Mahjik

Mahjik heads to the track...

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For those that may have missed in the intro story, it was posted here:  

Any bad memories with an rc car?

So, about 30 years in the making, and I finally made the trek out to the local track.  

 

For those that don't know, I purchased a Zahhak and upgraded it with just about every TRF part still available.  It's running a 17.5T motor and the ESC is in blinky mode.  I added some weights to the front (but probably need a little more).  I also wanted a 4wd buggy.  I had looked into a Durga as those look so cool, however, financially it didn't make a ton of sense.  After I would have upgraded the dampers and everything else, I would be more than a current chassis.  I was also concerned about replacement parts.  With that, I picked up a used 2016 XRAY XB4.  It was (still is) a little rough but is functional.  I changed the body to something more pleasing (a Jconcepts body) and added Jconcepts Bar Codes to both cars:

IMG_20190327_230624805.jpg

 

Now with both cars functioning, I picked a Monday to hit the track for practice night.  Unfortunately, I had to work late and the track is quite a drive so I missed the first attempt last week.  This week on Monday, I jump out of work early and headed home.  My gear was already packed in my track bag (I race in real life a Honda S2000 and I have a bag I use to carry extra clothes to the track) so all I had to do is change out of my work clothes and hit the road.

 

As I approach the track facility, I begin to get nervous.  I'm not entirely sure why.  I think I didn't want to appear to be a total noob or that a 30-some-odd year dream would suck.  I ended up sitting in my truck in front of the door, checking work email which was a way of stalling.  I eventually snapped out of it and walked in.  I headed over and paid my practice fee and then setup my pit table space.  There were about 10 other drivers in the facility practicing.  I strolled over to look at the track to try and understand the layout (again, stalling).  At this point, I'm not exactly sure where drivers are starting their cars so I wait for the next driver to place his car to start so I can see where everyone is starting at (again, stalling).

 

IMG_20190408_194610141.jpg[/

 

After a bit, a few of the drivers come off the stand and I'm about out of excuses.  There are about 4 drivers still going so I slowly make my way hoping the rest will take a break.  And they don't.  So, I put my car down and slowly walk up the stairs and begin to apologize for the chaos I'm about to cause.  They all chuckle and say "No worries, just have fun!"  The Zahhak is up first.  I start out just slowly going around the track.  My goal is to get my line of sight before trying to figure out jumping.  I make it around once slowly, before flipping it.  After a few minutes, I'm getting around ok but I can't control the car in the air so I figure not launching the car keeps me on the stand much longer (or other people from having to flip my car when they get theirs).  As I'm driving the Zahhak, everyone keeps coming up and asking it it was a Tamiya.  They all loved the car!

 

After a while, I decided to rest the Zahhak and grab the XB4.  The XB4 is running a blinky ESC (both are Tekin RS's) with a 13.5T motor.  Unfortunately, the XB4 was previously run on carpet so it's not really setup for dirt/clay.  This made it quite twitchy compared to the Zahhak.  I got to the first double and was just going to slowly go over without jumping and it nose dived and flipped.  That took all of 10 seconds.  :lol:  And older gentleman practicing for the leagues Stock Traxxas Bandit class said "I do that all the time".  The XB4 did get some attention, but not as much as the Zahhak.  I eventually started to understand some air control and started taking some of the jumps.  After a while, most of the racers were back so I was out there running with most of the cars.  There was another driver there with a Team Associated and another there with a TLR and I tried to keep up with them but I just couldn't do the big jumps yet (most of the rest were practicing for the stock Traxxas classes Bandit/Slash).  

 

Eventually, I flipped the XB4 and then got hit by a mod SC4WD at full speed.  It damaged my servo so the XB4 was retired for the night.  The Zahhak had cooled down, so I switched in a new battery and ran some more laps, gaining more confidence with the jumps.  At the end of the night, the 30 some odd year wait was more than worth it.  I'm sure I'll be back for more practice nights, but that night will be a solid memory for years to come.  

 

And the dirty cars waiting to be cleaned (yes, my wife asked me why the cars were inside the house in that dirty condition :P):

IMG_20190408_223132207.jpg

 

Granted, I have no other rc track experience, but couldn't be happier with the cars.  I'll probably get a modern 2wd buggy at some point but that would be much further down the line.  Gotta fix the XB4 before anything else.

 

If you have a track near by and you haven't been yet, definitely go try it!

 

 

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You made me want to buy Zahhak!  (wait, I got one already... phew, I dodge the bullet... or did I?)  

Positivity oozes from your experience.  I appreciate that very much.  Thank you for sharing!  

