10% to 20% richer or leaner?

[noste500]

I am switching from 10% nitro to 20%.
Will I need to richen it up or lean it out??

[mapleleafs]

you can richen it and have the same amount of power, or leave it the same and you will notice a significant increase in power.

[DavidH]

If the 20% nitro fuel has the same oil precentage and viscosity as the 10% nitro fuel. Then you will most likely not have to change the needles.
For example if the 10% nitro fuel has 18% High Viscosity Oil
And the 20% nitro has 18% HV Viscosity oil.
Then you may have to richen up 1 click for the 20%

If the 10% has heavy viscosity oil and the 20% has Low Viscosity oil. You may have to lean the engine a good number of clicks.
Oil precentage and weight has a more to do with richening or leaning the mixture more than nitro.

David

[noste500]

Its the coolpower green 10%, ( pretty sure its 18% lubricant )
and; coolpower red 20%, not sure on lube , will check that later.

I think my carbsmart will deal with 1 click if thats the case, correct?

Thanks

[BarracudaHockey]

If it were me, I'd crank it open a half a turn, turn the CS off and get the tuning close. Most times you go up in nitro you need to open the needle, better to start rich than burn something up.

[DavidH]

Originally Posted by noste500

Its the coolpower green 10%, ( pretty sure its 18% lubricant )
and; coolpower red 20%, not sure on lube , will check that later.

I think my carbsmart will deal with 1 click if thats the case, correct?

Thanks

There is two different 10% Coolpower Fuels


10%-MV
10%
18%
Multi

10%
10%
17%
Ultra-High

If the 20% Coolpower is the heli blend.
20%
20%
20%
Ultra-High

Your most likely going to have to open the needle some. The CP 20% heli has 20% HV oil. The CP 10% has 17% HV oil. Even the MV is 18% oil. So with more precentage of oil, I would suggest to open (richen) it about 1/4 turn from where it ran with the 10%. Then lean the mixture from there. Or just take the control arm off the mixture needle. Open it a 1/4 turn and re install the control arm for the Carb Smart. The 3% different in oil content of the same type oil will make it need to be open more.

David

[Mike SVOR]

The more you go up in nitro percentage, the richer the engine needs to run.
Higher nitro content needs to run at a different air fuel ratio than lower nitro content.

richen the needle

[DavidH]

Originally Posted by Mike SVOR

The more you go up in nitro percentage, the richer the engine needs to run.
Higher nitro content needs to run at a different air fuel ratio than lower nitro content.

richen the needle

That would be true if going from like 10% nitro to 60% nitro. But a 10% change in nitro does not really need any change provided the oil package in the fuel is the same in both nitro precentages.

For example if using a 10% nito fuel with 18% HV oil and switch to 20% nitro that uses 18% LV oil. The case may be that the needle setting for the 10%/18%HV fuel may be too rich for the 20%/18%LV fuel.

The needle for the 10% nitro fuel would need to be open more to let the higher viscosity oil in the fuel flow better in the needles.

Difficult to grasp that sometimes. But I have done a lot of fuel testing over the years and that has been the case most of the time.

David