confused about diff fluid

best fluid to use for crt on a clay track....just broke a rear cap joint probably from a jump landing

i'm running a 1515/2.5d on 6s geared 12/62 MMM ......truck wants to pull the front wheels slightely

just use naptha to clean the gears? and dry off with paper towels?

[Arct1k]

Try 7 20 3

[stum]

I run 7/30/5 with my 8ight-t on a similar surface

[GREYGHOST]

If you mix equal amounts of 50k and 10k would you then have 40k?

[stum]

50 + 10 = 60 /2 = 30k So no.. w/o doing the math I'd do about 25% 10k

[BrianG]

Originally Posted by stum

50 + 10 = 60 /2 = 30k So no.. w/o doing the math I'd do about 25% 10k

Equal parts of 50 and 10 gets you 22.5. It's not just getting an average. The formula is:

mixfluidA = ((log(targetvisc) - log(viscfluidB)) / (log(viscfluidA) - log(viscfluidB)) )

mixfluidB = 1 - mixfluidA;


To get a 40k mix, you need 86% of 50k and 14% of 10k.

[GREYGHOST]

Calculating the viscosity of a blended liquid consisting of two or more liquids having different viscosities is a three step procedure. The first step involves calculation of the Viscosity Blending Index (VBI) of each component of the blend using the following equation (known as a Refutas equation):

(1) VBI = 14.534 × ln[ln(v + 0.8)] + 10.975

where v is the viscosity in centistokes and ln is the natural logarithm (Loge).

The second step involves using this blending equation:

(2) VBI-blend = [wA × VBIA] + [wB × VBIB] + ... + [wX × VBIX]

where w is the weight fraction (i.e., % ÷ 100) of each component of the blend. In using the above blending equation, it is necessary that all viscosities are determined at the same temperature, for example, 100 °C.

The third and final step is to determine the viscosity of the blend by using the invert of equation (1):

(3) v = (ee(VBI - 10.975) ÷ 14.534) − 0.8

[lincpimp]

It is best to just buy the correct fluid, as reading the last 2 posts has given me a headache.

Considering you have slight tendancy to wheely, you may have about the right fluid in the center diff now, maybe a bit too thick. If the front tires are growing huge the fluid is too thin, and if the truck wheelies then the fluid is too thick. I think some front tire growth is acceptable, as it will help pull the truck around corners. The pro nitro racers run light fluid, and go thru a set of front tires in a single race... I noticed this when looking at the race action pics in the rc mags, and checking out the racer's riders section they usually do on the national race winners.

I run thicker fluid as I like wheelies (no racing for me!) and really like tires to last...

i asked chad bradley this question on neobuggy he said 20-30-1 i ran that the whole time i had my crt and loved it

[hoovhartid]

Originally Posted by GREYGHOST

If you mix equal amounts of 50k and 10k would you then have 40k?

if you want 40k, you need 86% 50k and 14% 10k.


http://www.gesilicones.com/gesilwiza...ng/fluid2.html

[BrianG]

Originally Posted by hoovhartid

if you want 40k, you need 86% 50k and 14% 10k.


http://www.gesilicones.com/gesilwiza...ng/fluid2.html

That's what I said earlier.

BTW: I have that same calculator at my site. I just viewed the formula the script uses and added my own error checking and such. Since it is directly based from that gelsilicones site, I put credits at the top of the page.

[JERRY2KONE]

It is best to just buy the correct fluid, as reading the last 2 posts has given me a headache.

You beat me to it James. I was thinking that exact same thing as I started reading their posts. If you have to work that hard to figure something like what portions of each grease to mix in order to get the right concoction for your setup, then it is time to just spend a few dollars and get the right grease in the first place. What a brain twister that is.

Thats what I love about this site though, is having PROs like them to answer a question like that, and then have guys like us who say just buy the right thing up front and avoid frying your brain.

[hoovhartid]

Originally Posted by BrianG

That's what I said earlier.

oops, I missed it the first time. I just scrolled back up and saw it...my bad

cool that you added it to your site tho.

[GREYGHOST]

Originally Posted by JERRY2KONE

It is best to just buy the correct fluid, as reading the last 2 posts has given me a headache.

You beat me to it James. I was thinking that exact same thing as I started reading their posts. If you have to work that hard to figure something like what portions of each grease to mix in order to get the right concoction for your setup, then it is time to just spend a few dollars and get the right grease in the first place. What a brain twister that is.

Thats what I love about this site though, is having PROs like them to answer a question like that, and then have guys like us who say just buy the right thing up front and avoid frying your brain.

Guys....easy....the 50k -10k thing was meant as a joke! I only quoted some professor's explanation of the formula when someone else did it too.....I thought it was funny....

[JERRY2KONE]

Guys....easy....the 50k -10k thing was meant as a joke! I only quoted some professor's explanation of the formula when someone else did it too.....I thought it was funny....



Yes we thought it was funny to, that was the point.