Results 1 to 18 of 18
  1. #1
    RC poster
    Join Date
    Dec 2018
    Posts
    10

    Question ~What Parts to Buy for 8S ~150mph Build?

    picking up a xo-1, want to go all out/speed run

    looking for help on what i need to buy. links would be a bonus.

    Motor:
    Motor mount:
    Esc: (besides the obvious Mamba XLX)
    Pinion:
    Tires:
    Other: anything else i need to upgrade to go these speeds?

    ive got batteries, servo, etc covered

  2. #2
    RC Qualifier
    Join Date
    Apr 2018
    Posts
    848
    Good luck!!

  3. #3
    RC Qualifier
    Join Date
    Nov 2016
    Location
    Atlanta, Georgia
    Posts
    943
    If you don’t want to run XLX and want to save on weight, you can actually use the original MMM on 8s. Many speed runners used it on 8s with a 2200kv motor to achieve gigantic numbers.

  4. #4
    RC Qualifier
    Join Date
    Dec 2017
    Location
    North Texas
    Posts
    619
    Motor: TP Power 4070 cm http://www.tppowerusa.com/motors/in-...4070-cm-2200kv
    Motor mount: Personally I think the factor mount is fine but there are other options http://www.fastlanercs.com/xo-1-muge...nt-kyosho.html

    Esc: Mamba XLX v 1.78 software
    Pinion: will have to figure it out... best to start around 25t and work your way up to see. Over gearing can slow you down and create massive heat.
    Tires: GRP S1 OR BSR purple foam

    Aerodynamics will be the biggest challenge. Only 1 person has reached 150 mph with this rc. IT WILL BE A CHALLENGE

    -Liberty

  5. #5
    RC poster
    Join Date
    Dec 2018
    Posts
    10
    thanks. yeah ill probly use a XLX.
    ive got a OG Mamba Monster (1) and a Mamba Monster X, but they both appear to be rated at 6S max.

    Liberty ive been seeing those motors mentioned here and there. but why did you suggest a smaller motor, the stock motor is 45/50 x 85mm
    i was looking at this one
    http://www.tppowerusa.com/motors/in-...product_id=481

    its a larger motor (more power) but less kv than yours. but maybe outright "Horsepower" is less important than RPMs for speedruns. probably true.

    yeah the XO is a large car. has to punch a very large hole in the air. thats definatly working against it.
    ive given some thought to cutting the entire roof off. from the door up. windshield and all. and plating the hole with lexan. would remove some of the frontal area and drag of the body.
    id also be curious how completely body less would react. or a buggy body at least.

  6. #6
    RC poster
    Join Date
    Dec 2018
    Posts
    10
    any suggestions for a GPS?
    all the videos i see seem to use a "Garmin Forerunner"
    pricy
    https://www.amazon.com/Garmin-Foreru...tronics&sr=1-9

  7. #7
    RC Qualifier kzsteve's Avatar
    Join Date
    Jan 2018
    Location
    norcal
    Posts
    274
    i thought the bigger kv would be faster , but was told the 2200kv would be faster . the garmin four runner will hold max speed
    when run is over . works well . my xo has run 104 - 108 on 2 5000 mah 25c 11.1 3 cell lipos . plenty fast for me . traction seems to be my biggest problem
    XO-1 GUY GETTING OLDER BY THE MINUTE

  8. #8
    RC Qualifier
    Join Date
    Nov 2016
    Location
    Atlanta, Georgia
    Posts
    943
    The mamba monster 1 and 2 are both rated for 6s lipo. The monster 2 is electronically limited to that, the monster 1 is not. The esc is very capable for using 8s and many have.

    Of course, this seems very serious, so the xlx will definitely be the way to go. TP’s long can 2200 would be my recommendation as it is 8s rated, but still has a high kv. Perfectly ideal if you ask me.

    75000rpm with 2200kv, 8s, sweet
    Last edited by Peeeenuuutt; 01-21-2019 at 04:30 PM.

  9. #9
    RC Qualifier kzsteve's Avatar
    Join Date
    Jan 2018
    Location
    norcal
    Posts
    274
    be sure to calculate gearing . important for high speed
    XO-1 GUY GETTING OLDER BY THE MINUTE

  10. #10
    RC poster
    Join Date
    Dec 2018
    Posts
    10
    Quote Originally Posted by Peeeenuuutt View Post

    Of course, this seems very serious, so the xlx will definitely be the way to go. TP’s long can 2200 would be my recommendation as it is 8s rated, but still has a high kv. Perfectly ideal if you ask me.
    i think that will be the direction i go. although i do have a giant castle 2200kv i may try first. just cause i already have it. might smoke it though?

    also did some research on GPS units, to include emailing Garmin themselves.

