Limitless Bought used, 1 run.

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Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
Here it is! $500 as is, 1 run. Really good condition.

IMG_20210403_084902537.jpg



Guy I purchased it from said he pulled it straight out of the box, slapped electronics in it, ran it, and that was it. It seems he is right as there is play in the pillow balls, toe and camber aren't even, body isn't even scratched, etc. I'll just treat it like I took it out of the box myself! That includes gently checking screw tightness, shocks, diffs are full, etc.

Speeking of electronics:
IMG_20210403_084943475.jpg


HW Max 6 Combo with 1650kv can. 17T pinion (I'll check gear mesh) and an ADS-15 Servo.

Being my first Speedrunning car, I have somewhat plotted the road (heh) ahead of me:
  1. Run it as is! (probably tomorrow) Go over all the factory "rtr" bits ~ anything one would go over with a rtr vehicle. Throw in an R6FG receiver, set endpoints, calibrate ESC. Check suspension geometry, meaning zero toe in front; average factory toe in the rear (measure each wheel, average the toe, and match it); zero camber front and rear; max caster. Preload the rear as per Raz's secrets vid. Balance the wheels and tires. I'll start with easy runs on 6S, see how it does with my phone as a GPS. Work up to 8S. Aim for consistant 100mph runs. I have an R7FG (dual antenna) receiver on the way, as well as a DS3225 Blue (coreless) to replace the ADS-15 asap, and a SkyRC GSM020 gps. I'll be putting these in as soon as they arrive, but I am too excide to wait for them :ROFLMAO:
  2. Check temp as I am running it, and boost the pinion until the motor/ESC stop being comfortable.
  3. Add a PPS mount and swap in my MMX8S and 2028 800KV, starting at the same spool RPM as the final gearing on the Max 6 setup and gradually gearing it faster.
At 120: Change over to GRP tires instead of hoons.
At 140: Change to a GT body
At 150: Change to foams

A few questions:

At what point, if any, should I start looking at upgrading to GP5 diffs?
What models and componds of GRP tires should I start looking at?
Apart from DeltaPlastik, are there any other GT bodies I should be looking for/at? Has anyone looked at the russian Unbreakables?

Anything else I should be on the lookout for/be thinking about as I begin running?
 
Messages
218
Reaction score
231
Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
Made a few passes on 6S, then jumped up to 8S and was able to push steady 100mph runs, with a hard push up to 110!

Next on the list is refining the gimmicky Arrma trimmable spoiler and putting in a set of GP5 diffs. Based on motor/esc temps, and being able to hold 6-7second full throttle pulls today, I should be able to gear it up a bit faster no problem. I will have to start considering switching to GRPs. Anyone have any recommendations on which tire/compound?
 

Monster Dork

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Washington PNW
Arrma RC's
  1. Kraton EXB
Zero toe in front is going to wander all over the place. Go with a touch of positive toe if anything. Zero in rear is good, but full scale tracks better at speed with a scosh of rear toe. It hurts tight steering, but that's not the point.

Sounds like you have an ideal track at the airport! Don't forget to shoot vids.
 

LibertyMKiii

Aerodynamics speed junkie
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Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 6s
  4. Typhon 6s
Toe is a funky subject because under throttle above 50% it can move/flex a bit.

I have heard guys running toe out with the assumption it will go to zero or slightly "In" under load. I cannot stand the instability of toe out on the rough roads we have around here.

Explanation from TireRack.com:

"Toe can also be used to alter a vehicle's handling traits. Increased toe-in will typically result in reduced oversteer, help steady the car and enhance high-speed stability. Increased toe-out will typically result in reduced understeer, helping free up the car, especially during initial turn-in while entering a corner"

toe angle.JPG

I always run a few degrees toe in front and rear. When different companies started offering rear hinge pin blocks that made the rear at zero degrees toe, people were crashing a lot more and went back to the factory toe in rear hinge block. I would say that is something worth doing when you are looking for those last 2-3 mph to beat some record. Until then leave the rear toe angle stock. Focus on front alignment, camber on all 4 corners, suspension travel limits, and weight balance.

For camber I always set just slightly negative (around 1 degree) Then watch your tire wear and re-adjust.
 
Messages
218
Reaction score
231
Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
After last weekend's runs around 100~110mph, and how incredibly stable it was, I'm happy with where the car sits. Everything is evened out L/R, and I am slightly toe in with 0 camber and maximum rear preload. I took a couple shortcuts just to get out and run it, but there is definitely room for improvement not just in speed, but in refinement of the car itself. I have a better receiver and servo on the way (25kg, 0.07sec, full stainless), as well as will be recalibrating ESC and programming it to run the proper direction instead of toggling reverse on the transmitter. Most importantly, however, I will (finally) be balancing the wheels/tires before next run.

