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Quick question on shock pistion / shock oil

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Quick question on shock pistion / shock oil

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Old 01-06-2019, 08:58 PM
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Default Quick question on shock pistion / shock oil

Quick question. If i'm using 1.1 & 4 hole piston with 35wt oil, what shock oil should I use if switching to 1.2 & 4 hole piston to get the same effect?
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Old 01-06-2019, 09:01 PM
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It's going to be thickher shock oil...that much I know. The question is how much thicker.
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Old 01-06-2019, 11:32 PM
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If you want the same effect then why bother changing at all?
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Old 01-07-2019, 01:01 AM
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There's good reasons for this.... But you should know why you're doing it.

So... you can get the same low speed damping by going to a heavier fluid. But high speed will happen at a different piston velocity. So it's not gonna be the same.

The math is something you can look up in machinarys handbook.
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Old 01-07-2019, 03:40 AM
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If you have RC crew chief it's easy to simulate different pistons and oils until they give the same damping ratio for a given spring, it also shows the change in damping at different velocities.
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Old 01-07-2019, 04:12 AM
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Originally Posted by LzREngineering View Post
If you have RC crew chief it's easy to simulate different pistons and oils until they give the same damping ratio for a given spring, it also shows the change in damping at different velocities.
computer program will never simulate track conditions
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Old 01-07-2019, 06:17 AM
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Originally Posted by Marcos.J View Post

computer program will never simulate track conditions
?
Simulating track conditions is entirely different to calculating damping, which is what we're talking about here.
And it is actually possible (not easy) to simulate track conditions fairly accurately if you have enough data.
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Old 01-07-2019, 06:28 AM
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In my earlier post, I should have said ‘similar’ effect not ‘same’ effect. I’m aware of what I’m doing. The main reason for doing this is that I purchased some machined piston for my Xray T4. Unfortunately, they don’t have it 1.1 & 4 holes only 1.2 & 4 holes. I’m pretty happy with my current shock package so I’m trying to achieve similar effect with 1.2 & 4 holes and going heavier on the shock oil.

I’m sure this can be mathematically calculated, but I’m too dumb for this fancy math and I don't have a machinest handbook ; ).

I’m just looking for a quick ball park answer.
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Old 01-07-2019, 06:57 AM
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Originally Posted by LzREngineering View Post
?
Simulating track conditions is entirely different to calculating damping, which is what we're talking about here.
And it is actually possible (not easy) to simulate track conditions fairly accurately if you have enough data.
5minutes practice session , go to pits make change , boom done
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Old 01-07-2019, 07:24 AM
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oh yea, i don't have RC Crew Chief. Looks pretty interesting though.
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Old 01-07-2019, 07:29 AM
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Assuming your 35wt oil is 425CST then 750CST gets you close at high and low speeds.


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Old 01-07-2019, 07:52 AM
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Thank you!
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