Losi XXX-S

Old 11-25-2004, 11:28 AM
  #12496  
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Actually, I think he's talking about the BK bones, the bearings on the axle pins.
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Old 11-28-2004, 05:20 PM
  #12497  
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Default Ackerman position

I'm slowly setting my car up for carpet. I still need tons of stick time, but I'm getting better.

I noticed on Boby Flack's set-up he used the forward Ackerman position and flipped the the bellcrank. What does "flipped" mean?. Did they swap from left to right or did they keep the bellcrank on the same side and just flipped them over?

Thanks
meche
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Old 11-28-2004, 06:00 PM
  #12498  
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Default Re: Ackerman position

Originally posted by meche
I'm slowly setting my car up for carpet. I still need tons of stick time, but I'm getting better.

I noticed on Boby Flack's set-up he used the forward Ackerman position and flipped the the bellcrank. What does "flipped" mean?. Did they swap from left to right or did they keep the bellcrank on the same side and just flipped them over?

Thanks
meche
Meche,

They stay on the same side.

If you swapped sides with the bellcranks, the turnbuckles would create bad geometry (wrong angle) to the steering knuckles.
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Old 11-28-2004, 08:46 PM
  #12499  
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In regards to building the shocks and the air bubbles. All shocks must have some air in them, if they are totally flled with oil, the shock wouldnt work at all. A liquid ( oil ) is not compressable, so with all oil and no air the shock would hydrolock. The amount of air in the shock will actually change how stiff or soft the shock is. In the case of RC cars its not a huge change, in motorcycle shocks its a HUGE difference. I usually try to run all my shocks with about the same amount of natural " rebound", which gives me an idea of how much air is in the shock. With no spring on the shock compress it and see how far up the shaft rebounds on its own. If your 2 fronts are equal and 2 rears are equal in distance, then your good to go. If one doesnt rebound and one does, then the one that doesnt rebound has too much air in it. If one rebounds more then the other, it has too much oil. If you cant compress it, or you try to and it pops the cartridge off.. well then you know you have too much oil and 0 air. My rule of thumb is to get the shock to rebound rouchly 1/8th of an inch. I ahve found that works quite well.
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Old 11-28-2004, 08:57 PM
  #12500  
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CoryCraig- Holy sheoot. Where have you been for the last couple years. Shoot me a PM, let me know if your racing.
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Old 11-28-2004, 10:54 PM
  #12501  
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Originally posted by CoryCraig
In regards to building the shocks and the air bubbles. All shocks must have some air in them, if they are totally flled with oil, the shock wouldnt work at all. A liquid ( oil ) is not compressable, so with all oil and no air the shock would hydrolock. The amount of air in the shock will actually change how stiff or soft the shock is. In the case of RC cars its not a huge change, in motorcycle shocks its a HUGE difference. I usually try to run all my shocks with about the same amount of natural " rebound", which gives me an idea of how much air is in the shock. With no spring on the shock compress it and see how far up the shaft rebounds on its own. If your 2 fronts are equal and 2 rears are equal in distance, then your good to go. If one doesnt rebound and one does, then the one that doesnt rebound has too much air in it. If one rebounds more then the other, it has too much oil. If you cant compress it, or you try to and it pops the cartridge off.. well then you know you have too much oil and 0 air. My rule of thumb is to get the shock to rebound rouchly 1/8th of an inch. I ahve found that works quite well.
Ummmmmm...The shock oil doesn't have to compress...It passes through the sized holes in the piston.
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Old 11-28-2004, 11:11 PM
  #12502  
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Originally posted by JRX-S Bill
Ummmmmm...The shock oil doesn't have to compress...It passes through the sized holes in the piston.
Well, the shock oil does need a place to go so the shock does need air to rebound.
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Old 11-29-2004, 06:30 AM
  #12503  
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Originally posted by primusblowsgoat
alright, i need help with a few things

1. what size are the standard droop screws, i thought it would be.050 but that didnt fit or maybe i dont have an .050...

I wouldn't spend money or time with the droop screws on the XXXS G+. They are mounted on the bumper, which is made of a softer material than the chassis, which flexes when there is pressure on them. This leads to erroneous droop settings. It is much better and more consistent controlling droop by shock length. Just adjust the ball end on the shock shaft to get the droop setting you want.
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Old 11-29-2004, 06:36 AM
  #12504  
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Originally posted by CoryCraig
In regards to building the shocks and the air bubbles. All shocks must have some air in them, if they are totally flled with oil, the shock wouldnt work at all...
It is still better to let the oil settle for several minutes to get rid of the bubbles in the shocks as this can lead to inconsistent dampening from shock to shock. The reason is, you can't control the amount of bubbles from one shock to another. Plus, air bubbles do change the way a shock performs. The pros do this, so I guess it must work.

