Some DB-01 Random questions

[Ignition]

Hey dude's !
I'm just rolled into the Offroad Scene and I must say, this is a great site/forum to search for info ! :thumbsup:

I got my DB-01 in the summer vacation and kinda rebuilding it right now, Santa ordered a 5,5T EzRun Brushless motor for me, and I got it for like 2 days ago.

After I got it, i went on some researching how the gearing should be and how fast it would go, but I saw a few topics of diffburning problems so I have some questions about it.

Yesterday i took the diff out of my Durga, cleaned it up, took the diff balls out and locked it, because a slipping diff is causing heat.

Saw in some topics I had to buy a TRF501X diff, but what do you guys mean ?
The diffjoints, or the diff itself ?

After some searching i found Heavy Duty (Aloy) Diffjoints from 3Racing, are these any better than the TRF501X diffjoints ?

What kind of things do I need to order with the diffjoints (and diff offcourse) to make my Durga even more 'bashproof' ?
(i know, it can't be 100% bashproof, but you guys know what i mean :p)

I allready got:
-Yeahracing Oilshocks
-Tamiya Slipperclutch
-Tamiya Universal Shafts (front only)
-Tamiya Carbon Reinforced Shocktowers
-DIY Locked reardiff :p
-Some spare pinions, spur gears, belts and reartires :D

And a friend of me is looking for some titanium/ceramic diffballs in his room :lol:


I saw that the EZrun engines are getting verry hot, so I want a new body, and cut some airvents in it, should a TRF501X body fit a DB-01 too ?

Thanks ! :)

[dimblum]

Congrats on your DB-01 build. I've been racing one at a local club track for over a year now. It's a great car and can be super durable with the right parts..

The first recommendation I can make is not to lock your rear diff.. Locking a diff on a 4WD car is very bad for traction control.. All of the problems people have had with melting diffs has always been linked to an incorrect diff build (wrong grease, built it backwards, etc) or they ran their diff way too loose..

Me and several other members have been racing their DB-01's competitively for some time now, and we have not had any diff problems - even when we run 6.5T or 5.5T brushless..


The TRF501X diff parts you have been hearing about are the diff joints themselves.. The TRF501X aluminum diff joints are much more reliable and way easier to work with than the stock plastic/aluminum hybrid joints that come in the DB-01 kit.. I would imagine the 3Racing joints would work just fine since 3Racing uses billet aluminum for their parts.. I have only used the Tamiya diff joints so far, so I cannot confirm the quality of the 3Racing joints.. I bet someone else probably could though..

The diff joints will require the diff plates, although the kit ones should be just fine.. I would highly recommend ceramic diff balls for the diff assembly.. This eliminates a little heat and you won't have to worry about the balls becoming deformed under stress..

The TRF501X body will not fit the DB-01 chassis. Unfortunately we can only use the Durga or Baldre bodies for a proper fit.. Both of these bodies have enough space for your electrics etc.. Proper gearing will solve a lot of the heat problems you might have while running brushless.. It's also good to invest in the Hop-Up Tamiya motor mount, the Tamiya Heat Sink plate and the DB-01R chassis or the Carbon Reinforced chassis.. Both the DB-01R and Carbon Reinforced chassis can accommodate the Heat Sink plate which will further help with motor cooling.. The Hop-Up Tamiya motor mount is lighter and cools much better than the kit motor mount.. It is expensive, but excellent.

Hope this helps.. If you need more information on gearing etc, please let me know.

Dan

[Ignition]

Hey, thanks for the info !

I locked the reardiff, ehm whats the right word ... ehh, till I got my Ceramic diff balls and TRF 501X diff Joints :lol:
It's just for testing (and adjusting) my 5,5T brushless motor on the road (big parkinglot, so i'm just driving in a straight line) so i guess, it's not a big problem ?