 

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Brilliant! I know exactly what you mean about all those things. Sounds very much like my first track day experience. And I don't worry about jumps. I am still rubbish at those too. I have my first track meet for a couple of months on Saturday and I am sooooo excited. This has just made me more. 

Some advice from a fellow Zahhak into TRF201 runner if I may? I have a modern mid motor and my 201 is still miles easier to drive, and probably more fun as a result. My humble suggestion would be to read up on setups and hone your Zahhak. Petitrc still has loads of TRF201X setups and the US TRF drivers had clay 17.5 in there I am sure. Big one will be gearing. My 201 has 13.5 now, but because I read up on gearing I am running 27/72 (associated B4 spur) to get a FDR of 6.9. I can barely tell if its slower than when it originally had a 9t motor with 23/79. @Effigy3 ran a 201 on clay in 17.5 and he was aiming for FDR under 6. I believe he ended up with a 69t associated spur and 30t pinion. You might need to cut away the cover to clear the pinion though. Apologies if you know all this and have already applied setups! Just excited to help. 

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8 hours ago, ThunderDragonCy said:

@Effigy3 ran a 201 on clay in 17.5 and he was aiming for FDR under 6. I believe he ended up with a 69t associated spur and 30t pinion. You might need to cut away the cover to clear the pinion though. Apologies if you know all this and have already applied setups! Just excited to help. 

No worries!  I'll take any and all information.  :)

I'll have to look back since it's been quite a while since I setup the Zahhak, but I believe the motor called for a FDR between 6.0-6.7.  I think I ended up around 6.5 for the FDR with the current gearing.  I did have the enlarge the mounting slots on motor plate and then use the Team Associated B4 gearbox cover to fit the pinion (thanks to the Facebook group for that info).  

 

I haven't done anything suspension/alignment wise yet.  I just made them drive straight (and the front weights since I knew the older 2wd have a tendency to understeer).  :)  That is next on my list is to start working on setup to get the cars to drive a little better for me.  I will say the Zahhak handled much better than I expected.  Love the big bore dampers on it and I did have the most fun with it.  However, that was also because the 13.5T was scaring me a little in the XRAY.  :o

 

 

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1 hour ago, TwistedxSlayer said:

Let's discuss the part were you race a real life S2000..... I love them cars. Please tell me more.

 

You bet!  For those that aren't aware, in the United States, we have two main semi-professional racing sanctions:  NASA and SCCA.  Yes, the same acronym as the space administration group.  :) My 'other' job, I'm the Chief Instructor for NASA Central Region.  Here's a few photos of the car:

 

312A2998.jpg

 

29846463245_f55104c238_o.jpg

 

It's currently getting a new engine so I'm hopeful to be racing again by the end of May.  B)

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1 hour ago, Mahjik said:

 

You bet!  For those that aren't aware, in the United States, we have two main semi-professional racing sanctions:  NASA and SCCA.  Yes, the same acronym as the space administration group.  :) My 'other' job, I'm the Chief Instructor for NASA Central Region.  Here's a few photos of the car:

 

312A2998.jpg

 

29846463245_f55104c238_o.jpg

 

It's currently getting a new engine so I'm hopeful to be racing again by the end of May.  B)

Very nice car and Uber cool job!

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A little update.  I took apart the servo for the XB4 and everything looked fine.  I made sure the gears were meshing properly and inspected everything else.  Plugged it back in to check the movement and it was working fine.   I think the hit from the SC4X4 jarred the upper gear out of place.  In short, it appears to be working fine now so I'll hit the track again next Monday.  ;)

 

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On 4/10/2019 at 11:43 AM, Mahjik said:

... then use the Team Associated B4 gearbox cover to fit the pinion (thanks to the Facebook group for that info).  
 

 

I must've missed that tip!  I've got my Tamiya gearbox cover all "customized" with a huge notch cut into it so there's room for the pinion to breath.  :)  I'll have to look into that AE option.

Thanks!

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On 4/10/2019 at 4:46 AM, Mahjik said:

If you have a track near by and you haven't been yet, definitely go try it!

Absolutely 👍

They're all RC guys and they all started somewhere! 

As with the full size, more track time you get, you'll get more confidence and the lap times will come.

More importantly,  have fun 😁

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On 4/16/2019 at 9:18 AM, Mahjik said:

A little update.  I took apart the servo for the XB4 and everything looked fine.  I made sure the gears were meshing properly and inspected everything else.  Plugged it back in to check the movement and it was working fine.   I think the hit from the SC4X4 jarred the upper gear out of place.  In short, it appears to be working fine now so I'll hit the track again next Monday.  ;)

 

 

15 hours ago, Effigy3 said:

I must've missed that tip!  I've got my Tamiya gearbox cover all "customized" with a huge notch cut into it so there's room for the pinion to breath.  :)  I'll have to look into that AE option.

