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Thread: Lower car body

  1. #1
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    Lower car body

    Hi,

    I have modified my Slash 4x4 platinum edition and added a computer to drive it autonomously. I race it at the DIY Robocar event with other autonomously RC cars. You can find one video here https://twitter.com/i/status/1148778226971316225 . My problem is that if I ran it faster than 11mph, it would tip over at the corner of the track. Is there a way to lower the car body?

    My friend ran a different car with a much lower body and could run much faster https://twitter.com/i/status/1157407660037169153
    Last edited by gecong; 08-02-2019 at 11:30 PM.

  2. #2
    RC Qualifier Panther6834's Avatar
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    Yes, the other car is faster...but, it's CONSTANTLY going off the track, almost always in the exact same locations. At least your car ALWAYS stayed on the track.
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  3. #3
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    You could use a 1/8 GT-like body (Delta Plastik has them for Slash) or you could use the body of a buggy.
    If that's allowed.

  4. #4
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    I am looking for ways to lower my current Slash 4x4. If I change to a different car, I need to re-engineering everything in the computer/sensor part.

    Also, the members from this meetup has been making consistent progress during the last a couple years, and the best lap time among all members have decreased from 40 seconds to 7 seconds. We expect it will decrease to 6 seconds when we meet 9/21 at Oakland. We believe it has a chance to beat human RC car drivers. You guys are welcome to come to the meetup and race human-vs-robo with us. It will be fun... More information at https://www.meetup.com/DIYRobocars/

  5. #5
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    If you want to lower your car (not only the body), you could shorten the shocks, by adding a spacer inside the shocks.
    It's quite easy to do.


  6. #6
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    Quote Originally Posted by Panther6834 View Post
    Yes, the other car is faster...but, it's CONSTANTLY going off the track, almost always in the exact same locations. At least your car ALWAYS stayed on the track.
    What is it with you and NOT answering the question??

    Iím pretty sure that the platinum comes with an lcg chassis and sway bars but correct me if Iím wrong. Make sure you have both of those. Really helps with rolling.

    Another thing you could do is get some thin small tires. Helps a lot with flipping.


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  7. #7
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    Hi @StijnH, this is exactly what I need. Before I do not, I would like to explained what modification I made to the car:

    1. Since I added weights (computer board and sensors) to the car, I replaced the original shock springs with much beefier
    ones (https://racecarj.com/products/spring-upgrade)
    2. I need the car to be very stable without any up-down movements, and also because I run it indoor on carpet, there is actually no need at all to have shocks, so I push the springs all the ways down to compress them as much as possible. This is good for my sensors to get reliable data, but unfortunately make my car very high. Please see the picture below.



    I do not need 2 above if I add a spacer inside the shocks, correct? And to make the car as low as possible, and as hard (stable) as possible, I need to insert a long spacer, correct?
    Last edited by gecong; 08-03-2019 at 04:02 PM.

  8. #8
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    Hi @StijnH, what kind of shock oil should I use when I do this?

  9. #9
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    Lower car body

    Quote Originally Posted by gecong View Post
    Hi @StijnH, what kind of shock oil should I use when I do this?
    You want pretty heavy weight shock oil because you are doing a strictly indoor smooth surface running. Should help with any extra movement.

  10. #10
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    I am thinking 75W

  11. #11
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  12. #12
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    I've no experience with this kind of setup.
    I guess I would start with 50W and see what effect it has on the handling (and grab a bottle of 75W).

    Succes with your project !

  13. #13
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    Quote Originally Posted by StijnH View Post
    I've no experience with this kind of setup.
    I guess I would start with 50W and see what effect it has on the handling (and grab a bottle of 75W).

    Succes with your project !
    Maybe it is easier just to replace to smaller wheels. Does anyone know small wheels for Slash 4x4? And is there any downside to use smaller wheels?