Sure, at the amateur level, we may not have the keen sense of feel that team drivers have, but more consistent we can get our cars to perform, the better chances we have at getting good results.

Rebound and compression in Losi shocks the same since it uses pistons with holes and no other way of changing setting independently, unlike performance shocks on a motorcycle.
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Old 11-29-2004, 06:53 AM
  #12505  
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i understand that the oil passes through the holes in the piston, but oil is arther thick, and it will try to displace when the piston is moved through it and it does need air to allow it to displace. A hole can only flow so much fluid through it at a given time. When a shock moves at a decent speed the hole cant handle the volume of oil needed to move through it at such a fast rate. The oil then begins to "pack" around the hole, kind of waiting its turn to pass through the hole. If you have ever heard the pros talk about pack, thats what they are talking about. Without air in the shock, the oil will pack as the piston tries to move instead of displacing and compressing the air in the shock allowing for more time to allow the oil to unpack and pass through the hole. Not to mention the fact that the piston and the shock shaft have volume themselves, so as the piston is pushed into the oil, the shock shaft begins to displace more of the oil as well ( its like sitting in a bath tub, the water level rises ). If you dont ahve enough air... it cant displace the oil and the shock hydrolocks.
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Old 11-29-2004, 07:06 AM
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Originally posted by CoryCraig
i understand that the oil passes through the holes in the piston, but oil is arther thick, and it will try to displace when the piston is moved through it and it does need air to allow it to displace. A hole can only flow so much fluid through it at a given time. When a shock moves at a decent speed the hole cant handle the volume of oil needed to move through it at such a fast rate. The oil then begins to "pack" around the hole, kind of waiting its turn to pass through the hole. If you have ever heard the pros talk about pack, thats what they are talking about. Without air in the shock, the oil will pack as the piston tries to move instead of displacing and compressing the air in the shock allowing for more time to allow the oil to unpack and pass through the hole. Not to mention the fact that the piston and the shock shaft have volume themselves, so as the piston is pushed into the oil, the shock shaft begins to displace more of the oil as well ( its like sitting in a bath tub, the water level rises ). If you dont ahve enough air... it cant displace the oil and the shock hydrolocks.
Good explanation...I see your point...Back to hmmmmmmmm...
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Old 11-29-2004, 07:17 AM
  #12507  
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Originally posted by CoryCraig
i understand that the oil passes through the holes in the piston, but oil is arther thick, and it will try to displace when the piston is moved through it and it does need air to allow it to displace...
Very true. There is a certain amount of air within a shock which comes from first closing the shock. Plus, there the little bit that comes from leakage from o-ring seal. This is why the shocks need to be rebuilt from time to time.

But, the point of letting the shocks sit for air bubbles to dissipate is to get more consistency when building the shocks. It goes back to the fact that you can't control the amount of ar bubbles from shock to shock.

Don't get me wrong... I do see your point.
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Old 11-29-2004, 10:09 AM
  #12508  
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well, im not rrefering to air bubbles, all RC shocks will ahve air bubbles. Even if you let them sit for a while after a race of use they will get air bubbles again. The oil is constantly being pushed about and its just a matter of time before the oil gets bubbles. Especialyl if you ahve too much air in the shock, then at full compression the top of the piston moves farther then the oil level in the shock and pulls the air into the oil as it rebounds, causing air bubbles. Now considering hte oil is constantly moving from G force, bumps, and wrecks, the shock no matter how perfectly built it is will get air bubbles in the oil. Piggy back shocks help alleviate this but thier cost/ weight to perfermance advantage is sub par in my opinion. What i am gettign at is determing how much air oyu ahve in the shock to begin with. The natural rebound of the shock shaft without a spring indicats how much you are compressing the air in the shock. No rebound means you arnt compressing the air at all or not enough to over come the weight of the shock shaft. If it rebounds fully then you are really compressing the air alot and it rebounds too far. Personally to me air bubbles arnt that big of an issue cause after 2 laps the shocks will have air bubbles anyway, i concentrate more on the amount of air in the shock to begin with.
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Old 11-29-2004, 10:58 AM
  #12509  
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Default Heatsink

Does anyone know if there is a motor heatsink that is made especially for the xxx-s g+?? If so, what is the part number? If nnot, what are other people using for heatsinks for their motors.
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Old 11-29-2004, 02:45 PM
  #12510  
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Ryan, i dont know of any heat sinks other then the ones you can put on the endbells, but they dont help a whole lot. There are some that are put around the motor, that arnt designed for the xx-s specifically, but do work. I dont know the part number, cause the one i have is old, it just happend to fit. I dont even use it that often. ALways better to get the motor nice and cold before the run anyway, at the end of the run its barely even warm.
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