Thanks!

 

You'll want "Team Associated 7460 B4/T4 Molded Gear Cover".  It's fits really well but it is a little larger on the edges.  You can't tell unless you are the car owner.  ;)

 

8 hours ago, Wooders28 said:

Absolutely 👍

They're all RC guys and they all started somewhere! 

As with the full size, more track time you get, you'll get more confidence and the lap times will come.

More importantly,  have fun 😁

 

I went back last week, and I was getting better.  The DN01 continued to perform well.  Although, I can tell my 17.5 is not as snappy as some of the more current 17.5's.  Granted, I'm not racing, but I do have it in blinky mode so no boost.  I can tell as the other 17.5 cars are able to clear some of the jumps easier even if they screw up the previous corner where as I need to maintain more corner speed to clear some of them.  I did get a lot more brave the last trip and started working the jumps more.

 

Unfortunately, the XB4 servo did the same thing again.  I pulled the servo apart at the track, it fixed itself so I went back out.  After the first jump, it did it again.  I looked it up and apparently the servo just isn't suited for offroad so I ordered a new servo.  I plan to heat back to the track next week and hopefully be able to run both buggies.

 

I did notice one of my Lipo packs did puff a bit.  I don't know why.  I'm only charging at 1C and I do storage charge after the track (and I'm not running them down to Lipo cut).  :(  At least the IR doesn't seem too far off the other packs currently.

 

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@Mahjik What's the largest pinion you can get under that Associated gear cover? If I go brushless I am going to need something pretty big to gear my rally conversion TRF201 appropriately. Thanks. 

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5 minutes ago, ThunderDragonCy said:

@Mahjik What's the largest pinion you can get under that Associated gear cover? If I go brushless I am going to need something pretty big to gear my rally conversion TRF201 appropriately. Thanks. 

Depending on your spur gear, I don't think you could go much bigger than a 36T.  I'm using 32T and I'm almost out of space on the motor plate.

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14 minutes ago, Mahjik said:

Depending on your spur gear, I don't think you could go much bigger than a 36T.  I'm using 32T and I'm almost out of space on the motor plate.

That's brilliant. Thanks. I have a 77t spur and a 34t pinion in the spares box to give me a final drive ratio of around 5.5. Sounds like I need to get one of these covers! 

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42 minutes ago, Mahjik said:

Depending on your spur gear, I don't think you could go much bigger than a 36T.  I'm using 32T and I'm almost out of space on the motor plate.

Just a little warning with upping the pinion and spur on the dn01. When i went brushless 3 yrs ago I melted my ball diff using a castle 4600kv combo with a 30t pinion and 69t spur. To say the car flew on 2s is an understatement. 

I now use 26 or 27t pinion and 77t spur which still flies

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2 hours ago, Mahjik said:

I went back last week, and I was getting better.  The DN01 continued to perform well.  Although, I can tell my 17.5 is not as snappy as some of the more current 17.5's.  Granted, I'm not racing, but I do have it in blinky mode so no boost.  I can tell as the other 17.5 cars are able to clear some of the jumps easier even if they screw up the previous corner where as I need to maintain more corner speed to clear some of them.  I did get a lot more brave the last trip and started working the jumps more.

Result! 👍

Go brave and add some timing, although setting how much timing / boost to add is an art in itself! 

I think you guys run things a bit differently over there, more about stock motor classes? If not, another option is to try and find a lower wind motor, get more grunt without having to mess about with esc settings.

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32 minutes ago, Rb4276 said:

Just a little warning with upping the pinion and spur on the dn01. When i went brushless 3 yrs ago I melted my ball diff using a castle 4600kv combo with a 30t pinion and 69t spur. To say the car flew on 2s is an understatement. 

I now use 26 or 27t pinion and 77t spur which still flies

 

I'm expecting the ball diff to likely get melted with prolonged use.  I will probably transition to a more modern 2wd buggy and move the DN01 to a shelf queen as I learn how to drive.  I have read many posts on those ball diffs requiring rebuilds so I figured I could get a few months of learning how to drive before the first needed rebuild.  I goal was to use it until the first meltdown and then retire it from track use.  

 

25 minutes ago, Wooders28 said:

Result! 👍

Go brave and add some timing, although setting how much timing / boost to add is an art in itself! 

