Why drill piston

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Old 10-17-2005, 08:32 AM
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Default Why drill piston

What is the point of drilling x-ray,yoke,hpi etc out to 1mm holes over the std holes
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Old 10-17-2005, 09:15 AM
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it affects the "pack" of the shock or how fast the shock reacts to bumps.

I believe it done because if your car gose over a bump with a smaller piston the shock sort of locks up as the oil can't pass through the hole fast enough, Different size holes in the piston affect the point at which this "lock up" occurs.

Not sure how well i explained the colin but i know what i mean
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Old 10-17-2005, 12:24 PM
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the reason for the bigger holes is that the flow rate is increased, thus making changing the oil weight a more accurate way of ajusting damping and keeping oil temp and damping more stable
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Old 10-17-2005, 01:05 PM
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nope

Q) why do the x-ray boy`s redrill there pistons out to 1mm holes
why not open up to 4 hole or 3 hole assuming the drivers are at 2 hole ones being used

ie;stuart rand drill he`s out to 1mm hole
why not replace them with 3 hole piston that yokomo have on there shock parts tree or the no2 piston

nathan is drilling out the HPI piston`s to 1mm diameter (tryied to on sunday)


nathen didn`t do it to the losi ones coz they are 1mm holes allready
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Old 10-17-2005, 01:33 PM
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Its so you know excatlly what size of piston you are running.
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Old 10-17-2005, 01:43 PM
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Drilling Pistons is something we used to do offroad. It does a number of things. One is you only have to buy one size piston. Ex: we always used losi 60's and drilled out what ever size you needed. Another reason is you know exactally what size the hole is. You are not counting on a mold to get it right. Third, you can make "in between" pistons. We used to run 55-6 you drill 2 holes at 55 and one at 56. I don't think that the average race can honestly tell the difference. I would drill pistons when I had to but for the most part I ran regular ones.
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Old 10-17-2005, 01:44 PM
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Originally Posted by drew85
Its so you know excatlly what size of piston you are running.
is that it

i thought it was some thing like
car builders make the piston holes to small for it to work properly
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Old 10-17-2005, 01:47 PM
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Originally Posted by Bob Barry
Drilling Pistons is something we used to do offroad. It does a number of things. One is you only have to buy one size piston. Ex: we always used losi 60's and drilled out what ever size you needed. Another reason is you know exactally what size the hole is. You are not counting on a mold to get it right. Third, you can make "in between" pistons. We used to run 55-6 you drill 2 holes at 55 and one at 56. I don't think that the average race can honestly tell the difference. I would drill pistons when I had to but for the most part I ran regular ones.

now we are getting some where
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Old 10-17-2005, 02:42 PM
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Colin , i read an indeapth artical about just this, but it was along time ago and i assure you it was stated that it was done for the reasons i stated. But as for trying to prove that now i just haven't got the knowledge to let ya.

But i CAN tell you a shock made up with a small piston hole and a thinner oil reacts differently to a shock with a larger piston hole and thicker oil even if they feel similar "in hand".

it's to do with fluid dynamic's or something
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Old 10-17-2005, 07:53 PM
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Well...... I guess we could try this link. I think Section 1.4 about Laminar VS. Turbulent Flow is what you want. Yet, this might be a bigger can of worms than we needed.

http://en.wikipedia.org/wiki/Fluid_dynamics

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Old 10-17-2005, 08:05 PM
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I was told by an off-road guy that the difference between a (for example) std #56 Losi piston and a drilled #56 Losi piston is that the drilled one will have slightly smaller holes. Since the drilled piston is exactly a #56 and the std ones the drill falls right through the hole.
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Old 10-18-2005, 12:07 AM
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Originally Posted by Merciless
Colin , i read an indeapth artical about just this, but it was along time ago and i assure you it was stated that it was done for the reasons i stated. But as for trying to prove that now i just haven't got the knowledge to let ya.

But i CAN tell you a shock made up with a small piston hole and a thinner oil reacts differently to a shock with a larger piston hole and thicker oil even if they feel similar "in hand".

it's to do with fluid dynamic's or something
i`m listening ,i`m listening

taking it all in & decifering it all
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Old 10-18-2005, 01:54 AM
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not sure am i on topic here. but check this thread

http://www.rctech.net/forum/showthre...=72516#newpost

perhaps there maybe something which explains the holes and thick/thin oil business.
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Old 10-18-2005, 03:56 AM
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Originally Posted by rcnewb2004
not sure am i on topic here. but check this thread

http://www.rctech.net/forum/showthre...=72516#newpost

perhaps there maybe something which explains the holes and thick/thin oil business.
There we go some people that actually know what there talking about !!
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Old 10-18-2005, 05:23 AM
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Hi Colin

I think the site that 'Merciless' was talking about can now be found at:
http://home.tiscali.be/be067749/58/
Chapter 2 has a good analysis of shocks.
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