Big Rock Speed runner

[Silverado86]

Started life as a BRCC but went through a ton of axels and spur gears and a few motors, now have a talion 6s to play with so I'm turning the BRCC into a speed runner
Amazon special 3674 2250kv motor Hr motor mount 27t pinion, metal spur and slipper from the 4s rigs, blx185 and some hoons , with a theoretical speed of 73mph on 4s and 110mph on 6s...
First attempt today I hit 78mph on 6s but 1. I didnt feel the road was long enough for it to stretch its legs. 2 I only have my phone GPS which I've heard are slow to refresh and 3 I didnt have a body on it because the stock BRCC one is long gone
Any one know of a speed run body that fits the LWB arrmas or any other tips?
Thank you
Also this has the longer typhon arms and turnbuckles as well as the HR extended 17mm hex

 

[jondilly1974]

Started life as a BRCC but went through a ton of axels and spur gears and a few motors, now have a talion 6s to play with so I'm turning the BRCC into a speed runner
Amazon special 3674 2250kv motor Hr motor mount 27t pinion, metal spur and slipper from the 4s rigs, blx185 and some hoons , with a theoretical speed of 73mph on 4s and 110mph on 6s...
First attempt today I hit 78mph on 6s but 1. I didnt feel the road was long enough for it to stretch its legs. 2 I only have my phone GPS which I've heard are slow to refresh and 3 I didnt have a body on it because the stock BRCC one is long gone
Any one know of a speed run body that fits the LWB arrmas or any other tips?
Thank you

Get a smaller GPS speed meter like the GSM-015 or the Dynamite. I have found that GRPs are my favorite so far. Make sure to get your car as low as possible. I used tubing inside the shocks under the pistons to limit travel. This effectively slams your car. Preload the shocks to make them stiff, especially the rear. Make sure you have enough road and radio range to be hitting full throttle by mid pass. Stay on it long enough to max it out. ??

 

[unclebrudy]

Not a super fast speed runner like most of the beasts here (yet), but I have no complaints about the stock Typhon body. @jondilly1974 hit the mid-90’s on the Typhon body (admittedly with some 3D printed mods) and there are tons of 100+ mph speed runners with videos on YouTube running the body. All you’d need are the body mounts and the wing/wing mount from Jennys, not terribly expensive for all the bits. Would bolt right on to your Big Rock.

For ultimate aero there is Delta Plastik USA, or you could custom one like @LibertyMKiii

 

[BashingBrian]

I gave up at 60.3mph on 3s with my various versions of my Granite speed runner, as I got an Infraction...???
Long and low was my thinking..?

Then longer...???

 

[LibertyMKiii]

Nice work so far @Silverado86
I suspect you might be right about at the max. I have found the BLX185 returns about 70-78% of the calculated speed so you are spot on already with 78mph

The key to going faster will be putting in a smaller spur gear. Most speed runners convert to Mod1 gears (it would be a custom solution)

 

[Silverado86]

Gonna give it a few more trys then maybe try to slot out the hot racing motor mount to fit a bigger pinion. 27t is currently the max you can fit

 

[jondilly1974]

Gonna give it a few more trys then maybe try to slot out the hot racing motor mount to fit a bigger pinion. 27t is currently the max you can fit

I got a 29T to fit but you need to carve out the power module housing to get it to fit. You will also need a smaller spur gear. I am running a 37T on a home made spool.

 

[Silverado86]

I'm sort of handy but how would you go about making a Spool for these rigs and is it mod 1 of .8 and metal or plastic?

 

[jondilly1974]

I'm sort of handy but how would you go about making a Spool for these rigs and is it mod 1 of .8 and metal or plastic?

Check out my build thread for the deets

https://www.arrmaforum.com/threads/arrma-typhon-3s-blx.15393/page-2

 

[Silverado86]

Thank you

 

[Silverado86]

Well I did it today behind my old closed Kmart with a long stretch of road (or so I thought) 109mph via my galaxy watch instead of my phone this time. 6s 2250 kv 3674 size motor and 27t pinion blx185. But after that run I went for another and ran out of road car flew in the grass and bounced off a chain link fence... cracked my chasis broken rear A arm bent my HR adjustable motor mount and shredded my pinion gear oh well

 

[jondilly1974]

Well I did it today behind my old closed Kmart with a long stretch of road (or so I thought) 109mph via my galaxy watch instead of my phone this time. 6s 2250 kv 3674 size motor and 27t pinion blx185. But after that run I went for another and ran out of road car flew in the grass and bounced off a chain link fence... cracked my chasis broken rear A arm bent my HR adjustable motor mount and shredded my pinion gear oh wellView attachment 68104

109mph is an incredible speed. You did that with a 27/57 gearing with open wheels and a wing? I can’t touch that with all of my mods. ????‍

 

[Silverado86]

Ran it with no body lol I like to live dangerously

 

[jondilly1974]

Did you video it? Would love to see that run.

 

[Silverado86]

Unfortunately no I don't have any kind of mount to video and was by myself and this thing is a hand full on 6s with the stock sloppyass steering, but after I fix everything I will definitely try and video it. doesn't look like any kit breakers have a LWB chassis in stock ??

 

[jondilly1974]

Unfortunately no I don't have any kind of mount to video and was by myself and this thing is a hand full on 6s with the stock sloppyass steering, but after I fix everything I will definitely try and video it. doesn't look like any kit breakers have a LWB chassis in stock ??

Yeah they run out fast. If you find some buy all you can and stock up. JRC is usually $9 each so I buy 2-3 at a time.

 

[LibertyMKiii]

I am in strong belief that when a crash occurs the GPS units do not show correct numbers.
Not trying to kick you while you are down (referring to the crash) but those numbers do not add up.

According to my experience with the BLX 185 you should see anywhere from 70% to 80% of the calculator's speed:
(putting you at 65-70 mph)

 

[Silverado86]

The first run I didnt crash it recorded the 109 second time it said the same thing but not sure if I reset it right it's my first time using this app on my watch. Not saying something went a fluke. The theoretical top speed is 110mph but I see what your saying but who knows it's a Amazon special motor maybe its its more then 2250kv ?? either way it felt like over 100 mph to me and I'm happy, I will rebuild and try again

 

[LibertyMKiii]

The first run I didnt crash it recorded the 109 second time it said the same thing but not sure if I reset it right it's my first time using this app on my watch. Not saying something went a fluke. The theoretical top speed is 110mph but I see what your saying but who knows it's a Amazon special motor maybe its its more then 2250kv ?? either way it felt like over 100 mph to me and I'm happy, I will rebuild and try again

Higher motor KV is very possible and would make the scenario true, but the numbers just don't add up for me. I recommend getting a SkyRC GSM-015 speed meter for accuracy.

Just an FYI on the calculator I see you input the voltage of 25.2V, but during the run voltage drops and the motor/car will never see those speeds because the RPMs will be down drastically due to voltage sag. If you look at my calculator screen shot I had input voltage at 19V because of voltage sag.

This is a good video that shows data logs of how voltage sag occurs during the run:

 

[Silverado86]

Well you guys were right... after getting her all fixed up and on a 26t pinion (LHS didnt have a 27t ??) there was a update to my watch and app I was using, all I could get out of her was 75mph on 6s ?? looks like I will be trying to make a smaller spur and trying again