Limitless Kaladeth's Limitless V2 - Technical Race Build

[kaladeth]

Day 2 Wreck 2 another fun day at the track.

@Jerold nice meeting you in person today! Bring your limitless next time we can set it up for track.

Was able to hit 23 second lap times - I think 20 continues to be a good target.

Adjusted front left toe, put more duolock on the ESC, cleaned up the wires with zip ties, zipped the second antenna to the brace, cut the excess Velcro on the battery straps. Swapped out Hoons with GRPs. Switched to 32t pinion. Used red loctite.

Crashed after completing several laps on the third round. Broke the front right shock rod end, and the nose.

End of the day.

 

[Jerold]

Day 2 Wreck 2 another fun day at the track.

@Jerold nice meeting you in person today! Bring your limitless next time we can set it up for track.

Was able to hit 23 second lap times - I think 20 continues to be a good target.

View attachment 345379

Adjusted front left toe, put more duolock on the ESC, cleaned up the wires with zip ties, zipped the second antenna to the brace, cut the excess Velcro on the battery straps. Swapped out Hoons with GRPs. Switched to 32t pinion. Used red loctite.

Crashed after completing several laps on the third round. Broke the front right shock rod end, and the nose.

End of the day.

It's always great to meet my "virtual friends" in real life.

I tried to measure the shock shaft on mine, but couldn't get the calipers in there very well. I came up with .165" ( ~4.1mm)

If you can verify the thread, McMasters might have an aluminum replacement. If not check Amain.

These might be too big?

https://www.mcmaster.com/products/rod-ends/shank-thread-size~m4/

 

[kaladeth]

Yup the shock shaft is 4 mm:
https://www.arrma-rc.com/en/product/shock-shaft-4x43mm-2/ARA330596.html

Wow McMaster-Carr! Brings back memories, used them a lot in my early years as a Controls Engineer.

Yes their M4 rod end is too wide and not thick enough.

Ordered the stock part already:
https://www.arrma-rc.com/en/product/shock-rod-end-set-2/ARAC8971.html

 

[Overkill]

@Overkill Any tire is ok

I have a set of GRPs on the way. What should I expect in terms of difference between the stock Hoons and GRP slicks?

I went from limitless hoons to super soft TO4s with flex wheels. The grip was night and day better. After I burn through this set I'll probably go to extra softs. How did it handle?

 

[kaladeth]

@Overkill My driving skill is probably not at a level that could distinguish much between the two; the grip did feel better, just not able to articulate it well yet. I am also not sure what the guys at the track gave me (they just hooked me up with some well-loved treaded GRPs - it had the white rim on it but I didn't get to ask what compound I would guess they are at least soft or softer). To the touch the GRPs are a lot stickier!

I am getting the slick soft/XM3 with rigid wheels today so as soon as I fix the shocks I will go try them out.

 

[Overkill]

For when you start playing with suspension here's what worked for my car as a reference. FYI it's a short wheelbase limitless with a castle 1717 and mmx8s on 4s. The "track" is a small 1/10 touring car layout in a parking lot. It had pretty bad understeer and was too stiff so the mechanical grip could have been a lot better. 32 lb/in springs front and rear. 6 hole tapered pistons with the taper up, front and rear. 4 hole tapered pistons and maybe 27lb/in springs will be the next change because it's still oversprung. 42.5wt shock oil. Diffs are 5k front, 3k center, 3k rear. Rear axles changed to cv. 2.9mm rear swaybar.

 

[kaladeth]

Had to wait for the red loctite to cure (spool set screw came loose!), but I think I finally have the (basic) setup dialed in. Good test run session this morning! Actual top speed 65 mph is amazingly pretty close to the theoretical calculation of 67.8 mph. Still running the old GRPs since the set I received were XM4 not XM3; sorting out a possible return. But the grip is definitely better on these super softs vs. the stock Hoons… could hardly make the car slide.

Re: braking, do you guys avoid hitting the brakes hard? I think this is how I wore down my Big Rock input gear, but that was when it was stock composite. How well can the Limitless (stock) drive train take constant hard braking?

Motor temp maxed at 109oF, ESC at 80oF, so no problems there.

I now have my second set of batteries (thank you Danny @ SMC!) and a bunch of spare parts. Ready for the next race day!