I think you guys run things a bit differently over there, more about stock motor classes? If not, another option is to try and find a lower wind motor, get more grunt without having to mess about with esc settings.

 

Yep, I'm going to look at a little timing on the motor and likely drop down one tooth on the pinion.  That would still keep me close to FDR for the motor.  The motor is a Trinity 24K 17.5 which was a good motor a few years ago.  However, compared to today's 17.5, it's just not as peppy.  I just mostly need just a little umpf to make sure I clear one of the doubles.

 

I'll likely never race it so technically there is no reason to run it in blinky mode.  I was just trying to get used to blinky mode in the event I wanted to jump into a race sometime in the near future (after I can completed a handful of laps without rolling).

 

 

 

BTW, I also tried some organic based tire sauce:

https://www.tdkrepair.com/product-page/highgripsauce

Granted, at my level, tire sauce is the last thing to look at but I was curious.  I had heard the horror stories of the toxic stuff most people used and had no desire to participate.  However, when I saw some racers talking about this, I had to try it.  It does smell like coconut, so you can apply it indoors.  It's not a strong smell that lingers for days and you don't need chemical gloves to apply it.  ;)  

Not sure if it was the track, the tire sauce, or the tires just getting broken in (I suspect all of the above) but I was really fighting grip rolling with the last trip to the track.  I think I grip rolled more than I wiped out from jumps.  :huh:

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I rebuild mine once or twice a year. After melting it and changing the gearing i never had an issue

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On 4/29/2019 at 2:41 PM, Rb4276 said:

I rebuild mine once or twice a year. After melting it and changing the gearing i never had an issue

Weird.  I raced my 201 in the 17.5 blinky class for a little over a year and never rebuilt the ball diff.  I ran a few different ESCs but the Speed Passion Reventon Pro 1.1 was the best.  I started with a TBLE-02S.  It was smooth but lacked real grunt.  I had a Novak Impact that lasted one race day.  Other than being horribly fragile it was a noticeable step up in performance.  I went with Speed Passion and it has been great.  They're a little harder to get than some other brands so I've switched over to HobbyWing for most of my cars now.  These were all running the same Trinity D3.5 series motor.  While technically an illegal ROAR motor, I'm such a poor driver no one gave me trouble running it.  ;)

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12 minutes ago, Effigy3 said:

Weird.  I raced my 201 in the 17.5 blinky class for a little over a year and never rebuilt the ball diff.  I ran a few different ESCs but the Speed Passion Reventon Pro 1.1 was the best.  I started with a TBLE-02S.  It was smooth but lacked real grunt.  I had a Novak Impact that lasted one race day.  Other than being horribly fragile it was a noticeable step up in performance.  I went with Speed Passion and it has been great.  They're a little harder to get than some other brands so I've switched over to HobbyWing for most of my cars now.  These were all running the same Trinity D3.5 series motor.  While technically an illegal ROAR motor, I'm such a poor driver no one gave me trouble running it.  ;)

Yea mine gets a little crunchy after a while, id say 4-5 months. Could be the power of the motor, i rebuilt it in october and only ran it once or twice since then. Ill see how long it lasts this time. 

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On 4/29/2019 at 10:26 AM, Mahjik said:

I did notice one of my Lipo packs did puff a bit.  I don't know why.  I'm only charging at 1C and I do storage charge after the track (and I'm not running them down to Lipo cut).  :(  At least the IR doesn't seem too far off the other packs currently.

 

The batteries I have been using are Lectron Pro from Common Sense RC.  I reached out to them and they are replacing the battery (fantastic customer service).

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Back at the track again, unfortunately not a great visit.

 

I looked at the motor on the DN01 and it was listed with a default timing of 50 on it.  However, I looked and it shipped to me at 20.  I increased the timing to the default was supposed to be and ran it.  It had a little more pep at the top end, but I'm going to switch to a smaller pinion to get a little more acceleration.  Some of the jumps have a short run so I need a little bit quicker acceleration to clear those.

 

The DN01 ran well for the first battery pack.  However, on the second pack, the rear upright broke after a jump.  Not all that surprising as something was bound to break at some point so I have the aluminum rear uprights on order.  I almost bought those originally when I built it and thought I did but apparently I did not.

 

I replaced the servo on the XB4 with a Muchmore low profile.  Never got a lap in....  I had adjusted the end points but the servo was just crap.  After two or three turns, the servo would stick to one side.  Protek 160T coming but it will be a few weeks before I can get back.

 

All in all, a little disappointing visit this time around (since it's quite a drive to and from the track), but looking forward to the next visit.

 

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