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Old 12-04-2008, 08:17 PM   #1
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Default shock pistons

im changing the shock set up on my rc8t and i only have the 1.3mmx6 pistons. im needing 1.4x6 well im wondering if i drilled the pistons to have 3 1.3 holes and 3 1.5 holes.. thats both 8.4mm of suface drilled out.. does this work or am i effed up?? lol
and i was thinking 3 2.36 holes to get close to the 1.2x6s..
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Old 12-04-2008, 09:13 PM   #2
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I would try using 5 or 10 wt less oil. If you drill the pistons out weird like that and don't like it, you are stuck with them that way. If you drop 5 wt oil and it isn't what you are looking for, then you can drop another 5 and see what it does. Or you could use a losi 1/2 weight.

Or do you not have any different oil either? I'm not an engineer so I couldn't tell ya if what you propose would get the same damping as the
6 x 1.4's.
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Old 12-04-2008, 09:26 PM   #3
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yeah i understand all that. i just basically want to know if 3 large holes works the same as 6 small ones
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Old 12-05-2008, 01:01 AM   #4
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Here's the forumula for the area of a circle:

π(radius)2 (pie time the radius squared)

If you use 3 1.3s and 3 1.5s:

so 3.14x(1.3/2)2 = 1.32665 sq mm X 3 = 3.97995 sq mm

3.14x(1.5/2)2 = 1.76625 sq mm x 3 = 5.29875 sq mm

3.97995 + 5.29875 = a total of 9.2787 sq mm

if you use a pistion with 6 1.4mm holes:

3.14x(1.4/2)2 x6 = 9.2316 sq mm

So yeah, it's the same...

Let's hear it for 6 years of college!
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Old 12-05-2008, 01:29 AM   #5
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I'm not so convinced about that.
Of course you are right about the area that is drilled from the piston, but a smaller hole will create more turbulences when pushed trough the oil than a larger hole. Therefore i would assume, a piston with 3 large holes will create less pack than a piston with 6 smaller holes in it. Even if the drilled area is about the same. The faster the shock moves the more you will feel a difference between the two.
Well that's at least my 2ct...
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Old 12-05-2008, 03:03 AM   #6
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Dammit. You're right... Lemme go find my Fluid Dynamics book... better find my book on Differential Equations too while I'm at it...
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Old 12-05-2008, 07:10 AM   #7
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its not the same. i tried it . im pretty sure 3 1.96 holes compare to 6 1.2 . i think that should be close. but im not 100% sure. but the 3 large holes didnt even feel like it had any fluid in the shock at all. it was bouncy. so i just put the 6 1.3 in it and its much better.
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Old 12-05-2008, 07:16 AM   #8
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My rc8t was always kicking up the rear end. So I went to 40wt in the rear and 45 with some Jammin 1.4 pistons and built them with rebound in the front. This made the truck much smoother in the rough areas and helped the truck jump better.


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