Limitless World record speed build, round 2.

[MambaSenton]

Good luck my guy!

 

[LibertyMKiii]

Good luck.
Make sure the rear is sitting higher than the front. You don't want it to backflip...

 

[limitless202+]

And of course, my road had construction. Hate it, but the people said they should be done in a week, then we had a snowstorm, FUN!
So i think its time. 16s time. That’s right, i have another castle 1100kv and XLX2 on the way. I think the SPC custom chassis should tolerate the dubGrub motor mount, with a little work. second xlx2 will Go where the stock esc mount and reciver box goes. 4 SRD packs will go on the sides, and that should do it.
i think this should go past the raz quad motor, if i leave it up to gearing. Lets see how this goes.

 

[LibertyMKiii]

I think dual motor builds will become more popular now.
Good luck man

 

[limitless202+]

Thanks liberty.
i hope this build hits my goal, i really don't wanna go dual LMT, thats expensive.
like really expensive.

 

[LibertyMKiii]

Thanks liberty.
i hope this build hits my goal, i really don't wanna go dual LMT, thats expensive.
like really expensive.

Yeah I don't think it is necessary. Two castle setups running moderate is 12+ hp each.
I doubt the tires can find enough traction to do anything more.

 

[limitless202+]

That’s what i think. If raz is doing 198MPH on 2 1717 motors, and thinks 210, 2x 20hp 2028 motors will fit the 200+ bill
by the way, does a 1717 actually have 15HP ???
and does the 2028 have 21?

 

[rotauq]

Yeah I don't think it is necessary. Two castle setups running moderate is 12+ hp each.
I doubt the tires can find enough traction to do anything more.

So we should get more tires

 

[limitless202+]

Lol oh yeah!
tires be thicc

 

[LibertyMKiii]

That’s what i think. If raz is doing 198MPH on 2 1717 motors, and thinks 210, 2x 20hp 2028 motors will fit the 200+ bill
by the way, does a 1717 actually have 15HP ???
and does the 2028 have 21?

It is my personal belief that those numbers in the logs are inflated quite a bit.

Also remember the ESC is sending that power and then the motor can convert about 90% to action. The other 10% is lost to heat generation. If the logs say 15hp ( around 11.2kW)
Then the 15 hp is reduced to 13.5 hp after the 90% efficiency of the motor.

That is just looking at the motor. Then you loose some power at the gears, diffs, and bearings. So the power that makes it to the wheels is again reduced.

Still then if you have 12hp x2 that is 24hp. If you cant go fast with 24hp in such a small car then you have another issue to address with the body/aerodynamics.

 

[limitless202+]

OMG SOMEONE SAID IT!!

yep, 15hp esc, 1.5hp gone like that.
98 percent efficiency through the gears.
call it 95 percent for diffs
95 for ceramic bearings.
so yea 12hp for a 1717 sounds right, meaning 48hp RC car for raz.
lets run the same math for the castle 2028.
I’ve seen about 14.5kw from my 2028, if you run the same math that means its final power is..
Meaning about 11.5 kw per motor, run 2 and you get A REAL 30hp RC car.
more things to consider is raz (on the quad) is running a 35 percent meshed spur, drop another percent.
also, hes only running 12S. That the equivalent of running my 150mph typhon on 3S.
This is where my bid comes into play. A 47hp quad motor RC car running a fraction of the voltage it can run, versus a 31hp RC car running as hard as it can.
another note, i might go to 1721 motors if these cant do it, but i think they can.
@LibertyMKiii do you agree with this?

 

[LibertyMKiii]

OMG SOMEONE SAID IT!!

yep, 15hp esc, 1.5hp gone like that.
98 percent efficiency through the gears.
call it 95 percent for diffs
95 for ceramic bearings.
so yea 12hp for a 1717 sounds right, meaning 48hp RC car for raz.
lets run the same math for the castle 2028.
I’ve seen about 14.5kw from my 2028, if you run the same math that means its final power is..
Meaning about 11.5 kw per motor, run 2 and you get A REAL 30hp RC car.
more things to consider is raz (on the quad) is running a 35 percent meshed spur, drop another percent.
also, hes only running 12S. That the equivalent of running my 150mph typhon on 3S.
This is where my bid comes into play. A 47hp quad motor RC car running a fraction of the voltage it can run, versus a 31hp RC car running as hard as it can.
another note, i might go to 1721 motors if these cant do it, but i think they can.
@LibertyMKiii do you agree with this?

It is all fuzzy math and guesses without measurement equipment, but in general yes.
We need a decent RC car dyno and wind tunnel

 

[limitless202+]

Yea, but when’s the last time you’ve seen one of those?
i really think the best speedrunning motor would be a custom rewound 2028 to about 1800kv.

 

[LibertyMKiii]

Yea, but when’s the last time you’ve seen one of those?
i really think the best speedrunning motor would be a custom rewound 2028 to about 1800kv.

I agree it needs more KV
The magnets on TP Motors are also significantly stronger.

 

[limitless202+]

I know, that why i think if 2028 motors don't do it, maybe some 5870’s ?
Also @LibertyMKiii was the backflipped CF body yours?

 

[LibertyMKiii]

I know, that why i think if 2028 motors don't do it, maybe some 5870’s ?
Also @LibertyMKiii was the backflipped CF body yours?

5870 is a 6 pole motor.
The general consensus is that 6 poles don't play well above 1500 kv with the XLX2 under heavy loads like we see in speed running.

Yes all the carbon bodies you see in Raz's videos are mine. He removed 90% of the front splitter which removed the front downforce

 

[limitless202+]

True, and i don't think TP makes a big 4 pole motor.
there is cordova, who i think makes one, but its expensive.

this is why you leave things the way they came raz!
id still like to get my hand on one @LibertyMKiii though!

 

[limitless202+]

Alright, so i ran it on my 1400 feet long road, and it went alright, the whole time i was on 6s, 1100kv, xlx2, aah you know the drill. First, i ran a 77mph warmup pass, then i did another pass to try to push harder, aannd i had a blow over. Here’s how it went, and i would want you guys to read it so if something happens to you, you might be able to look back on this, and get an idea why it happened.
so my road is like a dish, with a lip at the very end, and when you get the car all the way back, you speed up on the 100m slight downhill section, then on the 200m flattest portion (its all still very flat) you can hit your 100+ speeds, then when you are slowing down in the last 100m you lit a lip, like a ripple in the road, not a speed bump, but just enough to throw the car off, and spin out, i spun out at 86mph, not half bad for only using about 40 percent power.

 

[rotauq]

Alright, so i ran it on my 1400 feet long road, and it went alright, the whole time i was on 6s, 1100kv, xlx2, aah you know the drill. First, i ran a 77mph warmup pass, then i did another pass to try to push harder, aannd i had a blow over. Here’s how it went, and i would want you guys to read it so if something happens to you, you might be able to look back on this, and get an idea why it happened.
so my road is like a dish, with a lip at the very end, and when you get the car all the way back, you speed up on the 100m slight downhill section, then on the 200m flattest portion (its all still very flat) you can hit your 100+ speeds, then when you are slowing down in the last 100m you lit a lip, like a ripple in the road, not a speed bump, but just enough to throw the car off, and spin out, i spun out at 86mph, not half bad for only using about 40 percent power.

View attachment 206230

It's what makes finding the perfect road hard. When you think youve got some place perfect it's these details that can completely disqualify a seemingly perfect road...

 

[limitless202+]

I know, i have others though, and ill keep using this one, i just have to go on the brakes hard by then.