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Old 11-28-2009, 06:36 PM   #1
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Default Suspension help

My 1/8 scale nitro buggy's rear end squats when on throttle, real noticeable on the straightaway. I'm using the stiffest available springs and 30 wt oil. I cranked down on the spring collar and it helped some but also made the rear ride height high. Also when pushing down the rear on the bench it doesn't rebound back up as high and does so slowly. What should I change?
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Old 11-28-2009, 07:13 PM   #2
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your buggy should squat when accelerating.

when you sit your buggy down before adjusting ride height always compress the suspension and let it raise itself. this height is your ride height. a buggy should not have its suspension fully out in it's natural/neutral position.

if you want your buggy to stop squatting and ride as high as possible add spacers to the shock shafts to do so. you can use fuel tubing to do this. please note the squatting comes from your car grabbing traction. you prevent it from squatting them i doubt your traction will stick around.
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Old 11-28-2009, 08:54 PM   #3
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Most people like the weight transfer you get when the rear end really squats under acceleration. But if it is so bad that your chassis is slapping when you land jumps and bumps, then you should go to a thicker shock oil to help prevent this.
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Old 11-29-2009, 05:55 AM   #4
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The way I understand it, going to a thicker shock oil would only be kinda useful on a smaller straight.

The purpose for the shock oil is to dampen, slow things down in a nutshell.
So moving to a thicker oil may work for small sections because it would take slightly longer to re-act.

Changing the springs would be the way to go.
This is weight transfer which is what the springs are for, to take that weight.
Upping the spring weight should help prevent some of the squat.

Upping both the springs and oil would be the way to go I reckon.
Although it would most likely change your handling.

Correct me if I am wrong.
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Old 11-29-2009, 07:58 AM   #5
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No, you are correct. I just noticed he is already running the stiffest springs available, and 30W oil. I dont know anything about the shocks he uses, but 30W is pretty light.
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Old 11-29-2009, 09:08 AM   #6
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It sounds like your suspension is binding. Take your wheels and shocks off the car, hold the buggy in the air with one hand and lift both arms up all the way with the other hand and then let them go. they should drop freely. if not then you need to find the bind.
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Old 11-29-2009, 11:23 AM   #7
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Everyone, thanks for the suggestions. I just pulled the wheels/shocks and it does not feel like its binding. I am going to try heavier oil next. The straight is about 110 ft. This is an O'Donnell Z01B, the original, not the newer team kit. I'll ask the guys at the track, but it is very noticeable compared to all the other buggies. thanks again.
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Old 11-29-2009, 11:30 AM   #8
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Default Heavier center diff weight lube

You might want to run a heavier center diff weight lube to keep the front from spinning out and causing the rear to squat. I went to 15,000 weight center diff lube on my 8ight. 1.o truggy and It doesnt squat near as bad and the front tires dont balloon when I nail it.
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Old 11-29-2009, 01:34 PM   #9
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this always helps me out with suspension adjustments and stuff ..hope it helps yall
Attached Files
File Type: pdf handling explained.pdf (35.9 KB, 113 views)
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Old 12-01-2009, 05:10 AM   #10
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Originally Posted by burnineyes View Post
No, you are correct. I just noticed he is already running the stiffest springs available, and 30W oil. I dont know anything about the shocks he uses, but 30W is pretty light.
Ah, my bad, I didn't see the part where he said he was already running the stiffest.

So yeah, I would have to agree with the heavier oil, I spose 30wt for 1/8th is pretty light.
Either that or there is a bucket of lead sitting on it.
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Old 12-01-2009, 08:06 AM   #11
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Quote:
Originally Posted by elkman View Post
You might want to run a heavier center diff weight lube to keep the front from spinning out and causing the rear to squat. I went to 15,000 weight center diff lube on my 8ight. 1.o truggy and It doesnt squat near as bad and the front tires dont balloon when I nail it.
I'd argue that the stiffer center lube will cause more rear squat as it won't let the front unload. Letting the front pull out of the corners will usually offer more on-power steering as well. One local fast guy here that runs the Odonnell buggy runs really light oil in all the diffs, something ridiculous like 3-4-1.5 f-m-r and his buggy is always dialed on a similar sized track.
Question for Triple7, is your buggy handling poorly or are you just bothered by the visual aspect of the squat? I'd be more concerned with changing the performance than making it not look funny.
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Old 12-01-2009, 04:29 PM   #12
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"Question for Triple7, is your buggy handling poorly or are you just bothered by the visual aspect of the squat? I'd be more concerned with changing the performance than making it not look funny."

I'm still kind of new and just learning how to drive and do set ups. It handles ok for my limited skills and I'm trying to learn what changes in set up do for handling. Compared to everyone else it just looks funny but I was hoping to see how the handling would change if it didn't squat as bad.

I'm running 5-5-2 diff which is the basic set up from the kit.
Thanks everyone for your input and for the link to the set up guide.
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Old 12-06-2009, 08:18 AM   #13
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Quote:
Originally Posted by RC Dad View Post
I'd argue that the stiffer center lube will cause more rear squat as it won't let the front unload. Letting the front pull out of the corners will usually offer more on-power steering as well. One local fast guy here that runs the Odonnell buggy runs really light oil in all the diffs, something ridiculous like 3-4-1.5 f-m-r and his buggy is always dialed on a similar sized track.
Question for Triple7, is your buggy handling poorly or are you just bothered by the visual aspect of the squat? I'd be more concerned with changing the performance than making it not look funny.
I did what I suggested to my 1/8th Losi 8ight-t 1.0 and it worked for me.
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