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Old 03-29-2010, 10:43 PM   #1801
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underground does have a few bumps that threw my car off every time.
make sure its not bottoming out and causing the inconsistency.. try raising the car 0.2-0.5mm and see if it changes. A couple weeks ago I ran on a track that was so bumpy the car got better as I raised the car and lightened the shock oil.. (started with 5.0mm/ 5.2mm and I think by the end i was at 5.3/5.5 and had 550/350 start, and ended with 500/300)

good luck, spring term starts today. so if you guys have questions pm for my email address since I probably won't be on much for the next 2 months between school and racing.
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Old 03-30-2010, 07:25 AM   #1802
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at this place i actually almost went up to 6.2 mm
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Old 03-30-2010, 09:14 AM   #1803
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Does anyone know of any steering bushings (xray part 302291) that will work in the c hubs besides the xray brand? I don't consider myself cheap but paying $17 for four little bushings just doesn't set well with me when other companies sell them for $3 or $4 a package.
Anybody?
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Old 03-30-2010, 09:16 AM   #1804
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Anybody?
Unfortunately there aren't any alternatives.
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Old 03-30-2010, 10:42 AM   #1805
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Anybody?
I haven't found anything yet, Assoc, Tamiya and Losi aren't exact replacements, all are either too tall, too sloppy, or too small.
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Old 03-30-2010, 10:44 AM   #1806
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make sure its not bottoming out and causing the inconsistency.. try raising the car 0.2-0.5mm and see if it changes. A couple weeks ago I ran on a track that was so bumpy the car got better as I raised the car and lightened the shock oil.. (started with 5.0mm/ 5.2mm and I think by the end i was at 5.3/5.5 and had 550/350 start, and ended with 500/300)

good luck, spring term starts today. so if you guys have questions pm for my email address since I probably won't be on much for the next 2 months between school and racing.
I was going to suggest that as well. If you think you need the softness of the car to make it work in the corners but it has that skip/feel, increase the ride height.
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Old 03-30-2010, 10:59 AM   #1807
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Gary, you gotta hack up a pulley to do this though right?? Korgae mentioned it at the last WCICS. What other mods are required, do you have to run 50mm shafts?

Yes the stock pulley has to be opened up for the center section clearence. I also made it so I could shift the outer gear over to get better alignment with the idle pulleys, no belt rub. You have to use the 50mm shafts, you also have to shim the new diff as its just a bit narrower that a stock one, I have it biased to the left, again for belt alignment. When this is done with the 50mm shafts you may have a very slight bind, put its only with the shocks off and the left suspension all the way up, (top of tire close to top of shock tower), no where near where your suspension travel will ever get to. Some are trying to only run one idle gear per shaft, guess that could work, I haven't tried it myself. I think if your into a higher power class and do a lot of diff rebuilds this is a worthwhile mod. I ran it in stock and don't think it was a performance penalty.
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Old 03-30-2010, 08:36 PM   #1808
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I have created a model for the xray silicone oil. Cst, centistokes, is a measurement of kinematic viscosity - or the ratio between what we think of as viscosity and the fluid density. For the silicone oil we use in our shocks, fluid density is relatively constant (0.966 - 0.975).

There are two reasons why I even bothered. First, xray uses centistokes while the rest of RC uses what we call "weight". I really don't think "weight" is even the correct term, but it doesn't matter - its industry standard and we have some understanding of what the numbers mean in practice. Second, I wanted everyone to be more aware of what claims they are making regarding setup. I won't go so far as to call anyone crazy, but according to the model, the difference between 500 Cst and 550 Cst is 1 "weight". 1. one. single. uno. loneliest number.

Anyway, here are the numbers. Stuff in bold is given by xray in their setup books. If anyone disagrees, I'm not offended - so feel free. Also, I don't really feel like going through the arithmatic, but i plotted 1/Cst versus ln(WT). Then created the model function (R=0.999), and back calculated all values. Model predicted values are indicated in non-bold.

