Losi 8ight building and setup
11-20-2006, 07:58 AM
#811
My Blue Bird servos held up well at the farm all weekend, my first race with the 8ight. I did strip the nylon steering servo arm insert in the main though.
Last edited by ldawg; 11-20-2006 at 08:46 AM.
11-20-2006, 02:58 PM
#812
Originally Posted by Walt
My theory is that this is making the throttle servo itself a 'stressed member' of the chassis. The servo gets 'compressed' as the chassis tries to bend down in the middle, and 'stretched' as the chassis bends the other way.
Originally Posted by o.s. power
With the throttle servo, the radio tray not wrapping around does contribute to the problem, all of you that read this, try flexing your chassis and watch the servo, it moves with the radio tray instead of being isolated.
I think you guys may have found it. I tried flexing the car with the throttle servo out and the servo mount flexed like crazy. The side to side flex was significant. That would stress the case enough to cause gear binding and motor failure. Hmm. Now how do you fix that?
11-20-2006, 03:12 PM
#813
Has anyone tried the aluminum braces yet?
How much does it really change the handling?
How much does it really change the handling?
11-20-2006, 04:24 PM
#814
i really dont think that is the problem, i really dont think a servo case will flex.
its gotta be the way things are set up cause i havent had a servo go bad and i have used 2 different ones. was useing a hitec 5645 mg and upgraded to a kopropo high speed servo to get a little quicker throtal responce. both worked fine the hole time they were in the car.
its gotta be the way things are set up cause i havent had a servo go bad and i have used 2 different ones. was useing a hitec 5645 mg and upgraded to a kopropo high speed servo to get a little quicker throtal responce. both worked fine the hole time they were in the car.
11-20-2006, 08:34 PM
#815
Tech Master
iTrader: (14)
what type of track do you run on?
I think the only way to fix this problem is to make the area around the throttle servo fully closed and make the tray out of a stiffer material. The aluminum braces would change the handling too much, and may not fix the problem. To me the flexing problem is coming from the front of the car, the way the brace and top plate mount to each other, but maybe I am wrong.
I think the only way to fix this problem is to make the area around the throttle servo fully closed and make the tray out of a stiffer material. The aluminum braces would change the handling too much, and may not fix the problem. To me the flexing problem is coming from the front of the car, the way the brace and top plate mount to each other, but maybe I am wrong.
11-21-2006, 02:55 AM
#816
Tech Rookie
I'VE BEEN RUNNING TWO LOSI 8IGHT'S AND BEEN VERY HAPPY. I WON THE VERY FIRST RACE OUT WITH THE CAR. I HAVNT HAD ANY PROBLEMS WITH MY SERVOS. I USE HITEC AND KO PROPO. I THINK YOU GUYS ARE NOT SETTING YOUR LINKAGES UP CORRECTLY. BEST CAR OUT THERE, I WENT ABOUT 2 SECONDS A LAP FASTER THEN MY OLD MBX5. CANT WAIT FOR TRUGGY.
11-21-2006, 05:26 AM
#817
Tech Addict
iTrader: (2)
from the looks of the servo tray, it shouldn't be too hard to make up a new upper deck that moves the servo away from the centerline of the car to allow for the tray to go along both sides of the servo...might move it 6mm or something like that from what i can see in pictures although i don't have a car in my hands to look at 
11-21-2006, 07:23 AM
#818
I'm sure that some aftermarket guys are reading this right now, realizing they can make some money, and are developing a tray as we speak.
However, part of what makes the car stick so well in the rough, is the flexability. Making it very rigid will likely rob it of traction. I don't think the flexing is the issue that's killing servos. Mine is down right now while I patiently wait for clutch parts. Once I can get it back together, I'll have plenty of opportunity to further test the throttle servo that's in it now. So far, it's been fine. If you read back through, you'll see step by step what I did, and how long this one has lived...so far...
However, part of what makes the car stick so well in the rough, is the flexability. Making it very rigid will likely rob it of traction. I don't think the flexing is the issue that's killing servos. Mine is down right now while I patiently wait for clutch parts. Once I can get it back together, I'll have plenty of opportunity to further test the throttle servo that's in it now. So far, it's been fine. If you read back through, you'll see step by step what I did, and how long this one has lived...so far...
11-21-2006, 07:39 AM
#819
Well I built my car a few weeks ago and ran it last Thursday for the first time. One thing that I did was trim the throttle ball cup so the spring had no coil bind.
As for the aluminum braces, they are not out yet. I know Adam prefers to run the plastic braces.
As for the aluminum braces, they are not out yet. I know Adam prefers to run the plastic braces.
11-21-2006, 08:05 AM
#820
if you are running your carb slightly cocked to the side this is what is burnning servos. mine went to the side a tad this weekend at a race and it started binding up. i noticed it right away and pulled off the track and fixed it. so if you have your carb cocked to the side fix it to where its not. and your servo problem should go away.
11-21-2006, 08:21 AM
#821
Compared to my old Mugen the 8ight chassis is noticeably stiffer. I don't think flex is the problem. Just my opinion..
11-21-2006, 10:06 AM
#823
Tech Master
iTrader: (14)
Originally Posted by Davidka
Compared to my old Mugen the 8ight chassis is noticeably stiffer. I don't think flex is the problem. Just my opinion..
grab your car by the shock towers and twist away watching the tray by the throttle servo, you will see what I mean. I know the car/chassis is suppposed to flex, but the servo should be isolated from the twisting that the tray goes through, the way it is now, the servo is a stressed member of the tray, and should not be unless the case is titanium or something.
11-21-2006, 10:27 AM
#824
To get a 40/60(for example) f-r brake bias -and have ENOUGH brakes- you basically have to rip the tray out. 
This is due to the smaller surface area of the rear rotor and calipers. With the longer return spring and ball cup all add up in stressing the servo.
I'm using the losi tubing on the rear brake, and a piece of Venom tubing on the front brake. The Venom tubing has a larger inside diameter and will compress easier - this will take some of the load off the servo, and help achieve more rear brake bias.
Otherwise, make sure your brake setup isn't moving the tray, and you're using grommets on the servo ears. Obviously the servo should be secured with the proper amount of torque so the grommets can do their job.
Just my $.02
This is due to the smaller surface area of the rear rotor and calipers. With the longer return spring and ball cup all add up in stressing the servo.I'm using the losi tubing on the rear brake, and a piece of Venom tubing on the front brake. The Venom tubing has a larger inside diameter and will compress easier - this will take some of the load off the servo, and help achieve more rear brake bias.
Otherwise, make sure your brake setup isn't moving the tray, and you're using grommets on the servo ears. Obviously the servo should be secured with the proper amount of torque so the grommets can do their job.
Just my $.02
11-21-2006, 09:22 PM
#825
over all shock length ?
can someone clue me in? on setup sheets most are 95mm front and 106mm rear. what points are they measuring from? with the shock off the front fully extended it measures about 75mm. and the rear is nowhere near 106 fully extended. any help would be appreciated