the part number, he'd have to fill you in on it.

Radioshack has a terrible selection of caps. Basically you're looking for a few different features in a capacitor for this purpose. You want somewhere in the thousands of uF range, so I've heard of 2000uF, 4700uF is very common, and I haven't seen many go higher at this scale. Smaller size uF will do more to smooth voltage drops and reduce engine noise, higher will actually give you a bit more punch on takeoff. There are whole debates on the optimal capacity since the more capacity, the longer it takes to recharge after dumping it (say on hard acceleration). The other number you need to know is the voltage capacity. It'd be pointless for you to get a 50V cap when all you need is 10V or so, all the extra V capacity does is make the cap larger. Also, don't go by the straight 1.2V rating for this, since many packs peak at higher voltages (my 6 cells peak just under 9V). Finally you can get special purpose capacitors. In this case, potentiality picked up low impedance capacitors, which means low internal resistance and more power to the motor. You'll also see a lot of 4700uF 16V caps which will work fine too.

To solder the cap in, solder it parallel with the batteries to the ESC. So on my spy, I soldered the battery wires on the top, cap wires on bottom of the connection plate.

Finally, since you're about to throw on your mamba, you might not need it. I have no idea how power capacitors interact with brushless systems. I would guess that there is less motor interferance simply due to the design of a brushless motor (which is cool sh**), but maybe thats just because they're hella expensive.

If anyone has anything to add/correct, please do as I am by no means an expert.

[potentiality]

Actually the Mambas are suffering from a slight stuttering/cogging under hard acceleration.. Shawn from the company is sending out power caps to help reduce this from happening..

[TJFBryant]

REALLY...looks like I am going to have to get myself some then...
thanks for the update....I ll keep you guys informed on how everything works out.