 

[Jerold]

Had to wait for the red loctite to cure (spool set screw came loose!), but I think I finally have the (basic) setup dialed in. Good test run session this morning! Actual top speed 65 mph is amazingly pretty close to the theoretical calculation of 67.8 mph. Still running the old GRPs since the set I received were XM4 not XM3; sorting out a possible return. But the grip is definitely better on these super softs vs. the stock Hoons… could hardly make the car slide.

Re: braking, do you guys avoid hitting the brakes hard? I think this is how I wore down my Big Rock input gear, but that was when it was stock composite. How well can the Limitless (stock) drive train take constant hard braking?

Motor temp maxed at 109oF, ESC at 80oF, so no problems there.

I now have my second set of batteries (thank you Danny @ SMC!) and a bunch of spare parts. Ready for the next race day!

View attachment 345900

View attachment 345903

View attachment 345904

The braking depends on a lot of factors and you will need to dial it it.

If you are racing using the brakes to the absolute limit (threshold braking) will decrease your lap times, but it has to be controlled. The last thing you want is swapping ends under hard braking. Using the brakes also heats up your motor. Not much you can do other than heatsink and fans, but something to be aware of.

 

[Overkill]

The braking depends on a lot of factors and you will need to dial it it.

If you are racing using the brakes to the absolute limit (threshold braking) will decrease your lap times, but it has to be controlled. The last thing you want is swapping ends under hard braking. Using the brakes also heats up your motor. Not much you can do other than heatsink and fans, but something to be aware of.

Play with the drag brake also. If you set it right you can let it do the braking in most of the corners and it helps with consistency.

 

[SrC]

Check my math!

View attachment 343606

The big main difference to me here is the smaller 39 spur gear.

The braking depends on a lot of factors and you will need to dial it it.

If you are racing using the brakes to the absolute limit (threshold braking) will decrease your lap times, but it has to be controlled. The last thing you want is swapping ends under hard braking. Using the brakes also heats up your motor. Not much you can do other than heatsink and fans, but something to be aware of.

+1
Hard excessive Braking also heats up the ESC quite much, not just the motor.
Learn to "feather" your brake finger. Soft taps of the brakes are best. The ESC Brake Setting itself, is rather subjective. We all drive differently with different skill sets.

 

[SrC]

Following. Never considered the Lim as a track car. Should be interesting to watch. Good luck

+1

You had better make sure to run a Center diff for the track. A spool won't cut it. Working against you big time. You may also want to gear down way more than the 30T pinion there. Better have some spare pinions on hand to dial it in. If you want to keep up, lap after lap.
Also, I could be wrong, but you have way more power than you need. I don't know what the Track layout is there, and how technical the driving is. Or if you will be running 4s , 6s or 8s packs. Depending on the track rules....
Yeah when it comes to racing, a DNF is not a good thing. A crash is one thing....
But a Drive train or Overheating failure ( Thermal cut) is just a setup error. That's completely on you. Best to practice your setup a day or 2 before, with a Temp Gun in hand and to see if your Lipo's can even keep up with the race time event. Practice sessions. Depends how serious you are about racing.
Have fun.

 

[Jerold]

+1

You had better make sure to run a Center diff for the track. A spool won't cut it. Working against you big time. You may also want to gear down way more than the 30T pinion there. Better have some spare pinions on hand to dial it in. If you want to keep up, lap after lap.
Also, I could be wrong, but you have way more power than you need. I don't know what the Track layout is there, and how technical the driving is. Or if you will be running 4s , 6s or 8s packs. Depending on the track rules....
Yeah when it comes to racing, a DNF is not a good thing. A crash is one thing....
But a Drive train or Overheating failure ( Thermal cut) is just a setup error. That's completely on you. Best to practice your setup a day or 2 before, with a Temp Gun in hand and to see if your Lipo's can even keep up with the race time event. Practice sessions. Depends how serious you are about racing.
Have fun.

Hmm I never even thought about the spool being a disadvantage but I could see that. Real world here - I have 4runner Limited with a LSD center diff for full time AWD. When I put it in 4WD Hi, it locks that diff (AKA Spool) and it's no fun to turn at that point. The front and rear axles are fighting each other.

This is the track. The back straight is about 200 ft long and the cars get moving pretty good.