  14. #14
    RC Turnbuckle Jr. Squeegie's Avatar
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    Looking at the pictures of your shock set-up, if all you want to do is lower your overall chassis height, simply adjust your threaded upper spring retainer collars to the top of the shock bodies.
    Creativity is intelligence having fun. -Einstein

  15. #15
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    Quote Originally Posted by Squeegie View Post
    Looking at the pictures of your shock set-up, if all you want to do is lower your overall chassis height, simply adjust your threaded upper spring retainer collars to the top of the shock bodies.
    That will make the car too "soft", and the car will oscillate up and down when accelerating and braking, correct? That is not good for my sensor. I want my car always stay at the same height all time since I am running on flat carpet floor.

  16. #16
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    Lower car body

    Quote Originally Posted by gecong View Post
    Maybe it is easier just to replace to smaller wheels. Does anyone know small wheels for Slash 4x4? And is there any downside to use smaller wheels?
    Iím not sure of the names but one of my used slashís came with these 17mm HPI wheels. They have very large rims and very short and thin tires. I couldnít flip my Hcg with them. Maybe it was something else about the truck too but I feel like the tires were a big part of it.


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  17. #17
    RC Turnbuckle Jr. Squeegie's Avatar
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    You could always swap out your shocks with X0-1 shocks...
    Creativity is intelligence having fun. -Einstein

  18. #18
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    What is X0-1 shocks?

  19. #19
    RC Turnbuckle Jr. Squeegie's Avatar
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    Shocks from the Traxxas X0-1 car:

    https://traxxas.com/products/models/electric/xo-1-tsm

    Look up their shocks and springs:
    https://traxxas.com/products/models/...?t=accessories

    or you can get them complete from JennysRC, but they are out of stock right now.

    https://jennysrc.com/collections/tra...ant=8372811907

    They run out often, but also restock often as well. Just keep checking.

    Edit:
    Here is what mine looks like with X0-1 shocks and VG Racing springs for a Traxxas Revo:


    https://forums.traxxas.com/showthrea...Burning-Chrome

    https://www.vgracing.com/product/REVO_Spring.html

    There are many shorter/stiffer springs you can choose from for your Traxxas GTR shock bodies.
    Last edited by Squeegie; 08-05-2019 at 05:37 PM.
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  20. #20
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    You car is really nice.

  21. #21
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    If you don’t need/want any suspension travel and you want to go as low as possible, how about replacing the shocks and springs with simple turnbuckles, like the ones used for your steering linkage? You can make them any length you want and it’s a cheap solution. I made suspension linkage for my trail truck this way. I bought Traxxas rod ends and some threaded rod. Simple and dead reliable.

  22. #22
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    I agree with monkeyracing, if there is no suspension travel needed then use steering links or upper camber arms to replace the shock/spring with a solid link.
    This will eliminate most of the roll in corners and allow you to get the car very low.

  23. #23
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    DO you have link where I can buy solid link?

  24. #24
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    Quote Originally Posted by gecong View Post
    DO you have link where I can buy solid link?
    get a threaded rod and some end links

  25. #25
    RC Turnbuckle Jr. El Sob's Avatar
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    You could always try stretching your springs. It should keep them extremely stiff and since they will be longer it should set the truck down some. Or try cutting the spring. Lastly, pull the shock apart and set it to your desired height. Then glue the shock so it will no longer have any travel. If I still lived in the Bay, I would go watch your event.
    Member of the 10,000 + posts club! Here to help!

  26. #26
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    Quote Originally Posted by gecong View Post
    DO you have link where I can buy solid link?
    https://www.amazon.com/Traxxas-Blue-...NsaWNrPXRydWU=

    I would measure your current shock eye to eye when pushing down on the truck at the desired ride height and see if these will work. They have some amount of adjustment and might be in the ball park of where you need to be.

  27. #27
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    Thanks every one for your help. After the work according to @StijnH video, my car look like this:

    A video of it running autonomously https://twitter.com/i/status/1168659293001830400

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