As for aero on the stock body, what do you suggest for splitter/spoiler trimming? I ran it with the trimmable splitter removed and the spoiler untrimmed last weekend, but it was a serious parachute with how tall it is. I'm thinking about keeping the trimmable splitter off and knocking down the spoiler to the 1st trim line above flat (1/8" or so)
 

LibertyMKiii

Aerodynamics speed junkie
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Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 6s
  4. Typhon 6s
After last weekend's runs around 100~110mph, and how incredibly stable it was, I'm happy with where the car sits. Everything is evened out L/R, and I am slightly toe in with 0 camber and maximum rear preload. I took a couple shortcuts just to get out and run it, but there is definitely room for improvement not just in speed, but in refinement of the car itself. I have a better receiver and servo on the way (25kg, 0.07sec, full stainless), as well as will be recalibrating ESC and programming it to run the proper direction instead of toggling reverse on the transmitter. Most importantly, however, I will (finally) be balancing the wheels/tires before next run.

As for aero on the stock body, what do you suggest for splitter/spoiler trimming? I ran it with the trimmable splitter removed and the spoiler untrimmed last weekend, but it was a serious parachute with how tall it is. I'm thinking about keeping the trimmable splitter off and knocking down the spoiler to the 1st trim line above flat (1/8" or so)

Yeah man, it sounds like you got it dialed in. That is the annoying part, now you get to do the fun stuff of adjusting aero and slowly gearing up.
Trimming the rear wing down to the last rib will be ideal.

If you look at speed kings like Phillip he has the nose slammed all the way to the ground (might need longer droop screws) (if you had not seen it already drilling a hole in the upper arm makes accessing the droop screws much easier). He chose to remove the splitter so he could get the nose lower. Given the airport runway you have access to run on, this would be a great idea for you. Only problem is then you would need to adjust the shock travel limiters and probably re-align the toe/camber if you do lower it more.

1617823079165.png
 
Messages
218
Reaction score
231
Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
Heck yeah! That's awesome to hear that I am on the right track from someone as experienced as you, @LibertyMKiii , thank you.

I'll definitely drill the top arm to access the droops easier.

Baby steps for aero. I'm still running cross pad along one of the taxiways and on to a different piece of asphalt. Very smooth transition, better than any public street, but still a little bumpy. Might look at slamming the nose once I get fast enough to move onto an actual strip where there are no transitions and it is even smoother.
 

Jason F

Well-Known Member
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Arrma RC's
  1. Limitless
You allowed to have spectators?
My Wife has family in Bozeman, MT. I will be working in Missoula the beginning of next month.
 
Messages
218
Reaction score
231
Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
Absolutely! PM me when you end up coming through town and we can meet up, if even just for a beer or a quick bite. Might have to plan something at the airstrip a bit more after that.
 

Jason F

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Messages
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Reaction score
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Arrma RC's
  1. Limitless
Absolutely! PM me when you end up coming through town and we can meet up, if even just for a beer or a quick bite. Might have to plan something at the airstrip a bit more after that.
I will PM you!
Absolutely! PM me when you end up coming through town and we can meet up, if even just for a beer or a quick bite. Might have to plan something at the airstrip a bit more after that.
I will PM you
 
Messages
218
Reaction score
231
Location
Bozeman, MT
Arrma RC's
  1. Felony
  2. Limitless
  3. Kraton 8S
  4. Kraton 6s
  5. Kraton EXB
  6. Nero
  7. Raider
  8. Senton 3s
  9. Typhon 6s
Ok, so I got a bunch of work done refining things, and had an interesting realization...

- Installed and bound the dual antenna Radiolink R7FG
- Installed a DS3225sg, including resetting endpoints and eyeballing trim straight.
- Installed front GP5 diff, still have the rear to do, just ran out of time tonight.
- Recalibrated the ESC and set up drag break.

Playing around with my speed app, I realized I can make a sort of dope card. Dope meaning Data Observed on Previous Engagement. Used in long range shooting, a good dope card can be used to both interpolate and extrapolate data to dial extremely accurately for a huge array of ranges. Basically, after gathering a few data points, I may be able to establish a rough curve for predicting speeds based on gearing.

Screenshot_20210409-000253.png

This was my first setup, with my actual speed (110) compared to my potential (137). 80% of calculated due to drag, among other factors.

After installing the GP5 diffs, my potential rises to 151mph (unlikely to happen), but at 80% of calculated, I may be able to hit 121mph.

Screenshot_20210409-001452.png

More data means more accurate numbers, and as I go faster, I very much doubt that 80% potential will stay constant. I will likely be looking at a pretty significant drop in actual speeds when compared to calculated. Only time will tell, and I need more data.

(Note that since I was running with a miscalibrated ESC my first data point is effectively invalid, and I'll start recording dope with the GP5 diffs)
 
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