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Old 09-09-2005, 06:22 PM   #1
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Default 1/8 Buggy center diff ???

I'd like some opinions on how a buggy handles with a spooled center diff?

1/10 buggies have never had center diffs to distribute power and it works fine. I know they often use a one-way type device to aid in off power handling. Also the front diff sometimes is over-driven to create more front wheel speed.

But on-power is 100% to four wheels, so I'm wondering why doesn't it work well for 1/8? Is it only off-power or turn-in that is improved with the center diff?
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Old 09-09-2005, 08:52 PM   #2
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The center diff greatly improves how the car accelerates through rough sections of the track. At the Worlds in Sweden, many of the racers (especially the Europeans) ran very thick center diff oil, especially when the track was smooth.
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Old 09-10-2005, 02:04 AM   #3
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what aaron said and the fact that 1/10 electric buggies have a lot more steering than 1/8 buggies.

to add what aaron said, the center diff in a way determines how car will accelerate, meaning how hard the power will hit.
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Old 09-11-2005, 06:42 PM   #4
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The center dif does a number of things, the most important thing it keeps the car from doing wheelies or lifting the front tires and loosing steering. How many mts have you seen with broken drive line parts and Twisted dog bones. It also lets you over gear the front dif with minimum binding or buck in the drive line.
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Old 09-11-2005, 08:22 PM   #5
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One of the major things it also allows you to do is adjust the front to rear brake bias, those pretty dual rotors wouldn't do squat without a centre diff.
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Old 09-11-2005, 10:45 PM   #6
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Here are some more thoughts.

Center diff fluid:
Say you accelerate, weight transfers towards the rear (your buggy
squats - how much depending on several factors such as rear antisquat
plate, how hard you are on the gas, etc), a center diff with very light
oil will "diff" more towards the front to try to balance the load and
stabilize the buggy. This is great on a slick or maybe a tight track
where you want to feel the front diff pulling your car a little more
and keep you from "spinning out."

Now, say you put in very thick center diff oil in your center diff.
You accelerate, weight transfers towards the rear, a center diff with
very thick oil will "diff" less towards the front but will give you the
most torque at the rear of the buggy, ie more acceleration. This is
great for high bite tracks but on a slick track you may find your rear
end swinging around more.

BUT, straight line acceleration is but one aspect of a center diffs
purpose. Say you are on a track and you approach a woop section. a
car with very light fluid will transfer more torque to the front of the
buggy as soon as the front tires begin to loose contact with the apex
of the woop, hence your rear end feels less power and consequently the
front of your buggy's nose comes down nice and fast ready for the next
woop. your center diff is constantly "diffing" to keep the car
balanced through the woops. Now, if you had very thick oil in the
center, the nose of the buggy would come down a little slower because
it will not diff towards the front so fast. This can cause your buggy
to get out of shape easily because your front tires are not in contact
(think steering) as much with the ground.

Also, center diff oil can even depend on what engine you are running.
if you have an stupid fast engine, and you go too light on the center oil, you will
find your front tires ballooning to the point of almost flying off the
wheels down the straight away, so you may increase the center oil
weight a bit.
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Old 09-12-2005, 11:19 AM   #7
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Thanks guys. Let me explain why I asked about the diff:

I have a 777 I converted to electric brushless, and I was looking at some options for the drivetrain that would be possible only if I eliminated the center diff. But I won't do that if the buggy will handle really bad.

I didn't know if anyone has actually run (racing) the center diff locked. And if the handling issues can be overcome or if it's impossible to compete on the track. It doesn't sound good at this point... thanks.

When I get my car back running I might try locking the diff just so I can see it first hand.
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Old 09-12-2005, 07:12 PM   #8
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very well said speed bump!! back to the guy that needs a opion , I had a hpi mt that is 4wd no center dif, I had it set up fairly well and it didn't snap dog bones after I put a slipper clutch in. The clutch couldn't handle a lot of slip just enough to slip to protect the drive line. The difs were not sealed so I put grease in front and lite oil in the rear for lube only(free as you can get)this fixed rear from sliding out. The truck did ok it was way faster than a 2wd 10th truck
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Old 09-12-2005, 08:00 PM   #9
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Quote:
Originally Posted by SpeedBump57
BUT, straight line acceleration is but one aspect of a center diffs
purpose. Say you are on a track and you approach a woop section. a
car with very light fluid will transfer more torque to the front of the
buggy as soon as the front tires begin to loose contact with the apex
of the woop, hence your rear end feels less power and consequently the
front of your buggy's nose comes down nice and fast ready for the next
woop. your center diff is constantly "diffing" to keep the car
balanced through the woops. Now, if you had very thick oil in the
center, the nose of the buggy would come down a little slower because
it will not diff towards the front so fast. This can cause your buggy
to get out of shape easily because your front tires are not in contact
(think steering) as much with the ground.
Hi SpeedBump57,
Your explanation is very good.
Anyway, is "WOOP" a description for multiple ramps?
With lightly oiled centre diff, you described that the nose will dive easier. If the car takes off for a jump from a high ramp and its nosedive cannot be corrected at most times, does it mean if the centre diff is heavily oiled, it will help correct the nosedive problem?
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