Cst WT
100 20
150 23
200 25
250 27
300 28
350 30
400 31
450 32
500 33
550 34
600 35
700 36
800 38
900 39
1000 40
2000 50
10000 80
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Old 03-31-2010, 06:52 AM   #1809
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Originally Posted by ballsagna View Post
I have created a model for the xray silicone oil. Cst, centistokes, is a measurement of kinematic viscosity - or the ratio between what we think of as viscosity and the fluid density. For the silicone oil we use in our shocks, fluid density is relatively constant (0.966 - 0.975).

There are two reasons why I even bothered. First, xray uses centistokes while the rest of RC uses what we call "weight". I really don't think "weight" is even the correct term, but it doesn't matter - its industry standard and we have some understanding of what the numbers mean in practice. Second, I wanted everyone to be more aware of what claims they are making regarding setup. I won't go so far as to call anyone crazy, but according to the model, the difference between 500 Cst and 550 Cst is 1 "weight". 1. one. single. uno. loneliest number.

Anyway, here are the numbers. Stuff in bold is given by xray in their setup books. If anyone disagrees, I'm not offended - so feel free. Also, I don't really feel like going through the arithmatic, but i plotted 1/Cst versus ln(WT). Then created the model function (R=0.999), and back calculated all values. Model predicted values are indicated in non-bold.

Cst WT
100 20
150 23
200 25
250 27
300 28
350 30
400 31
450 32
500 33
550 34
600 35
700 36
800 38
900 39
1000 40
2000 50
10000 80
Because 'Wt' is not a standard and cSt is (or supposed to be) maths will be useless.

The numbers you have as 'weight' are too low as the cst gets higher.
The problem is weight is a BS term that has no standard where cSt is.
Weight actually ramps up as the numbers get higher compared with cSt.

300 should be around 25wt where 600 is around 40-45wt

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Old 03-31-2010, 10:53 AM   #1810
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Yes the stock pulley has to be opened up for the center section clearence. I also made it so I could shift the outer gear over to get better alignment with the idle pulleys, no belt rub. You have to use the 50mm shafts, you also have to shim the new diff as its just a bit narrower that a stock one, I have it biased to the left, again for belt alignment. When this is done with the 50mm shafts you may have a very slight bind, put its only with the shocks off and the left suspension all the way up, (top of tire close to top of shock tower), no where near where your suspension travel will ever get to. Some are trying to only run one idle gear per shaft, guess that could work, I haven't tried it myself. I think if your into a higher power class and do a lot of diff rebuilds this is a worthwhile mod. I ran it in stock and don't think it was a performance penalty.
We still need to weigh it as well...

@ Jim, I will be sending yours out shortly, I met with Gary and talked about a parts list for a complete conversion. 50MM bones, 3.0 blades, 2.5mm screws and I am a shim kit.

Let me know if you have the 50mm bones and I will send the rest out...

After seeing Gary's in action I am looking forward to trying it... Also made me think about the posibility's of what you and I talked abount with the front slipper we can chat later.
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Old 03-31-2010, 11:43 AM   #1811
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Hello

Can anyone suggest a setup for low-med grip technical track full of U-turns?

Thanks.
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Old 03-31-2010, 02:51 PM   #1812
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Hello

Can anyone suggest a setup for low-med grip technical track full of U-turns?

Thanks.
Carpet or asphalt, need a little more info. No matter which I think a major tuning point will be your droop settings. Weight transfer is going to be the killer.
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Old 03-31-2010, 03:15 PM   #1813
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one of the ways i found to tell what you need to do with your droop settings is if your chassis has marks or rubber on the edges of your chassis then its rolling through the corners about right if its rolling to much your car will almost stop in the corners. If you dont have enough your car will not have anything on the bottom of the chassis. this is just a way to play with my droop settings or if my car is loose or if it pushes than i also change it.
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Old 03-31-2010, 05:15 PM   #1814
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Carpet or asphalt, need a little more info. No matter which I think a major tuning point will be your droop settings. Weight transfer is going to be the killer.
oh, sorry forgotten to mention. It's asphalt. Thanks.
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Old 03-31-2010, 06:35 PM   #1815
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oh, sorry forgotten to mention. It's asphalt. Thanks.
No problem. This sounds like a ? for sidecarphil. Some help please.
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