    SkyRC speed meter refresh rate is 1Hz (1 time a second)
    Garmin Forerunner 301 is also 1Hz (1 time a second)
    the Dynamite speed meter is 10Hz (10 times a second)

    so i ordered the Dynamite (also 1/3 the price of Garmin)
    there are also several youtube comparison vids showing the Dynamite updating much/visually faster.
    found the best price here using google shopping http://www.advantagehobby.com/256353...yABEgK7jfD_BwE

  11. #11
    RC Qualifier
    Join Date
    Nov 2016
    Location
    Atlanta, Georgia
    Posts
    943
    If it's an old school (2015-before) NEU CASTLE motor that's not from a China eBay dealer than you'll be just fine. If it is a modern Chinese one then you'll most likely be fine, but instead of 100% you're looking at more of a 75%..

  12. #12
    RC poster
    Join Date
    Dec 2018
    Posts
    10
    yeah its 5-10 years old. bought it with a CC mamba monster combo back then, and have never used it.

  13. #13
    RC Qualifier
    Join Date
    Dec 2017
    Location
    North Texas
    Posts
    619
    Quote Originally Posted by STANG KILLA SS View Post
    thanks. yeah ill probly use a XLX.
    ive got a OG Mamba Monster (1) and a Mamba Monster X, but they both appear to be rated at 6S max.

    Liberty ive been seeing those motors mentioned here and there. but why did you suggest a smaller motor, the stock motor is 45/50 x 85mm
    i was looking at this one
    http://www.tppowerusa.com/motors/in-...product_id=481

    its a larger motor (more power) but less kv than yours. but maybe outright "Horsepower" is less important than RPMs for speedruns. probably true.

    yeah the XO is a large car. has to punch a very large hole in the air. thats definatly working against it.
    ive given some thought to cutting the entire roof off. from the door up. windshield and all. and plating the hole with lexan. would remove some of the frontal area and drag of the body.
    id also be curious how completely body less would react. or a buggy body at least.
    It is a bit confusing on the naming conventions. TP Powers 4070 motor measures 40x107mm
    These are rated at 9,000 watts.
    Lets say you are running 8s and your batteries are 33v by the time you get the car to its starting point for the run. During a run if you look at data logs you will see that your cells dropped from 4.18 per cell down to 3.125

    3.125 volts * 8 cells is 25Volts
    25v * 300 amps is 7,500 watts.
    Take away losses and motor efficiencies of 90% you might see 6,750 watts if you are lucky.
    Most people say we cant fully use the power capabilities of the 4070cm
    It is even worse on the larger motors.
    I will say I have a data log of the TP5670 (13xx) kv motor pulling 8200 watts using the XL-X

    Also worth noting something you can relate to 746 watts = 1 hp

    (I'm an electrical engineer btw)

    -Liberty

  14. #14
    RC Qualifier
    Join Date
    Nov 2016
    Location
    Atlanta, Georgia
    Posts
    943
    Quote Originally Posted by LibertyMKiii View Post
    It is a bit confusing on the naming conventions. TP Powers 4070 motor measures 40x107mm
    These are rated at 9,000 watts.
    Lets say you are running 8s and your batteries are 33v by the time you get the car to its starting point for the run. During a run if you look at data logs you will see that your cells dropped from 4.18 per cell down to 3.125

    3.125 volts * 8 cells is 25Volts
    25v * 300 amps is 7,500 watts.
    Take away losses and motor efficiencies of 90% you might see 6,750 watts if you are lucky.
    Most people say we cant fully use the power capabilities of the 4070cm
    It is even worse on the larger motors.
    I will say I have a data log of the TP5670 (13xx) kv motor pulling 8200 watts using the XL-X

    Also worth noting something you can relate to 746 watts = 1 hp

    (I'm an electrical engineer btw)

    -Liberty
    Ugh, smart people these days .

    Jokes aside, wow that’s crazy. That’s a ton of watts down the drain!

  15. #15
    RC poster
    Join Date
    Dec 2018
    Posts
    10
    liberty any chance you could post more info on that watts to HP conversion
    id like to learn more about that. and any other factors that affect the conversion


    the thing that bugs me is watt output is based on load. ie on an rc airplane (ive got 30)with a given setup (X) if you put a tiny prop on it it will make low watts/amps on the watt meter at WOT, but put a giant prop with a long of drag on the same identical setup, and the setup is working super hard and it will show a mega watt/amp draw on the watt meter, yet the power system is identical.