I think i'm ordering a Durga body with the diff joints and stuff to cut holes in for extra cooling, but they are hard to find, I normaly order my stuff at RcMart, but they only have the Bladre body, and I don't like that one so much :(
I searched at several webshops, but can't find it :(

About the cooling, the 'cooling plate' you said in your post, I got one, but it won't fit (after I got it, i researched (too late AGAIN ... :lol:) and saw it won't fit) but I'll mod it so it will fit.
About the motor cool things that you 'wrap' arround your motor, do I have to buy one with a fan on it (if they really excist :bored:), or just wrap a motor cooler around the motor ?

Oh yeah, I wanted to buy a Low-Mount spoilerset, because my spoiler is cracked (still need to tape it :p), does the front spoiler have any effect on the handling ?
I've seen it on some really pro-chassis, and it looks cool, but i'm just curious :woot:

About the gearing, I drive with a stock spur (91T) and a 23T Pinion, but I can't find on any site something about a recomended gear-ratio.
But I guess my ratio is too high, but I don't know wich pinion I have to buy :blush:

BigBig Thnx !

P.S.
Sorry about my English, I hope you all know what I mean ? :blush:

[dimblum]

Happy to help :)

The Durga body has always been a tough one to find spares of.. I ended up ordering a spare from Tamiya directly since I live in the USA. Problem is, they won't ship outside the USA? I wonder if Tamiya realizes how much more business they could get shipping outside the US.. I think it has something to do with trade agreements between the different Tamiya HQ's, but I feel for everyone that needs a certain part and no other vendor stocks it..

There was a time when Kamtech was selling a repro Durga body to curb the problem of getting one in the UK etc.. Tamiya unfortunately came down on Kamtech like a ton of bricks because they were reproducing a body for a 'production' vehicle as opposed to a discontinued 'vintage' vehicle. Kamtech had to stop producing the Durga repro body because of it.

Unfortunately I am not sure which vendors carry spare Durga bodies. Hopefully another Oople member might know..

--

So far I have not found any wrap around motor coolers/heatsinks that will fit with the Durga body attached (even the Baldre body would be a tight fit). I think that is why Tamiya made the motor heatsink plate for the DB-01. The hop-up motor mount and heatsink plate combo works really good - you will get better cooling with those parts than you would a wrap around motor heatsink (except for ones that use a fan, but they won't fit).

--

The TRF511/DB-01 wing set is excellent. I prefer it over the stock DB-01 wing.. Wings will always get beat up while racing, but it is the better one to have..

The front wing does help on the track.. I race on a hard pack dirt track and the front wing helps to stabilize the front end a little better allowing for better steering control.. Try taking some low speed and high speed turns with and without the front wing and you should notice a difference.. It is much more obvious when you are running on a loose surface like dirt and is less noticeable when running on a high traction surface like asphalt or tarmac.

--

I have covered gearing for the DB-01 in the past and can help target optimal gearing for your setup depending on what motor you are running. Different motor manufacturers are either very open or very stingy with their motor specs.. The more information you have, the better we can target gearing.. Novak seems to be one of the best when it comes to motor spec information. I believe you run a Hobbywing EZ-Run 5.5T brushless.. I know they use different specs than Novak, unfortunately I have not been able to find any recommendations from Hobbywing to cover a recommended gear ratio for their motors.. We can borrow information from the Novak specs to get us started. It won't be exactly right for your motor, but it should get us close.

Get ready for a detailed description. Here is an example I wrote to target optimal gearing for the DB-01:

Gearing works by targeting the optimum gear ratio to complement the motor you are running - this results in maximum motor performance without stressing or overheating your motor.. It's kind of like finding your cars "Chi" http://image2-0.rcuniverse.com/e1/forum/image/s45.gif

There is the long (all math) way, and there is the short (gearchart.com) way.. I will cover the easier -gearchart.com- method here.. If you want the long math way I can give it to you, but it is less fun.. Also, if you want to know how I got some of these numbers/ratios please feel free to ask.

This will help you target the -sweet spot- for gearing so you can get the most out of your motor without overheating...

NOTE: The most important thing to make this work is that you have a good idea what your motor "RPM" is and also what the target "Gear Ratio" is for your motor. High end companies like Novak provide this information (as do other brushless motor manufacturers). I found it harder to find this info for brushed motors...