 

[SrC]

That is one sweeet track there!!
I can see the blue groove lines going on there.
A spool will never cut! Get an Open Center Diff from JennysRC. Leaving it with 100k to start out with. Evaluate from there. Might need to even drop the diff oil down more. Thinner. IDK. Depends how you drive.
Concentrate on gearing for the turns and sweepers based on your chosen lines., That is where you will scrub the most speed. Slower lap times resulting. The straights, you should be geared more conservatively, to accommodate the turns. The priority is at the turns. Need a selection of pinion gears to dial you in. IMHO. Tires mean a lot as well. Will make you or break you. Try some tire prepping as well. If they allow it. Are the guys running Foams or Rubber tires there? Any Idea?
Best lap times are made when you navigate the Technical parts of the track most effectively and not on the straights. Driver skill is key as well.
I find that the Lims and Infr. inherently have a lot of "Steering Push" in the techncial parts (Understeer) Especially if over geared.
You need to make that work for you. Not fight you. Adapt your driving style to suit.
If I was having a hard time initially, I would even consider dialing in a slight bit of ESC Drag Brake. Will help you entering the turns, to setup your Apex and exit faster. Just some ideas.

 

[SrC]

I am going to guess that your best overall geared Top speed would be aprox. 35-40mh. Tops.... for best lap times.
Appears to be a narrow track suited for 1/8-1/10 models. I could be wrong. The Pix is deceiving me? Need to dial in your Punch well.
Don't overlook your ESC settings to become more comfortable. ie. adjusting Punch and Brake Force settings..

 

[Overkill]

I am going to guess that your best overall geared Top speed would be aprox. 35-40mh. Tops.... for best lap times.
Appears to be a narrow track suited for 1/8-1/10 models. I could be wrong. The Pix is deceiving me? Need to dial in your Punch well.
Don't overlook your ESC settings to become more comfortable. ie. adjusting Punch and Brake Force settings..

Using the Google maps scale that place is huge ~200 feet long. My car is geared for 38mph for a parking lot layout that's 1/4 the size.

I just pulled up the last set of results, are the races only 6 minutes? If they're that short and your temps were that low you can get way more aggressive with your electronics and save weight. I cooked my xr8 g2s and 4268 in 15 minute sessions on 100 degree days over and over and it never missed a beat. I know you just built it but long term if you get competitive race electronics and cutting weight could make a big difference.

 

[SrC]

Yeah though XR8 G2's can handle much heat. They are quite efficient.

 

[Overkill]

Yeah though XR8 G2's can handle much heat. They are quite efficient.

Yeah the motor too. It got so hot it would heat up the chassis below to the point you couldn't hold your finger on it.

 

[Jerold]

I am going to guess that your best overall geared Top speed would be aprox. 35-40mh. Tops.... for best lap times.
Appears to be a narrow track suited for 1/8-1/10 models. I could be wrong. The Pix is deceiving me? Need to dial in your Punch well.
Don't overlook your ESC settings to become more comfortable. ie. adjusting Punch and Brake Force settings..

I went for a bit to see what it was, I've never been there. It's a nice track and the people were very helpful. They were running 1/10 scale cars and they were flying, way faster than 40 mph. You're not kidding bout the punch control. The amount of torque he has is crazy. Gotta be super easy on the throttle. I was thinking Throttle delay might help a bit too. Kinda of does the same thing but it's controlled from the TX and give a more linear acceleration to full tilt boogie.

It's billed as a 1/5 scale track. It seems plenty wide. But even though it's a big track, it has real berms and walls that you want to avoid. Note the broken shock.

Here is some running video from an Internet Rando. No seriously I don't know this guy.

 

[SrC]

VERY Nice track. No track is perfect.
Except maybe The Tamiya 1/10 TC Track In Japan.
I can see now that is a quite wide, 1/5 track. Awesome.
I envy you.
Hard to find a large 1/5 scale Paved track. Extremely rare, and it's in nice condition.
1/10 scale TC's (the pros) will absolutely run as fast as 60-70 mph on the straights!
Don't expect that fast with 1/8 or larger scale.

 

[Jerold]

VERY Nice track. No track is perfect.
Except maybe The Tamiya 1/10 TC Track In Japan.
I can see now that is a quite wide, 1/5 track. Awesome.
I envy you.
Hard to find a large 1/5 scale Paved track. Extremely rare, and it's in nice condition.
1/10 scale TC's (the pros) will absolutely run as fast as 60-70 mph on the straights!
Don't expect that fast with 1/8 or larger scale.

It's currently behind a restaurant, next to the RR tracks in a light industrial area. Hopefully people ignore it.