Aug 18, 2019, 03:21 PM
Registered User
Help!

# trying to increase oil content of my fuel

I have a 1L bottle of 20% nitro / 16% oil. I want to increase the oil content to 20%. I have Sig Caster oil and will be getting a bottle of Klots synthetic which I plan to mix 50/50 then add to my fuel. I can't figure out just how much oil is needed to bring it up to 20% from 16%. I also have a few other bottles at 11%, 10% and 12% which I also want to bring up. Anyone know the math on this and can teach me the way?
 Aug 18, 2019, 06:20 PM A man with too many toys 128oz * 0.04 = 5.12 oz Last edited by RC Man; Aug 19, 2019 at 11:15 AM.
 Aug 18, 2019, 07:30 PM Registered User http://www.nitrorc.com/fuelws/oilonly.asp works for me.
Aug 18, 2019, 08:48 PM
AMA 46133
Quote:
 Originally Posted by Andy0679 I have a 1L bottle of 20% nitro / 16% oil. I want to increase the oil content to 20%. I have Sig Caster oil and will be getting a bottle of Klots synthetic which I plan to mix 50/50 then add to my fuel. I can't figure out just how much oil is needed to bring it up to 20% from 16%. I also have a few other bottles at 11%, 10% and 12% which I also want to bring up. Anyone know the math on this and can teach me the way?
Okie dokie. So you want to play with litre. So one litre is 1000cc. so you have 16% oil in this 1000cc which means you have 160cc of oil in your 1000cc of fuel. Now you want to increase the oil content to 20% so the formula for that is:

(160+X)/(1000+X)= .20

That means you want to increase the oil content by Xcc so it becomes 20 percent. However you are also increasing the total volume of fuel when yo add X amount of oil in the fuel thus we have the 1000cc+X on the bottom of the equation.

Now I have given back my high school algebra to the school 6000 miles away. However Google is my friend so a friendly Google gave me a web site to visit. I put in the equation and it showed me how it was solved.

You answer is you need to add 50cc of oil in that litre of fuel to make the total oil content to 20 percent.

Here is the link for the solution. I hope it copies:
https://quickmath.com/webMathematica...9%253D.20&v2=X

Ok it sort of copied but not the entire equation. If you want the solution step by step just go to the web site and click on the solve button after the formula.
 Aug 19, 2019, 10:55 AM Registered User One Liter...at 16% is too easy...... 1 L=1000 mL 16 %= 160 mL 4 %= 40 mL ad 40 mL to make total oil 20% or 200mL you will now have 1040 mL of fuel, so nitro and meth will be fractionally diluted....not enough to matter I mix or blend all my fuel need in 500mL or 1 liter batches base ten math is very simple....I am a US non metric guy.....but this just makes sense to me
Aug 19, 2019, 11:06 AM
Registered User
Quote:
 Originally Posted by Fredvon4 you will now have 1040 mL of fuel, so nitro and meth will be fractionally diluted....not enough to matter
The oil is also diluted.. you end up with 200ml oil, 1040 total, or ~19.2 percent.

seismicwave's formula is correct -

you'd need to add 50ml of oil to get 20%. (160+50) / (1000+50) = 0.2
 Aug 19, 2019, 12:43 PM Registered User Thread OP You guys are great. Thank you all. I was confused cause I was thinking about the dilute and kept getting hung up. Now my worry is the fuel I have, I believe is something like 98% synth and 2% caster. I need to be around 50/50 I believe but may be wrong. If thats the case, I should just add straight caster and forget adding synth right? I'll not be 50/50 and if maybe 80/20, yeah? Still no good for a plane engine right? Should I add much more caster oil? Last edited by Andy0679; Aug 19, 2019 at 12:48 PM.
Aug 19, 2019, 01:09 PM
AMA 46133
Quote:
 Originally Posted by Andy0679 You guys are great. Thank you all. I was confused cause I was thinking about the dilute and kept getting hung up. Now my worry is the fuel I have, I believe is something like 98% synth and 2% caster. I need to be around 50/50 I believe but may be wrong. If thats the case, I should just add straight caster and forget adding synth right? I'll not be 50/50 and if maybe 80/20, yeah? Still no good for a plane engine right? Should I add much more caster oil?
You don't need a whole lot of castor for most engines. So for your 1 Litre fuel mix just had 50 cc of oil and you can mix up anywhere from 50/50 which will be 25cc castor and 25cc synthetic to 80/20 80% synthetic and 20% castor. All depends on your application and environment. Are you planning on running the engine read hard? The more castor the more gooey mess you will encounter but the engine is a bit happier. Some user will swear by synthetic and some will swear by all castor but to me that an extremist view. We live in a world full of compromises. Do everything in moderation and you will be fine.
 Aug 19, 2019, 02:28 PM Registered User Thread OP No nothing extreme. Just flying my trainer
Aug 19, 2019, 04:59 PM
AMA 46133
Quote:
 Originally Posted by Andy0679 No nothing extreme. Just flying my trainer
Then any amount of castor oil is good. You can go from 80/20 all the way to 100% castor. Just remember to clean the engine after a day of flying so the castor residue won't gum up the engine. Wipe down the engine exterior with the plane so you don't have an engine that is encrusted with brown goo. Synthetic is a lot cleaner.
 Aug 19, 2019, 05:11 PM Registered User Thread OP My engine is an OS MAX .20 FP. I am trying to locate some 10% or even 15% nitro with 50/50 oil blend but right now all I have is some 20% nitro/ 16% oil car fuel. I'm told it's only car fuel due to the oil content and type. I am actually uncomfortable running it even remixed to higher oil/caster content. I've been having a lot of trouble tuning the engine too. I don't know what the proper specs are for rpm at idle to wot either. It sucks. As far as I understand, I'm to set high speed at wot so when it starts to lag or stall, turn it back 1/4 turn. Then for low speed (air bleed) I'm suposed to adjust so it doesn't stall in a throttle punch test. But then I have troubles with it loading up and flaming out after letting idle too long. I've tried from #4 to #8 plugs on 15% fuel. Last edited by Andy0679; Aug 19, 2019 at 06:59 PM.
 Aug 19, 2019, 06:07 PM Registered User What prop are you using?
 Aug 19, 2019, 06:17 PM Registered User Thread OP 9 x 6
 Aug 19, 2019, 06:53 PM Registered User We use an 8-6" on our .25s. That may be more suitable.
Aug 19, 2019, 07:00 PM
Registered User