Lets get started with a "real world" example for my Durga when I ran a Novak 17.5 brushless for Novice and Stock racing:

1. First lets go to www.gearchart.com (http://www.gearchart.com/) and click "Gearchart Creator" on the upper left side of the screen
2. The "Select an RC Car" pulldown menu does not have the Durga, DB01, etc.. So select "Pan Car (10/12th scale)" and we will fill in the blanks
3. The "Transmission Ratio" is 2.055.. It is the same for "ALL" DB-01 cars.
4. Next enter your "Spur" and "Pinion" sizes.. I switched to an 81T Spur gear and 31T Pinion gear when I installed my 17.5 Novak since it was better suited for the slower motor
5. The "Plot Spur/Pinion" option with the "Middle" setting is fine.
6. Now click the "Gear Ratio" button.. The chart it builds will have key information to see if you will -burn up the track- (yeah) or -burn up your motor- (bummer).
7. In my case I needed to know what Novak recommended as the Gear Ratio for my motor.. I went onto Novak's website and pulled up their gearing recommendations: http://www.teamnovak.com/tech_info/brushless/br_gearing.html
8. It showed that a 4WD (my Durga) should target a "6" (or 6.00) gear ratio with their 17.5 motor.. My Spur and Pinion combo put me at "5.37" so I was a little overgeared for their spec.. I wanted to push my motor a little bit for more speed, so this seemed fairly safe for a shorter 5min runs.. If I wanted to be right on spec with the Novak chart, then I would gear down to a 28T Pinion since that would be "5.94" which is super close to 6.00..

Ok, so this told me that I'm not likely to turn my motor into a -molten ball of fire- by pushing it too hard.. Now I wanted to get a ballpark on how fast my car might go..

9. The next part was "Rollout".. Rollout tells you how far your car will travel per motor revolution.. My Tire Diameter (measurement from one side of the tire to the other) was 85mm. It will likely be the same for you and most tires you will run..
10. Keep the "Increment" setting at "1mm" and click the "Rollout" button
11. I got "49.73", yipee!! What the heck does that mean.. Well, its telling me my Durga has the potential to travel 49.73mm every time the motor completes one revolution. That's about 1.9 inches.. This isn't too exciting yet, but it will help us get our MPH in the end..
12. The last part was the "Motor RPM".. This is important and requires as little guessing as possible to get an accurate number.. I consulted the "Novak Brushless Motor Spec Chart" to figure this out: http://www.teamnovak.com/products/brushless/motor_spec_chart.htm
13. The chart says that I am running 2200Kv (or RPM per volt) for my 17.5 motor. I'm using a 7.4v lipo, so I multiplied 2200 * 7.4 to get "16280" which is my max RPM.
14. I entered 16280 as my RPM and clicked "MPH".. The chart showed I had the potential to go 30.2 MPH.. Not bad for a 17.5 Brushless running with pretty safe gearing..

It worked well on the track and the motor did not heat up very much after each 5min run.. In reality, your car will not go quite as fast as the charts say because they do not account for weight, track conditions, friction, etc.. Most lipo batteries will give you an extra kick though because they can discharge at rates higher than NiMH can - i.e. Team Orion 3800Mah lipo has a 30C discharge rate.

Hopefully this will help take some of the guesswork out of your gearing.. If you get any strange results, please let me know. I will be happy to double check your results.

P.S. It's a little know fact, but you can buy multiple spur gears for the DB-01. I have run 3 different spurs myself..

Tamiya used the Kimbrough spur design for the DB-01. Tamiya only made the 91T stock spur, however you can buy the Associated Kimbrough Spur Gears which are a direct fit (78T, 81T, 84T and 87T).. No need to change the number of shims or the slipper pads when you reassemble the layshaft.. I ran different spurs to target optimum gearing for the slower 17.5T and 13.5T motors.. Here are some links:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEAK5&P=7
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEAK4&P=7
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEAK3&P=7
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXEAK2&P=7

Hope this helps.