    HP isnt like that. a 400 hp V8 makes 400 hp weither its reved at idle sitting still, or driving down the road towing 5000 lbs up hill.


    thats why id like to learn more about your watts to HP conversion. (plus would be cool to have a HP number for my new build )
    Last edited by STANG KILLA SS; 01-24-2019 at 11:37 AM.

  16. #16
    RC Turnbuckle Jr.
    Join Date
    Oct 2016
    Posts
    4,194
    Quote Originally Posted by STANG KILLA SS View Post
    liberty any chance you could post more info on that watts to HP conversion
    id like to learn more about that. and any other factors that affect the conversion


    the thing that bugs me is watt output is based on load. ie on an rc airplane (ive got 30)with a given setup (X) if you put a tiny prop on it it will make low watts/amps on the watt meter at WOT, but put a giant prop with a long of drag on the same identical setup, and the setup is working super hard and it will show a mega watt/amp draw on the watt meter, yet the power system is identical.

    HP isnt like that. a 400 hp V8 makes 400 hp weither its reved at idle sitting still, or driving down the road towing 5000 lbs up hill.


    thats why id like to learn more about your watts to HP conversion. (plus would be cool to have a HP number for my new build )
    P=IxV. So current times voltage equals watts. So with no load(in neutral) your voltage will be constant, but your current will be very low. Not much power output in watts. If you could monitor voltage and current, youd have real wattage numbers. Castle Escs with logging do just that, but I have a feeling there is no true current sensing capability. If they do Id like to see how they do it.

  17. #17
    RC Qualifier
    Join Date
    Dec 2017
    Location
    North Texas
    Posts
    619
    Quote Originally Posted by Gripdog7205 View Post
    P=IxV. So current times voltage equals watts. So with no load(in neutral) your voltage will be constant, but your current will be very low. Not much power output in watts. If you could monitor voltage and current, you’d have real wattage numbers. Castle Esc’s with logging do just that, but I have a feeling there is no true current sensing capability. If they do I’d like to see how they do it.
    I agree completely. I have always had the impression their numbers are a wild guess in those data logs. Along those lines the Max5 ESC is rated at 200 amps constant. I ran this esc along with the Caslte XL-X set to 350 amps limiting and my XMaxx ran exactly the same speed. One companies 200 amps is not the same as another. Much like battery C-ratings.

    Regardless the readings from the data logs are very useful. Seeing voltage, ripple voltage, motor rpm etc can help you adjust gearing to get to that perfect range.

    Much like air planes the load on the motor dictates amps, due to the prop used. This same idea applies in RC cars also. The difference here is gearing instead of prop size and pitch.
    One interesting example was my XMaxx. Running 29/46 I hit 72.5mph. I tried 43/46 and it went slower along with an additional 20-30 degrees F temperature on both the ESC and motor. It was too much gear for that motor (5882 Leopard 1360kv) On a different car with lighter weight and better aerodynamics it would be a different story, but regardless you need torque to push through that air.

    As far as watts to hp. 746 watts = 1 hp. This is output from the ESC. Like Gripdog7205 mentioned volts * amps = watts. If you have 8000 watts output from the ESC you will have to consider the motor can effectively convert around 90% of that power to "work". The rest gets turned into heat.

    Any way that you can reduce the aerodynamic frontal area of the car will be more valueable than adding power. Typically this means sculpting your own fiberglass body. (FYI carbon fiber blocks RF)
    This is also why if you look at Nic Case's 202mph car it was extremely narrow and low. Best examples of designs are found in bonneville land speed cars.

    Another interesting thing to consider especially on larger motors like the 56xx and 58xx motors is that the power curve on an electric motor is opposite of a piston engine. It starts around its peak and around 20k rpm starts dropping like a rock. This is where data logs can help greatly with gearing adjustments.

    -Liberty
    Last edited by LibertyMKiii; 01-24-2019 at 08:35 PM.

  18. #18
    RC poster
    Join Date
    Jun 2019
    Location
    United Kingdom
    Posts
    4

    What Parts to Buy for 8S 150mph Build

    This is a thread for people to post parts etc that would have a vin on it so maybe the person with that vehicle could be found etc. Darrell has another thread with transmission cases with vins. That is what this thread is about. Ill make this thread a sticky and see how it goes.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •