Limitless Considering starting speedrunning, limitless or something else?

[ABabyEater]

Basically, thread title.

I have access to a rarely used, often maintained public airstrip that can technically land a 737 (no keyhole at the end for it to turn around) and it is hard to sit here without using it for something.

I'm considering picking up a used Limitless (couple of runs, but darn near mint; current owner will keep electronics), on a great deal. I have gyro and non-gyro receivers for my Radiolink already, as well as a MMX8S with an 800kv 2028 (will need a PPS mount) to put in it. I have a spool with a couple of spurs (36T, and 32T I think) and 50T and 55T pinions. That leaves me needing a good, high speed digital servo, gps, and batteries, right? Maybe a few changes like a GT body, less aggressive spoiler.

So the question is, do I start with the Limitless and the parts I already have, or go with something else, likely a full build based off a titanium or carbon fiber GT chassis (Kraton, Typhon, etc)?

I've seen guys run a few different ways to maximize speed: more power, less weight, and better aero. It seems to me like less weight means more fragile, but at mph+ does that really matter? Won't most things break anyways?

 

[jondilly1974]

Start with that Limitless. You have most of what you need. I would say you’re going to need a 29T spool with that 800kv can. I would also get the GP5 42/15 diffs from the Infraction V2 to help make up some RPMs. Otherwise you have a great setup to get started. Get it going straight at 100mph and then build up from there. Once you hit a wall with the stock body, probably around 130mph or so, then get a GT body and build up from there.

 

[LibertyMKiii]

You will want upgraded dog bones like scorched, but the rest of the braces and strength upgrades are not needed.
If you get into a chassis bending situation it will be really bad at 100+ and those parts will not save the car LOL.

I agree with Jon's comments above. The low KV motor will need a 29t or lower spur. Saga custom RC offers 8mm bore pinions down to something like 18t, but you have to keep certain number of teeth total for the gears to mesh. With a significantly lower spur you likely wont need the GP5 diffs, but that is always an option.

For example:
24 spur with 46 pinion (70t total)
keeping the original 3.3 limitless diffs
24v assuming some voltage drop on 8s
could net a speed around 130 mph

You will need to check what teeth count have to be in mesh for the motor mount you are using. PPS is in the ball park of 70t but I don't know the exact range possible.

 

[ABabyEater]

Get it going straight at 100mph and then build up from there. Once you hit a wall with the stock body, probably around 130mph or so, then get a GT body and build up from there.

This seems like a really reasonable goal. Not only attainable, but also challenging, and it'll help me make sure I have things dialed.

Speaking of having things dialed, what should I be looking for in suspension geometry, as for Caster, Camber, and Toe? Just make sure everything is set left/right symmetrically, or alter some settings?

As I understand, the more positive Caster (lower pivot ball farther forward than upper), the better high speed stability.

The more negative camber, the better stability when cornering aggressively, but the worse straight line stability. This makes me think setting at 0 camber when at rest would be good, as when lifting the front under power slight positive camber would be induced.

Having more aggressive toe, in or out, front or back, reduces top speed, wears tires faster, and reduces straight line stability, right? Should I be shooting for a zero toe setup?


Or... Am I way overthinking everything until I get to that 100mph mark?

Does anyone know what speed the Limitless Hoons are rated for?

 

[Hammer Down]

I have access to a rarely used, often maintained public airstrip that can technically land a 737 (no keyhole at the end for it to turn around) and it is hard to sit here without using it for something.

Lucky Dog!!!

 

[ABabyEater]

I bought it. 1 run on it with a Max 6 combo, figured that would be a good starting point. Had all the weird Lexan "extra downforce" bits and bobs on it. Worth keeping them attached or nah? Otherwise all factory settings, tires not balanced, camber/toe, shock load, etc. I'll get a new thread going once I start really diving in.

 

[jondilly1974]

This seems like a really reasonable goal. Not only attainable, but also challenging, and it'll help me make sure I have things dialed.

Speaking of having things dialed, what should I be looking for in suspension geometry, as for Caster, Camber, and Toe? Just make sure everything is set left/right symmetrically, or alter some settings?

As I understand, the more positive Caster (lower pivot ball farther forward than upper), the better high speed stability.

The more negative camber, the better stability when cornering aggressively, but the worse straight line stability. This makes me think setting at 0 camber when at rest would be good, as when lifting the front under power slight positive camber would be induced.

Having more aggressive toe, in or out, front or back, reduces top speed, wears tires faster, and reduces straight line stability, right? Should I be shooting for a zero toe setup?


Or... Am I way overthinking everything until I get to that 100mph mark?

Does anyone know what speed the Limitless Hoons are rated for?

I set mine up with as neutral stance as possible in all ways. My rear still has the stock toe for now, but I have a zero toe rear C block coming from CRCU. Fronts are dead neutral toe, but a little toe in is OK. Toe out will put you off the road quickly. As far as caster, I haven’t adjusted that yet so I don’t have advice there other than I know what you mentioned is correct.

Hoons shouldn’t be trusted above 120mph. They also don’t have as much grip as GRPs at any speed. I don’t like using them for speed runs period. I don’t trust them at all.

 

[ABabyEater]

Hoons shouldn’t be trusted above 120mph. They also don’t have as much grip as GRPs at any speed. I don’t like using them for speed runs period. I don’t trust them at all.

I'll keep this in mind as I get things up and running. With the first goal of a consistent 100mph for myself and the car, I am fine sticking with Hoons for now, but I might change that going forward depending on how things go.

 

[jondilly1974]

I'll keep this in mind as I get things up and running. With the first goal of a consistent 100mph for myself and the car, I am fine sticking with Hoons for now, but I might change that going forward depending on how things go.

Just know that if you start losing grip, it will slide where it wants. They don’t have braking traction either. Especially at 100mph. You will be driving on ice essentially.

 

[ABabyEater]

Just know that if you start losing grip, it will slide where it wants. They don’t have braking traction either. Especially at 100mph. You will be driving on ice essentially.

Good thing I have a 3750x125ft surface to learn on.

And a 5700x75ft one for once I get better.

 

[jondilly1974]

Good thing I have a 3750x125ft surface to learn on.

And a 5700x75ft one for once I get better.

.