Hey, thanks for the info !

I locked the reardiff, ehm whats the right word ... ehh, till I got my Ceramic diff balls and TRF 501X diff Joints :lol:
It's just for testing (and adjusting) my 5,5T brushless motor on the road (big parkinglot, so i'm just driving in a straight line) so i guess, it's not a big problem ?

I think i'm ordering a Durga body with the diff joints and stuff to cut holes in for extra cooling, but they are hard to find, I normaly order my stuff at RcMart, but they only have the Bladre body, and I don't like that one so much :(
I searched at several webshops, but can't find it :(

About the cooling, the 'cooling plate' you said in your post, I got one, but it won't fit (after I got it, i researched (too late AGAIN ... :lol:) and saw it won't fit) but I'll mod it so it will fit.
About the motor cool things that you 'wrap' arround your motor, do I have to buy one with a fan on it (if they really excist :bored:), or just wrap a motor cooler around the motor ?

Oh yeah, I wanted to buy a Low-Mount spoilerset, because my spoiler is cracked (still need to tape it :p), does the front spoiler have any effect on the handling ?
I've seen it on some really pro-chassis, and it looks cool, but i'm just curious :woot:

About the gearing, I drive with a stock spur (91T) and a 23T Pinion, but I can't find on any site something about a recomended gear-ratio.
But I guess my ratio is too high, but I don't know wich pinion I have to buy :blush:

BigBig Thnx !

P.S.
Sorry about my English, I hope you all know what I mean ? :blush:

[Ignition]

Thanks again for the info man ! :thumbsup:

Tonight at 1 o'clock I ordered this stuff by RcMart:
-Tamiya (#53988) Ball Diff Pulley (37T)
-Tamiya (#51287) TRF501X Diff Plate
-Tamiya (#51286) TRF501X Differential Joint
-Tamiya (#54134) Buggy Racing Wing Set (Lowered)
-*Yeah Racing (#YA-0167TC) 540 Motor Heat Sink (TC) (hopefully it will fit :o)
-Tamiya (#53912) Led Light (Ø3 OR) (For my TT-01 Drifter :lol:)
And I get the titanium diff balls (from a Schumacher touring car chassis) from a friend of me, he found them :thumbsup:



The places where I drive, is the 'Track' at a local RC shop here, it's a little loose dirt track (with 'hard' dirt underneath the 'loose cover').
I just drove 1 time with my durga at there, but next year I wanted to drive more often (ones a month or so).
And the other place I drive is a very big parking lot, where I just do some speedruns and chase TT-01's or M03's of my friends, not really 'racing' just going straight (it's mostly 1 time a month too :p)

I just liked the wings, and my wing is cracked and these 2 are cheaper than the 'stock' DB-01 wing :confused::thumbsup:
So why not :p


After I entered all my settings in the GearChart machine, it says I'm running an 8.13 gearing (91T spur and 23T pinion)
The Novak site says me to run 8,5 (with an on-road car) or 11 (with an 4wd offroad car)
What should I do right now ? :bored:

About the Body, I saw RcModel.HK, they sell them, but they are out of stock, I will mail them, if I have an answer I will place it right here :)

Again, BIG thanks dude ! :thumbsup:

[dimblum]

Sorry for the late reply, been busy with Christmas preparations.. :)

I checked up on your gearing and found a little information about the EZRun 5.5T.. Although Hobbywing doesn't really give any specs, I did find out that your motor runs at 6000Kv. The same 5.5T Novak runs at 7400Kv, so it is delivering more power per volt compared to the EZRun.. This means that matching your motor will probably be a little undergeared if we match Novak's gearing spec. Undergearing doesn't hurt anything, but its always more fun to try and find the optimal gearing to give you a little more speed around the track without hurting your motor.

In Novaks chart 8.13:1 would mean you are overgeared for offroad racing - since Novak recommends 11.00:1. Basically any gearing ratio 'under' the recommended number pushes you toward the "overgeared" category. You will get more top speed and less torque, but you also run the risk of overheating your motor after a long run. Extreme overgearing of a motor will not only overheat and possibly damage your motor, you will also hit a point where you no longer gain speed and/or you even loose speed [point of diminishing return].

The opposite is true when you undergear.. Lets say your Gear ratio was 12.00:1. You would not likely have any heat problems with your motor, you would gain torque and you would loose potential top speed etc..

Don't panic though! Your gearing might be very close to optimal for your motor.. Since your 5.5T is running at a lower Kv rating compared to the Novak, your optimal gearing might be more like 10.00:1 or 9.00:1

Here is a good way to test it. Dropping down to a 17T pinion would set your gearing to exactly 11.00:1. Use this as a starting point to match the Novak spec and run your car for 5-6min. Take it off the track and check the motor temp with an infrared temp gun etc.. Brushless motor temps should not exceed 160-170 degrees Fahrenheit typically.

Odds are you will be undergeared for your motor - so your car will run without any overheating problems, but your top speed will suffer.. Let the motor cool down completely and gear up your pinion 1 to 2 teeth. A 19T pinion for example will change your gear ratio to 9.84:1. Give your car another run around the track for 5-6min and check the heat on your motor again.. Keep doing this until you find that sweet spot where your car runs nice and fast and your motor is still a little below 160F after the run. This should be the optimal gearing for your motor.

Let me know what results you get.. I am interested in how the EZRun motors compare to the Novak gearing.


If it helps, I was able to find another link for a seller for the the Durga body. It looks like they have some in stock:

http://www.muchhobby.com/shopping/product_info.php?products_id=880&language=en



Thanks again for the info man ! :thumbsup:

Tonight at 1 o'clock I ordered this stuff by RcMart:
-Tamiya (#53988) Ball Diff Pulley (37T)
-Tamiya (#51287) TRF501X Diff Plate
-Tamiya (#51286) TRF501X Differential Joint
-Tamiya (#54134) Buggy Racing Wing Set (Lowered)
-*Yeah Racing (#YA-0167TC) 540 Motor Heat Sink (TC) (hopefully it will fit :o)
-Tamiya (#53912) Led Light (Ø3 OR) (For my TT-01 Drifter :lol:)
And I get the titanium diff balls (from a Schumacher touring car chassis) from a friend of me, he found them :thumbsup:



The places where I drive, is the 'Track' at a local RC shop here, it's a little loose dirt track (with 'hard' dirt underneath the 'loose cover').
I just drove 1 time with my durga at there, but next year I wanted to drive more often (ones a month or so).
And the other place I drive is a very big parking lot, where I just do some speedruns and chase TT-01's or M03's of my friends, not really 'racing' just going straight (it's mostly 1 time a month too :p)

I just liked the wings, and my wing is cracked and these 2 are cheaper than the 'stock' DB-01 wing :confused::thumbsup:
So why not :p


After I entered all my settings in the GearChart machine, it says I'm running an 8.13 gearing (91T spur and 23T pinion)
The Novak site says me to run 8,5 (with an on-road car) or 11 (with an 4wd offroad car)
What should I do right now ? :bored:

About the Body, I saw RcModel.HK, they sell them, but they are out of stock, I will mail them, if I have an answer I will place it right here :)

Again, BIG thanks dude ! :thumbsup:

[Carno]

Which track do you race at Ignition?

[Ignition]

Big thanks again DimBlum, I will replace the pinion to the 17T, I don't want to overheat/damage it immediatly.
After I clicked the link about the body, I ordered it immediatly, but I haven't pay any shipping costs, is this possible, or do I have to pay it later ?
Never bought something on that shop so...

@Carno: nice om te zien dat hier nog meer nederlanders zitten, ik rijd (race niet echt) in Geulle (das in de buurt van Valkenburg in Limburg :)) niet echt in de buurt voor jou, add me anders even op msn, *** :)

[Carno]

Ah ok ik dacht dat je misschien dezelfde track reed als mij. Maar limburg is een eindje fietsen :lol:
Ik gebruik geen MSN btw dus dat word lastig.